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                                                                    EXHIBIT 10.1


                        JOINT MARKETING AND SERVICES AGREEMENT


    This JOINT MARKETING AND SERVICES AGREEMENT (this "Agreement") is made and
entered into as of the 22nd day of July 1997 (the "Effective Date"), by and
between IXC Internet Services, Inc., a Delaware corporation ("IXC"), and PSINet
Inc., a New York corporation ("PSINet").

    WHEREAS, IXC and PSINet have entered into an IRU and Stock Purchase
Agreement of even date herewith (the "IRU Agreement"), pursuant to which IXC
will provide to PSINet the right to use certain fibers and capacity on IXC's
fiber optic telecommunications system and PSINet will exchange therefor shares
of its stock;

    WHEREAS, PSINet is in the business of providing, on a dial and dedicated
basis to wholesale and end user customers, Internet connectivity and related
services;

    WHEREAS, IXC desires to create and market various service offerings to
customers incorporating or consisting entirely of an Internet services
component; and

    WHEREAS, PSINet is willing to provide such Internet services, and IXC is
willing to purchase such Internet services, on the terms and subject to the
conditions of this Agreement.

    NOW, THEREFORE, in consideration of the premises and the mutual covenants
of this Agreement, the Parties agree as follows:

1.       DEFINITIONS.

         For purposes of this Agreement, certain terms have been defined below
and elsewhere in this Agreement (including the attached Schedules) to encompass
meanings that may differ from, or be in addition to, the normal connotation of
the defined word. Unless the context clearly indicates otherwise, any term
defined or used in the singular shall include the plural. A defined word
intended to convey its special meaning is capitalized when used.

    "Affiliate" has the meaning set forth in Section 19.1 of the IRU Agreement.

    "Agreement" has the meaning set forth in the preamble.

    *

    "Claim" means any pending or threatened claim, action, proceeding or suit
by any Third Party.

    "Confidential Information" has the meaning set forth in Section 10.1.

    "Cure Period" has the meaning set forth in Section 9.2.1.

    "Damages" means any loss, debt, liability, damage, obligation, claim,
demand, judgment or settlement of any nature or kind, known or unknown,
liquidated or unliquidated, including without limitation all reasonable costs
and expenses incurred (legal, accounting or otherwise).


*   Confidential material has been omitted and filed separately with the 
    Securities and Exchange Commission.


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    "Documentation" shall mean Reseller Documentation and End User
Documentation.

    "Effective Date" has the meaning set forth in the preamble.

    "End User Documentation" shall mean all documentation provided by PSINet
for use by end users of its services in connection with the use and operation of
the materials describing such services, as such documentation may be amended,
modified or supplemented from time to time.

    "Indemnifying Party" has the meaning set forth in Section 13.1.

    "Infrastructure" has the meaning set forth in Section 6.1.

    "Intellectual Property Rights" shall mean all intangible property rights
protectible by law throughout the world including all copyrights (including,
without limitation, the exclusive right to reproduce, distribute copies of,
display and perform the copyrighted work and to prepare derivative works),
copyright registrations and applications, trademark rights (including trade
dress), trademark registrations and applications, service mark rights, service
mark registrations and applications, patent rights (including the right to apply
therefor), patent applications therefor (including the right to claim priority
under applicable international conventions) and all patents issuing thereon, and
inventions, whether or not patentable, together with all utility and design,
know-how, specifications, trade names, mask-work rights, trade secrets, moral
right, author's rights, algorithms, rights in packaging, goodwill and other
intangible property rights, as may exist now and/or hereafter come into
existence, and all renewals and extensions thereof, regardless of whether any of
such rights arise under the laws of the United States or of any other state,
country or jurisdiction.

    "Internet" has the meaning set forth in Section 19.1 of the IRU Agreement.

    "IRU Agreement" has the meaning set forth in the recitals of this
Agreement.

    "IXC" has the meaning set forth in the preamble.

    "IXC Customer" means any purchaser of a service offering that includes
Services provided by PSINet under this Agreement. As used in this Agreement, an
"IXC Customer" shall include (i) any party with which IXC enters into an
agreement relating to the sale of services that include Services, (ii) any party
that purchases Services for which billing is provided by IXC, (iii) any party
that purchases Value-Added Services from IXC pursuant to Section 5.1.1, and (iv)
any purchaser of services that include Services from an IXC Reseller. In cases
where IXC uses Services provided by PSINet under this Agreement for its own
internal purposes, IXC shall be deemed an "IXC Customer" for purposes of this
Agreement.

    "IXC Customer Information" shall mean all information relating to each IXC
Customer collected in connection with the provision of Services to such IXC
Customer, including without limitation the name, address, usage, features and
services purchased, locations served, payment history and all other information
identifiable to a particular customer.

    "IXC Documents" has the meaning set forth in Section 5.1.4.

    "IXC Internet Services" means those Services offered by IXC to IXC
Customers.

    "IXC Resellers" has the meaning set forth in Section 5.1.1.


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    "IXC Sales Support Group" has the meaning set forth in Section 3.2.

    "Managed Connectivity Services" or "MCS" has the meaning set forth in
Section 2.1.1.

    "Marks" shall mean trade names, logos, trademarks, trade devices, trade
dress, service marks, symbols, abbreviations or registered marks, or
contractions or simulations thereof, or any other indicia or origin.

    "Material Provision" shall mean any provision of this Agreement (including,
without limitation, payment provisions) the breach of which by one Party is
determined by an arbitration pursuant to Section 15.18 to constitute a material
adverse effect on the use and enjoyment by the other Party of the benefits of
this Agreement.

    "Multiple End-User Restrictions" has the meaning set forth in Section
5.1.2.

    "Opportunity Consulting Services" or "OCS" has the meaning set forth in
Section 2.1.3.

    "Party" means IXC, individually, or PSINet, individually.

    "Parties" means IXC and PSINet, collectively.

    "Person" has the meaning set forth in Section 19.1 of the IRU Agreement.

    "PSINet" has the meaning set forth in the preamble.

    "PSINet Documents" has the meaning set forth in Section 7.4.

    "PSINet Marks" shall mean the PSINet Primary Marks, the PSINet VAS Marks,
such other Marks as are used by PSINet to promote, advertise and market the
Services, and such other Marks as the Parties shall agree upon in writing.

    "PSINet Point of Presence" shall mean one of the points of presence
representing a point of interconnection on the PSINet network. The initial
PSINet Points of Presence are listed in Schedule 6.2 to this Agreement, and
PSINet shall promptly update such schedule during the Term on reasonable notice
to IXC. At any time during the term of this Agreement, PSINet Points of Presence
could be collocated with points of presence on the IXC network pursuant to
Section 6.1.

    "PSINet Primary Marks" shall mean the Marks "PSINet" and "PSINet" and logo
types thereof all as the same may be changed from time to time.

    "PSINet VAS Marks" shall mean such Marks as are used by PSINet to promote,
advertise and market Value Added Services.

    "Releasing Party" has the meaning set forth in Section 12.2.

    "Reseller Documentation" shall mean all documentation made available by
PSINet for use by any reseller or distributor of services of the type comprising
the Services to describe the methods and procedures used by PSINet in the
provisioning and support of users of services of the type comprising any of the
Services provided under this Agreement, as such documentation may be amended,
modified or supplemented from time to time.

    "Sales Support Services" has the meaning set forth in Section 3.1.

    "Services" means Managed Connectivity Services, Value Added Services and
Opportunity Consulting Services.


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    "Term" has the meaning set forth in Section 9.1.

    "Third Party" means an entity other than a Party or any Affiliate of a
Party.

    "Transaction Documents" has the meaning set forth in Section 19.1 of the
IRU Agreement.

    "Value Added Services" or "VAS" has the meaning set forth in Section 2.1.2.

2.       SERVICE DESCRIPTION(S).

    2.1  Initial Description of Services Provided by PSINet. From and after the
Effective Date, on the terms and subject to the conditions set forth in this
Agreement, PSINet shall provide to IXC, and IXC shall have the right to purchase
from PSINet, the following services:

         2.1.1     Managed Connectivity Services ("MCS"), which consist of the
provision of dial-up and dedicated access to the Internet via the PSINet network
to customers and all related products and services now or hereafter offered or
provided by PSINet that deliver or facilitate such access. The initial Managed
Connectivity Services shall comply with the applicable descriptions set forth on
Schedule 2.2, for PSINet's Intranet, LAN-on-Demand, InterMAN, InterFrame,
Wholesale Dial and InterRamp services, including, without limitation, the
functional, technical and performance requirements set forth in such Schedule.
From time to time, the Parties may agree on such modifications to the
functional, technical and performance requirements for MCS as are necessary to
address requirements of IXC Customers. At such times as PSINet provides enhanced
versions of MCS, PSINet shall make such enhanced versions of MCS available to
IXC, and the Parties may agree, for purposes of this Agreement, upon the
functional, technical and performance requirements for such services, which
requirements shall, at a minimum, ensure that such services comply with the
applicable minimum requirements in Section 2.2.

         2.1.2 Value Added Services ("VAS"), consisting of the following
services and products now or hereafter offered by PSINet or a controlled United
States Affiliate: (i) InternetPaper, (ii) Internet Security Services, (iii)
PSIWeb, (iv) any other services or products developed jointly by the Parties,
and (v) any other services or products now or hereafter marketed or offered by
PSINet as a generally available service or product offering other than MCS which
are not subject to exclusive marketing relationships with Third Parties. The
initial Value Added Services shall comply with the applicable descriptions set
forth on Schedule 2.2. From time to time, the Parties may agree on such
modifications to the functional, technical and performance requirements for VAS
as are necessary to address requirements of IXC Customers. At such times as
PSINet provides enhanced versions of VAS, PSINet shall make such enhanced
versions of VAS available to IXC, and the Parties may agree, for purposes of
this Agreement, upon the functional, technical and performance requirements for
such services, which requirements shall, at a minimum, ensure that such services
comply with the applicable minimum requirements in Section 2.2.

         2.1.3 Opportunity Consulting Services ("OCS"), will consist of
pre-sales technical support and post-sales development and/or implementation
support to address specific IXC-identified market opportunities. At such times
as the situation warrants, the Parties may agree, for purposes of this
Agreement, upon the functional, technical and performance requirements for such
services, which requirements shall, at a minimum, ensure that such services
comply with the applicable minimum requirements in Section 2.2. Certain joint
teaming efforts of the Parties shall be conducted in accordance with Schedule
2.1.3 hereto.

         2.1.4 IXC shall have the right and option to have any other PSINet
services included under this Agreement on terms and conditions reasonably


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consistent herewith. In addition, upon such time that PSINet discontinues a
service generally among its customers, PSINet may remove such service from this
Agreement, but only after providing IXC with at least 30 days' prior written
notice of its intention to do so. If PSINet so removes a service, PSINet will
continue to honor all existing IXC and IXC Reseller service agreements with end
customers by continuing to make such service available to IXC Customers through
the shorter of (i) the end of the term of their respective service agreements,
and (ii) the end of the two-year period commencing on the expiration of PSINet's
30-day notice period.

         2.1.5 Notwithstanding anything to the contrary contained herein,
PSINet reserves the right to modify, alter, improve or change any and all of the
PSINet services comprising the Services covered by this Agreement, and this
Agreement will cover the sales of Services as they may be modified, altered,
improved or changed by PSINet from time to time. Subject to Section 2.1.4, in
all cases where such modification, alteration or change will reduce the
functionality of any PSINet service component comprising the IXC Internet
Services, PSINet will not effect such modifications, alterations or changes
without IXC's specific written approval. Such approval will not be unreasonably
withheld, delayed or conditioned.

    2.2  Minimum Requirements. The MCS, VAS and OCS provided by PSINet under
this Agreement, as described in Schedule 2.2, shall at all times meet the
following minimum requirements:

         2.2.1 The MCS, Internet Security Services and PSIWeb services provided
by PSINet under this Agreement shall be offered and provided with features and a
level of quality that, on average and taken as a whole, equal or exceed that
provided by other leading providers of Internet services offering comparable
services in a substantial portion of the geographic area in which Services are
available pursuant to this Agreement. The Parties agree to work together on a
broader range of service offerings as needed to address market demand. For
purposes of this Agreement, Services shall be deemed to be available to IXC in
any geographic area in which PSINet provides services to customers or, subject
to the last sentence of Section 2.7, in which PSINet has an Affiliate, strategic
partner or other cooperating provider providing services in such area of the
type made available to IXC under this Agreement.

         2.2.2 The MCS and VAS provided by PSINet under this Agreement shall be
offered and provided with features and an overall level of quality that equals
or exceeds that which PSINet offers or provides any other customer.

         2.2.3 The MCS and VAS provided by PSINet under this Agreement shall
comply with all Documentation relating to the MCS and VAS offered or provided by
PSINet as of the Effective Date and as updated from time to time provided that
no such update may operate to have a material adverse impact on (i) any MCS or
VAS (including without limitation the level or quality of service provided to
IXC Customers), taken as a whole, without the prior written consent of IXC
(which shall not be unreasonably withheld, delayed or conditioned), except to
the extent necessary to deal with network emergencies and other circumstances
beyond the control of PSINet, in which case PSINet shall consult with IXC
concerning such change as soon as reasonably practicable, or (ii) any other
Services without providing IXC with advance written notice of such changes as
soon as reasonably practicable.

         2.2.4 PSINet shall not make any changes (i) to any MCS or VAS that may
reasonably be expected to have a material adverse impact on such Service
(including without limitation the level or quality of service provided to IXC
Customers), taken as a whole, without the prior written consent of IXC, except
to the extent necessary to deal with network emergencies and other circumstances
beyond the control of PSINet, in which case PSINet shall consult with IXC
concerning such change as soon as reasonably practicable, or (ii) to any OCS


                                      -5-


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Services provided IXC without providing IXC with advance written notice of such
changes as soon as reasonably practicable.

         2.2.5 The OCS provided to IXC by PSINet shall be performed by PSINet
employees or its subcontractors as deemed by PSINet to be best qualified and
available to perform the task at hand as identified by IXC. Under no
circumstances may PSINet change subcontract relationships in effect at the time
of proposal submission without IXC's specific written approval. Such approval
shall not be unreasonably withheld, delayed or conditioned. PSINet officers
supervising the performance of the services will be empowered to commit the
resources of PSINet to the extent and scope of such officer's authority.

         2.2.6 In the event that Services, as defined herein, or portions of
Services, are provided to IXC by PSINet via a contractual relationship with a
Third Party, PSINet is obligated to maintain such a relationship to the extent
practicable. Should such relationship require that IXC enter into a similar
agreement with the Third Party, PSINet shall use commercially reasonable efforts
to assist IXC in establishing the relationship and securing rates and levels of
service of at least those provided to PSINet by the Third Party.

    2.3  Documentation. PSINet represents that (i) Schedule 2.3 contains a true
and complete list of all Documentation relating to the MCS and VAS offered or
provided by PSINet as of the Effective Date, and (ii) true and complete copies
of all such Documentation have been provided to IXC prior to the Effective Date.
In the event PSINet amends, modifies or supplements any such Documentation, or
creates new Documentation in connection with enhanced versions of MCS or
additional VAS added pursuant to Section 1.1, PSINet shall as soon as
practicable provide IXC with written notice of any such amendments,
modifications, supplements or new Documentation, including copies of the
foregoing.

    2.4  License to Documentation and Other Intellectual Property Rights.

         2.4.1 PSINet grants IXC and IXC Resellers a limited, non-exclusive,
royalty-free, license, in the geographic area in which Services are available to
IXC pursuant to this Agreement, throughout the Term, to (i) copy, but not modify
sales literature and product descriptions (Schedule 2.3 list) in any form, (ii)
integrate the Documentation, or any part thereof, into IXC's catalogs, price
lists, brochures and related sales materials, and (iii) demonstrate, market,
distribute and solicit orders for the Services and warrants that it has such
right to grant. The grant of the foregoing license shall not entitle or in any
way be construed to entitle IXC to (a) use PSINet Marks in connection with IXC's
sales, advertisements and promotion of the Services, except in materials
provided (or approved by PSINet prior to IXC's use thereof) by PSINet; (b)
distribute any Services outside the United States of America in violation of any
United States export restrictions; (c) distribute any Services outside of the
geographic areas in which Services are then available to IXC pursuant to this
Agreement; (d) sublicense any of its rights under this Agreement, except as
expressly permitted by this Agreement; or (e) make any agreement or incur any
liability for or on behalf of PSINet except as expressly contemplated by this
Agreement.

         2.4.2 Except for the limited license specifically granted to IXC in
this Agreement, PSINet shall at all times retain full and exclusive right, title
and ownership interest in and to the Services, the PSINet network, all PSINet
Marks and any and all other Intellectual Property Rights or trade secret rights
related thereto. IXC shall notify PSINet of any action by any Third Party known
or suspected by IXC to constitute an infringement of PSINet's proprietary
rights. IXC shall honor all reasonable requests by PSINet, other than engaging
as a party in litigation, to perfect and protect, at PSINet's expense, any
rights of PSINet in the Services, the PSINet network or such Intellectual
Property Rights or trade secret rights.


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         2.4.3 PSINet represents that no further licenses to Intellectual
Property Rights are needed by IXC to market, offer, provision or use the IXC
Internet Services as contemplated by this Agreement, in the geographic area in
which Services are available to IXC pursuant to this Agreement.

    2.5  PSINet Liability for Affiliate Obligations. To the extent that
PSINet's performance of its obligations hereunder causes PSINet to assign or
delegate all or part of its liabilities, obligations and commitments hereunder
to any of its Affiliates, PSINet covenants and agrees that it shall use its
reasonable efforts to cause any such Affiliate to perform such liabilities,
obligations and commitments in accordance with the terms and provisions hereof.
In the event of such an assignment or delegation, PSINet shall remain liable for
all of its liabilities, obligations and commitments hereunder.

    2.6  Forecasts. The Parties agree to coordinate in estimating the level and
location of demand and traffic for Services during the term of this Agreement.
In that connection, no later than the 15th day of the first month of each
calendar quarter during the term of this Agreement, IXC will provide PSINet with
its projected requirements for each Service, indicating amounts, types and
location during each of the following four calendar months. In the event that
there should be a material change in IXC's proposed requirements as set forth in
the most recent forecast, IXC, as promptly as practicable, shall update such
forecast in order to reflect such change. These forecasts shall be used for the
planning convenience of PSINet and shall not be binding upon IXC, but PSINet
intends to use the forecasts to estimate needed staffing, network provisioning
and product levels for its performance of the terms of this Agreement and shall
only be responsible for using commercially reasonable efforts to satisfy demand
to the extent it materially exceeds such forecasts. IXC shall provide its
initial projected requirements for Services within 15 business days after the
Effective Date. All forecasts provided under this Section 2.6 shall be treated
as Confidential Information of IXC pursuant to Section 10.

    2.7  Geographic Scope. It is the intent of the Parties that IXC be
permitted to provide the IXC Internet Services to the IXC Customers, on the
terms and subject to the conditions of this Agreement, in all of the geographic
areas in which PSINet is now, or at anytime during the Term is then, providing
services to its customers. Notwithstanding the foregoing, IXC acknowledges and
understands that PSINet is not now capable of independently providing certain
services in certain geographic areas outside of the continental United States of
America. To the extent that IXC desires to provide IXC Internet Services to IXC
Customers situated in such geographic areas and PSINet has an Affiliate,
strategic partner or cooperating provider offering services therein, IXC may
request that PSINet obtain a quote from such Affiliate, strategic partner or
cooperating provider for such IXC Internet Services. Within five business days
after such request, PSINet shall contact the appropriate Affiliate, strategic
partner or cooperating provider for purposes of obtaining such quote. The
provision of services under this Section 2.7 by such Affiliate, strategic
partner or cooperating partner to PSINet shall be the subject of negotiation
and, if reached by such parties, agreement. *

* Notwithstanding anything in this Agreement to the contrary, PSINet shall
  not be obligated to provide Services to an IXC Customer or Third Party in
  those geographic areas in which PSINet is not offering services unless (i)
  it has an Affiliate, strategic partner or cooperating provider in a




* Confidential material has been omitted and filed separately with the 
  Securities and Exchange Commission

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  particular geographic area, and (ii) such Affiliate, strategic partner or
  cooperating provider agrees to provide such services on terms and
  conditions to Texas' satisfaction.

  2.8  Services Provided by IXC. PSINet shall be presented with the
opportunity to execute IXC's standard reseller agreement for IXC service, on the
terms and subject to the conditions set forth in such agreement.

*

4.     CUSTOMER SUPPORT SERVICES.

  4.1  PSINet will provide customer support through its customer support
group or through a Third Party (as determined by PSINet in its sole discretion)
for the Services (other than InterRamp Remote Access services) sold to IXC
Customers as contemplated by this Agreement; provided that PSINet will not be
responsible for providing customer support to any IXC Customer purchasing
Services under a private label which exceeds the level of support which PSINet
is obligated to provide to its customers pursuant to PSINet's service agreements
for the applicable Services, as such agreements may be amended from time to
time. PSINet also may assist IXC with making arrangements for the provision of
customer support with respect to the InterRamp Remote Access services to be sold
to IXC Customers pursuant to this Agreement. IXC acknowledges, however, that IXC
is solely responsible for the provision of such customer support and PSINet
shall have no liability with respect thereto.

  4.2  Notwithstanding the foregoing, IXC shall be responsible for all
pricing and service plans, billing and collections with respect to IXC
Customers.


5. IXC RIGHTS AND RESPONSIBILITIES.

  5.1  IXC Use and Sales of Services.

       5.1.1 IXC may use the Services made available to it pursuant to this
Agreement, on the terms and subject to the conditions hereof, (i) for its own
account, (ii) subject to Section 5.1.2, for resale to IXC Customers, or (iii)
subject to Section 5.1.2, for resale to Third Parties for further resale or
distribution (such Third Parties which, notwithstanding the definition of "Third
Parties" herein, include, without limitation, IXC Customers (including those
which are Affiliates of IXC) are referred to herein as "IXC Resellers"), either
alone or in combination with any other products and services. Services offered
by IXC that incorporate MCS and VAS made available to it pursuant to this
Agreement shall, at IXC's discretion, be branded exclusively as IXC services or
otherwise as IXC shall determine. IXC shall specify the design of any user
interface associated with any MCS or VAS, consistent with the preceding
sentence. IXC will have complete discretion to determine the prices to be
charged to IXC Customers for the Services provided under this Agreement and IXC
shall be solely responsible for establishing and collecting customer charges for
services it or its customers offer through the PSINet network and for preparing
and mailing invoices to IXC Customers. In addition, IXC shall be responsible for
payment of the total amounts invoiced it by PSINet (except for any amounts
disputed by IXC in good faith) regardless of whether IXC is paid by its
customers. Subject to the provisions of Section 5.4, IXC shall also have
complete discretion to determine the other terms and conditions on which IXC
makes such Services available to IXC Customers; provided that neither IXC nor
its customers may offer warranties or representations for the Services that
would obligate or otherwise bind PSINet beyond those stated in the applicable
service agreements.  


* Confidential material has been omitted and filed separately with the 
  Securities and Exchange Commission


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  Except as otherwise provided in this Agreement, except as reasonably
necessary for PSINet to assist IXC during the introduction of IXC Internet
Services under this Agreement, IXC shall provide the primary interface to IXC
Customers in connection with the marketing, offering or provision of IXC
services that incorporate the Services, including (a) providing first tier
support for non-MCS and non-VAS IXC services and (b) handling communications to
and business relations with IXC Customers related to contractual agreements,
handling invoicing and payment matters, and handling inquiries and questions
from IXC Customers about Services.

       5.1.2 Subject to Section 2.7, IXC acknowledges and agrees that it may
not offer for sale or distribution to any IXC Customer or IXC Reseller any
Services until such Services are made generally available by PSINet in the
applicable geographic area. Without limiting the generality of the foregoing,
IXC acknowledges and agrees that no Service may be offered for sale or
distribution by IXC to any IXC Customer or IXC Reseller for multiple end-user
use in any particular geographic area until such Service is made generally
available by PSINet for multiple end-user use in such geographic area (the
"Multiple End-User Restrictions"). IXC will use reasonable efforts to cause each
IXC Reseller to include a provision in its agreements with its customers that
such customer will not engage in any conduct that would violate any of the
Multiple End-User Restrictions.

       5.1.3 Notwithstanding anything in Section 5.1.1 to the contrary, the
Parties agree that the determination of customer interfaces, marketing,
provisioning and delivery for jointly developed new product or services
offerings incorporating IXC services or Services as described herein will be
determined by mutual agreement.

       5.1.4 Periodic Audit Rights. PSINet shall have the right, upon
reasonable notice and at a date and time mutually agreed upon by the Parties, to
enter the premises of IXC for the purpose of auditing any of IXC's books of
accounts, documents, records (in any media), papers and files (the "IXC
Documents") relating to its compliance with the provisions of this Agreement.
PSINet shall bear the expense of the audit unless the audit reveals that (i) the
amounts collected by PSINet from IXC hereunder are more than two (2) percent
less than that which should have been paid by IXC to PSINet, or (ii) IXC has not
complied with either or both of the first two sentences of Section 5.1.2, in
which case, the entire cost of the audit shall be borne by IXC. Payment of any
amounts found due and owing PSINet shall be made promptly by IXC upon demand by
PSINet.

  5.2  Use of Marks. Except as provided herein or by advance written consent
of the other Party, each of IXC and PSINet agrees not to (i) display or use, in
advertising or otherwise, any of the other's Marks, (ii) permit any Affiliate to
display or use any of the other's Marks, or (iii) give permission to display or
use any of the other's Marks to any Third Party. Any use by one Party of any of
the other's Marks shall be subject to such other Party's advance approval in
writing, in its discretion, subject to compliance with guidelines provided by
it. Neither Party shall claim ownership or any other rights in any of the
other's Marks. Upon termination or expiration of this Agreement, any and all
rights or privileges granted by IXC or PSINet to use any Marks shall immediately
expire and each Party shall immediately discontinue the use of such Marks.
Nothing herein shall preclude either Party from making factual references to the
other in government filings, disclosure documents and other public statements,
except as otherwise set forth in the IRU Agreement.

  5.3  Introductory Marketing Campaign. IXC shall have complete discretion
regarding its marketing of the Services provided that neither IXC nor its
customers may offer warranties or representations for the Services that would
obligate or otherwise bind PSINet beyond those stated in the applicable service
agreements or to make any other warranties, promises or representations with


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respect to the Services or the PSINet network. In connection with such marketing
activities, IXC shall prominently mention PSINet's role in the provision of such
services in an introductory press release, the content of which shall be
mutually agreed to by the Parties in accordance with Section 19.11 of the IRU
Agreement.

  5.4  Provisions Applicable to End Users.

       5.4.1     IXC's Use of Services. IXC's use of Services in IXC's
capacity as end user of Services for its own account shall be governed by
Schedule 5.4.1 and the terms and conditions of this Agreement generally.

       5.4.2     Agreements with IXC Customers Other than IXC. IXC's
agreements with IXC Customers (other than IXC) to provision Services shall
comply with Schedule 5.4.2.

6.     INFRASTRUCTURE.

  6.1  Use of IXC Equipment and Facilities. Except as otherwise agreed to by
the Parties, in providing the Services to IXC under this Agreement, PSINet may,
in its sole discretion, purchase infrastructure, equipment, facilities and
services necessary for the transmission of data (collectively, "Infrastructure")
from IXC provided (i) PSINet is not restricted from purchasing such
Infrastructure from IXC under contractual obligations binding on PSINet at the
time the purchase decision is being considered, (ii) such Infrastructure meets
PSINet's reasonable functional, technical and performance requirements, and
(iii) IXC offers such Infrastructure to PSINet at a price and on terms and
conditions that, on average or taken as a whole, are competitive as compared to
those offered to PSINet in good faith by other leading providers of
infrastructure, equipment, facilities and services similar to the Infrastructure
at the time IXC makes its offer.

  6.2  Provisioning of Customers. In connection with the provision of MCS
hereunder, it is the intention of the Parties that IXC shall assume
responsibility for providing, at IXC's expense or the expense of the IXC
Customer, connectivity between the IXC Customer's premises and any PSINet Point
of Presence listed in Schedule 6.2 (as such schedule may be modified or
supplemented from time to time) that is selected by IXC, subject to Section 6.3.
PSINet shall assume responsibility for providing and conditioning Customer
premises equipment, consistent with Section 2 herein. Notwithstanding the
foregoing, the Parties acknowledge that the articulation of procedures to
accomplish coordinated provisioning of Services involving a dedicated access
component by the Parties may not be in place for a period after the Effective
Date. During this period, PSINet shall assume this responsibility and shall be
paid at the rates as indicated in Schedule 7.1. IXC shall notify PSINet of its
readiness to transition this responsibility.

  6.3  Interconnection with PSINet Facilities. IXC and PSINet shall
coordinate with respect to (i) the definition of the interfaces between the IXC
network and the PSINet network at the PSINet Points of Presence, (ii) the
management of traffic routed by PSINet from the premises of IXC Customers to
PSINet Points of Presence, and (iii) access by PSINet to the IXC network for the
purposes of providing Services under this Agreement. PSINet shall be responsible
for the day-to-day management of the PSINet network relating to the provision of
Services, including monitoring and taking actions necessary to remedy problems
with, or disruption of, the Services, establishment and maintenance of routing
tables and routing policies at Points of Presence, and establishment and
maintenance of peering points with the global Internet.

  6.4  Customer Transfers. At any time, IXC shall have the right to migrate
IXC Customers to such services as provided by IXC or on IXC's behalf by a Third
Party. PSINet shall provide all reasonable cooperation in support, to the extent
practicable, of a seamless, minimally disruptive migration of such IXC Customers


                                     -10-


<PAGE>


in connection with such services (including without limitation all IXC Customer
Information and, to the extent practicable, any necessary transfer of customer
addresses).

  6.5  Interfaces. The Parties shall develop methods, procedures and
associated interfaces for cooperating on a "seamless" basis in all areas
relating to the marketing and provision of the Services, including without
limitation order processing, customer care, network monitoring and maintenance,
and problem escalation and resolution; provided, however, that PSINet shall in
no event be obligated to provide services or support of any kind to IXC or IXC
Customers which exceeds that which it is required to provide to its own
customers pursuant to PSINet's service agreements for the applicable comparable
services, as such agreements may be amended from time to time. The Parties shall
use commercially reasonable efforts to agree on an initial plan to accomplish
the foregoing, including appropriate training of each other's employees, by no
later than 30 days after the Effective Date. At any time during the Term, PSINet
will cooperate in good faith with IXC in connection with inquiries concerning
potential problems affecting any aspect of the provision of Services.

7.     PRICING AND PAYMENT.

  7.1  * 

  7.2  Independent End-Customer Pricing. Each of the Parties will have
complete discretion regarding the prices that it charges to its customers for
its services.

  7.3  *

       7.3.5     Promotional Pricing. In addition to the * specified under
this Section 7, the parties shall also agree from time to time on promotional
and other pricing as may be appropriate to take maximum advantage of market
opportunities.

       7.3.6     Dispute Resolution. Any dispute relating to the * or any
adjustments thereof, applicable under this Section 7.1 shall be resolved
pursuant to Section 15.18 of this Agreement.

*

  7.5  Invoicing and Payment. During the Term, PSINet shall invoice IXC for
Services delivered to each IXC Customer. Such invoices shall be delivered by
PSINet to IXC in both paper and electronic form with content and formats as
agreed to by the Parties. IXC shall pay PSINet for the Services according to the
schedule set forth in Schedule 7.1. IXC agrees to pay PSINet, in advance, as
invoiced by PSINet, each month during the term, all fees and other charges with
respect to MCS and VAS, and in arrears for OCS, payable under this Agreement for
such month. All such fees for MCS and VAS for the initial month of service for
any IXC Customer shall be prorated for the portion of the month beginning on the
date on which the IXC Customer service commences and ending on the last calendar
day of such initial month and the amount invoiced by PSINet, with respect to
each such IXC Customer shall include such prorated fees and the fees and charges
payable for the following full month.


* Confidential material has been omitted and filed separately with the
  Securities and Exchange Commission
 

                                     -11-


<PAGE>


  7.6  Credits/Adjustments. All IXC Customers shall be granted service
disruption credits and adjustments, quality of service commitment credits and
adjustments, and the like as may be established by PSINet with respect to PSINet
customers, and as modified from time to time, by PSINet, at its sole discretion.
In the event that IXC, as promptly as practicable, notifies PSINet after
learning of the failure of PSINet to deliver any of the Services to any IXC
Customer, IXC will be entitled to a credit representing any reasonable
adjustment requested by IXC and approved in advance by PSINet as a result of
such failure to meet customer service expectations.

  7.7  Late Payment. PSINet invoices for amounts payable under this Agreement
shall be due within 30 days of the date of invoice. If a dispute arises as to
any portion of an invoice, IXC shall pay the undisputed amount of such invoice
when due and shall notify PSINet in writing of the disputed amount no later than
30 days from the date of invoice.

  7.8  Payment Dispute Resolution. In the event of payment dispute, the
PSINet Authorized Representative and the IXC Authorized Representative (as such
capitalized terms are defined in the IRU Agreement) will first attempt in good
faith to promptly resolve the dispute. If the dispute has not been resolved by
the Authorized Representatives within 14 days after IXC's notice, or if either
Party will not agree to meet within such 14-day period, the matter will be
referred to the Chief Executive Officer of PSINet and the Chief Executive
Officer of IXC who will in good faith attempt to resolve the dispute. If the
dispute remains unresolved within an additional 14-day period, the dispute shall
be submitted to arbitration as per the IRU Agreement.

  In the event that any amount remains unpaid after its due date, such amount
shall be subject to an interest charge equal to the lesser of one and one-half
percent of the unpaid balance per month or the maximum rate allowed under
applicable state law and, if such amount shall not have been paid in full within
five business days of the applicable due date when no bona fide dispute exists,
PSINet may, without any liability to IXC, at its option, suspend the provision
of services under this Agreement until such amount is paid in full.

8.     NO RESTRICTIONS.

  Notwithstanding any other provision of this Agreement, except as provided
in Section 2.7, nothing in this Agreement shall limit or in any way affect (i)
the performance of any Party's obligations under a binding agreement in effect
as of the Effective Date (and each Party shall disclose to the other such
agreements that, to such Party's knowledge, are in effect as of such date to the
extent possible consistent with any obligations of confidentiality owing to
Third Parties), (ii) PSINet's right to provide Internet services for its own
account directly to any end user or wholesale customer (subject to section 10)
or otherwise to engage in services involving packet, frame relay, asynchronous
transfer mode or other Internet services, (iii) IXC's right to build, operate
and maintain its own global network, and (iv) either Party's right in any way to
market, offer or provide any products and services that are not, generally,
marketed principally as Internet services.


9.     TERM AND TERMINATION.

  9.1  Term. The term of this Agreement shall commence on the Effective Date
and shall end on the earlier of (i) the termination of the IRU Agreement, and
(ii) such earlier date as of which this Agreement expires or is terminated
pursuant to Section 9.2.

  9.2  Termination.


                                     -12-


<PAGE>


       9.2.1     A Party may deliver to the other Party a written "Notice of
Default" in the event that the other Party has breached any Material Provision
hereunder. Such Notice of Default must prominently contain the following
sentences in capital letters: "THIS IS A FORMAL NOTICE OF A BREACH OF CONTRACT.
FAILURE TO CURE SUCH BREACH WILL HAVE SIGNIFICANT LEGAL CONSEQUENCES." A Party
that has received a Notice of Default shall have thirty (30) days to cure the
alleged breach (and, if the defaulting Party shall have commenced actions in
good faith to cure such defaults which are not susceptible of being cured during
such 30-day period, such period shall be extended (but not in excess of 90
additional days) while such Party continues such actions to cure (the "Cure
Period"). If such Party fails to cure the breach within the Cure Period, as long
as such default shall be continuing, the non-defaulting Party shall have the
right to either (i) suspend its performance or payment obligations under this
Agreement and/or any of the Transaction Documents (other than obligations under
Section 15.8(a) of the IRU Agreement and the Standstill Agreement (as defined in
the IRU Agreement)), (ii) seek an order of specific performance, and/or (iii)
seek the award of compensatory damages.

       9.2.2     PSINet shall terminate, or use commercially reasonable
efforts to terminate, the access rights of any IXC Customer as soon as is
reasonably practicable upon written notice from IXC or any IXC Customer to do so
or upon mutually agreed upon electronic process with receipt confirmed, but
shall have no liability in connection therewith.

       9.2.3     PSINet shall have the right to terminate any IXC Customer on
written notice to IXC (or sooner, if required by law, provided, however that
PSINet should thereafter provide written notice to IXC) in the event of any use
or alleged use by such IXC Customer of the Services or the PSINet network which
is in violation of any law, regulation or treaty, any of the Multiple End-User
Restrictions, PSINet's Net Abuse Policy (available at PSINet's web site at
'http:\\www.psi.net'), any community standard or accepted Internet policy or
which results in the receipt by PSINet of any formal or informal complaint.


10.    CONFIDENTIAL INFORMATION.

  10.1 Nondisclosure. If either Party acquires Confidential Information of
the other, such receiving Party shall maintain the confidentiality of the
disclosing Party's Confidential Information, shall use such Confidential
Information only for the purposes for which it is furnished and shall not
reproduce or copy it in whole or in part except for use as authorized in this
Agreement. Without limiting the generality of the foregoing, neither Party shall
use the Confidential Information of the other Party to solicit the other Party's
customers or to otherwise compete unfairly with the other Party. Confidential
Information shall mean all information of the disclosing Party which it treats
as confidential or proprietary including, without limitation, all of the
following: (i) information concerning customers and the contractual terms under
which services are being provided to such customer by a Party; and (ii) all
customer lists and other information regarding the customers of a Party.
Confidential Information shall not include information which is or hereafter
becomes generally available to others without restriction or which is obtained
by the receiving Party without violating the disclosing Party's rights under
this Article 10 or any other obligation of confidentiality. The terms and
conditions of this Agreement shall constitute Confidential Information. PSINet
and IXC shall cooperate to request confidential treatment as may be mutually
agreed by them with respect to certain terms of this Agreement and the
transactions contemplated hereby in any filing with the Securities and Exchange
Commission, any other government authority or any securities exchange or stock
market.

  10.2 Duration. With respect to all Confidential Information, the Parties'
rights and obligations under this Article shall remain in full force and effect
following the termination of this Agreement.


                                     -13-


<PAGE>


  10.3 Ownership. All materials and records which constitute Confidential
Information, other than service orders and copies of this Agreement, shall be
and remain the property of, and belong exclusively to, the disclosing Party, and
the receiving Party agrees either to surrender possession of and turn over or to
destroy and certify to the other Party the destruction of all such Confidential
Information which it may possess or control upon request of the disclosing Party
or upon the termination of this Agreement.

  10.4 Injunctive Relief. The Parties acknowledge and agree that, in the
event of a breach or threatened breach by any Party of any provision of this
Article, the other Party will have no adequate remedy in money or damages and,
accordingly, shall be entitled to an injunction against such breach. However, no
specification in this Section of a specific legal or equitable remedy shall be
construed as a waiver or prohibition against any other legal or equitable
remedies in the event of a breach of this Section of this Agreement.

  10.5 Legal Obligation to Disclose. Each Party shall be released from its
obligations under this Section 10 with respect to information which such Party
is required to disclose to others pursuant to obligations imposed by law, rule
or regulation or securities exchange or stock market rule; provided, however,
that prior to any such required disclosure, such Party shall, to the extent
practicable, provide written notice and consult with the other Party.

11.    REPRESENTATIONS AND WARRANTIES.

  11.1 By PSINet. PSINet represents and warrants to IXC that (i) it is a
corporation duly organized, validly existing and in good standing in the State
of New York; (ii) it has full corporate power and authority to own and operate
the Services and the PSINet network and to carry on its business as presently
conducted; (iii) it has, or has licensed, sufficient right, title and interest
in and to the Services, the PSINet Marks (within the United States) and the
PSINet network; (iv) it has all requisite authority to execute and deliver this
Agreement and to carry out the transactions contemplated hereby; (v) this
Agreement is a valid and binding obligation of PSINet, enforceable against
PSINet in accordance with its terms except as such enforceability may be limited
by laws relating to creditors' rights generally and the exercise of judicial
discretion in accordance with general equitable principles; and (vi) the
licenses granted and obligations owed to IXC hereunder do not conflict with the
rights granted or obligations owed by PSINet to any Third Party.

  EXCEPT FOR THE REPRESENTATIONS AND WARRANTIES SPECIFICALLY SET FORTH IN
THIS SECTION 11.1, PSINET MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND
WHATSOEVER, WHETHER EXPRESS, IMPLIED OR STATUTORY, AND PSINET EXPRESSLY
DISCLAIMS AND EXCLUDES ALL OTHER REPRESENTATIONS AND WARRANTIES OF ANY KIND.
WITHOUT LIMITING THE GENERALITY OF THE FOREGOING, PSINET MAKES NO WARRANTY TO
IXC OR ANY OTHER PERSON OR ENTITY, WHETHER EXPRESS, IMPLIED OR STATUTORY, AS TO
THE DESCRIPTION, QUALITY, COMPLETENESS, MERCHANTABILITY OR FITNESS FOR ANY
PARTICULAR PURPOSE OF ANY INTERNET SERVICE OR ANY OTHER SERVICE PROVIDED
HEREUNDER OR DESCRIBED HEREIN, OR AS TO ANY OTHER MATTER, ALL OF WHICH
WARRANTIES ARE HEREBY EXCLUDED AND DISCLAIMED.

  11.2 By IXC. IXC represents and warrants to PSINet that (i) it is a
corporation duly organized, validly existing and in good standing in the State
of Delaware; (ii) it has full corporate power and authority to carry on its
business as presently conducted; (iii) it has sufficient right, title and
interest in and to the IXC Marks, (iv) it has all requisite authority to execute
and deliver this Agreement and to carry out the transactions contemplated
hereby; (v) this Agreement is a valid and binding obligation of IXC, enforceable
against IXC in accordance with its terms except as such enforceability may be
limited by laws relating to creditors' rights generally and the exercise of
judicial discretion in accordance with general equitable principles and (vi) the


                                     -14-


<PAGE>


obligations owed to PSINet hereunder do not conflict with the rights granted or
obligations owed by IXC to any Third Party.

  EXCEPT FOR THE REPRESENTATIONS AND WARRANTIES SPECIFICALLY SET FORTH IN
THIS SECTION 11.2, IXC MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND
WHATSOEVER, WHETHER EXPRESS, IMPLIED OR STATUTORY, AND IXC EXPRESSLY DISCLAIMS
AND EXCLUDES ALL OTHER REPRESENTATIONS AND WARRANTIES OF ANY KIND.

12.    LIMITATION OF LIABILITY.

  12.1 Limitation of Liability. Except for direct damages otherwise
specifically provided for in this Agreement, in no event shall IXC or PSINet be
liable for any special, incidental, direct, indirect, punitive, reliance or
consequential damages, whether foreseeable or not, arising under this Agreement
or from any breach or partial breach of the provisions of this Agreement or
occasioned by any defect in the Services or other service provided hereunder,
delay in availability of the Services or any service provided hereunder, failure
of the Services or other service provided hereunder, interruptions or outages of
the PSINet network or any other cause whatsoever or arising out of any act or
omission by IXC or PSINet, as applicable, its employees, servants and/or agents,
including but not limited to, damage or loss of data, property or equipment,
loss of profits or revenue, cost of capital, cost of replacement services, or
claims of customers for service interruptions or transmission problems.

  12.2 Release; Indemnification. Each Party (each Party in such capacity
being referred to as the "Releasing Party") releases, assumes and agrees to
indemnify, defend, protect and save the other Party harmless from and against
any claim, damage, loss, liability, cost and expense (including reasonable
attorneys' fees) in connection with any loss or damage to any physical property
or facilities of the Releasing Party or any injury to or death of any Person
arising out of or resulting in any way from the negligence or misconduct of the
Releasing Party or its employees, servants, contractors and/or agents.

13.    INDEMNIFICATION.

  13.1 Indemnification Obligations. IXC and PSINet (hereinafter where either
has undertaken the action or inaction to be indemnified against shall be known
as the "Indemnifying Party") agree to assume all liability for and indemnify,
defend and hold harmless the other Party or any third Party claiming through the
other Party, from and against all liability, loss, cost, damage, expense or
cause of action, of whatsoever character, or injury or death of any Person and
damage to or destruction of any property, including, without limitation, third
Parties and all related expenses, including, but not limited to, reasonable
attorneys' fees, investigators' fees and litigation expenses and costs of
enforcing this Section 13 arising out of or relating to, in whole or in part,
any of the following:

         (i)     claims for libel, slander, infringement of copyright or
                 unauthorized use of a trade secret, trade name or service mark
                 that results from the transmission of material over the PSINet
                 network by the Indemnifying Party, authorized representatives
                 of the Indemnifying Party or other Persons not associated
                 with, or related to, either IXC or PSINet; or

         (ii)    claims of any Third Party arising out of the negligent or
                 willful act or omission of the Indemnifying Party or its
                 agents, servants, employees, contractors or representatives
                 (other than IXC, if PSINet is the Indemnifying Party, or
                 PSINet, if IXC is the Indemnifying Party); or

         (iii)   claims for patent infringement arising out of the use of the
                 PSINet network by the Indemnifying Party or any Person


                                     -15-


<PAGE>


                 authorized by the Indemnifying Party or resulting from the
                 acts of the Indemnifying Party or the Indemnifying Party's
                 representatives in combining the PSINet network with the
                 facilities of the Indemnifying Party or others, or using the
                 PSINet network either alone or in connection with that of the
                 Indemnifying Party or others; or

         (iv)    claims, except as otherwise set forth herein, for the material
                 breach of or failure to comply, in any material respect, with
                 any term or condition of this Agreement by the Indemnifying
                 Party or its officers, employees or invitees; or

         (v)     claims resulting from patent or trade secret infringement or
                 infringement or unauthorized use of trade secrets or trade
                 name by the Indemnifying Party in connection with this
                 Agreement.

    In addition, PSINet will defend, indemnify and hold IXC harmless from and
against any claim or threat of claim by an IXC Customer or an IXC Reseller which
is based on any warranty, promise or representation made by IXC as part of a
service agreement and for which PSINet is responsible in accordance with the
terms of this Agreement. Similarly, IXC will defend, indemnify and hold PSINet
harmless from and against any claim or threat of claim which is based on any
warranty, promise or representation made by IXC to a Third Party for which
PSINet is not responsible in accordance with the terms of this Agreement.

    PROVIDED, HOWEVER, NOTWITHSTANDING ANY PROVISION OF THIS AGREEMENT TO THE
CONTRARY, IN NO EVENT SHALL EITHER PARTY BE LIABLE TO THE OTHER (OR TO ANY THIRD
PARTY CLAIMING THROUGH SUCH OTHER PARTY) FOR CONSEQUENTIAL, INCIDENTAL,
EXEMPLARY OR PUNITIVE DAMAGES, AND THE FOREGOING INDEMNITIES SHALL NOT APPLY
WITH RESPECT TO SUCH DAMAGES.

    13.2 Notices and Defense. The Indemnifying Party shall provide the other
Party with notice of any such claim by a Third Party, and assure the defense of
such claim, on the terms and subject to Sections 9.2 and 9.3 of the IRU
Agreement.

14. NON-SOLICITATION.

         a.   From the date hereof until three years after the Closing Date,
neither IXC nor any of its Affiliates will, directly or indirectly, either alone
or in association with others in any part of the world induce, request,
encourage or assist any employee of PSINet or its Affiliates to terminate his or
her employment with PSINet, or to join with or become employed by, render
services to or otherwise be engaged by IXC or any of its Affiliates in any
direct or indirect capacity.

         b.   From the date hereof until three years after the Closing Date,
neither PSINet nor any of its Affiliates will, directly or indirectly, either
alone or in association with others in any part of the world induce, request,
encourage or assist any employee of IXC or its Affiliates to terminate his or
her employment with IXC, or to join with or become employed by, render services
to or otherwise be engaged by PSINet or any of its Affiliates in any direct or
indirect capacity.

         c.   If, at the time of enforcement of Section 14, a court shall hold
that the duration, scope, geographic area or other restrictions stated herein
are unreasonable under circumstances then existing, the Parties agree that the
maximum duration, scope, geographic area or other restrictions deemed reasonable
under such circumstances by such court shall be substituted for the stated
duration, scope, geographic area or other restrictions.


                                     -16-


<PAGE>


15. MISCELLANEOUS.

    15.1 Independent Contractors. The Parties are acting as independent
contractors and under no circumstances shall any of the employees of one Party
be deemed the employees of the other for any purpose. Except as otherwise
expressly provided in this Agreement, this Agreement does not constitute either
Party as the agent or legal representative of the other Party and does not
create a partnership or joint venture between the Parties. Except as otherwise
expressly provided in this Agreement, neither Party shall have any authority to
act for the other Party in any agency or other capacity, to make commitments of
any kind for the account of, or on behalf of, the other Party or to contract for
or bind the other Party in any manner whatsoever. This Agreement confers no
rights of any kind upon any Third Party.

    15.2 Force Majeure. Notwithstanding any provision in this Agreement to the
contrary, neither Party shall be liable for failure to fulfill its obligations
hereunder (except with respect to payment or other monetary obligation or as
otherwise specifically set forth herein) if such failure is due to causes beyond
its reasonable control, including, without limitation, actions or failures to
act of the other Party or, acts of God, flood, fire, storm, catastrophe,
governmental prohibitions or regulations, viruses which did not result from the
acts or omissions of such Party, its employees or agents, national emergencies,
acts of public enemies, national emergency, insurrections, riots or wars,
breakdown of or damage to plants or equipment or facilities (other than arising
out of the neglect of or mishandling by such Party), the relevant portion of the
Internet is down due to a technology failure (other than arising out of the
neglect of or mishandling by such Party), failure of a supplier to supply
necessary materials or equipment in a timely manner, destruction of property,
embargoes, boycotts, governmental legislation or regulations, orders or acts of
civil or military authorities, governmental acts or orders of courts or
administrative agencies, or strikes, lockouts, work stoppages or other labor
difficulties. The time for any performance required hereunder shall be extended
by the delay incurred as a result of such act of force majeure, and each Party
shall act with diligence to correct such force majeure.

    15.3 Delays or Omissions. No delay or omission to exercise any right, power
or remedy accruing to a Party under this Agreement shall impair any such right,
power or remedy of such Party nor shall it be construed to be a waiver of any
such breach or default, or an acquiescence therein, or of any similar breach or
default thereafter occurring; nor shall any waiver of any single breach or
default be deemed a waiver of any other breach or default theretofore or
thereafter occurring. Any waiver, permit, consent or approval of any kind or
character on the part of either Party of any breach or default under this
Agreement, or any waiver on the part of either Party of any provisions or
conditions of this Agreement must be made in writing and shall be effective only
to the extent specifically set forth in such writing. All remedies, either under
this Agreement or by law or otherwise afforded to a Party, shall be cumulative
and not alternative.

    15.4 Binding Agreement. This Agreement shall be binding upon and shall
inure to the benefit of the Parties hereto and their respective successors and
permitted assigns. No Person or entity other than the Parties hereto (and their
respective successors and permitted assigns) is or shall be entitled to bring
any action to enforce any provision of this Agreement against either of the
Parties, and the covenants and agreements set forth in this Agreement shall be
solely for the benefit of, and shall be enforceable only by, the Parties or
their respective successors and assigns as permitted hereunder.

    15.5 Additional Actions, Documents and Information. Each of the Parties
agrees that it will, at any time, prior to, at or after the date hereof, take or
cause to be taken such further actions, and execute, deliver and file or cause
to be executed, delivered and filed such further documents and instruments and


                                     -17-


<PAGE>


obtain such consents, as may be reasonably requested in order to fully
effectuate the purposes, terms and conditions of this Agreement.

    15.6 Notices. (a) All notices and other communications required or
permitted hereunder shall be in writing and shall be mailed by certified or
registered mail (return receipt requested), express air courier, charges
prepaid, or facsimile addressed as follows:

    To IXC:                                 with a copy to:

    IXC Internet Services, Inc.             IXC Communications, Inc.
    500 Plaza on the Lake, Suite 200        5000 Plaza on the Lake, 
    Austin, TX 78746-1050                   Suite 200, Austin,
    Attn: Chairman                          TX 78746
    Facsimile: (512) 328-0239               Attention: General Counsel
                                            Facsimile: (512) 328-7902

                                            Riordan & McKinzie
                                            695 Town Center Drive, 
                                            Suite 1500
                                            Costa Mesa, California 92626
                                            Attn: Michael P. Whalen
                                            Facsimile: (714) 549-3244

    To PSINet:                              with copy to:

    PSINet Inc.                             PSINet Inc.
    510 Huntmar Park Drive                  510 Huntmar Park Drive
    Herndon, Virginia 20170                 Herndon, Virginia 20170
    Facsimile: 703.397.5318                 Facsimile: 703.904.9527
    Attn:  Vice President and               Attn: General Counsel
           General Manager,
           Wholesale Group


or to such other address as either Party shall have furnished to the other in
writing.

         (b) If a notice is given by either Party by certified or registered
mail, it will be deemed received by the other Party on the fifth business day
following the date on which it is deposited for mailing. If a notice is given by
either Party by air express courier, it will be deemed received by the other
Party on the next business day following the date on which it is provided to the
air express courier. If a notice is given by facsimile, it will be deemed
received by the other Party after confirmation of receipt. Notwithstanding the
foregoing, any payments made under this Agreement shall be deemed received only
when actually received.

    15.7 Attorneys' Fees. If any arbitration is commenced between the Parties
regarding the performance of this Agreement, the prevailing Party shall be
entitled, in addition to such other relief as may be granted, to a reasonable
sum for its attorneys' fees in such proceeding and for the expenses and costs of
such proceeding as the arbitrator may determine.

    15.8 Assignment. No assignment of this Agreement or of any rights or
obligations hereunder may be made by either Party without the prior written
consent of the other Party hereto and any attempted assignment without the
required consent shall be void; provided, however, that notwithstanding the
foregoing, (i) each Party shall have the right to pledge, assign or otherwise
transfer this Agreement and its rights hereunder, in whole or in part, as
collateral security to any lender, and (ii) each Party shall have the right to
assign or transfer this Agreement and its rights hereunder, in whole or in part,


                                     -18-


<PAGE>


to any direct or indirect wholly-owned subsidiary of that Party or to any Person
into which that Party may be merged or consolidated or which purchases all or
substantially all of the assets of that Party; provided, however, that (a) such
subsidiary or Person agrees to be bound by the terms of this Agreement and (b)
any such assignment or transfer shall not relieve that Party from any liability
or obligation under this Agreement.

    15.9 No Third Party Beneficiaries. No provision to this Agreement is
intended, nor shall any be interpreted, to provide or create any Third Party
beneficiary rights or any other rights of any kind in any client, customer,
affiliate, shareholder, partner of any Party or any other Third Party; unless
specifically provided otherwise herein, and except as so provided, all
provisions hereof, shall be personal solely between the Parties to this
Agreement.

    15.10     Export Controls. IXC agrees and acknowledges that any export of
the Services and the subsequent use thereof is subject to U.S. export control
laws and regulations. IXC shall not directly or indirectly transfer the
Services, or the documentation relating thereto, to any country or location
outside of the United States without obtaining the prior written consent of
PSINet.

    15.11     Severability. In case any provision of this Agreement shall be
invalid, illegal or unenforceable, such provision shall be construed so as to
render it enforceable and effective to the maximum extent possible in order to
effectuate the intention of this Agreement; and the validity, legality and
enforceability of the remaining provisions hereof shall not in any way be
affected or impaired thereby.

    15.12     Public Announcements. Each Party shall have the right to review,
comment upon and approve any publicity materials, press releases or other public
statements by the other that refer to, or that describe any aspect of, this
Agreement made prior to, or within 90 days after, the Effective Date; provided,
however, that with respect to disclosure documents required under the Securities
Exchange Act of 1934, as amended, subject to the last sentence of this Section
15.12, each Party shall only have the right to prior review and to comment upon
the other Party's disclosure documents. Each Party agrees that it will not issue
any such publicity materials, press releases or public statements without the
prior written approval of the other Party. The provisions of this section shall
survive termination of this Agreement for a period of two years, except for the
last sentence hereof which shall survive as may be mutually agreed by them for
the Term.

    15.13     Expenses. Each Party shall pay its own legal and other costs
incurred in connection with this Agreement and in the preparation for and
consummation of the transactions provided for herein.

    15.14     Taxes. IXC shall be liable for and shall reimburse PSINet for all
taxes and related charges, however designated, resulting from the provision of
Services as contemplated hereby, including federal, state, provincial or local
sales, use or value-added taxes (VAT) and excise taxes, imposed in connection
with or arising from the provision of Services. In no event shall IXC be
obligated to pay income taxes levied upon PSINet's net income or any real or
personal property taxes assessed against PSINet or PSINet's property, including
any gross receipts taxes assessed in lieu of net income or property taxes,
provided that, if the terms of the relevant statute or ordinance imposes such
gross receipts tax upon IXC, then IXC shall be liable for such tax.

    15.15     Survival of Obligations. The Parties' rights and obligations
that, by their nature, would continue beyond the termination, cancellation, or
expiration of this Agreement, shall survive such termination, cancellation or
termination.


                                     -19-


<PAGE>


    15.16     Titles and Subtitles. The titles of the Articles and Sections of
this Agreement are for convenience of reference only and are not to be
considered in construing this Agreement.

    15.17     Governing Law. This Agreement shall be governed in all respects
by the laws of the State of Delaware without reference to its principles of
conflicts of laws.

    15.18     Dispute Resolution. Any controversy or claim arising out of or
relating to this Agreement or with respect to an alleged breach of the terms
hereof, subject to Section 7.8, above, shall be resolved in accordance with the
provisions of Section 19.14 of the IRU Agreement. 

    15.19     Entire Agreement/Amendments. This Agreement and the Reciprocal
Confidentiality Agreement constitutes the full and entire understanding and
agreement between the Parties with regard to the subjects hereof and supersedes
all prior oral and written agreements, commitments and understandings with
respect to such matters. Neither this Agreement nor any term hereof may be
amended, waived, discharged or terminated, except by a written instrument signed
by the Parties hereto.

    15.20     Counterparts. This Agreement may be executed simultaneously in
two or more counterparts, each counterpart shall be deemed to be an original,
and all counterparts individually or together shall constitute one and the same
instrument.

    15.21     Schedules. The information set forth in the following Schedules
to this Agreement is intended to supplement the information contained in this
Agreement. In the event of any conflict between the terms of this Agreement and
the information contained in the Schedules hereto, the terms of this Agreement
shall prevail and control.

BOTH Parties represent and warrant that the Person whose signature appears below
is duly authorized to enter into this Agreement on behalf of the Party.

IN WITNESS WHEREOF, THE PARTIES HAVE ENTERED INTO THIS AGREEMENT AS OF THE
EFFECTIVE DATE:

IXC Internet Services, Inc.              PSINet Inc.

By:   /s/ RALPH J. SWETT                 By:   /s/ WILLIAM L. SCHRADER
Name:     RALPH J. SWETT                 Name:     WILLIAM L. SCHRADER
Title:    Chairman, President and CEO    Title:    Chairman, President and CEO
Date:     7/22/97                        Date:     7/22/97


                                     -20-
<PAGE>


                                    SCHEDULE 2.1.3
                                           
                               MASTER TEAMING AGREEMENT
                                           

Definitions:

     "Client" refers to a major domestic or worldwide corporation which either
issues a request for Proposal or would be receptive to an unsolicited Proposal
for procurement of products and/or services of the types provided by the
Parties.

     "Project" refers to a certain procurement of services by and delivery to
Client.

     "Proposal" refers to the documentation of the plan, approach, methodology,
deliverables, costs, etc. submitted to a Client.

     "Team Leader" shall mean the Party submitting the proposal to Client and
fulfilling the leadership role in Project management.

     "Team Member" shall mean the Party who is not the Team Leader.

     All other capitalized terms used herein but which are not otherwise defined
shall have the meanings given to them in the Joint Marketing and Services
Agreement to which this Schedule 2.1.3 is attached (the "Marketing Agreement").


ARTICLE I - INTRODUCTION AND SCOPE.

1.1  With respect to IXC, this Agreement applies only to the Internet Services
     and Broadband Services divisions of IXC and to teaming efforts regarding
     the products and services of such divisions. In addition, this Agreement
     shall apply only to teaming efforts regarding products and services to be
     sold and/or provided in the Territory, except as stated below. The Parties
     acknowledge that Projects may be performed outside the Territory either
     directly or indirectly through local subsidiaries or subcontractors and may
     be under this Agreement or under separate agreements of their respective
     local subsidiaries, all as the Parties may agree from time-to- time. The
     Parties will endeavor to ensure that the provisions of any such separate
     agreement, to the extent reasonably possible, will be the same as those of
     this Agreement. However, because of the various legal and business
     requirements of such subsidiaries or imposed on such subsidiaries, certain
     modifications of the provisions of this Agreement may be required for its
     adoption for use in such instances.

1.2  This Agreement applies only to the preparation and submission of Proposals
     and other related activities and performance of the Parties in order to
     obtain a contract from the applicable Client. The provision of products
     and/or services by a Party hereto as subcontractor to the other Party
     hereto as prime contractor will be under a separate agreement, as stated in
     Section 2.3 of this Agreement.

1.3  Either Party may request the other Party's participation in the development
     of a Proposal. Such request will be in writing in the form of a Statement
     of Intent To Develop A Proposal (the "Statement of Intent") substantially
     in the form of Exhibit A hereto, signed by a requesting Party. Such
     Statement of Intent may contain a brief preliminary description of the
     products and services each Party would provide, with the full description
     of the products and services to be provided by a Party as subcontractor to
     the other Party as prime contractor, and the applicable fees and charges,
     to be agreed upon and completed at a later


                                    Schedule 2.1.3
                                     Page 1 of 12

<PAGE>

     date and incorporated in a subcontract to be negotiated and executed by the
     Parties with respect to the applicable Project. The Party receiving such a
     request to participate will respond in writing as to whether or not it will
     participate in the Proposal and Project by the earlier of (i) ten (10)
     business days after its receipt of the request, or (ii) thirty (30) days
     prior to the due date of the Proposal. A Party's election to participate
     shall be effected by executing and returning the Statement of Intent. An
     election to decline the offer to participate shall be effected by sending
     written notice of this decision to the offering Party. In the event of an
     election to decline participation, the following provisions of this
     Agreement will not apply to the applicable Proposal and Project: Articles
     III, IV and V, and Section 2.3.


ARTICLE II - RELATIONSHIP OF THE PARTIES.

2.1  The Parties shall act as independent contractors in the performance of this
     Agreement. Neither Party shall act as agent for or partner of the other
     Party for any purpose whatsoever, and the employees of one Party shall not
     be deemed the employees of the other Party.

2.2  Nothing in this Agreement shall be construed to grant either the Team
     Leader or the Team Member the right to make commitments of any kind for or
     on behalf of the other Party without the prior written consent of the other
     Party.

2.3  It is understood and agreed that, in the event a contract is awarded to the
     Team Leader by the Client, the Team Leader will be the prime contractor. In
     such event, the Team Leader agrees, subject to the Client's approval,
     promptly upon receipt of the contract award, to negotiate in good faith a
     subcontract with the Team Member for performance of its proposed portions
     of the Project. The Parties agree to use reasonable efforts to negotiate
     and agree upon model form subcontract agreements which shall be used as
     standard form agreements, to the extent reasonably possible, between Team
     Leader and Team Member for Team Member's provision of products and or
     services with respect to Projects.


ARTICLE III - PROPOSAL PREPARATION AND SUBMISSION TO CLIENT.

3.1  Each Party shall use reasonable commercial efforts to prepare its portions
     of the Proposal for a Project and to obtain the award to the applicable
     prime contractor hereunder of a contract for the Project.

3.2  The Team Member shall submit to the Team Leader all necessary technical and
     business data and information concerning its proposed portion of the
     Project, including pricing data, required for use in preparation of the
     Proposal. The Team Member shall make available appropriate and high-quality
     personnel to provide reasonable assistance to the Team Leader in the
     preparation of the Proposal as directed by the Team Leader.

3.3  The Team Leader shall prepare the Proposal, integrate the information
     provided by the Team Member and submit the Proposal to the Client. The Team
     Leader agrees to consult with the Team Member on all matters concerning the
     portion of the Project to be performed by the Team Member prior to
     submission of the Proposal to the Client.

3.4  The Team Leader shall identify the Team Member as a proposed subcontractor
     and describe the Team Member's Project responsibilities in the Proposal.

                                    Schedule 2.1.3
                                     Page 2 of 12

<PAGE>

3.5  The Team Leader shall handle contract negotiations with the Client and,
     subject to Client approval, the Team Member will have the opportunity to be
     present at meetings with the Client related to its proposed portion of the
     Project.

3.6  The Team Leader agrees to consult with and obtain the concurrence of the
     Team Member prior to making any Proposal change relating to the Team
     Member's proposed portion of the Project.

3.7  The Team Leader agrees to keep the Team Member advised of all changes in
     the Client's requirements affecting the Team Member's proposed portion of
     the Project and as to the probability of contract award to the team.

3.8  The Team Leader shall use its best efforts to obtain the contract award,
     including participation in oral presentations and preparation of best and
     final offers, and the Team Member agrees to assist in such efforts as the
     Team Leader may reasonably require.

3.9  All contacts with the Client with respect to the Project Proposal shall be
     the responsibility of the Team Leader. Any contacts made by the Team Member
     with the Client shall be only with the full knowledge, prior concurrence
     and participation of the Team Leader.


ARTICLE IV - PROJECT SUBCONTRACT.

4.1  In the event of a contract award to the Team Leader, the Parties shall
     immediately commence good faith negotiations of a subcontract consistent
     with the terms of this Agreement, the applicable Proposal, and the
     applicable prime contract, as may be appropriate, encompassing the Team
     Member's proposed portion of the Project. The Team Leader agrees to use its
     best efforts to secure approval of such subcontract by the Client in the
     event such approval is necessary. Team Leader, with Team Member's
     agreement, may authorize Team Member to begin work, at the direction of the
     Team Leader, prior to execution of the subcontract, for the specific
     Project, subject to the terms of the model form subcontract agreement
     referred to in Section 2.3, above.

4.2  The specific work to be performed by the Team Member will be described in
     the applicable subcontract and/or in orders issued thereunder by Team
     Leader from time to time. Article V below describes generally the products
     and services to be provided by the Parties with respect to Projects.

4.3  The subcontract with the Team Member shall include, among other appropriate
     provisions, those provisions for the prime contract between the Team Leader
     and the Client which the prime contract requires are to be flowed down to a
     subcontractor, provided that Team Member either was aware of such flow-down
     requirement before preparation of Team Member's portion of the Proposal or
     subsequently agrees to such provisions. Team Member will advise Team
     Leader, prior to submission of the Proposal, of any such flow-down
     provisions of the proposed Client prime contract as to which Team Member
     takes exception; any such provisions, of which Team Member was aware, to
     which exception is not taken will be included in the subcontract.


                                    Schedule 2.1.3
                                     Page 3 of 12

<PAGE>

ARTICLE V - GENERAL RESPONSIBILITIES FOR PRODUCTS AND SERVICES.

5.1  IXC generally will provide products and services of the following types for
     Projects:

                                     [TO FOLLOW]

5.2  "Corporation" generally will provide products and services of the following
     types for Projects:

                                     [TO FOLLOW]


ARTICLE VI - COST AND EXPENSES.

6.1  Each Party will bear all of its own costs and expenses relating to the
     preparation of Proposals and to the performance of its other obligations
     and activities under this Agreement. Neither Party will charge the other
     Party for any services unless specifically agreed otherwise in writing by
     the Parties.


ARTICLE VII - PROPRIETARY INFORMATION.

7.1  Each Party anticipates that it may be necessary to provide access to
     information of a confidential or proprietary nature (hereinafter referred
     to as "Proprietary Information") to the other Party in the performance of
     this Agreement. To the extent possible, Proprietary Information shall be
     clearly identified or labeled as such by the disclosing Party at the time
     of disclosure. Where concurrent identification of such information is not
     feasible, the disclosing Party shall provide such identification as
     promptly thereafter as possible. However, whether or not so designated,
     each Party's client lists, business plans, and the pricing of its products
     and services will be deemed the confidential information of such Party.

7.2  Each Party agrees that it will hold such Proprietary Information
     confidential in the same manner as it holds its own Proprietary Information
     of like kind, but in any case, by the use of at least reasonable care.
     Disclosures of Proprietary Information shall be restricted to those
     individuals who are participating in preparation of the Proposal and other
     work related to the Project. Each Party shall return all such Proprietary
     Information of the other upon termination of the Agreement and completion
     of all pending Projects.

7.3  Neither Party shall reproduce, disclose or use Proprietary Information of
     the other except as follows:

(a)  Proprietary Information furnished by the Team Leader may be used by the
     Team Member in performing its obligations under this Agreement and any
     resulting subcontract.

(b)  Proprietary Information furnished by the Team Member may be used by the
     Team Leader in performing its obligations under this Agreement, including
     preparation of the Proposal for submission to the Client, and in
     performance of a resulting subcontract between the Parties for a Project.

(c)  Proprietary Information furnished by either Party may be used in accordance
     with written authorization received from the disclosing Party.

7.4  The limitations on reproduction, disclosure, and use of Proprietary
     Information shall not apply to, and neither Party shall be liable for,

                                    Schedule 2.1.3
                                     Page 4 of 12

<PAGE>

     reproduction, disclosure or use of Proprietary Information of the other to
     the extent such information: (1) becomes known to the public from a source
     other than the receiving Party; (2) was or becomes known to the receiving
     Party from a Third Party having the right to disclose it and having no
     obligation of confidentiality to the disclosing Party with respect to the
     applicable information; (3) is furnished to others by its owner without
     restriction on disclosure; (4) is independently developed by personnel of
     the receiving Party who have not had access to such information; or (5) is
     disclosed pursuant to governmental or judicial requirement.

7.5  Neither the signing of this Agreement nor the furnishing of any Proprietary
     Information by either Party to the other shall be construed as granting the
     other Party expressly, by implication, by estoppel or otherwise, any
     license under any invention, patent, trademark, copyright or other
     proprietary right now or hereafter owned or controlled by the Party
     disclosing and furnishing same.

7.6  Each Party admits for all purposes that any violation or threatened
     violation of this Article VII shall constitute an irreparable injury to the
     disclosing Party for which monetary damages provide an inadequate remedy,
     and agrees that, in addition to all other rights provided by law to which
     the disclosing Party shall hereby be entitled, it shall have the right to
     seek to have an injunction or equivalent remedy issued against the
     receiving Party to prevent said Party from violations or further violations
     of this Article VII.

7.7  The provisions of this Article VII shall survive termination of this
     Agreement and any Proposal effort.


ARTICLE VIII - INTELLECTUAL PROPERTY RIGHTS.

8.1  All rights in and to inventions conceived and/or reduced to practice, and
     in and to works of authorship created in the performance of this Agreement
     (and any resulting subcontracts signed by the Parties for a Project, except
     as the Parties agree otherwise in any such subcontracts) shall be the sole
     and entire property of the originating Party, including full ownership and
     title to related patents, copyrights and other intellectual property. In
     the event of joint inventions or joint works or authorship, the Parties
     shall engage in good faith negotiations to establish respective ownership
     rights therein. Failing agreement within thirty (30) days from initiation
     of good faith negotiations by either Party, [the Parties shall be deemed to
     have joint ownership, without right of account, of the intellectual
     property rights embodied in such new inventions and/or works of
     authorship.]

8.2  Notwithstanding the foregoing, with respect to any Proposal effort by the
     Parties, it is understood and agreed that Team Member shall grant a license
     or transfer rights to Team Leader and/or the Client in inventions, works of
     authorship, data and information as required by the terms of the applicable
     request for Proposal for a Project, provided that Team Member was aware of
     such terms at the time Team Member prepared its portion of the Proposal,
     and except to the extent exceptions are taken to the applicable provisions
     of the request for Proposal. Such license or transfer of rights shall not
     exceed the requirements of the prime contract for such Project.
     Intellectual property rights embodied in preexisting equipment or computer
     software shall remain the sole property of its then owner, provided,
     however, such owner hereby agrees to license such software for use by the
     Client to the extent required by the prime contract.


                                    Schedule 2.1.3
                                     Page 5 of 12

<PAGE>

ARTICLE IX - NON-EXCLUSIVITY/EXCLUSIVITY OF RELATIONSHIP.

9.1  Except as stated below, the participation of the Parties in a Project under
     this Agreement shall be on a non-exclusive basis, and each Party shall
     retain complete freedom to work alone or with other Third Parties in
     bidding or performing work on any such Project. However, on a case-by-case
     basis, the Parties may agree, with respect to any particular Project, to
     participate with each other on an exclusive teaming basis, and, in the
     event of such an agreement to team exclusively, it shall be under the
     following terms.

(a)  [Neither Party may enter into or participate in a teaming agreement or
     effort with another Third Party for the purpose of proposing to provide
     products or services for a Project subject to this Agreement of the types
     for which it is responsible under this Agreement.]

(b)  [Neither Party may quote, offer to provide, provide, offer to sell, or sell
     to the applicable Client or to any prime or subcontractor to the applicable
     Client any products or services relating to the applicable Project of the
     types for which it is responsible under this Agreement, other than pursuant
     to a Proposal under this Agreement or a subcontract between the Parties.]

(c)  [With respect to IXC, the exclusive teaming obligations and restrictions
     stated above shall apply only to its IXC Internet Services division, and
     the other divisions and business units of IXC Communications, Inc. are free
     of any such obligations and restrictions.]

(d)  Notwithstanding the foregoing, in the event that any other division of IXC
     invites IXC Internet Services division to participate with it in any
     Proposal for any Project or to provide any products or services with
     respect to a Project, IXC Internet Services division may do so, provided
     that such other division of IXC became aware of such Project other than
     through a violation of the rights of "Corporation" regarding protection of
     its Proprietary Information under this Agreement. In the event the IXC
     Internet Services division participates or provides any products or
     services as described above in this Section 9.1(d), both Parties to this
     Agreement will be relieved of and discharged from the exclusive teaming
     obligations and restrictions stated above with respect to the applicable
     Proposal and Project.

9.2  The Parties will be relieved of and discharged from the above exclusive
     teaming obligations and restrictions to the extent that either Party's
     participation in the applicable Project with any other Third Party is
     pursuant to any agreement executed prior to its agreement to team
     exclusively hereunder. Each Party will exert best efforts to advise the
     other Party of any such previously existing agreement as soon as possible.
     In the event that a Party participates in a Project with a Third Party
     under the circumstances described above in this Section 9.2 and that such
     Party is relieved of and discharged from the said exclusive teaming
     obligations and restrictions under this Section 9.2, the other Party may,
     at its option, terminate the applicable Proposal under this Agreement
     and/or participate in the Project itself, independently of the other Party,
     or with any other Third Party, and will be deemed relieved of and
     discharged from the above-referenced exclusive teaming obligations and
     restrictions.

9.3  The Parties will be relieved of and discharged from the above exclusive
     teaming obligations and restrictions to the extent provided under Section
     15.4, below, regarding termination of a Proposal effort.

                                    Schedule 2.1.3
                                     Page 6 of 12

<PAGE>

ARTICLE X - LIMITATION OF LIABILITY.

10.1 NEITHER PARTY WILL BE LIABLE FOR ANY INDIRECT, SPECIAL, PUNITIVE,
     INCIDENTAL OR CONSEQUENTIAL DAMAGES OF ANY KIND (INCLUDING, BUT NOT LIMITED
     TO, LOST PROFITS) INCURRED OR ARISING OUT OF THE PERFORMANCE OF THIS
     AGREEMENT EVEN IF THAT PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
     DAMAGES.


ARTICLE XI - NON-SOLICITATION.

11.1 Neither Party shall actively solicit for employment any of each other's
     personnel during the period of such employees' assignment to or work on any
     Proposal and for the period of six (6) months following termination of
     assignment of each such employee to the Proposal effort. Publicizing
     available employment positions in newspapers or other media of mass
     communication shall not be deemed active solicitation for employment under
     this provision.


ARTICLE XII - FORCE MAJEURE.

12.1 Neither Party shall be liable for any failure to perform or for any delay
     in performance of this Agreement where the failure or delay is due to acts
     of God or public enemy, war, riot, embargo, fire, explosion, sabotage,
     flood, accident, strikes, lockouts or other labor disturbances or to
     enactment, promulgation or issuance of any laws, regulations, orders or
     decrees of any competent governmental, regulatory or judicial authority,
     or, without limiting the foregoing, to any circumstances beyond such
     Party's reasonable control. During such period of disability, each Party's
     obligations will be suspended and commensurately extended until such time
     as performance is no longer prevented or hindered, provided that if such
     period extends for the shorter of (I) thirty (30) days, or (ii) a period of
     such duration that either Party consequently reasonably determines that
     affected Proposal efforts are jeopardized, either Party thereafter may
     terminate this Agreement as it applies to any adversely affected Proposal,
     if such right is exercised before the disability is remedied and
     performance is resumed.


ARTICLE XIII - PUBLIC ANNOUNCEMENT.

13.1 Any news release, public announcement, advertisement or publicity released
     by either Party concerning this Agreement, any Proposal, or any contract
     award related thereto, will be subject to the prior review, comment and
     approval of the other Party, except that this Agreement and its terms may
     be disclosed by either Party as required by any law, regulation or court
     order. Any such publicity shall give due credit to the contribution of each
     Party.


ARTICLE XIV - GOVERNING LAW.

14.1 This Agreement shall be construed in accordance with the local law of the
     State of Texas.


                                    Schedule 2.1.3
                                     Page 7 of 12

<PAGE>

ARTICLE XV - TERM AND TERMINATION OF AGREEMENT AND PROPOSAL EFFORTS.

15.1 This Agreement is effective upon execution by both Parties and will
     continue in effect thereafter for an initial term of one (1) year.
     Thereafter, the term of this Agreement will be deemed renewed
     automatically, subject to termination as set forth below or as other-wise
     provided in this Agreement.

15.2 Either Party may terminate this Agreement, for its convenience, with or
     without cause, upon at least thirty (30) days advance written notice to the
     other Party, effective as of the end of the initial term or at any time
     thereafter. With respect to the performance of obligations regarding any
     Proposal which would extend beyond the termination of this Agreement, the
     provisions of this Agreement applicable to such performance and the
     corresponding rights and obligations of the Parties will be deemed to
     survive the termination of this Agreement and continue in effect as
     required for the completion of such performance.

15.3 With respect to a Proposal, the rights and obligations of the Parties under
     this Agreement, except any obligations relating to the protection of a
     Party's confidential information, shall terminate upon the first to occur
     of any of the following events:

(a)  cancellation of the applicable request for Proposal or modification of the
     said request for Proposal resulting in the deletion of the requirement of
     the Team Member's products or services or a substantial portion thereof;

(b)  elimination by the Client of the Team Leader from consideration as prime
     contractor or award of the prime contract to a company other than the Team
     Leader);

(c)  award of a prime contract to the Team Leader which does not include the
     Team Member's products or services or a substantial portion thereof;

(d)  notification by the Client that the Team Member is unacceptable as a
     subcontractor, or a direction by the Client to utilize a subcontractor
     other than the Team Member, or a determination by either, the Client or the
     Team Leader that the Team Member's offerings do not fully comply with the
     mandatory requirements of the request for Proposal;

(e)  notification of termination by either Party in the event the Parties are
     unable to agree, negotiating in good faith, on the terms and conditions of
     the SUBCONTRACT, within sixty (60) days (or such longer period as the
     Parties may agree) from the award of a prime contract to Team Leader.

(f)  execution of the applicable subcontract between the Parties;

(g)  filing by or against either Party of a petition or a resolution made or
     passed by either Party for the bankruptcy, winding-up, liquidation or
     dissolution of such Party, or the appointment of a receiver or trustee in
     respect of such Party or of its assets, or the acknowledgment by such Party
     of its inability to meet its debts as they fall due, or a general
     assignment of the assets of such Party for the benefit of its creditors;

(h)  termination by either Party under Article XII of this Agreement;

(i)  determination, made reasonably and in good faith, by Team Leader to
     withdraw a Proposal for the reason that it has no reasonable prospect of
     being awarded the prime contract, making continuation of the Proposal
     effort uneconomical or impractical.


                                    Schedule 2.1.3
                                     Page 8 of 12

<PAGE>

(j)  notification of termination, effective thirty (30) days after such
     notification, by a Party to the other Party as a result of a material
     breach or default of this Agreement by the other Party which is not cured,
     corrected or remedied by the expiration of such thirty-day period; 

15.4 In the event any Proposal effort is terminated under Sections 15.3(a) 
     through (i), above, both Parties will be deemed relieved of and discharged
     from any exclusive teaming obligations and restrictions under Article IX or
     any other exclusive teaming provision with respect to the applicable
     terminated Proposal effort. In the event a Party terminates any Proposal
     effort as a result of the other Party's breach under Section 15.3(j),
     above, such terminating (non-breaching) Party will be deemed relieved of
     and discharged from any exclusive teaming obligations and restrictions as
     stated above in this Section 15.4. Except as otherwise stated in this
     Section 15.4 or elsewhere in this Agreement, the said exclusive teaming
     obligations and restrictions will survive such termination.


ARTICLE XVI - CONDUCT OF THE PARTIES.

16.1 Neither Party, in the performance of this Agreement, shall take any action
     that would be illegal under any applicable rule, regulation or law. The
     Parties and their respective business associates shall avoid any practices
     that are unlawful, improper or unethical and shall conduct themselves at
     all times in a manner that will avoid any appearance of impropriety on the
     part of either Party in the event of public disclosure.


ARTICLE XVII - SURVIVAL.

17.1 In addition to those provisions hereof expressly stated to survive this
     Agreement, any provisions of this Agreement and the related rights and
     obligations of the parties which, by their nature, should survive
     termination of this Agreement, will so survive and continue in effect as
     appropriate.


ARTICLE XVIII - GENERAL.

18.1 All notices, requests, consents and other communications hereunder shall be
     deemed to have been duly given if delivered in accordance with Section 15.6
     of the Marketing Agreement.

18.2 Except as otherwise stated in this Agreement or the Marketing Agreement,
     this Agreement may not be assigned or otherwise transferred by either
     Party, in whole or in part, without the express prior written consent of
     the other Party. No provision of this Agreement may be waived except by a
     writing by the Party to be charged, nor may this Agreement be amended
     except by a writing executed by an authorized representative of each Party.

18.3 The foregoing represents the complete and exclusive statement of the
     agreement between the Parties and supersedes any prior oral or written
     agreements, Proposal, commitments, understandings, or communications with
     respect to the subject matter of this Agreement.

                                    Schedule 2.1.3
                                     Page 9 of 12

<PAGE>

     IN WITNESS WHEREOF, the Parties have caused this Agreement to be executed
by their duly authorized representatives, with the intention of being legally
bound hereby.

[IXC INTERNET SERVICES]                   ("CORPORATION" NAME)

By:                                       By: 
     (Signature)                                 (Signature)
Name:                                     Name: 
Title:                                    Title:
Date:                                     Date: 


Master Teaming Agreement

Between IXC INTERNET SERVICES and ______________ dated___________________.





                                    Schedule 2.1.3
                                     Page 10 of 12

<PAGE>

                                      EXHIBIT A
                                           
                   FORM OF STATEMENT OF INTENT TO DEVELOP A PROPOSAL
                                           

Client:____________________________

________________________________________________________________________________

Team Leader:____________________________________________________________________

Team Member:____________________________________________________________________

Request For Proposal Title/number (if applicable)_______________________________

Proposal Due Date (if applicable)_______________________________________________

Development of Proposal. The parties agree to jointly develop a client proposal
under which each party would provide the respective products and services
generally and briefly described as follows:

________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________





                                    Schedule 2.1.3
                                     Page 11 of 12

<PAGE>

ACKNOWLEDGEMENT: This Statement of Intent To Develop A Proposal is issued
pursuant to the Master Teaming Agreement identified above. All of the terms and
conditions of the said Master Teaming Agreement are incorporated in and made a
part of this document as if expressly set forth herein.

IXC Internet Services                   ("Corporation" name)

By:                                     By:
Name:                                   Name:
Title:                                  Title:



                                    Schedule 2.1.3
                                     Page 12 of 12

<PAGE>

                                     SCHEDULE 2.2

                               PSI SERVICE COMMITMENTS


1.  In providing Managed Connectivity Services under this Agreement, PSI will,
    at a minimum, comply with the following performance requirements:

    (a)  Service Availability. 24 x 7 (subject to scheduled downtime for
         network maintenance during low traffic periods, upon not less than one
         week notice, when possible, to IXC and affected IXC Customers).

    (b)  Service Reliability. 99.5%, excluding network problems (i) occurring
         between the customer's premise and the PSI Points-of-Presence, and
         (ii) occurring beyond the point where information exits the PSI
         backbone.

    (c)  Installations. Including acceptance and compliance with the minimum
         performance capabilities, PSI will complete as soon as practical but
         to occur no later than (i) 45 days after receipt of order by PSI and
         (ii) three business days following IXC or LEC provisioning of circuits
         pursuant to an assignment of customer addresses by InterNIC (which
         assignment will be requested promptly by PSI following receipt of
         order). In cases in which new circuits do not need to be provisioned
         in connection with a new installation, new customers may be given a
         shorter committed date for completion of installations.

    (d)  Problem Responsiveness. The Parties will develop a mutually agreeable
         interface to the PSI trouble ticket system and appropriate problem
         escalation procedures to address the needs of IXC and IXC Customers.

*




*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission


                                     Schedule 2.2
                                     Page 1 of 2


<PAGE>

    (a)  Class B Allocation and Transfer. Immediately upon execution of the
         Joint Marketing and Services Agreement to which this Schedule is
         attached (the "Marketing Agreement"), PSI will allocate a class
         B-sized block of address space, transfer all existing IXC (the PSI
         customer) addresses to it, and grant IXC all of PSI's right, title and
         interest in and to such class B address block. PSI will assist IXC in
         obtaining a class B from the InterNic (or other authority). At such
         time as such class B is allocated, IXC will transfer all of IXC's
         right, title and interest in and to such class B address block to PSI.

    (b)  Infrastructure Engineering. PSI will, at all times, treat the IXC
         class B as it would one of its own class B's for the purposes of
         routing, peering, and network throughput optimization.

3.  Announcement. The services specified by IXC will be provided as a feature
    or function of the new PSI product/price plan for the ISP business market.
    Such plan is not completed. Upon completion, PSI will provide Internet
    routing for IXC and IXC customer networks via a separate AS number(s)
    assigned by appropriate Internet authorities. PSI will assist IXC in
    obtaining the necessary AS number(s), ownership of which is to be
    transferred and assigned to IXC. Notwithstanding the foregoing, PSI will
    obtain and implement updates to its ISP peering relationships and router
    configurations to allow full Internet routing for the IXC AS number(s) and
    associated networks at such time as PSI is able to do so.

4.  Peering. PSI acknowledges that IXC reserves the right to establish its own
    peering relationships with other ISPs. PSI will work jointly with IXC to
    ensure appropriate routing for IXC between PSI and IXC borders.

5.  Hardware. PSI will make the equipment in Appendix 1 to this Schedule 2.2
    available for resale by IXC unless PSI is prevented from doing so by its
    contracts with the equipment suppliers. Should such supplier agreements
    prevent such resale, PSI will assist IXC in acquiring its own licenses to
    do so. The prices on Appendix 1 to this Schedule 2.2 may be changed to
    reflect the then PSI acquisition cost for such. Prices charged to IXC by
    PSI shall, however, be subject to the most favored pricing provisions of
    the Marketing Agreement.

6.  Terms. PSI's obligations with respect to delivery of Services under the
    Marketing Agreement to an IXC Customer is, for all Services, subject to
    compliance by such IXC Customer, with the terms and conditions set forth in
    PSI's standard service agreements relating to the comparable services
    offered by PSI to PSI customers.

7.  Cooperation. The Parties shall cooperate with each other to ensure that the
    product service descriptions, whether contained in the Documents, service
    agreements, world-wide web site pages or elsewhere, at all times fairly and
    accurately describe the features and functions of the Services.





                                     Schedule 2.2
                                     Page 2 of 2


<PAGE>

                              APPENDIX 1 TO SCHEDULE 2.2

PSINET
INTRANET WAREHOUSE - HARDWARE LIST

Product Number               Description                                Prices
--------------               -----------                                ------

ROUTERS:
ascend-50          Ascend Pipeline 50 Router (with integrated NT1)       $    *
                   Compatible with LAN-ISDN

ascend-P130        Ascend Pipeline 130 Router (with integrated NT1 
                   and T1 CSU/DSU)                                            *
                   Compatible with LAN-ISDN and interFrame 128K-T1 
                   Services

cisco-2504         Cisco 2504 Router (TokenRing, v. 35, IP Only)              *
                   Compatible with interFrame, InterPPP, and 
                   LAN-ISDN (18 Channel)

cisco-2514         Cisco 2514 Dual Ethernet Router                            *
                   Compatible with InterFrame and InterPPP Services

comp-sys-900i      Compatible Systems MicroRouter 900i Single                 *
                   Ethernet Router
                   Compatible with LAN-DIAL, LAN-ISDN (18 Channel), 
                   InterPPP and InterFrame 56K Services

comp-sys-1220i     Compatible Systems MicroRouter 1220i Dual Ethernet 
                   Router                                                     *
                   Compatible with LAN-DIAL, LAN-ISDN (18 Channel), 
                   InterPPP and InterFrame 56K-T1 Services

comp-sys-1220iV35  Compatible Systems MicroRouter 1220i Dual Ethernet 
                   Router (with v.35 cable)                                   *
                   Compatible with LAN-DIAL LAN-ISDN (18 Channel), 
                   InterPPP and InterFrame 56K bps-T1 Services

comp-sys-1270i     Compatible Systems MicroRouter 1270i Dual 
                   Ethernet Router (with integrated T1 CSU/DSU)               *
                   Compatible with LAN-Dial, LAN-ISDN (18 
                   Channel), and InterFrame 56K-T1 services 

farallon-netop     Farallon Netopia 640 ISDN Router (with integrated NT1)     *
640                PC version for unlimited users. Compatible with 
                   LAN-ISDN Service

farallon-netop     Farallon Netopia 440 ISDN Router (with integrated NT1)     *
440                Macintosh version for unlimited users. 
                   Compatible with LAN-ISDN Service

livingston-irx     Livingston IRX-211 Firewall Router (with v.35 cable)       *
221                Compatible with Interframe and InterPPP Services

proteon-           Proteon Globetrotter 60 (with v.35 cable)                  *
globetrot 60       Compatible with Interframe Service


*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission





                                APPENDIX 1 TO SCHEDULE 2.2
                                       Page 1 of 2


<PAGE>


Product Number               Description                                Prices
--------------               -----------                                ------
rockwell-nh-bri    Rockwell NetHopper NH-BRI 616 (with integrated NT1)     *
                   Includes internal analog modem. Compatible with 
                   LAN-ISDN and LAN-DIAL Services.

MODEMS & CSU/DSUS:                                                         0
astro-nx1          Astrocom NX1 T1 CSU/DSU (Including sub-rate T1)         *
                   Compatible with Interframe 128K-T1 Services

astro-2364         Astrocom 2364 56K CSU/DSU                               *
                   Compatible with Interframe 56K and InterPPP Services

usr-sportPC        US Robotics Sportster 33.6 Kbps Modem                   *
                   PC version compatible with InterRamp and LAN-DIAL 
                   Services

usr-sportMAC       US Robotics Sportster 33.6 Kbps Modem                   *
                   Macintosh version compatible with InterRamp and 
                   LAN-DIAL Services

MISCELLANEOUS:
3com-ImpactPC      3Com Impact (with external TA/NT1)                      *
                   PC version compatible with InnerRamp Service via ISDN

3com-ImpactMAC     3Com Impact (with external TA/NT1)                      *
                   Macintosh version compatible with InterRamp Service 
                   via ISDN

motorola-          Motorola Bitsurfer Pro (with external TA/NT1 and two 
bitsurfPC          analog ports)                                           *
                   PC version compatible with LAN-ISDN and InterRamp 
                   Service via ISDN.

motorola-          Motorola Bitsurfer PRO (with external TA/NT1 and 
bitsurMAC          two analog ports)                                       *
                   Macintosh version compatible with LAN-ISDN and 
                   InterRamp Service via ISDN.

nt-nt1             Northern TelecomTM Standalone NT1 Model A               *
                   Includes 2 watt power supply. Compatible with 
                   InterRamp and LAN-ISDN Services.

Note:              Continental U.S. Shipping:

Orders in Virginia must
includes a 4.5% sales tax. 

                   Hardware: There is a [*] shipping fee for all 
                   hardware purchased through PSINet.

Terms: Net 30 days.


*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission


                              APPENDIX 1 TO SCHEDULE 2.2
                                     Page 2 of 2


<PAGE>


                             Attachments to Schedule 2.2
                                           
                                           
                                           
                                           
                                           
                                     Requirements
                                           
                                         for
                                           
                            Managed Connectivity Services
                                           
                                         and
                                           
                                 Value-Added Services
                                           


<PAGE>


          DEDICATED INTERNET ACCESS SERVICE SERVICE REQUIREMENTS VERSION 1.1
                                           
1.       Overview


PSI's Dedicated Internet Access services provide full-time dedicated Internet
access via point-to-point 56K and T1 leased lines or SMDS metropolitan area
network T1 and T3 connections.

The PSI Dedicated Internet Access services include:

         o PSINet InterFrame
         o PSINet InterMAN

The PSI Dedicated Internet Access service specifications are included in
Schedule 2.3.

2.       Wholesale Service Branding

PSI is to deliver the Dedicated Internet Access service to IXC and IXC Customers
on a branded basis, such that the service is delivered to the end customer as an
IXC or IXC Reseller branded service. Service branding is to be present in the
following areas:

         o    Sales collateral
         o    Service manuals and other service-related material.
         o    All PSI contact with the end customer, such as during order
              verification, service provisioning, and customer support
         o    Email addresses and web site domain names for customer support,
              service status, service information.
         o    Service usage reports

Where additional investment and resources are required, PSI will state estimated
costs in advance for which IXC or the IXC Reseller is responsible.

3.       Delivery Processes

Documented delivery processes are to be developed by PSI. PSI will work to
integrate internal processes with IXC's service processes, specifically in the
areas of:

         o    Sales support
         o    Order processing
         o    Service provisioning
         o    Customer support
         o    Network operation procedures and escalation
         o    Trouble ticketing and tracking
         o    Billing

PSI must create and maintain delivery process documentation specific to the
items listed above.

4.  Service Implementation

IXC is responsible for:

         o    Submitting accurate and correct service order information to PSI





                             Attachments to Schedule 2.2
                                     Page 2 of 35


<PAGE>


PSI is responsible for:

         o    Via IXC, ordering, installing, and configuring the customer's
              communications circuit
         o    Internet service provisioning and configuration (IP addresses,
              DNS, routing, etc.) for the customer's network o Registration and
              assignment of IP address numbers
         o    Registration of the customer's domain name
         o    Implementation of routing information as required for the
              customer's environment.

PSI's installation technicians are responsible for remotely assisting the
customer's technical liaison in the physical installation of the customer
premise equipment (CPE).

Service implementation details are described below.

4.1.     Site Planning and Preparation Coordination

Site planning coordination will be provided by PSI to the customer's designated
point of contact. This helps customers to prepare for installation of the
Dedicated Internet Access service. Customers need to provide space and power for
the CPE equipment, an attachment to the customer's internal network, and at
least one computer with TCP/IP support.

4.2.     Communications Circuit Ordering

PSI is responsible for ordering (from IXC, on behalf of the customer) and
maintaining the communications circuit necessary for delivery of service. IXC
will either provide the circuit itself or order one from another
telecommunications vendor and at IXC's cost.

4.2.1.   Inside Wiring

PSI arranges for IXC to terminate the circuit in proximity to the planned
location of the premises equipment. Any cost associated with extending the
circuit to this location (inside wiring) is passed on to the customer.

4.3.     Customer Premise Equipment

The customer premises equipment package consists of a TCP/IP router with
appropriate LAN and WAN interfaces, a CSU/DSU corresponding to the connection
type, and associated cables.

4.3.1.   Supported Customer Premise Equipment

PSI will only support CPE that has been tested by PSI and certified for
compatibility with PSI services. PSI will maintain a current WWW list of
certified and supported CPE.

4.3.2.   Customer Premise Equipment Provisioning

Managed services (e.g., InterMAN, InterFrame with RouteWaller) require that the
CPE be owned and operated by PSI. When the customer prefers to own and operate
their own equipment, CPE may be purchased through PSI. When purchased through
PSI, the package of service equipment utilized by each customer is to be
pre-assembled by PSI and subjected to a hardware quality acceptance test by PSI
before delivery to the customer site. Equipment not purchased through PSI is
subject to verification of suitability by PSI. PSI will consider non-certified
routers on a case-by-case basis.


                             Attachments to Schedule 2.2
                                     Page 3 of 35


<PAGE>


Customers providing their own premises equipment must maintain the premises
equipment to current hardware and software revision levels for compatibility
with the PSI service.

4.4.     Customer Premise Equipment Staging and Configuration

To ease installation, equipment is to be either pre-configured by PSI before
delivery to the IXC customer site or PSI assists in remotely configuring after
it is connected to the network.

For customer premise equipment supplied by PSI, PSI is responsible for
pre-configuring the customer premise equipment with its initial configuration
information prior to shipping to the IXC customer site.

When the IXC customer supplies the premise equipment, PSI is responsible for
providing to the customer initial configuration information for the customer
premise equipment sufficient to enable IP connectivity to the customer's
network.

4.5.     Customer Ppremise Equipment Installation

PSI's installation technicians are responsible for remotely assisting the IXC
customer's technical liaison in the installation of the premises equipment. The
customer's technical liaison performs the physical installation of the premises
equipment. On-site CPE installation by a PSI field technician or agent is to be
provided by PSI on an optional basis (InterFrame) unless otherwise specified in
the service specification (InterMAN). Please see attached price sheet.

4.6.     Ipaddress Allocation

*

4.7.     IP Routing Service

4.7.1.   IP Routing for IXC Customers

PSI must perform any IP routing configuration changes to its network routers
necessary to enable Internet routing for IP traffic destined to or received from
the IXC customer's network.

*

4.8.     Domain Name Service (DNS)

PSI is to provide IXC Dedicated Internet Access customers with primary and/or
secondary domain name service as necessary for successful presence on the
Internet.



*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission



                             Attachments to Schedule 2.2
                                     Page 4 of 35


<PAGE>


4.8.1.   Domain Name Registration

On behalf of IXC customers, PSI is to perform registration of the customers'
domains with the InterNIC and/or its successors. PSI is to submit domain name
registrations to the InterNIC using registration and billing information
provided to PSI by IXC or the IXC Reseller as part of the customer order.
InterNIC or its successor(s) will invoice the IXC customer directly for the
domain name registered.

For existing customer domains, PSI is responsible for assisting IXC customers
with the transfer of existing domain name service to the PSI nameservers, using
processes designed to minimize any discontinuity of Domain Name Service for the
customer's domains.

4.8.2.   Domain Name Service Operation

DNS service provided to IXC customers by PSI must be maintained on multiple
nameservers which are physically diverse and connected to the PSI backbone at
different points.

IXC customers may elect to run and administer their own primary and/or secondary
nameservers. For customers running their own primary nameserver, PSI is to offer
secondary nameservice for the customer's domains on at least two PSI
nameservers.

Nameservice for one domain per customer connection is part of the basic service.
Nameservice for additional domains is available as an option. Please see
attached fee schedule.

4.8.3.   DNS Updates

For IXC customer domains for which PSI provides primary nameservice, PSI must
perform updates to the customer domain zone information as reasonably requested
by the customer. Zone update procedures are to be documented by PSI and provided
to IXC. PSI is to provide a web interface as soon as possible that allows IXC
customers to make changes to their domain information interactively.

Turnaround time for updated IXC customer DNS information to be available on the
Internet via Internet accessible PSI nameservers must be no more than 24 hours.

4.9.     Acceptance Testing

PSI is to conduct ping test to the customer's site to ensure that the customer
premise router can successfully communicate over the IXC Dedicated Internet
Access service and service billing by PSI to IXC may be initiated. Additional
tests will be performed thereafter to verify the proper operation of the on-site
equipment package, the local access facility, and the PSI Internet
infrastructure, including IP routing, DNS, Usenet news, and other services.

4.10.    Acceptance Criteria.

PSI implementation of service for IXC Dedicated Internet Access service
customers is considered complete when the following criteria have been met:

4.10.1.  A circuit has been installed and configured to give the customer
the amount of bandwidth contracted for between the customer location and the PSI
Point-of-Presence (POP). If a Frame Relay connection, PVCs have been configured
with appropriate CIR and burst values as contracted for by the customer.

4.10.2.  The Dedicated Internet Access router and associated premises
equipment is installed at the customer site, and IP connectivity between the



                             Attachments to Schedule 2.2
                                     Page 5 of 35


<PAGE>



customer network and the Internet (including routing outside PSI networks)
exists.

PSI must verify IP connectivity through a test which:

         o    sends repeated pings through the Internet to the customer site
              and verifies that the pings were received.
         o    in cases when the premises equipment configuration supports it,
              PSI must verify IP routing through a trace route test.

4.10.3.  IP addresses have been allocated from IXC's address space to the
customer for use on their network.

4.10.4.  Any necessary routing changes have been made in PSI's network
routers so that routes to the customers IP networks and addresses are announced
to the Internet.

4.10.5.  For customers with their own domain, the domain is registered
with the InterNIC and any PSI-supplied primary and secondary DNS servers are
operational for it.

4.10.6.  Any initial customer requested packet-filtering option has been
installed in the customer premise Dedicated Internet Access router.

4.10.7.  The customer has been informed that the Internet service is
available for implementation of Internet application such as, Telnet, FTP,
E-Mail or WWW, and has acknowledged that they plan to configure these
applications within the installation phase or that they do not intend to at this
time. Billing will commence upon a successful ping test and not acceptance of
working Internet application.

4.10.8.  The customer has been informed of the operational status of the
customer's Internet connection and been provided with documentation of (i) the
Internet service configuration, and (ii) the acceptance test results.

4.10.9.  IXC has been informed of the operational status of the customer's
Internet connection and been provided with documentation of (i) the Internet
service configuration, and (ii) the acceptance test results.

4.10.10. The IXC customer has been given an information package designed
for new Dedicated Internet Access customers.

5.  SERVICE OPTIONS

5.1.     Usenet News Service

IXC offers NNTP news feeds and/or NNRP news server access to its Dedicated
Access Internet Service customers. PSI is responsible for working with the IXC
customer to determine whether the size of the customer's Internet access line is
sufficient to meet the customer's network news requirements. PSI is to provide
the IXC customer with Usenet News access via an NNTP news feed from PSI's news
servers to the customer's news server, or alternately by allowing the IXC
customer to directly access PSI's news server with client software using the
NNRP protocol.

Please see fee schedule for pricing.


                             Attachments to Schedule 2.2
                                     Page 6 of 35


<PAGE>

5.1.1.   NNTP News Feed

As a prerequisite to receiving a Usenet News Feed, the IXC customer must install
a news server. PSI is responsible for assisting the IXC customer in determining
the news feed parameters.

Once the server is in place and the service is established, PSI is to maintain
the news feeds for all IXC customers receiving NNTP news feeds.

PSI's news servers are to accept news postings from the customer's news server
and propagate these postings on to other Usenet news servers on the Internet.

IXC customers may request changes to the list of news groups fed from PSI's news
servers, during normal business hours and at a frequency averaging up to one
change request per week. PSI is responsible for implementing the required
changes on the PSI news servers within 24 hours.

Please see fee schedule for pricing.

5.1.2.   NNRP News Access

The IXC Dedicated Access Internet Service customer may chose not to run a news
server on their network and instead request NNRP access to PSI's news servers as
a client. PSI must provide NNRP access to the IXC Dedicated Access Internet
Service customer for up to 25 newsreader clients. PSI's news servers are to
accept Usenet news postings from the customer's NNRP clients and propagate these
postings on to other Usenet news servers on the Internet.

Please see fee schedule for pricing.

5.2.     Network Usage Statistics Reporting

PSI is responsible for providing Network Usage Statistics Reporting to IXC
Dedicated Internet Access service customers. Network Usage Statistics Reports
are to be traffic summary reports that allow customers to track access line
utilization and peak activity periods.
The usage report must be produced on a regular basis (daily, weekly, and
monthly) and is to be provided to the customer and to IXC via email and the Web.

The usage information is to be collected from the customer premises and other
network equipment using SNMP and other measurement tools.

Please see fee schedule for pricing.

5.3.     Emergency Backup Service

In the event of a failure in connectivity between the customer's location and
the PSI Point-of-Presence (POP) due to POP equipment failure or failure of the
circuit connecting the customer location to the PSI POP, PSI must provide to the
customer a PSI dial-up packet access point within four hours after disruption of
service (except as provided in Section 15.2 of the Marketing Agreement). This
service option must be requested and set up in advance of an event.

6.       Network Operations Support

PSI's is responsible for network operations support for network services
provided to IXC Dedicated Internet Access service as described in this section.



                             Attachments to Schedule 2.2
                                     Page 7 of 35


<PAGE>


6.1.     PSI Infrastructure Operations Support

PSI must monitor the PSI network 24 hours a day, 365 days a year. PSI is to
provide proactive operations support and troubleshooting of all network and
service infrastructure components providing service to IXC customers, including
IXC-provided circuits (such as circuits from the PSI POP to the customer
premise).

PSI will use SNMP and other software tools to monitor the network. This software
must be supplemented with additional tools to monitor non- SNMP equipment,
domain name servers, NNTP news servers and feeds, and other network services.

All network services (routing, DNS, email servers, Usenet news, NTP, security,
etc.) must be monitored for availability and performance. The monitoring
software must report the status of the network to a display which is monitored
throughout the day.

Service outages are to be automatically detected. Troubleshooting procedures and
customer notification will occur within * of an outage.

IXC and PSI will work jointly on resolution procedures.

6.1.1    Network Reports

PSI is to provide IXC with network status logs on a regular basis to provide IXC
with the ability to evaluate staff responsiveness and network availability. All
changes in the PSI network status must be logged.

PSI is to provide IXC with regular reports on the status of the PSI network.
Report information is to be defined by IXC, and will include but not be limited
to:

*

6.2      Customer Connectivity Support

PSI must monitor IXC customers' connectivity to ensure continuous Internet
connectivity is provided to the customer network. IXC Dedicated Internet Access
customer connectivity outages must be detected by PSI and acted upon by PSI
within * .

PSI must follow up on loss of connectivity using documented trouble resolution
procedures as jointly developed by IXC and PSI.

6.3      Communications Link Maintenance

PSI is responsible for monitoring and maintaining the communications link
between the Customer and PSI. This includes problem diagnosis and any necessary
vendor interaction for dispatch and repair. PSI's staff is to escalate
communications circuit problems using documented trouble resolution procedures
as jointly developed by IXC and PSI.



*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission



                             Attachments to Schedule 2.2
                                     Page 8 of 35


<PAGE>


6.4      Customer Premises Equipment Maintenance for Interman

If the customer has contracted for customer premise Internet router and CSU/DSU
maintenance, PSI is responsible for maintaining the customer premise equipment.
PSI must diagnose failures, usually with the assistance of the technical liaison
designated by the customer at the site, and shall determine whether equipment
replacement is required.

6.4.1    On-Site CPE Repair / Replacement for Interman

PSI is responsible for performing the actual equipment replacement with
telephone assistance (as necessary).

Response time for performing customer premise equipment replacement must meet
the schedule described within the PSI customer maintenance contract.

7.       Technical Services and Customer Support

IXC is to provide first level customer support for all IXC Dedicated Access
Internet customers.

7.1      Standard Service Customer Support Helpline

PSI must staff an IXC Customer Support helpline with trained and qualified PSI
customer support representatives from 8am-8pm EST/EDT Monday through Friday.
Customer support staff must be trained in supporting Dedicated Internet Access
service customers. Additionally, an outage support hotline (Netwatch) shall be
staffed 24 hours per day, 7 days per week, 365 days per year for network access
emergency reporting to IXC and its customers.

7.1.1    Customer Support Helpline Response Time

Calls to the PSI-provided IXC customer support hotline must be answered within *
rings., 8am-8pm EST/EDT Monday through Friday. For similar response times
off-hours, optional support may be available (at additional cost).

7.2      Customer Support Email Mailbox See Section 7.4.

7.3      Fault Isolation and Problem Resolution

PSI is to perform fault isolation for problems related to the PSI provided
service. Fault isolation may involve coordination among network operators and
technicians, staff at the affected site, telecommunications carriers, and other
vendors. Depending on the specific technologies used, the process may involve
testing equipment, reconfiguring routers, or diagnosing communications link
problems. PSI is responsible for diagnosing service problems and tracking repair
progress. PSI is to use documented trouble resolution procedures as jointly
developed and agreed upon by PSI and IXC.

7.4      Trouble Ticketing System

PSI must use a Trouble Ticketing System to track problems from initial report
through satisfactory resolution. As PSI staff works to resolve problems, the
current status must be maintained in the Trouble Ticketing System.

*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission

                             Attachments to Schedule 2.2
                                     Page 9 of 35


<PAGE>



7.4.1    IXC Customer Access to Trouble Ticketing System

IXC customers will be provided access by PSI to any trouble tickets related to
their service, as soon as the technology is available to PSI. If additional
programming is required to deliver this functionality, it will be costed out and
provided to IXC in advance. The trouble ticketing system should provide
designated customer contacts with automatic access to the trouble tickets via
web interfaces.

PSI Backbone status information should also be made available to IXC Customer
contacts requesting same via the same interfaces.

7.4.2    IXC Reseller Access to Trouble Ticketing System

IXC resellers will be provided access by PSI to any trouble tickets related to
the service, as soon as the technology is available to PSI. If additional
programming is required to deliver this functionality, it will be costed out and
provided to IXC in advance. The trouble ticketing system should provide
designated IXC Reseller contacts with automatic access to the trouble tickets
via web interfaces.

PSI Backbone status information should also be made available to IXC Reseller
contacts requesting same via the same interfaces.

7.4.3    IXC Access to Trouble Ticketing System

IXC will be provided access by PSI to any trouble tickets related to the service
provided to IXC, IXC Resellers and their end customers, as soon as the
technology is available to PSI. If additional programming is required to deliver
this functionality, it will be costed out and provided to IXC in advance. The
trouble ticketing system should provide designated IXC contacts with automatic
access to the trouble tickets via web interfaces.

PSI Backbone status information should also be made available to IXC Reseller
contacts requesting same via the same interfaces.

PSI is to work with IXC to integrate trouble ticketing systems and processes as
much as reasonably possible.

7.5      PROBLEM NOTIFICATION

7.5.1    IXC Customer Problem Notification

The PSI operations staff must inform the technical contact of IXC Dedicated
Internet Access service customers of any outages affecting their service. The
operations staff must also keep Dedicated Internet Access customers informed of
any widespread outages on connecting networks.


7.5.2    IXC Reseller Problem Notification

The PSI operations staff must inform the technical contact of IXC Resellers of
any outages affecting service to their end customers. The operations staff must
also keep IXC Resellers informed of any widespread outages on connecting
networks.



                             Attachments to Schedule 2.2
                                    Page 10 of 35


<PAGE>


7.5.3    IXC Problem Notification

The PSI operations staff must inform the IXC technical contacts of any outages
affecting service to IXC, IXC Resellers, or IXC end customers. The operations
staff must also keep IXC informed of any widespread outages on connecting
networks.

7.6      Software and Configuration Support for Interman

PSI is responsible for coordinating software updates and configuration changes
on the customer premise router and CSU/DSU equipment of IXC customers as
required to provide Internet service. Notice of software changes is to be made
to the customer technical contacts, and every effort must be made to perform
maintenance during off-hours.

7.7      Escalation Procedures

Documented customer support processes are to be developed jointly by PSI and
IXC. Specific process documentation is required for the following:

         o    customer support procedures
         o    trouble escalation procedures
         o    trouble ticketing, tracking, and resolution

PSI must provide information to the IXC customer describing customer support,
problem resolution, and trouble escalation procedures, customer contact
information, and trouble reporting methods.

8.       Security Procedures

The following services provide security procedures: RouteWaller (InterFrame),
SecureEnterprise (InterFrame and InterMAN), and PSI IntraNet.

Additionally, PSI's Net Abuse policy shall apply to all IXC customers.


                             Attachments to Schedule 2.2
                                    Page 11 of 35


<PAGE>


        SWITCHED LAN INTERNET ACCESS SERVICE SERVICE REQUIREMENTS VERSION 1.1
                                           
1.  Overview

PSI's Switched LAN Internet Access services provide on-demand switched
connectivity to the Internet via an analog modem (9.6 - 33.6 Kbps) or an ISDN
NT1 (64 - 128 Kbps) and a customer premise router. Connectivity is provided to
the customer's LAN rather than a single system, via the customer premise router.
Connections are established between the customer premise and an PSI
Point-of-Presence (POP) using the Point-to-Point Protocol (PPP).

The PSI Switched LAN Internet Access services include:

         o    PSINet LAN-On-Demand (LAN-Dial and LAN-ISDN)

The PSI Switched LAN Internet Access service specification is included in
Schedule 2.3.

2.  Wholesale Service Branding

PSI is to deliver the Switched LAN Internet Access service to IXC and IXC
Customers on a branded basis, such that the service is delivered to the end
customer as an IXC or IXC Reseller branded service. Service branding is to be
present in the following areas:

         o    Sales collateral
         o    Service manuals and other service-related material.
         o    All PSI contact with the end customer, such as during order
              verification, service provisioning, and customer support
         o    Email addresses and web site domain names for customer support,
              service status, service information. o Service usage reports

Where additional investment and resources are required, PSI will state estimated
costs in advance for which IXC or the IXC reseller is responsible.

3.  Delivery Processes

Documented delivery processes are to be developed by PSI. PSI must work to
integrate internal processes with IXC's service processes, specifically in the
areas of:

         o    sales support
         o    order processing
         o    service provisioning
         o    customer support
         o    network operation procedures and escalation
         o    trouble ticketing and tracking
         o    billing

PSI must create and maintain delivery process documentation specific to the
items listed above.

4.  Service Implementation

PSI is responsible for providing and maintaining dial-up Points-of-Presence
(POPs) with analog modem and ISDN access capability that allow local switched
access from the customer location. PSI will provide modem ports via dial-up
access numbers for IXC Switched LAN Internet Access Service customers.


                             Attachments to Schedule 2.2
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<PAGE>

IXC is responsible for:

         o    Submitting accurate and correct service order information to PSI

PSI is responsible for:

         o    Internet service provisioning and configuration ( * , DNS,
              routing, etc.) for the customer's network

*

         o    Registration of the customer's domain name

         o    Implementation of routing information as required for the
              customer's environment.

PSI is responsible for remotely assisting the customer's technical liaison in
the physical installation of the customer premise equipment (CPE).

Implementation support details are described below.

4.1.          Site Planning and Preparation Coordination

Site planning coordination must be provided by PSI to the customer's designated
point of contact. This helps customers to prepare for installation of the
Switched LAN Internet Access service. Customers need to provide space and power
for the CPE equipment, an attachment to the customer's internal network, and at
least one computer with TCP/IP support.

4.2.          Communications Circuit Ordering

The customer is responsible for ordering and having installed an analog phone
line or an ISDN line to support the service at its sole cost.

The customer should arrange for the circuit to terminate in proximity to the
planned location of the premises equipment. Any cost associated with extending
the circuit to the planned location of the premises equipment (inside wiring) is
the responsibility of customer.

4.3.          Customer Premise Equipment

The customer premise equipment package consists of a TCP/IP router with
appropriate LAN and WAN interfaces, an analog modem or ISDN NT1 device, and
associated cables.

4.3.1.        Supported Customer Premise Equipment

PSI will only support CPE that has been tested by PSI and certified for
compatibility with PSI services. PSI will maintain a current WWW list of
certified and supported CPE.



*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission


                             Attachments to Schedule 2.2
                                    Page 13 of 36


<PAGE>


4.3.2.        Customer Premise Equipment Provisioning

The customer premise equipment may be purchased through PSI. When purchased
through PSI, the package of service equipment utilized by each customer is to be
pre-assembled by PSI and subjected to a hardware quality acceptance test by PSI
before delivery to the customer site. Equipment not purchased through PSI is
subject to verification of suitability by PSI.

Customers providing their own premises equipment must maintain the premises
equipment to current hardware and software revision levels for compatibility
with the PSI service.

4.4.               Equipment Staging and Configuration

For customer premise equipment supplied by PSI, PSI is responsible for
pre-configuring the customer premise equipment with its initial configuration
information prior to shipping to the IXC customer site.

When the IXC customer supplies the premise equipment, PSI is responsible for
providing to the customer initial configuration information for the customer
premise equipment sufficient to enable IP connectivity to the customer's
network.

4.5.          Customer Premise Equipment Installation - Not Applicable

4.6.          Customer Premise Equipment

PSI is responsible for remotely assisting the IXC customer's technical liaison
in the installation of the premises equipment. The customer's technical liaison
performs the physical installation of the premises equipment.

*

PSI is responsible for maintaining a record of all IP address allocations for
each IXC customer. PSI is to provide this information to IXC on a regular basis.

4.8.          IP Routing Service

PSI must perform any IP routing configuration changes to its network routers
necessary to enable Internet routing for IP traffic destined to or received from
the IXC customer's network.

4.8.1.        Routing Service for Multiple Connected Networks

BGP routing is not available to IXC Switched LAN Internet Access customers.

4.9.           Domain Name Service (DNS)

PSI is to provide IXC Switched LAN Internet Access customers with primary and/or
secondary domain name service as necessary for successful presence on the
Internet.

4.9.1.        Domain Name Registration

On behalf of IXC customers, PSI is to perform registration of the customers'
domains with the InterNIC and/or its successors. PSI is to submit domain name
registrations to the InterNIC using registration and billing information
provided to PSI by IXC or the IXC Reseller as part of the customer order.

*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission


                             Attachments to Schedule 2.2
                                    Page 14 of 36


<PAGE>

For existing customer domains, PSI is responsible for assisting IXC customers
with the transfer of existing domain name service to the PSI nameservers, using
processes designed to minimize any discontinuity of Domain Name Service for the
customer's domains. InterNIC or its successor(s) will invoice the IXC customer
directly for the domain name registered.

For IXC customer domains for which PSI is to operate the primary nameserver, PSI
is to register with the InterNIC only the secondary nameservers. This is to
ensure that DNS lookups are not affected during rebooting of the primary
nameserver.

4.9.2.        Domain Name Service Operation.

DNS service provided to IXC customers by PSI must be maintained on multiple
nameservers which are physically diverse and connected to the PSI backbone at
different points.

IXC customers may elect to run and administer their own primary and/or secondary
nameservers. For customers running their own primary nameserver, PSI is to offer
secondary nameservice for the customer's domains on at least two PSI
nameservers. Nameservice for one domain per customer connection is part of the
basic service. Nameservice for additional domains is available as an option.
Please see attached fee schedule.

4.9.3.        DNS Updates

For IXC customer domains for which PSI provides primary nameservice, PSI must
perform updates to the customer domain zone information as reasonably requested
by the customer. Zone update procedures are to be documented by PSI and provided
to IXC. PSI is to provide a web interface as soon as possible that allows IXC
customers to make changes to their domain information interactively.

Turnaround time for updated IXC customer DNS information to be available on the
Internet via Internet accessible PSI nameservers must be no more than 24 hours.

4.10.    Acceptance Testing

PSI is to conduct tests to the customer's site to ensure that the customer
premise router can successfully communicate over the IXC Switched LAN Internet
Access service. Service billing will commence seven business days after account
creation by PSI. Additional tests will be performed thereafter to verify the
proper operation of the on-site equipment package, the local access facility,
and the PSI Internet infrastructure, including IP routing, DNS, Usenet news, and
other services.

4.11.    Acceptance Criteria

PSI implementation of service for IXC Switched LAN Internet Access service
customers is considered complete when the following criteria have been met:

4.11.1.       A dial-in port matching the customer's contract port type and
speed is available to the customer at the local IXC Point-of-Presence (POP).

4.11.2.       The customer is able to successfully establish a PPP connection

4.11.3.       The Switched LAN Internet Access router and associated premises
equipment is installed at the customer site, and IP connectivity between the
customer network and the Internet (including routing outside PSI networks)
exists. PSI must verify IP connectivity through a test which:


                             Attachments to Schedule 2.2
                                    Page 15 of 36


<PAGE>


(a)           sends repeated pings through the Internet to the customer site
and verifies that the pings were received.

(b)           in cases when the premises equipment configuration supports it,
PSI must verify IP routing through a traceroute test.

*

(d)           Any necessary routing changes have been made in PSI's network
routers so that routes to the customers IP networks and addresses are announced
to the Internet.

(e)           For customers with their own domain, the domain is registered
with the InterNIC and any PSI-supplied primary and secondary DNS servers are
operational for it.

(f)           Any initial customer requested packet-filtering has been
installed in the customer premise Switched LAN Internet Access router.

(g)           The customer has been informed that the Internet service is
available from implementation of Internet application such as, Telnet, FTP,
E-Mail or WWW, and has acknowledged that they plan to configure these
applications within the installation phase or that they do not intend to at this
time. Billing will commence upon a successful ping test and not acceptance of
working Internet application.

(h)           The customer has been informed of the operational status of the
customer's Internet connection and been provided with documentation of (i) the
Internet service configuration, and (ii) the acceptance test results.

(i)           IXC has been informed of the operational status of the customer's
Internet connection and been provided with documentation of (i) the Internet
service configuration, and (ii) the acceptance test results.

(j)           The IXC customer has been given an information package designed
for new Switched LAN Internet Access customers.

5.  Service Options

5.1.          Usenet News Service

5.2.          Usenet News

IXC offers NNRP news server access to its Switched LAN Internet Access Service
customers. PSI is responsible for working with the IXC customer to determine
whether the size of the customer's Internet access line is sufficient to meet
the customer's network news requirements. PSI is to provide the IXC customer
with Usenet News access by allowing the IXC customer to directly access PSI's
news server with client software using the NNRP protocol.

Please see fee schedule for pricing.

5.2.1.        NNTP News Feed

NNTP news feeds are not available to Switched LAN Internet Access service
customers.


*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission


                             Attachments to Schedule 2.2
                                    Page 16 of 36


<PAGE>

5.2.2.        NNRP News Access

NNRP access is be provided by PSI to IXC's Switched LAN Internet Access service
customers. PSI must provide NNRP access to the IXC Dedicated Access Internet
Service customer for up to 25 newsreader clients. PSI's news servers are to
accept Usenet news postings from the customer's NNRP clients and propagate these
postings on to other Usenet news servers on the Internet

Please see fee schedule for pricing.

5.2      Network Usage Statistics Reporting

PSI is responsible for providing Network Usage Statistics Reporting to IXC
Switched LAN Internet Access service customers. Network Usage Statistics Reports
are to be traffic summary reports that allow customers to track access line
utilization and peak activity periods.

The usage report must be produced on a regular basis (daily, weekly, and
monthly) and is to be provided to the customer and to IXC via email and the Web.

The usage information is to be collected from the customer premises and other
network equipment using SNMP and other measurement tools.

Please see fee schedule for pricing.

5.3.          Emergency Backup Service

In the event of a failure in connectivity between the customer's location and
the PSI Point-of-Presence (POP) due to POP equipment failure ) then the customer
may use a different dialup POP.

6.            Network Operations Support

PSI is responsible for network operations support for network services provided
to IXC Switched LAN Internet Access service as described in this section.

6.1.          PSI Infrastructure Operations Support

PSI must monitor the PSI network 24 hours a day, 365 days a year. PSI is to
provide proactive operations support and troubleshooting of all network and
service infrastructure components providing service to IXC customers, including
IXC-provided circuits (such as circuits from the PSI POP to the customer
premise).

PSI is to use SNMP and other software to monitor the network. This software must
be supplemented with additional tools to monitor non-SNMP equipment, domain name
servers, NNTP news servers and feeds, and other network services.

All network services (routing, DNS, email servers, Usenet news, NTP, security,
etc.) must be monitored for availability and performance. The monitoring
software must report the status of the network to a display which is monitored
throughout the day.

Service outages are to be automatically detected within *
and acted upon using trouble resolution procedures agreed upon by PSI and IXC.

*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission


                             Attachments to Schedule 2.2
                                    Page 17 of 36


<PAGE>

6.1.1.        Network Reports

PSI is to provide IXC with network status logs on a regular basis to provide IXC
with the ability to evaluate staff responsiveness and network availability. All
changes in the PSI network status must be logged.

PSI is to provide IXC with regular reports on the status of the PSI network.
Report information is to be defined by IXC, and will include but not be limited
to:

*
 Please see example attached.

6.2.     Customer Connectivity Support

PSI must monitor PSI's connectivity to ensure continuous Internet connectivity
is available to the customer network. Outages affecting IXC Switched LAN
Internet Access customer connectivity outages must be detected by PSI and acted
upon by PSI within * .

PSI staff must follow up on loss of connectivity using documented trouble
resolution procedures as jointly developed by IXC and PSI.

6.3.          Communications Link Maintenance

PSI is responsible for monitoring the backbone and POP equipment. This includes
problem diagnosis and any necessary vendor interaction for dispatch and repair.
PSI's staff is to escalate communications circuit problems using documented
trouble resolution procedures as jointly developed by IXC and PSI.

7.             Technical Services and Customer Support

IXC is to provide first level customer support for all IXC Switched LAN Internet
Access customers.

7.1.           24-Hour Customer Support Helpline

PSI must staff an IXC Customer Support helpline with trained and qualified PSI
customer support representatives from 8am-8pm EST/EDT Monday through Friday.
Customer support staff must be trained in supporting Dedicated Internet Access
service customers. Additionally, an outage support hotline (Netwatch) shall be
staffed 24 hours per day, 7 days per week, 365 days per year for network access
emergency reporting to IXC and its customers.

7.1.1.        Customer Support Helpline Response Time

Calls to the PSI-provided IXC customer support hotline must be answered within *
rings., 8am-8pm EST/EDT Monday through Friday. For similar response times
off-hours, optional support may be available (at additional cost).

7.2.          Customer Support Email Mailbox

See section 7.4.


*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission

                             Attachments to Schedule 2.2
                                    Page 18 of 36


<PAGE>






                             Attachments to Schedule 2.2
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<PAGE>

7.3.          Fault Isolation and Problem Resolution

PSI is to perform fault isolation for problems related to the PSI provided
service. Fault isolation may involve coordination among network operators and
technicians, staff at the affected site, telecommunications carriers, and other
vendors. Depending on the specific technologies used, the process may involve
testing equipment, reconfiguring routers, or diagnosing communications link
problems. The PSI operations staff is responsible for diagnosing service
problems and tracking repair progress. PSI is to use documented trouble
resolution procedures as jointly developed and agreed upon by PSI and IXC.

7.4.          Trouble Ticketing System

PSI must use a Trouble Ticketing System to track problems from initial report
through satisfactory resolution. As PSI staff works to resolve problems, the
current status must be maintained in the Trouble Ticketing System.

7.4.1.        IXC Customer Access to Trouble Ticketing System

IXC customers must be provided access by PSI to any trouble tickets related to
their service, as soon as the technology is available to PSI. If additional
programming is required to deliver this functionality, it will be costed out and
provided to IXC in advance. The trouble ticketing system should provide
designated customer contacts with automatic access to the trouble tickets via
web interfaces.

PSI Backbone status information must also be made available to IXC customer
contacts requesting same via the same interfaces.

7.4.2.        IXC Reseller Access to Trouble Ticketing System

IXC resellers must be provided access by PSI to any trouble tickets related to
the service provide to their end customers, as soon as the technology is
available to PSI. If additional programming is required to deliver this
functionality, it will be costed out and provided to IXC in advance.. The
trouble ticketing system should provide designated IXC Reseller contacts with
automatic access to the trouble tickets via web interfaces.

PSI Backbone status information must also be made available to IXC Reseller
contacts requesting same via the same interfaces.

7.4.3.        IXC Access to Trouble Ticketing System

IXC must be provided access by PSI to any trouble tickets related to the service
provide to IXC, IXC Resellers and their end customers, as soon as the technology
is available to PSI. If additional programming is required to deliver this
functionality, it will be costed out and provided to IXC in advance. The trouble
ticketing system should provide designated IXC contacts with automatic access to
the trouble tickets via web interfaces.

PSI Backbone status information must also be made available to IXC Reseller
contacts requesting same via the same interfaces.

PSI is to work with IXC to integrate trouble ticketing systems and processes as
much as reasonably possible.




                             Attachments to Schedule 2.2
                                    Page 20 of 36


<PAGE>

7.5.          Problem Notification

7.5.1.        IXC Customer Problem Notification

PSI must inform the technical contact of IXC Switched LAN Internet Access
service customers of any outages affecting their service. The operations staff
must also keep Switched LAN Internet Access customers informed of any widespread
outages on connecting networks.

7.5.2.        IXC Reseller Problem Notification

The PSI operations staff must inform the technical contact of IXC Resellers of
any outages affecting service to their end customers. The operations staff must
also keep IXC Resellers informed of any widespread outages on connecting
networks.

7.5.3.        IXC Problem Notification

The PSI operations staff must inform the IXC technical contacts of any outages
affecting service to IXC, IXC Resellers, or IXC end customers. The operations
staff must also keep IXC informed of any widespread outages on connecting
networks.

7.6.          Software and Configuration Support

PSI is responsible for coordinating software updates and configuration changes
on the customer premise router and CSU/DSU equipment of IXC customers as
required to provide Internet service. Notice of software changes is to be made
to the customer technical contacts, and every effort must be made to perform
maintenance during off-hours.

7.7.          Escalation Procedures

Documented customer support processes are to be developed by PSI. Specific
process documentation is required for the following:

         o    customer support procedures
         o    trouble escalation procedures
         o    trouble ticketing, tracking, and resolution

PSI must provide information to the IXC customer describing customer support,
problem resolution, and trouble escalation procedures, customer contact
information, and trouble reporting methods.

8.            Security Procedures

The following services provide security procedures: RouteWaller (InterFrame),
SecureEnterprise (InterFrame and InterMAN), and PSI IntraNet.

Additionally, PSI's Net Abuse policy shall apply to all IXC customers.


                             Attachments to Schedule 2.2
                                    Page 21 of 36


<PAGE>

            MANAGED INTRANET WAN SERVICE SERVICE REQUIREMENTS VERSION 1.1
                                           
1.       Overview

PSI's Managed Intranet WAN services provide private IP networking with mediated
Internet access for a single organizations with multiple site. Private internal
IP traffic is logically isolated from the public Internet through integration of
Frame Relay PVCs and managed private routing. Exchange traffic between the
customer's private intranet and the public Internet is mediated through a
centrally specified security policy which is implemented globally at all
intranet sites. External traffic never intermingles with internal traffic. The
service is a fully managed turnkey solution that includes all necessary CPE
required to deliver the service.

The PSI Managed Intranet services include:

o PSI IntraNet

The PSI Managed Intranet service specification is included in Schedule 2.2.

2.       Wholesale Service Branding

PSI is to deliver the Managed Intranet WAN service to IXC and IXC Customers on a
branded basis, such that the service is delivered to the end customer as an IXC
or IXC Reseller branded service. Service branding is to be present in the
following areas:

         o    Sales collateral
         o    Service manuals and other service-related material
         o    All PSI contact with the end customer, such as during order
              verification, service provisioning, and customer support
         o    Email addresses and web site domain names for customer support,
              service status, service information
         o    Service usage reports

Where additional investment and resources are required, PSI will state estimated
costs in advance for which IXC or the IXC Reseller is responsible.

3.       Delivery Processes

Documented delivery processes are to be developed by PSI. PSI will work to
integrate internal processes with IXC's service processes, specifically in the
areas of:

         o    Sales support
         o    Order processing
         o    Service provisioning 
         o    Customer support
         o    Network operation procedures and escalation
         o    Trouble ticketing and tracking
         o    Billing

PSI must create and maintain delivery process documentation specific to the
items listed above.



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<PAGE>

4.       Service Implementation

PSI's Managed Intranet WAN Service is to provide to IXC and IXC resellers:

         o    Full service provisioning, through IXC, of all communications
              circuits and hardware, including ordering, installation, and
              configuration
         o    Provisioning and maintenance of customer premise equipment -
              CSU/DSUs and IP routers
         o    Internet service provisioning and configuration ( * where
              appropriate, DNS, routing, etc) for the customer's  network
         o    Registration of customer's domain name
         o    Configuration and management of the Intranet WAN CPE routers
         o    24 x 7 proactive network monitoring, fault isolation, and
              management
         o    Single point of contact for trouble reporting and problem
              resolution
         o    Security policy planning and management services for Internet
              access control

PSI's installation technicians are responsible for remotely assisting the
customer's technical liaison in the physical installation of the customer
premise equipment (CPE).

Service implementation details are described below.

4.1.     Site Planning and Preparation Coordination

Site planning coordination is to be provided by PSI to the customer's designated
point of contact. This helps customers to prepare for installation of the
Intranet WAN service. Customers need to provide space and power for the CPE
equipment, an attachment to the customer's internal network, and at least one
computer with TCP/IP support.

4.2.     Communications Circuit Ordering

PSI is responsible for ordering (from IXC, on behalf of the customer) and
maintaining the communications circuits necessary for delivery of service. IXC
will either provide the circuits itself or order them from another
telecommunications vendor at IXC's expense.

4.2.1    Inside Wiring

PSI will coordinate with the customer on inside wiring. The customer should
arrange for the circuit to terminate in proximity to the planned location of the
premises equipment. Any cost associated with extending the circuit to the
planned location of the premises equipment (inside wiring) is the responsibility
of customer.

4.3.     24 X 7 Proactive Network Monitoring, Fault Isolation, and Management

PSI is to provide 24 x 7 monitoring of the Intranet WAN service. Any detected
faults are acted upon immediately, isolated to their cause, and proactively
managed through resolution.



*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission


                             Attachments to Schedule 2.2
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<PAGE>

4.4.     Single Point of Contact

PSI is to provide the IXC customer with a single point of contact for trouble
reporting and resolution for any problems related to the Intranet WAN service.
PSI is responsible for interacting with all communications circuit and hardware
equipment vendors as needed to maintain the Intranet WAN.

4.5.     Network Usage Statistics Reporting

PSI is responsible for producing Network Usage Statistics Reports as part of the
Managed Intranet WAN service. Reports are to include a traffic summary that
allows customers to track WAN line utilization and peak activity periods. The
usage report is to be produced on a regular basis (daily, weekly, and monthly)
and is to be provided to the customer via email and/or the Web. The usage
information is to be collected from the customer premises equipment using SNMP
tools, among other methods.

4.6.     Customer Premise Equipment

The customer premises equipment package consists of a TCP/IP router with
appropriate LAN and WAN interfaces, a CSU/DSU corresponding to the connection
type, and associated cables.

PSI provides all necessary CPE required for the Managed Intranet WAN service.

4.6.1.   Customer Premise Equipment Staging and Configuration

PSI is responsible for pre-configuring the CPE before delivery to the customer
sites and remotely configuring the CPE after it is connected to the network. PSI
remotely assists the customer's technical liaison in the installation of the
premises equipment at each Intranet WAN site. The customer's technical liaison
performs the physical installation of the premises equipment. On-site CPE
installation by an PSI field technician or agent is to be made available by PSI
to the IXC Customer on an optional basis.

4.6.2.   CPE Router Management

As a part of the Managed Intranet WAN service, PSI is responsible for managing
the CPE routers at each site on the Intranet WAN on an ongoing basis. Management
is to include:

         o    Router software upgrades
         o    Router access control list changes as requested by IXC or the IXC
              customer
         o    Router configuration changes as new sites are added to the
              Intranet WAN
         o    24 x 7 monitoring of the Intranet WAN for inter-site connectivity
         o    24 x 7 monitoring of the Intranet WAN routers for correct
              operation 
         o    24 x 7 monitoring of Intranet WAN line utilization
         o    Generation of usage statistics reports on a daily, weekly, and
              monthly basis

4.7.     Acceptance Testing

PSI is to conduct ping test to the customer's site to ensure that the customer
premise router can successfully communicate over the IXC Managed Intranet WAN
service and service billing by PSI to IXC may be initiated. Additional tests


                             Attachments to Schedule 2.2
                                    Page 24 of 36


<PAGE>


will be performed thereafter to verify the proper operation of the on-site
equipment package, the local access facility, and the PSI infrastructure.

4.8.     Acceptance Criteria

PSI implementation of service for IXC Managed Intranet WAN service customers is
considered complete when the following criteria have been met:

4.8.1    Circuits and PVCs have been installed at each site and configured
to give the customer the amount of bandwidth contracted for between the customer
location and the PSI Point-of-Presence (POP).

4.8.2    The Managed Intranet WAN router and associated premises equipment
is installed at the customer site, and IP connectivity exists between the
customer networks at each site and the Internet (including routing outside PSI
networks). PSI must verify IP connectivity through a test which:

         (i) sends repeated pings through the Internet to the customer site 
and verifies that the pings were received.

         (ii) in cases when the premises equipment configuration supports it, 
PSI must verify IP routing through a traceroute test.

*

         (iv) Any necessary routing changes have been made in PSI's network 
routers so that routes to the customers IP networks and addresses are 
announced to the Internet.

         (v) For customers with their own domain, the domain is registered 
with the InterNIC and any PSI-supplied primary and secondary DNS servers are 
operational for it.

         (vi) Any initial customer requested packet-filtering option has been 
installed in the customer premise Managed Intranet WAN router.

         (vii) The customer has been informed that the Internet service is 
available from implementation of Internet application such as, Telnet, FTP, 
E-Mail or WWW, and has acknowledged that they plan to configure these 
applications within the installation phase or that they do not intend to at 
this time. Billing will commence upon a successful ping test and not 
acceptance of working Internet application.

         (viii) The customer has been informed of the operational status of 
the customer's Intranet WAN connection and been provided with documentation 
of (i) the Intranet WAN service configuration, and (ii) the acceptance test 
results.

         (ix) IXC has been informed of the operational status of the 
customer's Intranet WAN connection and been provided with documentation of 
(i) the Intranet WAN service configuration, and (ii) the acceptance test 
results.

         (x) The IXC customer has been given an information package designed 
for new Managed Intranet WAN customers.

5.       Service Options

There are currently no service options available with the Managed Intranet WAN
service.

*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission


                             Attachments to Schedule 2.2
                                    Page 25 of 36


<PAGE>

6.       Network Operations Support

PSI is responsible for network operations support for network services provided
to IXC Managed Intranet WAN service as described in this section.

6.1.     PSI Infrastructure Operations Support

PSI must monitor the PSI network 24 hours a day, 365 days a year. PSI is to
provide proactive operations support and troubleshooting of all network and
service infrastructure components providing service to IXC customers, including
IXC-provided circuits (such as circuits from the PSI POP to the customer
premise).

PSI will use SNMP and other software tools to monitor the network. This software
must be supplemented with additional tools to monitor non- SNMP equipment,
domain name servers, NNTP news servers and feeds, and other network services.

All network services (routing, DNS, email servers, NTP, security, etc.) must be
monitored for availability and performance. The monitoring software must report
the status of the network to a display which is monitored throughout the day.

Service outages are to be automatically detected. Troubleshooting procedures and
customer notification will occur within * of an outage.

IXC and PSI will work jointly on resolution procedures.

6.1.1.   Network Reports.

PSI is to provide IXC with network status logs on a regular basis to provide IXC
with the ability to evaluate staff responsiveness and network availability. All
changes in the PSI network status must be logged.

PSI is to provide IXC with regular reports on the status of the PSI network.
Report information is to be defined by IXC, and will include but not be limited
to:

*

Please see example attached.

6.2.     Customer Connectivity Support

PSI must monitor IXC Intranet WAN customers' connectivity to ensure continuous
IP connectivity among the Intranet WAN sites. IXC customer's Intranet WAN
connectivity outages must be detected by PSI and acted upon by PSI within * .

PSI must follow up on loss of connectivity using documented trouble resolution
procedures as jointly developed by IXC and PSI.




*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission


                             Attachments to Schedule 2.2
                                    Page 26 of 36


<PAGE>

6.3.     Communications Lik Maintenance

PSI is responsible for monitoring and maintaining the communications link
between the customer and PSI. This includes problem diagnosis and any necessary
vendor interaction for dispatch and repair. PSI's staff is to escalate
communications circuit problems using documented trouble resolution procedures
as jointly developed by IXC and PSI.

6.4.     Customer Premises Equipment  Maintenance for Interman

If the customer has contracted for customer premise Internet router and CSU/DSU
maintenance, PSI is responsible for maintaining the customer premise equipment.
PSI must diagnose failures, usually with the assistance of the technical liaison
designated by the customer at the site, and shall determine whether equipment
replacement is required.

6.4.1.   On-site CPE Repair / Replacement for InterMAN

PSI is responsible for performing the actual equipment replacement with
telephone assistance (as necessary).

Response time for performing customer premise equipment replacement must meet
the schedule described within the PSI customer maintenance contract.

7.       Technical Sservices and Ccustomer Support

IXC is to provide first level customer support for all IXC Managed Intranet WAN
customers.

7.1.     Standard Service Customer Support Helpline

PSI must staff an IXC Customer Support line with trained and qualified PSI
customer support representatives from 8am-8pm EST/EDT Monday through Friday.
Customer support staff must be trained in supporting Managed Intranet WAN
service customers. Additionally, an outage support hotline (Netwatch) shall be
staffed 24 hours per day, 7 days per week, 365 days per year for network access
emergency reporting to IXC and its customers.

7.1.1.   Customer Support Helpline Response Time

Calls to the PSI-provided IXC customer support hotline must be answered within
seven rings., 8am-8pm EST/EDT Monday through Friday. For similar response times
off-hours, optional support may be available (at additional cost).

7.2.     Customer Support Email Mailbox

         See section 7.4

7.3.     Fault Isolation and Problem Resolution

PSI is to perform fault isolation for problems related to the PSI provided
service. Fault isolation may involve coordination among network operators and
technicians, staff at the affected site, telecommunications carriers, and other
vendors. Depending on the specific technologies used, the process may involve
testing equipment, reconfiguring routers, or diagnosing communications link
problems. PSI is responsible for diagnosing service problems and tracking repair
progress. PSI is to use documented trouble resolution procedures as jointly
developed and agreed upon by PSI and IXC.


                             Attachments to Schedule 2.2
                                    Page 27 of 36


<PAGE>


7.4.     Trouble Ticketing System

PSI must use a Trouble Ticketing System to track problems from initial report
through satisfactory resolution. As PSI works to resolve problems, the current
status must be maintained in the Trouble Ticketing System.

7.4.1.   IXC Customer Access to Trouble Ticketing System

IXC customers will be provided access by PSI to any trouble tickets related to
their service, as soon as the technology is available to PSI. If additional
programming is required to deliver this functionality, it will be costed out and
provided to IXC in advance. The trouble ticketing system should provide
designated customer contacts with automatic access to the trouble tickets via
web interfaces

PSI Backbone status information should also be made available to customer
contacts requesting same via the same interfaces.

7.4.2.   IXC Reseller Access to Trouble Ticketing System

IXC resellers will be provided access by PSI to any trouble tickets related to
the service, as soon as the technology is available to PSI. If additional
programming is required to deliver this functionality, it will be costed out and
provided to IXC in advance. The trouble ticketing system should provide
designated IXC Reseller contacts with automatic access to the trouble tickets
via web interfaces.

PSI Backbone status information should also be made available to IXC Reseller
contacts requesting same via the same interfaces.

7.4.3.   IXC Access to Trouble Ticketing System

IXC will be provided access by PSI to any trouble tickets related to the service
provided to IXC, IXC Resellers and their end customers, as soon as the
technology is available to PSI. If additional programming is required to deliver
this functionality, it will be costed out and provided to IXC in advance. The
trouble ticketing system should provide designated IXC contacts with automatic
access to the trouble tickets via web interfaces

PSI Backbone status information should also be made available to IXC Reseller
contacts requesting same via the same interfaces

PSI is to work with IXC to integrate trouble ticketing systems and processes as
much as reasonably possible

7.5.     Problem Notification.

         7.5.1.   IXC Customer Problem Notification. PSI must inform the 
technical contact of IXC Managed Intranet WAN service customers of any 
outages affecting their service. The operations staff must also keep Managed 
Intranet WAN customers informed of any widespread outages on connecting 
networks

         7.5.2.   IXC Reseller Problem Notification. PSI must inform the 
technical contact of IXC Resellers of any outages affecting service to their 
end customers. The operations staff must also keep IXC Resellers informed of 
any widespread outages on connecting networks

         7.5.3.   IXC Problem Notification. PSI must inform the IXC technical 
contacts of any outages affecting service to IXC, IXC Resellers, or IXC end

                             Attachments to Schedule 2.2
                                    Page 28 of 36


<PAGE>


customers. The operations staff must also keep IXC informed of any widespread
outages on connecting networks

7.6.     Software and Configuration Support for InterMAN. PSI is responsible
for coordinating software updates and configuration changes on the customer
premise router and CSU/DSU equipment of IXC customers as required to provide
Internet service. Notice of software changes is to be made to the customer
technical contacts, and every effort must be made to perform maintenance during
off-hours

7.7      Escalation Procedures. Documented customer support processes are to be
developed jointly by PSI and IXC. Specific process documentation is required for
the following:

         o    customer support procedures

         o    trouble escalation procedures

         o    trouble ticketing, tracking, and resolution

PSI must provide information to the IXC customer describing customer support,
problem resolution, and trouble escalation procedures, customer contact
information, and trouble reporting methods.

8.       Security Procedures

PSI's security procedures include a default Interim Security Policy for new
intranet sites, security policy planning before the sites are integrated into an
intranet, verification of identity of the customer technical contact before
requests for changes are accepted, and sign-off by the customer technical
contact of implementation plans before changes are implemented

Additionally, PSI's Net Abuse policy shall apply to all IXC customers.


                             Attachments to Schedule 2.2
                                    Page 29 of 36


<PAGE>

           INTERNET REMOTE ACCESS SERVICE SERVICE REQUIREMENTS VERSION 1.1
                                           
1.       Overview

The PSI Internet Remote Access service provides on-demand switched connectivity
to the Internet for corporate user groups of telecommuters and mobile workers
via analog modems (9.6 - 33.6 Kbps) or ISDN NT1s (64 - 128 Kbps), and
centralized account management by the customer technical administrator through a
web-based Account Management System. Connectivity is provided for client access
for single systems. Connections are established between the users and a PSI
Point-of-Presence (POP) using the Point-to-Point Protocol (PPP).

The PSI Internet Remote Access services include:

         o    InterRamp Remote Access for Business

The PSI Remote Access service specification is included in Schedule 2.3.

Additional service requirements to be decided.


                             Attachments to Schedule 2.2
                                    Page 30 of 36


<PAGE>



         MANAGED INTERNET SECURITY SERVICES SERVICE REQUIREMENTS VERSION 1.1
                                           

1.       OVERVIEW

PSI's Managed Internet Security services provide security policy planning and
implementation for Internet access control and remote user authentication
services. Security services are provided to the customer as a value-added option
to a PSI Dedicated Internet Access service, and include all necessary CPE
required to deliver the service.

The PSI Managed Internet Security services include:

         o    RouteWaller (for InterFrame)

         o    SecureEnterprise (for InterFrame and InterMAN)

The PSI Managed Internet Security service specifications are included in
Schedule 2.3.

Additional service requirements to be decided.



                             Attachments to Schedule 2.2
                                    Page 31 of 36


<PAGE>


                INTERNET FAX SERVICE SERVICE REQUIREMENTS VERSION 1.1
                                           

1.       OVERVIEW

PSI's Internet Fax service provides global hardcopy delivery of documents
through the Internet to any fax machine in the world. Traffic is routed from the
fax client on the customer user desktop to a server where the best price can be
attained for the final dial-out connection.

The PSI Internet Fax services include:

         o    PSInet InternetPaper

The PSI Internet Fax service specification is included in Schedule 2.3.

Additional service requirements to be decided.


                             Attachments to Schedule 2.2
                                    Page 32 of 36


<PAGE>


          WHOLESALE DIAL-UP INTERNET ACCESS SERVICE REQUIREMENTS VERSION 1.0
                                           


1.       Overview

PSI's Wholesale Dial-up Internet Access services provide, on a wholesale basis,
on-demand switched connectivity to the Internet via an analog modem (9.6 - 33.6
Kbps) or an ISDN NT1 (64 - 128 Kbps). The PSI Wholesale Dial-up Internet Access
services include:

         o    PSINet Consumer Wholesale

The PSInet Consumer Wholesale service descriptions are included in Schedule 2.3.

2.       Wholesale Service Branding

PSI is to deliver the Dial-up Internet Access service on a branded basis, such
that the service is delivered to the end customer as an IXC / IXC reseller
branded service. Service branding is to be present in the following areas:

         o    Sales collateral
         o    End user software diskettes
         o    User manuals and other service-related material.
         o    All PSI contact with the end customer, such as during order
              verification, service provisioning, and customer support
         o    Email addresses and web site domain names for customer support,
              service status, service information.
         o    Domain names used for end user account, as reflected in user
              email addresses and user web page location identifiers.
         o    Service usage reports

PSI will provide service branding pricing under separate cover.

3.       Delivery Processes

Documented delivery processes are to be developed by PSI and are subject to
approval by IXC. PSI will work to integrate internal processes with IXC's
service processes, specifically in the areas of:

         o    order processing
         o    service provisioning
         o    customer support
         o    network operation procedures and escalation
         o    trouble ticketing and tracking
         o    billing

PSI must create and maintain delivery process documentation specific to the
items listed above.

PSI has created the processes above and have incorporated them into the Consumer
Wholesale Users Guide, previously supplied to IXC.

4.       Service Implementation

PSI is to provide IXC with a dial-up Internet access product. RADIUS
authentication shall be performed by PSI. PSI provides modem ports, traffic
propagation, authentication and second level support. Customer support, software
fulfillment and billing may be outsourced.


                             Attachments to Schedule 2.2
                                    Page 33 of 36


<PAGE>


Implementation details are described below.

4.1.     Dial-Up Pop Infrastructure

PSI is responsible for installing and maintaining the network infrastructure for
providing analog and ISDN dial-up Internet access at multiple dial-up
Points-of-Presence (dial-up POPs) across the U.S. as well as 800 number Internet
access.

4.1.1.   Port Availability

PSI is responsible for maintaining an adequate number of modem and ISDN ports
for the dial-up service at each dial-up POP, based on the ratio of user accounts
to modem ports (user:modem ratio). User:Port ratios are to be maintained at no
more than approximately * at each PSI dial- up POP. PSI is to monitor the
user:port ratios of user accounts to available modem ports at each dial-up POP.
PSI will use best efforts to ensure the network is maintained at a level which
meet reasonable commercial standards and shall maintain its network in good
condition and repair. User:Port ratios are to be calculated for each separate
dial-up POP, with analog and ISDN ratios calculated separately.

PSI will provide IXC with real-time, 24hr/day access to its POPs for IXC's
analysis and debugging.

4.2.     Radius Authentication

PSI is to install and maintain distributed RADIUS authentication servers to be
used for verifying user authentication. PSI's distributed RADIUS servers must be
configured to communicate with a central RADIUS server that contains the IXC
customer's authorized user database.

4.3.     Optional End User Software

PSI is to provide, for a fee, IXC or IXC Reseller branded, pre-configured
Internet access software on appropriate media (3.5" floppy or CD- ROM), and
appropriate operating system (Windows 3.1, Win 95, NT, MacOS).

4.3.1.   Internet Connectivity Software Suite

The end user dial-up access software is to include:

         o    An IP connectivity software suite of
         o    Dial-up communications 
         o    TCP/IP stack
         o    PPP software
         o    Netscape or Internet Explorer web browser
         o    E-mail reader
         o    News reader
         o    Service Initiation Screens




*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission


                             Attachments to Schedule 2.2
                                    Page 34 of 36


<PAGE>

4.3.2.   Software Customizing and Branding

The Internet access software media is to be available as private-label, branded
software. Branding is to include the following:

         o    Custom diskette packaging that reflects the IXC Customer dial-up
              service brand
         o    Customized Service Initiation and Welcome screen
         o    Custom screen logo
         o    Custom initial default home page for the web browser included
              with the software.
         o    Custom user manuals that reflects the IXC Customer dial-up
              service brand.

4.3.3.   Software Fulfillment

PSI is to arrange for the Internet access software to be delivered to the end
user upon receiving an account activation order for a new customer of the IXC
Reseller. The software shipment can be contracted by PSI to a fulfillment house
company that specializes in software diskette distribution. PSI is responsible
for the end user receiving the software no more than ten days following the
account activation order being received by PSI. PSI will provide a fee schedule
to IXC based on IXC sales projections given to the fulfillment house by PSI.

4.4.     Optional End User Help Desk

First tier end user help desk support is to be coordinated by PSI, or an agreed
upon subcontractor, for a fee. Help desk support is to include

         o    help regarding the installation and use of supported desktop
              connectivity software, including web browser and email
         o    trouble reporting regarding use of the wholesale dial-up service
         o    general use of the dial-up service

Dial-up customer support is provided on a branded basis, with PSI customer
support representatives answering the phone in the name of the IXC Reseller.
Fees for this service are directly proportional with the amount of users the IXC
Reseller has using the network and are priced out separately for each
participating IXC Reseller. Call answering is to be customized in accordance
with the IXC Reseller's policies and procedures and may add additional cost to
each IXC Reseller.

4.5.     Optional Email Services

End user email services are to be offered by PSI, or its subcontractor, for an
added fee. Wholesale dial-up user mailboxes are to be hosted by PSI on a
managed, industry standard SMTP/POP3 e-mail server. Each user is to be provided
with their own email address and storage for up to 5 MB or 35 days of unread
mail, whichever is less. The mailserver is to be configured using a domain name
specific to the IXC Customer's branded dial-up service, which is the domain name
that is to appear in the end-users' email addresses.

PSI, or its subcontractor, is to host and manage the mail service with the same
robustness and operational care as is considered best practice within the
industry. PSI, or its subcontractor, is responsible for providing to IXC and the
IXC Reseller Web-based email administration tools for managing the email
service.


                             Attachments to Schedule 2.2
                                    Page 35 of 36


<PAGE>

4.6      Optional Usenet News Services

End user Usenet News services are offered by PSI to IXC Wholesale Dial-up
customers. An additional fee may apply.

4.7      Account Usage Call Records

PSI, or its subcontractor, is responsible for reporting detailed account call
record information to the IXC on a regular basis (daily, weekly, monthly).
Separate call record information must be provided to IXC for each IXC reseller
customer, as well as total aggregate call record information. Call records are
to be provided via electronic files as well as via a secure Web server
accessible to the IXC. PSI will provide a fee schedule based on these criteria.



                             Attachments to Schedule 2.2
                                    Page 36 of 36



<PAGE>

                                     SCHEDULE 2.3
                                           
                                    DOCUMENTATION
                                           


1.       Service Descriptions - As per the Attachments to Schedule 2.2

2.       Standard Contract - PSI Standard Customer Agreement and all Addenda

3.       *

         Other Marketing Materials/Collateral


*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission




                                  Schedule 2.3
                                  Page 1 of 1 



<PAGE>


                                  SCHEDULE 3.1
                                           
                                 SALES SUPPORT
                                           
                                          *
                                           



*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission









                                  Schedule 3.1
                                  Page 1 of 1 


<PAGE>


                                 SCHEDULE 5.4.1
                                           
                    PROVISION GOVERNING IXC USE OF SERVICES
                                           
The following provisions shall apply to IXC's use of Services in IXC's capacity
as an end user of Services for its own account (provided that such provisions
shall be modified automatically to the extent PSI waives such provisions, or
imposes less restrictive provisions, on its customers under its standard terms
and conditions and normal business practices (including where exceptions are
routinely granted to customers), or for any other reseller or distributor of
services of the type comprising the Services):

(A)       IXC shall be solely responsible for the content of any transmissions
          over the Internet by IXC and any person or Third Party utilizing IXC's
          facilities with IXC's consent. IXC agrees that it and any such person
          or Third Party utilizing IXC's facilities shall not knowingly disrupt
          other network users, network services or network equipment.
          Disruptions include, but are not limited to, distribution of
          unsolicited advertising or chain letters, propagation of computer
          worms and viruses, and using the network to make unauthorized entry to
          any other machine accessible via the network.

(B)       Except as expressly set forth in or contemplated by the Joint
          Marketing and Services Agreement to which this Schedule is attached
          (the "Marketing Agreement"), PSI DISCLAIMS ALL EXPRESS AND IMPLIED
          WARRANTIES, INCLUDING WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
          PARTICULAR PURPOSE. PSI shall not be liable for any damages that IXC
          may suffer arising out of use, or inability to use, the Services or
          products provided hereunder unless such damage is caused by a
          negligent, reckless or intentional act of PSI. PSI shall not be liable
          for unauthorized access by Third Parties to IXC's transmission
          facilities or premise equipment or for unauthorized access to or
          alteration, theft, loss or destruction of IXC's data files, programs,
          procedures or information through accident, fraudulent means or
          devices or any other method provided that the foregoing shall not
          relieve PSI from responsibility for any of the foregoing to the extent
          it results from PSI's actions (or inactions) while responsible for
          security and system administration within the IXC network. Except as
          expressly set forth in or contemplated by the Marketing Agreement, in
          any instance involving performance or nonperformance by PSI with
          respect to Services or products provided hereunder, (a) the price paid
          for Services which were not provided, or (b) in the case of products,
          the products shall be repaired or replaced by the manufacturer,
          subject to applicable warranty. Except as expressly set forth in or
          contemplated by the Marketing Agreement, in the case of refund for
          lost Services, credit will be issued only for periods of lost Service
          greater than twenty-four (24) hours.

(C)       IXC agrees to comply with U.S. law with regard to the transmission of
          technical data which is exported from the United States using the
          Services.

(D)       The following additional provisions shall apply to the following types
          of Services (as indicated): Dedicated Internet Access Service (PSINet
          InterFrame), Dedicated Internet Access Service (PSINet InterMAN),
          Switched LAN Internet Access Service, Managed Intranet WAN Service,
          Internet Remote Access Service, Managed Internet Security Services,
          PSINet InternetPaper Service and PSINet Consumer Wholesale Service:


                                 Schedule 5.4.1
                                  Page 1 of 23


<PAGE>
 
            DEDICATED INTERNET ACCESS SERVICE CUSTOMER CONTRACT PROVISIONS
                                           
                                 PSINET INTERFRAME
                                           
Psinet Network Usage.

     A. Compliance with Law and Policy. Customer has read and agrees to comply
     with PSINet's Net-Abuse Policy ("Policy") as currently set forth on
     PSINet's Web site (http://www.psi.net) and as the Policy may be modified by
     PSINet in its sole discretion from time to time. Any content, material,
     message or data made available or transmitted through the Service, wherever
     it is sent from, viewed, received, or retrieved, that is in violation of
     (i) any local, state, federal or international law, regulation or treaty;
     (ii) the Policy; or (iii) any community standard or accepted Internet
     policy is prohibited. Any such violation may be deemed a material breach of
     this Agreement and PSINet may, in its sole discretion, disable or terminate
     the Service with written notice to Customer, but without any cure period. 

     B. Customer-Only Traffic. The right to use the Service is strictly limited
     to Customer only and does not extend to any other person, corporation or
     entity except for wholly-owned affiliates of Customer and those members of
     Customer's staff and consultants in the course of performing work for
     Customer. 

     C. Third-Party Traffic. Customer may host world-wide web sites on behalf of
     third parties. In addition, Customer may feed USENET News to a third party,
     but may not send any posting from that third party, including, but not
     limited to, electronic mail, back to PSINet's wide-area network system (the
     "Network") or the Internet through the Service. Any other third party
     traffic, including packet access and electronic mail, whether sent or
     received through Customer's facilities by or on behalf of a third party
     through the Service, is expressly prohibited.

Customer Network Security. PSINet provides no user access security with respect
to any of Customer's facilities or facilities of others. Customer shall be
responsible for user/access security as well as access to its network or to the
Network. PSINet will assist in network security breach detection or
identification, but shall not be liable for any inability, failure or mistake in
doing so.

Service Assurance. If Customer notifies PSINet immediately upon its failure to
access the Network through Customer's standard means or the backup mechanisms
provided with the Service, and PSINet determines in its reasonable commercial
judgment that the Network is therefore unavailable to Customer ("Unavailable"),
one of the following will apply:

     1. If PSINet determines that the Network is Unavailable for one (1) or more
     consecutive hours during any calendar month, PSINet, upon Customer's
     request, will credit Customer's monthly invoice the pro-rated charges for
     one (1) day's Service fee; or 

     2. If PSINet determines that the Network is Unavailable for an aggregate of
     four (4) or more hours during any calendar month, PSINet, upon Customer's
     request, will credit Customer's monthly invoice the pro-rated charges for
     one (1) week's Service fee.

These two options are not cumulative. For purposes of this section, scheduled
maintenance will not be considered to be Unavailability. PSINet shall not be
responsible for any toll charges incurred by Customer's use of any telephone
company ("Telco") or other telecommunications services as a result of this 


                                  Schedule 5.4.1
                                   Page 2 of 23


<PAGE>


section. THE FOREGOING TWO OPTIONS STATE PSINET'S SOLE OBLIGATION, AND
CUSTOMER'S SOLE REMEDY, FOR NETWORK UNAVAILABILITY.

Special Terms for the "On-Site Service" Option. 

     "On-site service" Option Specifics.
     
     (1) Equipment Access and Connection. The Equipment shall be installed and
     maintained by PSINet or its subcontractors as PSINet shall designate in
     writing. Customer shall provide 24 hour per day, 7 days per week access to
     the Equipment (with appropriate escort if required by Customer) by
     PSINet-designated individuals. If Customer cannot provide this access, any
     Service Assurance remedy provided above is suspended during such time.
     Customer shall not allow its personnel or others on its premises to tamper
     with the Equipment. PSINet will verbally authorize on an event-by-event
     basis individuals at Customer's location to open Equipment cabinets for
     appropriate routine and emergency reasons. Customer shall retain the right
     to disconnect the Equipment from its LAN at any time. PSINet reserves the
     right to shut down the Equipment at Customer's location in accordance with
     PSINet's emergency operating procedures with notification to Customer.
     Relocation of the Equipment may only be performed by PSINet or its
     subcontractors at Customer's expense. PSINet is not responsible for Service
     disruptions caused by Customer's Equipment relocation requirements. 

     (2) Security Filtering Sub-Option. If initialed on Customer's Order Form,
     PSINet shall provide the Security Filtering Sub-Option along with the
     On-Site Service Option. PSINet shall provide packet filtering based on
     network number and protocol for non-Customer networks, and on an individual
     host basis for Customer host computers.

          (a)  Customer will delegate two security contacts, a primary and a
          secondary. Contact names, phone numbers, fax numbers, and electronic
          mail addresses must be provided to PSINet on the Order Form. PSINet
          will take direction ONLY from these contacts. 

          (b)  Customer security contacts must participate in an initial phone
          consultation with PSINet's Security Coordinator. 

          (c)  Customer requests must be made by electronic mail or fax to the
          designated PSINet address to facilitate an audit trail. 

          (d)  PSINet Network Operations can be instructed by other Customer
          contacts to disable non-PSINet access (for instance, MAE-East and CIX
          access).

LIMITED WARRANTIES. 

     A. SERVICE. PSINET WARRANTS THAT THE SERVICE WILL OPERATE SUBSTANTIALLY IN
     CONFORMANCE WITH THE SPECIFICATIONS. PSINET MAKES NO OTHER WARRANTIES OF
     ANY KIND, WHETHER EXPRESSED, IMPLIED OR STATUTORY, INCLUDING, BUT NOT
     LIMITED TO, ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS OF THE SERVICE
     FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT OF ANY THIRD PARTY RIGHTS.
     CUSTOMER IS RESPONSIBLE FOR ASSESSING ITS OWN COMPUTER AND TRANSMISSION
     NETWORK NEEDS, AND THE RESULTS TO BE OBTAINED THEREFROM. USE OF ANY
     INFORMATION OBTAINED THROUGH THE SERVICE IS AT CUSTOMER'S RISK. PSINET
     SPECIFICALLY DENIES ANY RESPONSIBILITY FOR THE ACCURACY OR QUALITY OF
     INFORMATION OBTAINED THROUGH THE SERVICE. 

     B. EQUIPMENT. PSINET REPRESENTS AND WARRANTS THAT DURING THE TERM OF THIS
     AGREEMENT IT WILL MAKE REASONABLE EFFORTS TO ENSURE THE EQUIPMENT OPERATES 


                                  Schedule 5.4.1
                                   Page 3 of 23


<PAGE>


     SUBSTANTIALLY IN CONFORMANCE WITH THE SPECIFICATIONS. ANY UNAUTHORIZED
     CHANGES TO OR INAPPROPRIATE USAGE OF THE EQUIPMENT, HOWEVER, WILL VOID THE
     FOREGOING WARRANTY. PSINET DOES NOT WARRANT THAT THE EQUIPMENT WILL BE
     ENTIRELY FREE FROM DEFECTS OR THAT ITS OPERATION WILL BE ERROR FREE.
     FURTHERMORE, CUSTOMER ACKNOWLEDGES THAT PSINET HAS MADE NO OTHER
     REPRESENTATION OR WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH RESPECT TO
     THE CONDITION OR PERFORMANCE OF THE EQUIPMENT, OR ITS MERCHANTABILITY OR
     FITNESS FOR A PARTICULAR PURPOSE. C. GENERAL. EACH PARTY ACKNOWLEDGES THAT
     IT HAS READ AND UNDERSTANDS THIS AGREEMENT AND AGREES TO BE BOUND BY ITS
     TERMS. EACH PARTY FURTHER WARRANTS THAT IT HAS FULL CORPORATE POWER AND
     AUTHORITY TO ENTER INTO AND DELIVER THIS AGREEMENT AND TO PERFORM ITS
     OBLIGATIONS HEREUNDER, AND THAT THE PERSON WHOSE SIGNATURE APPEARS BELOW IS
     DULY AUTHORIZED TO ENTER INTO THIS AGREEMENT ON BEHALF OF THAT PARTY.

LIMITATION OF LIABILITY. EXCEPT FOR CUSTOMER'S PAYMENT OBLIGATIONS HEREUNDER,
NEITHER PARTY SHALL BE LIABLE FOR DIRECT DAMAGES GREATER THAN THE SUM TOTAL OF
PAYMENTS MADE BY CUSTOMER TO PSINET DURING THE SIX (6) MONTHS IMMEDIATELY
PRECEDING THE EVENT FOR WHICH DAMAGES ARE CLAIMED. EXCEPT FOR THE FOREGOING,
PSINET SHALL HAVE NO LIABILITY TO CUSTOMER WITH RESPECT TO (I) ANY CLAIM, LOSS
OR DAMAGE OF ANY KIND OR NATURE WHATSOEVER INCLUDING THE ACTIVE OR PASSIVE
NEGLIGENCE OR STRICT LIABILITY OF PSINET FOR CLAIMS ARISING OUT OF OR IN
CONNECTION WITH THE SERVICE OR THE EQUIPMENT, WHETHER OR NOT KNOWN OR DISCLOSED
TO PSINET; (II) ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, PUNITIVE OR
CONSEQUENTIAL LOSSES OR DAMAGES RESULTING FROM THE DELIVERY, INSTALLATION,
MAINTENANCE, OPERATION OR USE OF THE SERVICE OR THE EQUIPMENT; (III) ANY ACT OR
OMISSION OF ANY OTHER ENTITY FURNISHING EQUIPMENT, PRODUCTS OR SERVICES TO
CUSTOMER; (IV) ANY PERSONAL OR PROPERTY DAMAGES DUE TO THE LOSS OF STORED,
TRANSMITTED OR RECORDED DATA RESULTING FROM THE SERVICE OR THE EQUIPMENT, EVEN
IF PSINET HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES; AND (V) ANY LOSS
OR DAMAGES DUE TO THE FAULT OR NEGLIGENCE OF CUSTOMER OR ITS EMPLOYEES, AGENTS
OR REPRESENTATIVES.

IN NO EVENT SHALL EITHER PARTY BE LIABLE FOR ANY INDIRECT, INCIDENTAL,
EXEMPLARY, PUNITIVE OR OTHER CONSEQUENTIAL DAMAGES WHETHER OR NOT FORESEEABLE,
INCLUDING, BUT NOT LIMITED TO, DAMAGES FOR THE LOSS OF DATA, GOODWILL OR
PROFITS, ARISING OUT OF OR IN RELATION TO THIS AGREEMENT EVEN IF ADVISED
BEFOREHAND OF THE POSSIBILITY OF SUCH LIABILITY. THE PARTIES AGREE TO WORK IN
GOOD FAITH TO IMPLEMENT THE PURPOSES OF THIS AGREEMENT, BUT RECOGNIZE THAT THE
SERVICE COULD NOT BE MADE AVAILABLE UNDER THESE TERMS OR OTHER SIMILAR TERMS
WITHOUT A SUBSTANTIAL INCREASE IN COST IF PSINET WERE TO ASSUME A GREATER DEGREE
OF LIABILITY TO CUSTOMER.


                                  Schedule 5.4.1
                                   Page 4 of 23


<PAGE>


                          DEDICATED INTERNET ACCESS SERVICE
                             CUSTOMER CONTRACT PROVISIONS
                                           

                                   PSINET INTERMAN


PSINET NETWORK USAGE.

     A. Compliance With Law and Policy. Customer has read and agrees to comply
     with PSINet's Net-Abuse Policy ("Policy") as currently set forth on
     PSINet's Web site (http://www.psi.net) and as the Policy may be modified by
     PSINet in its sole discretion from time to time. Any content, material,
     message or data made available or transmitted through the Service, wherever
     it is sent from, viewed, received, or retrieved, that is in violation of
     (i) any local, state, federal or international law, regulation or treaty;
     (ii) the Policy; or (iii) any community standard or accepted Internet
     policy is prohibited. Any such violation may be deemed a material breach of
     this Agreement and PSINet may, in its sole discretion, disable or terminate
     the Service with written notice to Customer, but without any cure period. 

     B. Customer-Only Traffic. The right to use the Service is strictly limited
     to Customer only and does not extend to any other person, corporation or
     entity except for wholly-owned affiliates of Customer and those members of
     Customer's staff and consultants in the course of performing work for
     Customer. 

     C. Third-Party Traffic. Customer may host world-wide web sites on behalf of
     third parties. In addition, Customer may feed USENET News to a third party,
     but may not send any posting from that third party, including, but not
     limited to, electronic mail, back to PSINet's wide-area network system (the
     "Network") or the Internet through the Service. Any other third party
     traffic, including packet access and electronic mail, whether sent or
     received through Customer's facilities by or on behalf of a third party
     through the Service, is expressly prohibited.

Customer Network Security. PSINet provides no user access security with respect
to any of Customer's facilities or facilities of others. Customer shall be
responsible for user/access security as well as access to its network or to the
Network. PSINet will assist in network security breach detection or
identification, but shall not be liable for any inability, failure or mistake in
doing so.

     PSINET-PROVIDED EQUIPMENT. 

     (1) Equipment Space. Customer shall provide and maintain suitable Equipment
     Space meeting or exceeding the requirements set forth in the
     Specifications. 

     (2) Equipment. The Equipment Space will house Equipment owned by PSINet
     required for the Service. PSINet shall retain all right, title, and
     interest in the Equipment at all times. PSINet will provide Equipment in
     order to facilitate the connection between Customer's network and the Telco
     circuit leading to the Network. The particular make and model of Equipment
     shall be selected for Customer by PSINet in its sole discretion. If PSINet
     determines in its sole reasonable judgment that the Equipment is defective,
     PSINet shall replace the defective Equipment at no cost to Customer. THE
     FOREGOING STATES PSINET'S SOLE OBLIGATION, AND CUSTOMER'S SOLE REMEDY, FOR
     ANY DEFECTIVE EQUIPMENT. 


                                  Schedule 5.4.1
                                   Page 5 of 23


<PAGE>


     (3) Equipment Access and Connection. The Equipment shall be installed and
     maintained by PSINet, or its subcontractors as PSINet shall designate in
     writing. Customer shall provide 24 hour per day, 7 days per week access to
     the Equipment (with appropriate escort if required by Customer) by
     PSINet-designated individuals. If Customer cannot provide this access, any
     Service Assurance remedy provided below is suspended during such time.
     Customer shall not allow its personnel or others on its premises to open
     the Equipment cabinets. PSINet will verbally authorize on an event-by-event
     basis individuals at Customer's location to open Equipment cabinets for
     appropriate routine and emergency reasons. Customer shall retain the right
     to disconnect the Equipment from its LAN at any time. PSINet reserves the
     right to shut down the Equipment at Customer's location in accordance with
     PSINet's emergency operating procedures with notification to Customer. 

     (4) Equipment Relocation. Relocation of the Equipment may only be performed
     by PSINet or its subcontractors at Customer's expense. PSINet is not
     responsible for Service disruptions caused by Customer's Equipment
     relocation requirements. 

     (5) Equipment Return. Upon termination of the Service for any reason,
     Customer agrees immediately to allow the return of the Equipment to PSINet.
     PSINet retains all rights to recover possession of the Equipment from
     Customer.

Security Filtering Option. If initialed on Customer's Order Form, PSINet shall
provide the Security Filtering Option. PSINet shall provide packet filtering
based on network number and protocol for non-Customer networks, and on an
individual host basis for Customer host computers. 

     (1) Customer will delegate two security contacts, a primary and a
     secondary. Contact names, phone numbers, fax numbers, and electronic mail
     addresses must be provided to PSINet on the Order Form. PSINet will take
     direction ONLY from these contacts. 

     (2) Customer security contact points must participate in an initial phone
     consultation with PSINet's Security Coordinator. 

     (3) Customer requests must be made by electronic mail or fax to the
     designated PSINet address to facilitate an audit trail. (4) PSINet Network
     Operations can be instructed by other Customer contacts to disable
     non-PSINet access (for instance, MAE-East and CIX access).

Service Assurance. If Customer notifies PSINet immediately upon its failure to
access the Network through Customer's standard means or the backup mechanisms
provided with the Service, and PSINet determines in its reasonable commercial
judgment that the Network is therefore unavailable to Customer ("Unavailable"),
one of the following will apply:

     1. If PSINet determines that the Network is Unavailable for one (1) or more
     consecutive hours during any calendar month, PSINet, upon Customer's
     request, will credit Customer's monthly invoice the pro-rated charges for
     one (1) day's Service fee; or 

     2. If PSINet determines that the Network is Unavailable for an aggregate of
     four (4) or more hours during any calendar month, PSINet, upon Customer's
     request, will credit Customer's monthly invoice the pro-rated charges for
     one (1) week's Service fee.

These two options are not cumulative. For purposes of this section, scheduled
maintenance will not be considered to be Unavailability. PSINet shall not be 


                                  Schedule 5.4.1
                                   Page 6 of 23


<PAGE>


responsible for any toll charges incurred by Customer's use of any telephone
company ("Telco") or other telecommunications services as a result of this
section. THE FOREGOING TWO OPTIONS STATE PSINET'S SOLE OBLIGATION, AND
CUSTOMER'S SOLE REMEDY, FOR NETWORK UNAVAILABILITY.

LIMITED WARRANTIES. 

     A. SERVICE. PSINET WARRANTS THAT THE SERVICE WILL OPERATE SUBSTANTIALLY IN
     CONFORMANCE WITH THE SPECIFICATIONS. PSINET MAKES NO OTHER WARRANTIES OF
     ANY KIND, WHETHER EXPRESSED, IMPLIED OR STATUTORY, INCLUDING, BUT NOT
     LIMITED TO, ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS OF THE SERVICE
     FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT OF ANY THIRD PARTY RIGHTS.
     CUSTOMER IS RESPONSIBLE FOR ASSESSING ITS OWN COMPUTER AND TRANSMISSION
     NETWORK NEEDS, AND THE RESULTS TO BE OBTAINED THEREFROM. USE OF ANY
     INFORMATION OBTAINED THROUGH THE SERVICE IS AT CUSTOMER'S RISK. PSINET
     SPECIFICALLY DENIES ANY RESPONSIBILITY FOR THE ACCURACY OR QUALITY OF
     INFORMATION OBTAINED THROUGH THE SERVICE. 

     B. EQUIPMENT. PSINET REPRESENTS AND WARRANTS THAT DURING THE TERM OF THIS
     AGREEMENT IT WILL MAKE REASONABLE EFFORTS TO ENSURE THE EQUIPMENT OPERATES
     SUBSTANTIALLY IN CONFORMANCE WITH THE SPECIFICATIONS. ANY UNAUTHORIZED
     CHANGES TO OR INAPPROPRIATE USAGE OF THE EQUIPMENT, HOWEVER, WILL VOID THE
     FOREGOING WARRANTY. PSINET DOES NOT WARRANT THAT THE EQUIPMENT WILL BE
     ENTIRELY FREE FROM DEFECTS OR THAT ITS OPERATION WILL BE ERROR FREE.
     FURTHERMORE, CUSTOMER ACKNOWLEDGES THAT PSINET HAS MADE NO OTHER
     REPRESENTATION OR WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH RESPECT TO
     THE CONDITION OR PERFORMANCE OF THE EQUIPMENT, OR ITS MERCHANTABILITY OR
     FITNESS FOR A PARTICULAR PURPOSE. 

     C. GENERAL. EACH PARTY ACKNOWLEDGES THAT IT HAS READ AND UNDERSTANDS THIS
     AGREEMENT AND AGREES TO BE BOUND BY ITS TERMS. EACH PARTY FURTHER WARRANTS
     THAT IT HAS FULL CORPORATE POWER AND AUTHORITY TO ENTER INTO AND DELIVER
     THIS AGREEMENT AND TO PERFORM ITS OBLIGATIONS HEREUNDER, AND THAT THE
     PERSON WHOSE SIGNATURE APPEARS BELOW IS DULY AUTHORIZED TO ENTER INTO THIS
     AGREEMENT ON BEHALF OF THAT PARTY.

LIMITATION OF LIABILITY. EXCEPT FOR CUSTOMER'S PAYMENT OBLIGATIONS HEREUNDER,
NEITHER PARTY SHALL BE LIABLE FOR DIRECT DAMAGES GREATER THAN THE SUM TOTAL OF
PAYMENTS MADE BY CUSTOMER TO PSINET DURING THE SIX (6) MONTHS IMMEDIATELY
PRECEDING THE EVENT FOR WHICH DAMAGES ARE CLAIMED. EXCEPT FOR THE FOREGOING,
PSINET SHALL HAVE NO LIABILITY TO CUSTOMER WITH RESPECT TO (I) ANY CLAIM, LOSS
OR DAMAGE OF ANY KIND OR NATURE WHATSOEVER INCLUDING THE ACTIVE OR PASSIVE
NEGLIGENCE OR STRICT LIABILITY OF PSINET FOR CLAIMS ARISING OUT OF OR IN
CONNECTION WITH THE SERVICE OR THE EQUIPMENT, WHETHER OR NOT KNOWN OR DISCLOSED
TO PSINET; II) ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, PUNITIVE OR
CONSEQUENTIAL LOSSES OR DAMAGES RESULTING FROM THE DELIVERY, INSTALLATION,
MAINTENANCE, OPERATION OR USE OF THE SERVICE OR THE EQUIPMENT; (III) ANY ACT OR
OMISSION OF ANY OTHER ENTITY FURNISHING EQUIPMENT, PRODUCTS OR SERVICES TO
CUSTOMER; (IV) ANY PERSONAL OR PROPERTY DAMAGES DUE TO THE LOSS OF STORED,
TRANSMITTED OR RECORDED DATA RESULTING FROM THE SERVICE OR THE EQUIPMENT, EVEN
IF PSINET HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES; AND (V) ANY LOSS
OR DAMAGES DUE TO THE FAULT OR NEGLIGENCE OF CUSTOMER OR ITS EMPLOYEES, AGENTS
OR REPRESENTATIVES.

IN NO EVENT SHALL EITHER PARTY BE LIABLE FOR ANY INDIRECT, INCIDENTAL,
EXEMPLARY, PUNITIVE OR OTHER CONSEQUENTIAL DAMAGES WHETHER OR NOT FORESEEABLE,
INCLUDING, BUT NOT LIMITED TO, DAMAGES FOR THE LOSS OF DATA, GOODWILL OR
PROFITS, ARISING OUT OF OR IN RELATION TO THIS AGREEMENT EVEN IF ADVISED
BEFOREHAND OF THE POSSIBILITY OF SUCH LIABILITY. THE PARTIES AGREE TO WORK IN
GOOD FAITH TO IMPLEMENT THE PURPOSES OF THIS AGREEMENT, BUT RECOGNIZE THAT THE
SERVICE COULD NOT BE MADE AVAILABLE UNDER THESE TERMS OR OTHER SIMILAR TERMS
WITHOUT A 


                                  Schedule 5.4.1
                                   Page 7 of 23


<PAGE>


SUBSTANTIAL INCREASE IN COST IF PSINET WERE TO ASSUME A GREATER DEGREE OF
LIABILITY TO CUSTOMER.












                                  Schedule 5.4.1
                                   Page 8 of 23


<PAGE>


 
                         SWITCHED LAN INTERNET ACCESS SERVICE
                             CUSTOMER CONTRACT PROVISIONS
                                           

PSINET NETWORK USAGE.

     A. Compliance With Law and Policy. Customer has read and agrees to comply
     with PSINet's Net-Abuse Policy ("Policy") as currently set forth on
     PSINet's Web site (http://www.psi.net) and as the Policy may be modified by
     PSINet in its sole discretion from time to time. Any content, material,
     message or data made available or transmitted through the Service, wherever
     it is sent from, viewed, received, or retrieved, that is in violation of
     (i) any local, state, federal or international law, regulation or treaty;
     (ii) the Policy; or (iii) any community standard or accepted Internet
     policy is prohibited. Any such violation may be deemed a material breach of
     this Agreement and PSINet may, in its sole discretion, disable or terminate
     the Service with written notice to Customer, but without any cure period. 

     B. Customer-Only Traffic. The right to use the Service is strictly limited
     to Customer only and does not extend to any other person, corporation or
     entity except for wholly-owned affiliates of Customer and those members of
     Customer's staff and consultants in the course of performing work for
     Customer. 

     C. Third-Party Traffic. Customer may host world-wide web sites on behalf of
     third parties. In addition, Customer may feed USENET News to a third party,
     but may not send any posting from that third party, including, but not
     limited to, electronic mail, back to PSINet's wide-area network system (the
     "Network") or the Internet through the Service. Any other third party
     traffic, including packet access and electronic mail, whether sent or
     received through Customer's facilities by or on behalf of a third party
     through the Service, is expressly prohibited.

Service Usage. No more than one connection can be used at any time with a
Service as paid for by Customer and assigned by PSINet. If two individuals or
groups need to simultaneously access PSINet through separate phone lines, then
they would have to acquire two Services, and so on. Service use is defined as a
connection with a PSINet modem or access device using the public switched
telephone system (e.g. POTS lines or ISDN circuits). This single phone line
connection does allow for multiple individual user sessions.

Customer Network Security. PSINet provides no user access security with respect
to any of Customer's facilities or facilities of others. Customer shall be
responsible for user/access security as well as access to its network or to the
Network. PSINet will assist in network security breach detection or
identification, but shall not be liable for any inability, failure or mistake in
doing so.

Service Assurance. If Customer notifies PSINet immediately upon its failure to
access the Network through Customer's standard means, including multiple
alternative dialup POPs, provided with the Service, and PSINet determines in its
reasonable commercial judgment that the Network is therefore unavailable to
Customer ("Unavailable"), one of the following will apply:

     1. If PSINet determines that the Network is Unavailable for one (1) or more
     consecutive hours during any calendar month, PSINet, upon Customer's
     request, will credit Customer's monthly invoice the pro-rated charges for
     one (1) day's Service fee; or 


                                  Schedule 5.4.1
                                   Page 9 of 23


<PAGE>


     2. If PSINet determines that the Network is Unavailable for an aggregate of
     four (4) or more hours during any calendar month, PSINet, upon Customer's
     request, will credit Customer's monthly invoice the pro-rated charges for
     one (1) week's Service fee.

These two options are not cumulative. For purposes of this section, scheduled
maintenance will not be considered to be Unavailability. PSINet shall not be
responsible for any toll charges incurred by Customer's use of any telephone
company ("Telco") or other telecommunications services as a result of this
section. THE FOREGOING TWO OPTIONS STATE PSINET'S SOLE OBLIGATION, AND
CUSTOMER'S SOLE REMEDY, FOR NETWORK UNAVAILABILITY.

LIMITED WARRANTIES.

     A. Service. PSINET WARRANTS THAT THE SERVICE WILL OPERATE SUBSTANTIALLY IN
     CONFORMANCE WITH THIS AGREEMENT. PSINET MAKES NO OTHER WARRANTIES OF ANY
     KIND, WHETHER EXPRESSED, IMPLIED OR STATUTORY, INCLUDING, BUT NOT LIMITED
     TO, ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS OF THE SERVICE FOR A
     PARTICULAR PURPOSE AND NON-INFRINGEMENT OF ANY THIRD PARTY RIGHTS. CUSTOMER
     IS RESPONSIBLE FOR ASSESSING ITS OWN COMPUTER AND TRANSMISSION NETWORK
     NEEDS, AND THE RESULTS TO BE OBTAINED THEREFROM. USE OF ANY INFORMATION
     OBTAINED THROUGH THE SERVICE IS AT CUSTOMER'S RISK. PSINET SPECIFICALLY
     DENIES ANY RESPONSIBILITY FOR THE ACCURACY OR QUALITY OF INFORMATION
     OBTAINED THROUGH THE SERVICE. 

     B. Equipment. PSINET REPRESENTS AND WARRANTS THAT DURING THE TERM OF THIS
     AGREEMENT IT WILL MAKE REASONABLE EFFORTS TO ENSURE THE EQUIPMENT OPERATES
     SUBSTANTIALLY IN CONFORMANCE WITH THIS AGREEMENT. ANY UNAUTHORIZED CHANGES
     TO OR INAPPROPRIATE USAGE OF THE EQUIPMENT, HOWEVER, WILL VOID THE
     FOREGOING WARRANTY. PSINET DOES NOT WARRANT THAT THE EQUIPMENT WILL BE
     ENTIRELY FREE FROM DEFECTS OR THAT ITS OPERATION WILL BE ERROR FREE.
     FURTHERMORE, CUSTOMER ACKNOWLEDGES THAT PSINET HAS MADE NO OTHER
     REPRESENTATION OR WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH RESPECT TO
     THE CONDITION OR PERFORMANCE OF THE EQUIPMENT, OR ITS MERCHANTABILITY OR
     FITNESS FOR A PARTICULAR PURPOSE. 

     C. General. EACH PARTY ACKNOWLEDGES THAT IT HAS READ AND UNDERSTANDS THIS
     AGREEMENT AND AGREES TO BE BOUND BY ITS TERMS. EACH PARTY FURTHER WARRANTS
     THAT IT HAS FULL CORPORATE POWER AND AUTHORITY TO ENTER INTO AND DELIVER
     THIS AGREEMENT AND TO PERFORM ITS OBLIGATIONS HEREUNDER, AND THAT THE
     PERSON WHOSE SIGNATURE APPEARS BELOW IS DULY AUTHORIZED TO ENTER INTO THIS
     AGREEMENT ON BEHALF OF THAT PARTY.

LIMITATION OF LIABILITY. EXCEPT FOR CUSTOMER'S PAYMENT OBLIGATIONS HEREUNDER,
NEITHER PARTY SHALL BE LIABLE FOR DIRECT DAMAGES GREATER THAN THE SUM TOTAL OF
PAYMENTS MADE BY CUSTOMER TO PSINET DURING THE SIX (6) MONTHS IMMEDIATELY
PRECEDING THE EVENT FOR WHICH DAMAGES ARE CLAIMED. EXCEPT FOR THE FOREGOING,
PSINET SHALL HAVE NO LIABILITY TO CUSTOMER WITH RESPECT TO (I) ANY CLAIM, LOSS
OR DAMAGE OF ANY KIND OR NATURE WHATSOEVER INCLUDING THE ACTIVE OR PASSIVE
NEGLIGENCE OR STRICT LIABILITY OF PSINET FOR CLAIMS ARISING OUT OF OR IN
CONNECTION WITH THE SERVICE OR THE EQUIPMENT, WHETHER OR NOT KNOWN OR DISCLOSED
TO PSINET; (II) ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, PUNITIVE OR
CONSEQUENTIAL LOSSES OR DAMAGES RESULTING FROM THE DELIVERY, INSTALLATION,
MAINTENANCE, OPERATION OR USE OF THE SERVICE OR THE EQUIPMENT; (III) ANY ACT OR
OMISSION OF ANY OTHER ENTITY FURNISHING EQUIPMENT, PRODUCTS OR SERVICES TO
CUSTOMER; (IV) ANY PERSONAL OR PROPERTY DAMAGES DUE TO THE LOSS OF STORED,
TRANSMITTED OR RECORDED DATA RESULTING FROM THE SERVICE OR THE EQUIPMENT, EVEN
IF PSINET HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES; AND (V) ANY LOSS
OR DAMAGES DUE TO THE FAULT OR NEGLIGENCE OF CUSTOMER OR ITS EMPLOYEES, AGENTS
OR REPRESENTATIVES.


                                  Schedule 5.4.1
                                  Page 10 of 23


<PAGE>

IN NO EVENT SHALL EITHER PARTY BE LIABLE FOR ANY INDIRECT, INCIDENTAL,
EXEMPLARY, PUNITIVE OR OTHER CONSEQUENTIAL DAMAGES WHETHER OR NOT FORESEEABLE,
INCLUDING, BUT NOT LIMITED TO, DAMAGES FOR THE LOSS OF DATA, GOODWILL OR
PROFITS, ARISING OUT OF OR IN RELATION TO THIS AGREEMENT EVEN IF ADVISED
BEFOREHAND OF THE POSSIBILITY OF SUCH LIABILITY. THE PARTIES AGREE TO WORK IN
GOOD FAITH TO IMPLEMENT THE PURPOSES OF THIS AGREEMENT, BUT RECOGNIZE THAT THE
SERVICE COULD NOT BE MADE AVAILABLE UNDER THESE TERMS OR OTHER SIMILAR TERMS
WITHOUT A SUBSTANTIAL INCREASE IN COST IF PSINET WERE TO ASSUME A GREATER DEGREE
OF LIABILITY TO CUSTOMER.









                                  Schedule 5.4.1
                                  Page 11 of 23


<PAGE>




                           MANAGED INTRANET WAN SERVICE
                           CUSTOMER CONTRACT PROVISIONS


PSINET NETWORK USAGE. 

     A. Compliance With Law and Policy. Customer has read and agrees to comply
     with PSINet's Net-Abuse Policy ("Policy") as currently set forth on
     PSINet's Web site (http://www.psi.net) and as the Policy may be modified by
     PSINet in its sole discretion from time to time. Any content, material,
     message or data made available or transmitted through the Service, wherever
     it is sent from, viewed, received, or retrieved, that is in violation of
     (i) any local, state, federal or international law, regulation or treaty;
     (ii) the Policy; or (iii) any community standard or accepted Internet
     policy is prohibited. Any such violation may be deemed a material breach of
     this Agreement and PSINet may, in its sole discretion, disable or terminate
     the Service with written notice to Customer, but without any cure period. 

     B. Customer-Only Traffic. The right to use the Service is strictly limited
     to Customer only and does not extend to any other person, corporation or
     entity except for wholly-owned affiliates of Customer and those members of
     Customer's staff and consultants in the course of performing work for
     Customer. 

     C. Third-Party Traffic. Customer may host world-wide web sites on behalf of
     third parties. In addition, Customer may feed USENET News to a third party,
     but may not send any posting from that third party, including, but not
     limited to, electronic mail, back to PSINet's wide-area network system (the
     "Network") or the Internet through the Service. Any other third party
     traffic, including packet access and electronic mail, whether sent or
     received through Customer's facilities by or on behalf of a third party
     through the Service, is expressly prohibited.

Customer Equipment and Network. PSINet provides no user access security with
respect to any of Customer's facilities or facilities of others. PSINet will
assist in enforcing a customer-specified access policy as provided in the
Specifications subject to the limits of the implementing equipment and the level
of subscribed service. PSINet is not liable for any inability, failure or
mistake in implementing, enforcing, or monitoring the enforcement of the
specified policy.

PSINET-PROVIDED EQUIPMENT. 

     (1) Equipment Space. Customer shall provide and maintain suitable Equipment
     Space meeting or exceeding the requirements set forth in the
     Specifications. 

     (2) Equipment. The Equipment Space at each site specified by Customer will
     house Equipment owned by PSINet required for the Service. PSINet shall
     retain all right, title, and interest in the Equipment at all times. PSINet
     will provide Equipment at each site to provide the connection between
     Customer's network and the Telco circuit leading to the Network. The
     particular make and model of Equipment shall be selected for Customer by
     PSINet in its sole discretion. If PSINet determines in its sole reasonable
     judgment that the Equipment is defective, PSINet shall replace the
     defective Equipment at no cost to Customer. THE FOREGOING STATES PSINET'S
     SOLE OBLIGATION, AND CUSTOMER'S SOLE REMEDY, FOR ANY DEFECTIVE EQUIPMENT. 


                                  Schedule 5.4.1
                                  Page 12 of 23


<PAGE>


     (3) Equipment Access and Connection. The Equipment shall be maintained by
     PSINet or its subcontractors. Customer shall not allow its personnel or
     others on its premises to open the Equipment cabinets. PSINet will verbally
     authorize on an event-by-event basis individuals at Customer's location to
     open Equipment cabinets for appropriate routine and emergency reasons.
     Customer shall retain the right to disconnect the Equipment from its LAN at
     any time. PSINet reserves the right to shut down the Equipment at
     Customer's location in accordance with PSINet's emergency operating
     procedures with notification to Customer. 

     (4) Equipment Relocation. PSINet is not responsible for Service disruptions
     caused by Customer's Equipment relocation requirements. 

     (5) Equipment Return. Upon termination of the Service for any reason,
     Customer agrees immediately to allow the return of the Equipment to PSINet.
     PSINet retains all rights to recover possession of the Equipment from
     Customer.

LIMITED WARRANTIES. 

     A. Service. PSINET WARRANTS THAT THE SERVICE WILL OPERATE SUBSTANTIALLY IN
     CONFORMANCE WITH THE SPECIFICATIONS. PSINET MAKES NO OTHER WARRANTIES OF
     ANY KIND, WHETHER EXPRESSED, IMPLIED OR STATUTORY, INCLUDING, BUT NOT
     LIMITED TO, ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS OF THE SERVICE
     FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT OF ANY THIRD PARTY RIGHTS.
     CUSTOMER IS RESPONSIBLE FOR ASSESSING ITS OWN COMPUTER AND TRANSMISSION
     NETWORK NEEDS, AND THE RESULTS TO BE OBTAINED THEREFROM. USE OF ANY
     INFORMATION OBTAINED THROUGH THE SERVICE IS AT CUSTOMER'S RISK. PSINET
     SPECIFICALLY DENIES ANY RESPONSIBILITY FOR THE ACCURACY OR QUALITY OF
     INFORMATION OBTAINED THROUGH THE SERVICE. 

     B. Equipment. PSINET REPRESENTS AND WARRANTS THAT DURING THE TERM OF THIS
     AGREEMENT IT WILL MAKE REASONABLE EFFORTS TO ENSURE THE EQUIPMENT OPERATES
     SUBSTANTIALLY IN CONFORMANCE WITH THE SPECIFICATIONS. ANY UNAUTHORIZED
     CHANGES TO OR INAPPROPRIATE USAGE OF THE EQUIPMENT, HOWEVER, WILL VOID THE
     FOREGOING WARRANTY. PSINET DOES NOT WARRANT THAT THE EQUIPMENT WILL BE
     ENTIRELY FREE FROM DEFECTS OR THAT ITS OPERATION WILL BE ERROR FREE.
     FURTHERMORE, CUSTOMER ACKNOWLEDGES THAT PSINET HAS MADE NO OTHER
     REPRESENTATION OR WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH RESPECT TO
     THE CONDITION OR PERFORMANCE OF THE EQUIPMENT, OR ITS MERCHANTABILITY OR
     FITNESS FOR A PARTICULAR PURPOSE. 

     C. General. EACH PARTY ACKNOWLEDGES THAT IT HAS READ AND UNDERSTANDS THIS
     AGREEMENT AND AGREES TO BE BOUND BY ITS TERMS. EACH PARTY FURTHER WARRANTS
     THAT IT HAS FULL CORPORATE POWER AND AUTHORITY TO ENTER INTO AND DELIVER
     THIS AGREEMENT AND TO PERFORM ITS OBLIGATIONS HEREUNDER, AND THAT THE
     PERSON WHOSE SIGNATURE APPEARS BELOW IS DULY AUTHORIZED TO ENTER INTO THIS
     AGREEMENT ON BEHALF OF THAT PARTY.

LIMITATION OF LIABILITY. EXCEPT FOR CUSTOMER'S PAYMENT OBLIGATIONS HEREUNDER,
NEITHER PARTY SHALL BE LIABLE FOR DIRECT DAMAGES GREATER THAN THE SUM TOTAL OF
PAYMENTS MADE BY CUSTOMER TO PSINET DURING THE SIX (6) MONTHS IMMEDIATELY
PRECEDING THE EVENT FOR WHICH DAMAGES ARE CLAIMED. EXCEPT FOR THE FOREGOING,
PSINET SHALL HAVE NO LIABILITY TO CUSTOMER WITH RESPECT TO (I) ANY CLAIM, LOSS
OR DAMAGE OF ANY KIND OR NATURE WHATSOEVER INCLUDING THE ACTIVE OR PASSIVE
NEGLIGENCE OR STRICT LIABILITY OF PSINET FOR CLAIMS ARISING OUT OF OR IN
CONNECTION WITH THE SERVICE OR THE EQUIPMENT, WHETHER OR NOT KNOWN OR DISCLOSED
TO PSINET; (II) ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, PUNITIVE OR
CONSEQUENTIAL LOSSES OR DAMAGES RESULTING FROM THE DELIVERY, INSTALLATION,
MAINTENANCE, OPERATION OR USE OF THE SERVICE OR THE EQUIPMENT; (III) ANY ACT OR
OMISSION OF ANY OTHER ENTITY FURNISHING EQUIPMENT, PRODUCTS OR SERVICES TO 


                                  Schedule 5.4.1
                                  Page 13 of 23


<PAGE>


CUSTOMER; (IV) ANY PERSONAL OR PROPERTY DAMAGES DUE TO THE LOSS OF STORED,
TRANSMITTED OR RECORDED DATA RESULTING FROM THE SERVICE OR THE EQUIPMENT, EVEN
IF PSINET HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES; AND (V) ANY LOSS
OR DAMAGES DUE TO THE FAULT OR NEGLIGENCE OF CUSTOMER OR ITS EMPLOYEES, AGENTS
OR REPRESENTATIVES.

IN NO EVENT SHALL EITHER PARTY BE LIABLE FOR ANY INDIRECT, INCIDENTAL,
EXEMPLARY, PUNITIVE OR OTHER CONSEQUENTIAL DAMAGES WHETHER OR NOT FORESEEABLE,
INCLUDING, BUT NOT LIMITED TO, DAMAGES FOR THE LOSS OF DATA, GOODWILL OR
PROFITS, ARISING OUT OF OR IN RELATION TO THIS AGREEMENT EVEN IF ADVISED
BEFOREHAND OF THE POSSIBILITY OF SUCH LIABILITY. THE PARTIES AGREE TO WORK IN
GOOD FAITH TO IMPLEMENT THE PURPOSES OF THIS AGREEMENT, BUT RECOGNIZE THAT THE
SERVICE COULD NOT BE MADE AVAILABLE UNDER THESE TERMS OR OTHER SIMILAR TERMS
WITHOUT A SUBSTANTIAL INCREASE IN COST IF PSINET WERE TO ASSUME A GREATER DEGREE
OF LIABILITY TO CUSTOMER.







                                  Schedule 5.4.1
                                  Page 14 of 23


<PAGE>


                       INTERNET REMOTE ACCESS SERVICE CUSTOMER
                                 CONTRACT PROVISIONS


PSINET NETWORK USAGE. 

     A. Compliance With Law and Policy. Customer along with each End-User, has
     read and agrees to comply with PSINet's Net-Abuse Policy ("Policy") as
     currently set forth on PSINet's Web site (http://www.psi.net) and as the
     Policy may be modified by PSINet in its sole discretion from time to time.
     Any content, material, message or data made available or transmitted
     through an Account wherever it is sent from, viewed, received, or
     retrieved, that is in violation of (i) any local, state, federal or
     international law, regulation or treaty; (ii) the Policy; or (iii) any
     community standard or accepted Internet policy is prohibited. Any such
     violation may be deemed a material breach of this Agreement and PSINet may,
     in its sole discretion, disable or terminate an Account or the Service with
     written notice to Customer, but without any cure period. 

     B. Customer-Only Traffic. The right to use an Account is strictly limited
     to Customer only and does not extend to any other person, corporation or
     entity except for wholly-owned affiliates of Customer and those members of
     Customer's staff and consultants in the course of performing work for
     Customer. 

     C. Third-Party Traffic. Customer's End-Users may feed USENET News to a
     third party, but may not send any posting from that third party, including,
     but not limited to, electronic mail, back to the Network or the Internet
     through an Account. Any other third party traffic, including packet access
     and electronic mail, whether sent or received through Customer's facilities
     by or on behalf of a third party through the Service, is expressly
     prohibited.

Customer Network and Facilities. Customer shall remain responsible for
user/access security as well as access to its network or to the Network. PSINet
provides no user access security with respect to any of Customer or its
End-Users' facilities or facilities of others. PSINet will assist in network
security breach detection or identification, but shall not be liable for any
inability, failure or mistake in doing so.

"First-Line" Service Support. Customer's MIS/Technical administrator or contact
is solely responsible for all first line customer support for End-Users. If
End-Users require additional support, only Customer's designated Help Desk or
MIS/Technical contact may request support directly from PSINet's Customer
Support Group (CSG).

10.  NO WARRANTIES. NEITHER PSINET, ITS AFFILIATES, DIRECTORS, EMPLOYEES AND
SUBCONTRACTORS WARRANT ANY CONNECTION TO, TRANSMISSION OVER, NOR RESULTS OR USE
OF, ANY NETWORK CONNECTION OR FACILITIES PROVIDED (OR FAILED TO BE PROVIDED)
UNDER THIS AGREEMENT. CUSTOMER IS RESPONSIBLE FOR ASSESSING ITS OWN COMPUTER AND
TRANSMISSION NETWORK NEEDS, AND THE RESULTS TO BE OBTAINED THEREFROM. USE OF ANY
INFORMATION OBTAINED VIA AN ACCOUNT IS AT CUSTOMER AND THEIR END-USER'S RISK.
PSINET SPECIFICALLY DENIES ANY RESPONSIBILITY FOR THE ACCURACY OR QUALITY OF
INFORMATION OBTAINED THROUGH THE ACCOUNTS. PSINET MAKES NO WARRANTIES OF ANY
KIND, WHETHER EXPRESSED, IMPLIED OR STATUTORY, INCLUDING, BUT NOT LIMITED TO,
ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS OF THE SERVICE FOR A PARTICULAR
PURPOSE AND NON-INFRINGEMENT OF ANY THIRD PARTY RIGHTS.

PSINET MAKES NO WARRANTY WITH RESPECT TO ANY SOFTWARE OR HARDWARE USED OR
PROVIDED BY PSINET IN CONNECTION WITH AN ACCOUNT. ANY PATENT, TRADEMARK, TRADE
SECRET OR WARRANTY INFRINGEMENTS, WHETHER ACTUAL OR ALLEGED, ARE THE DIRECT 


                                  Schedule 5.4.1
                                  Page 15 of 23


<PAGE>


RESPONSIBILITY OF THE MANUFACTURER OF SAID HARDWARE OR SOFTWARE PRODUCT. PSINET
ASSUMES NO RESPONSIBILITY FOR ANY ACTIONS OR LIABILITIES ARISING FROM THE
POSSESSION OR USE OF THESE SOFTWARE OR HARDWARE PRODUCTS.

11.  Limitation of Liability. EXCEPT FOR CUSTOMER'S PAYMENT OBLIGATIONS
HEREUNDER, NEITHER PARTY SHALL BE LIABLE FOR DIRECT DAMAGES GREATER THAN THE SUM
TOTAL OF PAYMENTS MADE BY CUSTOMER TO PSINET DURING THE SIX (6) MONTHS
IMMEDIATELY PRECEDING THE EVENT FOR WHICH DAMAGES ARE CLAIMED. EXCEPT FOR THE
FOREGOING AND WITHOUT LIMITING ITS GENERALITY, PSINET SHALL HAVE NO LIABILITY TO
CUSTOMER OR ANY THIRD PARTY WITH RESPECT TO (I) ANY CLAIM, LOSS OR DAMAGE OF ANY
KIND OR NATURE WHATSOEVER INCLUDING THE ACTIVE OR PASSIVE NEGLIGENCE OR STRICT
LIABILITY OF PSINET FOR CLAIMS ARISING OUT OF OR IN CONNECTION WITH THE
INDIVIDUAL ACCOUNTS OR SERVICE OR RELATED HARDWARE OR SOFTWARE WHETHER OR NOT
KNOWN OR DISCLOSED TO PSINET; (II) ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
PUNITIVE OR CONSEQUENTIAL LOSSES OR DAMAGES RESULTING FROM THE DELIVERY,
INSTALLATION, MAINTENANCE, OPERATION OR USE OF THE INDIVIDUAL ACCOUNTS OR
SERVICE OR RELATED HARDWARE OR SOFTWARE; (III) ANY ACT OR OMISSION OF ANY OTHER
ENTITY FURNISHING HARDWARE, SOFTWARE OR SERVICES TO CUSTOMER; (IV) ANY PERSONAL
OR PROPERTY DAMAGES DUE TO THE LOSS OF STORED, TRANSMITTED OR RECORDED DATA
RESULTING FROM ANY INDIVIDUAL ACCOUNT, THE SERVICE OR RELATED HARDWARE OR
SOFTWARE, EVEN IF PSINET HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES;
AND (V) ANY LOSS OR DAMAGES DUE TO THE FAULT OR NEGLIGENCE OF CUSTOMER OR ITS
EMPLOYEES, AGENTS OR REPRESENTATIVES.

IN NO EVENT SHALL EITHER PARTY BE LIABLE FOR ANY INDIRECT, INCIDENTAL,
EXEMPLARY, PUNITIVE OR OTHER CONSEQUENTIAL DAMAGES WHETHER OR NOT FORESEEABLE,
INCLUDING, BUT NOT LIMITED TO, DAMAGES FOR THE LOSS OF DATA, GOODWILL OR
PROFITS, ARISING OUT OF OR IN RELATION TO THIS AGREEMENT EVEN IF ADVISED
BEFOREHAND OF THE POSSIBILITY OF SUCH LIABILITY. THE PARTIES AGREE TO WORK IN
GOOD FAITH TO IMPLEMENT THE PURPOSES OF THIS AGREEMENT, BUT RECOGNIZE THAT THE
INDIVIDUAL ACCOUNTS AND SERVICE COULD NOT BE MADE AVAILABLE UNDER THESE TERMS OR
OTHER SIMILAR TERMS WITHOUT A SUBSTANTIAL INCREASE IN COST IF PSINET WERE TO
ASSUME A GREATER DEGREE OF LIABILITY TO CUSTOMER OR OTHER THIRD PARTIES.





                                  Schedule 5.4.1
                                  Page 16 of 23


<PAGE>


                          MANAGED INTERNET SECURITY SERVICES
                             CUSTOMER CONTRACT PROVISIONS
                                           

     Security Services Defined. Customer desires certain additional security
     services offered by PSS (the "Security Services") as specified in the
     "RouteWalle(SM) Managed Perimeter Security Service Specifications," and the
     "SecureEnterpriseTM Enterprise-Wide Managed Security Service
     Specifications" which are collectively called the "Specifications" and are
     incorporated herein by reference. The Security Services are designed to
     provide certain access control techniques or information to Customer
     regarding its computer or computer network(s)' connection to the Network
     and the Internet. The addition of the Security Services for Customer as
     contemplated in this Agreement requires Customer to possess or acquire a
     Dedicated Internet Access Service (InterFrame, for the RouteWaller Security
     Service, and InterFrame or InterMAN, for the SecureEnterprise Security
     Service) from PSINet Inc. which connects Customer's host computer or local
     area network (LAN) to the PSINet wide-area network system (the "Network")
     and the Internet.

3.   Security Services Policy Creation and Implementation. 

     A. Limited Scope. WHILE PSS WILL ENDEAVOR TO PROVIDE AND/OR INSTALL
     EQUIPMENT OR CONSULTING AND IMPLEMENTATION EXPERTISE, AS APPLICABLE IN
     CONJUNCTION WITH THE SELECTED SECURITY SERVICE, CUSTOMER ACKNOWLEDGES THAT
     IT IS FAMILIAR WITH AND HAS HAD ADEQUATE OPPORTUNITY TO EVALUATE THE
     SECURITY SERVICE SELECTED AND THAT PSS WILL ONLY ULTIMATELY ACT UPON THE
     POLICY AND PROCEDURES ESTABLISHED AND COMMUNICATED IN WRITING BY CUSTOMER
     THROUGH ITS AUTHORIZED REPRESENTATIVES (SPECIFICALLY, THE "SECURITY
     OFFICERS" IDENTIFIED BY CUSTOMER IN THE SECURITY SERVICES ORDER FORM
     ("ORDER FORM") WHICH IS INCORPORATED HEREIN BY REFERENCE). ANY AND ALL SUCH
     WRITTEN COMMUNICATIONS SHALL BE APPENDED TO THIS AGREEMENT TO THE EXTENT
     AGREED UPON BY PSS. 

     B. Procedure. 

     (1)  Customer shall delegate two Security Officers, a primary and a
          secondary. Security Officer names, phone numbers, fax numbers, and
          electronic mail addresses must be provided to PSS on the order form.
          PSS will take direction ONLY from these Security Officers for Security
          Service. 

     (2)  Customer Security Officers must participate in an initial phone
          consultation with PSS's Security Coordinator. 

     (3)  Customer requests for security provisions shall be made by electronic
          mail or fax to the designated PSS address to facilitate an audit
          trail. 

     (4)  PSS Network Operations can be instructed by other Customer contacts to
          disable non-PSS access (for instance, MAE-East, MAE-West or CIX
          access). 

     (5)  The Security Service can only be facilitated using PSS provided
          equipment at Customer's site and with Customer's employees. (6) PSS
          will ship PSS-owned equipment only to Customer's Security Officers for
          Customer either to install or have PSS personnel install.


                                  Schedule 5.4.1
                                  Page 17 of 23


<PAGE>


4.   PSS-Owned Equipment: 

     A. PSS-Owned Equipment Usage Grants. PSS hereby grants Customer a
     non-exclusive license to use the PSS-owned Equipment associated with the
     selected Security Service, along with any related user documentation,
     subject to the terms provided herein. Customer agrees and acknowledges that
     it has no right, title or interest in or to any of the PSS-owned Equipment,
     including, but not limited to, any related patents, trademarks, copyrights
     or other proprietary rights, except as specifically set forth herein. 

     (1)  CUSTOMER MAY 

          (a)  make copies of the software portions of the PSS-owned Equipment
               for backup and archival purposes only, provided that the software
               and all proprietary notices remain intact. 

          (b)  make copies of the PSS-owned Equipment's documentation, provided
               that such documentation is copied in its entirety and all
               proprietary notices remain intact. 

     (2)  CUSTOMER MAY NOT 

          (a)  rent, lend, sublicense or lease the PSS-owned Equipment to
               another party. 

          (b)  modify, disassemble, decompile or reverse engineer any portion of
               the PSS-owned Equipment.

     B.   PSS-Owned Equipment Space. In order to allow for the Security Service,
     Customer shall, during the term of this Agreement, provide and maintain
     suitable Equipment Space. The Equipment Space will house the PSS-owned
     Equipment required for the Security Service. Customer shall retain the
     right to disconnect the PSS-owned Equipment from its LAN at any time;
     however such action will suspend the Security Service and any associated
     warranties provided by PSS. 

     C.   Relocation of PSS-Owned Equipment. Should Customer deem it necessary
     to have the PSS-owned Equipment relocated, Customer shall be responsible
     for moving the PSS-owned Equipment under PSS supervision. PSS shall not be
     responsible for any Security Service disruptions caused by the PSS-owned
     Equipment's relocation. 

     D.   Usage of PSS-Owned Equipment. Should PSS provide PSS-owned Equipment
     to Customer (as will be labeled by PSS) for its use as part of this
     Agreement, title to the Equipment shall be and remain in PSS at all times,
     and Customer shall have no interest therein except as expressly provided
     under this Agreement. Customer assumes full responsibility for, and, in the
     event of lost or damaged PSS-owned Equipment, shall pay the replacement
     cost plus 5% to the nearest $10.00, plus any applicable shipping and
     handling charges. Upon termination of this Agreement, Customer shall
     immediately return all PSS-owned Equipment to PSS. 

     E.   Reprogramming/Repairing PSS-Owned Access Control Cards. In the event
     Customer requires PSS to reprogram or repair an individual Access Control
     Card owned by PSS and already in use by Customer, Customer shall be
     responsible for all shipping fees to and from PSS and will incur a one-time
     handling fee of $25.00 per PSS-owned Access Control Card.


                                  Schedule 5.4.1
                                  Page 18 of 23


<PAGE>
 
7.   Confidential Information. 

     A.   Acknowledgment of Confidentiality. Each Party hereby acknowledges that
     it may be exposed to confidential and proprietary information belonging to
     the other party or relating to its affairs, including materials expressly
     designated or marked as confidential. Confidential Information does not
     include (i) information already known or independently developed by the
     recipient; (ii) information in the public domain through no wrongful act of
     the recipient, or (iii) information received by recipient from a third
     party who was free to disclose it. 

     B.   Covenant Not to Disclose. Each party hereby agrees that it shall not
     use, commercialize or disclose the other party's Confidential Information
     to any person or entity, except to its own employees or agents having a
     "need to know" such information in connection with the performance of this
     Agreement, and to such other recipients as the other party may approve in a
     signed, written document. Neither party shall alter or remove from any
     software, documentation or other Confidential Information of the other
     party (or any third party) any proprietary, copyright, trademark or trade
     secret legend. The parties' obligations of confidentiality under this
     Agreement shall survive termination of this Agreement for any reason.

8.   Non Circumvention. During the term of this Agreement and for a period of
eighteen (18) months thereafter, Customer agrees not to hire, solicit, nor
attempt to solicit the services, of any employee or subcontractor of PSS, its
parent or affiliate companies, without PSS' prior written consent; provided,
however, that Customer is not prevented from employing such person who contacts
Customer on his or her own initiative and without any direct or indirect
solicitation by Customer. Violation of this provision shall, in addition to
other relief, entitle PSS or its parent company to assert liquidated damages
against Customer equal to one hundred fifty (150) percent of the solicited
person's annual compensation.

9.   Customer Equipment and Network. PSS IS NOT RESPONSIBLE TO CUSTOMER FOR THE
COST OR EXPENSE OF ADMINISTRATIVE, TECHNICAL, EMERGENCY AND SUPPORT PERSONNEL AT
CUSTOMER'S LOCATION NECESSARY FOR DEALING WITH PSS OR FOR PROVIDING AND
MAINTAINING CUSTOMER'S OWN COMPUTER EQUIPMENT AND NETWORK OR INTERNET ACCESS.
CUSTOMER SHALL CONTINUE TO BE RESPONSIBLE FOR USER/ACCESS SECURITY AND NETWORK
ACCESS TO ITS COMPUTER OR COMPUTER NETWORK(S). PSS WILL ASSIST IN NETWORK
SECURITY BREACH DETECTION OR IDENTIFICATION IN ACCORDANCE WITH THE SECURITY
SERVICE SELECTED AND INDUSTRY STANDARDS, BUT DOES NOT GUARANTEE A SECURE
COMPUTER OR COMPUTER NETWORK(S) OR ASSUME RESPONSIBILITY FOR ANY INABILITY,
FAILURE OR MISTAKE BY PSS IN PROVIDING SUCH ASSISTANCE.

10.  Limited Performance Warranty on PSS-Owned Equipment. PSS REPRESENTS AND
WARRANTS THAT DURING THE TERM OF THIS AGREEMENT IT WILL MAKE REASONABLE EFFORTS
TO ENSURE THE PSS-OWNED EQUIPMENT USED IN CONNECTION WITH THE SECURITY SERVICE
OPERATES SUBSTANTIALLY IN CONFORMANCE WITH THE RELEVANT SPECIFICATIONS. ANY
UNAUTHORIZED CHANGES TO OR INAPPROPRIATE USAGE OF THE PSS-OWNED EQUIPMENT;
HOWEVER, WILL VOID ANY WARRANTY PROVIDED HEREUNDER.

PSS DOES NOT WARRANT THAT THE EQUIPMENT WILL BE ENTIRELY FREE FROM DEFECTS OR
THAT ITS OPERATION WILL BE ERROR FREE. FURTHERMORE, CUSTOMER ACKNOWLEDGES THAT
PSS HAS MADE NO OTHER REPRESENTATION OR WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, WITH RESPECT TO THE CONDITION OR PERFORMANCE OF THE EQUIPMENT, OR ITS
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. EXCEPT AS EXPRESSLY
PROVIDED ABOVE, PSS SHALL HAVE NO LIABILITY TO CUSTOMER WITH RESPECT TO (I) ANY
CLAIM, LOSS OR DAMAGE OF ANY KIND OR NATURE WHATSOEVER INCLUDING THE ACTIVE OR
PASSIVE NEGLIGENCE OR STRICT LIABILITY OF PSS FOR CLAIMS ARISING OUT OF OR IN
CONNECTION WITH THE EQUIPMENT, WHETHER OR NOT KNOWN OR DISCLOSED TO PSS; (II)
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, PUNITIVE OR CONSEQUENTIAL LOSSES OR
DAMAGES 


                                  Schedule 5.4.1
                                  Page 19 of 23


<PAGE>


RESULTING FROM THE DELIVERY, INSTALLATION, MAINTENANCE, OPERATION, SERVICE OR
USE OF THE EQUIPMENT EXCEPT AS SPECIFIED ABOVE; (III) ANY ACT OR OMISSION OF ANY
OTHER ENTITY FURNISHING EQUIPMENT, PRODUCTS OR SERVICES TO CUSTOMER; (IV) ANY
PERSONAL OR PROPERTY DAMAGES OR FOR LOSS OF STORED, TRANSMITTED OR RECORDED DATA
RESULTING FROM THE EQUIPMENT, EVEN IF PSS HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGES; AND (V) ANY LOSS OR DAMAGES DUE TO THE FAULT OR NEGLIGENCE OF
CUSTOMER OR ITS EMPLOYEES, AGENTS OR REPRESENTATIVES.

EXCEPT AS EXPRESSLY SET FORTH ABOVE, PSS MAKE NO WARRANTIES WITH RESPECT TO: 

     A. Non-PSS-Owned Equipment. WITH RESPECT TO EQUIPMENT NOT OWNED BY PSS, PSS
     ASSIGNS TO CUSTOMER AND CUSTOMER MAY HAVE THE BENEFIT OF ANY MANUFACTURER'S
     WARRANTIES AND THE EQUIPMENT'S SERVICE AGREEMENTS (THE PERFORMANCE AND
     CHARACTER OF WHICH SHALL IN ALL CASES BE GOVERNED BY THE APPLICABLE THIRD
     PARTY LICENSE AGREEMENTS) TO THE EXTENT AVAILABLE AND ASSIGNABLE BY PSS;
     PROVIDED, HOWEVER, THAT CUSTOMER'S SOLE REMEDY FOR THE BREACH OF ANY SUCH
     WARRANTY, INDEMNIFICATION OR SERVICE AGREEMENT SHALL BE ACTIONS OR CLAIMS
     AGAINST THE MANUFACTURER, AND NOT AGAINST PSS, ITS PARENT COMPANY, THEIR
     DIRECTORS, EMPLOYEES AND AGENTS, NOR SHALL ANY SUCH BREACH HAVE ANY EFFECT
     WHATSOEVER ON THE RIGHTS AND OBLIGATIONS OF EITHER PARTY WITH RESPECT TO
     THIS AGREEMENT. 

     B. Security Services. CUSTOMER IS RESPONSIBLE FOR ASSESSING ITS OWN
     COMPUTER AND TRANSMISSION NETWORK NEEDS, AND THE RESULTS TO BE OBTAINED
     THEREFROM. EXCEPT AS SPECIFICALLY PROVIDED IN THE SECTION ABOVE IN
     CONNECTION WITH THE RELATED PSS-OWNED EQUIPMENT, PSS MAKES NO WARRANTIES OF
     ANY KIND, WHETHER EXPRESSED, IMPLIED OR STATUTORY, WITH RESPECT TO THE
     SECURITY SERVICES, INCLUDING, BUT NOT LIMITED TO, ANY IMPLIED WARRANTY OF
     MERCHANTABILITY OR FITNESS OF THE SECURITY SERVICE FOR A PARTICULAR
     PURPOSE. PSS MAKES NO WARRANTY TO ANY THIRD PARTY WHO MAY RELY UPON THE
     SECURITY OF CUSTOMER'S COMPUTER OR COMPUTER NETWORK. C. BREACHES IN
     SECURITY. CUSTOMER AGREES THAT IN NO EVENT SHALL PSS, ITS PARENT COMPANY,
     THEIR AFFILIATES, DIRECTORS, EMPLOYEES AND AGENTS BE HELD LIABLE FOR ANY
     SECURITY BREACH EXPERIENCED BY CUSTOMER, ITS USERS OR OTHERS RELYING ON
     CUSTOMER'S COMPUTER OR COMPUTER NETWORK, WHETHER OR NOT RELATED TO OR
     ARISING FROM THE SECURITY SERVICE, OR FOR ANY FAILURE OF THE SECURITY
     SERVICE TO PERFORM IN ANY RESPECT.

11.  Limitation of Remedies and Liabilities. CUSTOMER AND PSS ACKNOWLEDGE THAT
THE FOLLOWING PROVISIONS REFLECT A FAIR ALLOCATION OF RISK: 

     A. Remedies. CUSTOMER'S SOLE AND EXCLUSIVE REMEDIES FOR PSS'S DEFAULT
     HEREUNDER SHALL BE (I) TO OBTAIN THE REPAIR, REPLACEMENT OR CORRECTION OF
     THE DEFECTIVE EQUIPMENT TO THE EXTENT WARRANTED ABOVE OR, IF PSS REASONABLY
     DETERMINES THAT SUCH REMEDY IS NOT ECONOMICALLY OR TECHNICALLY FEASIBLE,
     (II) TO OBTAIN AN EQUITABLE PARTIAL OR FULL REFUND OF AMOUNTS PAID WITH
     RESPECT TO THE DEFECTIVE SECURITY SERVICE. CUSTOMER MAY TERMINATE THIS
     AGREEMENT AND RECOVER AMOUNTS PAID HEREUNDER WITH RESPECT TO THE INFRINGING
     SECURITY SERVICE, IN WHICH CASE, SUCH TERMINATION AND RECOVERY SHALL BE
     CUSTOMER'S SOLE AND EXCLUSIVE REMEDY IN RESPECT THEREOF.

     B. Liabilities. PSS SHALL NOT BE LIABLE FOR ANY AMOUNT EXCEEDING THE SUM OF
     FEES PAID FOR THE SECURITY SERVICE AT ISSUE DURING THE TWELVE (12) MONTHS
     PRECEDING SUCH CLAIM. IN NO EVENT SHALL EITHER PARTY BE LIABLE, WHETHER IN
     CONTRACT, TORT (INCLUDING NEGLIGENCE) OR OTHERWISE, FOR ANY PUNITIVE,
     SPECIAL, INDIRECT, INCIDENTAL OR OTHER CONSEQUENTIAL DAMAGES (INCLUDING
     LOST SAVINGS, PROFIT OR BUSINESS INTERRUPTION, LOSS OR MISAPPROPRIATION OF
     DATA, OR LOSS OR MISAPPROPRIATION OF CONFIDENTIAL OR PROPRIETARY
     INFORMATION, EVEN IF THE PARTY IS ADVISED IN ADVANCE OF SUCH POSSIBILITY)
     OF THE OTHER PARTY OR ANY THIRD PARTIES ARISING OUT OF OR IN RELATION TO
     THIS AGREEMENT. THE PARTIES AGREE TO WORK IN GOOD FAITH TO 


                                  Schedule 5.4.1
                                  Page 20 of 23


<PAGE>

     IMPLEMENT THE PURPOSES OF THIS AGREEMENT, BUT RECOGNIZE THAT THE SECURITY
     SERVICE TO BE PROVIDED BY PSS COULD NOT BE MADE AVAILABLE UNDER THESE TERMS
     OR OTHER SIMILAR TERMS WITHOUT A SUBSTANTIAL INCREASE IN COST IF PSS WERE
     TO ASSUME A GREATER DEGREE OF LIABILITY TO CUSTOMER.

12. Insurance. Each party shall maintain adequate insurance protection covering
its respective activities hereunder, including coverage for statutory worker's
compensation, comprehensive general liability for bodily injury and tangible
property damage, as well as adequate coverage for vehicles, and for losses
attributable to fraudulent modification, damage or destruction of electronic
data.

13. Export Controls. Customer agrees and acknowledges that any export of the
Equipment used for the Security Services is subject to U.S. export control laws
and regulations. Customer shall not directly or indirectly transfer the
Equipment, or the documentation relating thereto, to any country or location
outside of the United States without obtaining the prior written consent of PSS.

Force Majeure. Neither party shall be responsible for, and will not be
considered in breach or default of this Agreement on account of, any failure to
perform or delay in performance of any obligations hereunder caused by acts of
God, flood, fire, storm, war, public enemy, labor disturbances, including
strikes and lockouts, Equipment malfunction, failure of the Equipment
manufacturer to deliver Equipment, governmental regulations or interferences or
any other event not within the reasonable control of the responsible party and
which that party is unable to overcome by the exercise of reasonable diligence,
provided that such party will use its best efforts to resume normal performance.





                                  Schedule 5.4.1
                                  Page 21 of 23


<PAGE>


                             PSINET INTERNETPAPER SERVICE
                             CUSTOMER CONTRACT PROVISIONS
                                           

Service Support. Only Customer's MIS/Technical contact, designated below, may
request technical support assistance for the Option directly from PSINet's
Customer Support Group (CSG).

No Warranty. PSINET PROVIDES THE OPTION ON AN "AS IS" BASIS. PSINET MAKES NO
OTHER WARRANTIES OF ANY KIND, WHETHER EXPRESSED, IMPLIED OR STATUTORY,
INCLUDING, BUT NOT LIMITED TO, ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS
OF THE OPTION FOR A PARTICULAR PURPOSE AND NON- INFRINGEMENT OF ANY THIRD PARTY
RIGHTS. CUSTOMER IS RESPONSIBLE FOR ASSESSING ITS OWN COMPUTER AND TRANSMISSION
NETWORK NEEDS, AND THE RESULTS TO BE OBTAINED THEREFROM. USE OF ANY INFORMATION
OBTAINED THROUGH THE OPTION IS AT CUSTOMER'S RISK. PSINET SPECIFICALLY DENIES
ANY RESPONSIBILITY FOR THE ACCURACY OR QUALITY OF INFORMATION OBTAINED THROUGH
THE OPTION.

Limitation of Liability. EXCEPT FOR CUSTOMER'S PAYMENT OBLIGATIONS HEREUNDER, IN
NO EVENT SHALL EITHER PARTY BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
EXEMPLARY, PUNITIVE OR OTHER CONSEQUENTIAL DAMAGES WHETHER OR NOT FORESEEABLE,
INCLUDING, BUT NOT LIMITED TO, DAMAGES FOR THE LOSS OF DATA, GOODWILL OR
PROFITS, ARISING OUT OF OR IN RELATION TO THIS ADDENDUM EVEN IF ADVISED
BEFOREHAND OF THE POSSIBILITY OF SUCH LIABILITY. THE PARTIES AGREE TO WORK IN
GOOD FAITH TO IMPLEMENT THE PURPOSES OF THIS ADDENDUM, BUT RECOGNIZE THAT THE
OPTION COULD NOT BE MADE AVAILABLE UNDER THESE TERMS OR OTHER SIMILAR TERMS
WITHOUT A SUBSTANTIAL INCREASE IN COST IF PSINET WERE TO ASSUME A GREATER DEGREE
OF LIABILITY TO CUSTOMER.


                                  Schedule 5.4.1
                                  Page 22 of 23


<PAGE>




                          PSINET CONSUMER WHOLESALE SERVICE
                            SUBSCRIBER CONTRACT PROVISIONS
                                           

Termination of Access. Subscribers are required to comply with PSINet's
Net-Abuse Policy ("Policy") as currently set forth on PSINet's Web site
(HTTP://WWW.PSI.NET) and as the Policy may be modified by PSINet in its sole
discretion from time to time. Any content, material, message, or data made
available or transmitted through the Network, wherever it is sent from, viewed,
received, or retrieved, that is in violation of (i) any local, state, federal or
international law, regulation or treaty; (ii) the Policy; or (iii) any community
standard or accepted Internet policy is prohibited. In the event of violation of
the foregoing by any Subscriber, PSINet will advise Retailer accordingly, and
PSINet reserves the right, in its sole discretion, to terminate such
Subscriber's Access immediately with written notice to Retailer.

Indemnification of PSINET. SUBSCRIBER SHALL INDEMNIFY AND HOLD HARMLESS PSINET
AND PSINET'S DIRECTORS, OFFICERS, EMPLOYEES, AGENTS AND ADVISORS FROM AND
AGAINST ANY AND ALL CLAIMS OF OTHER PERSONS OR ENTITIES ARISING OUT OF ANY
MATERIAL, MESSAGE, DATA, INFORMATION OR OTHER CONTENT TRANSMITTED OR MADE
AVAILABLE BY SUBSCRIBER OR ARISING OUT OF OTHER ACTS OR OMISSIONS OF SUBSCRIBER.





                                  Schedule 5.4.1
                                  Page 23 of 23




<PAGE>
                                    SCHEDULE 5.4.2

                     PROVISIONS IN AGREEMENTS WITH IXC CUSTOMERS


Except as otherwise contemplated under Section 5.1 of the Joint Marketing and
Services Agreement to which this Schedule is attached (the "Marketing
Agreement"), IXC shall require that any IXC Customer to which Services are
provided enter into an agreement that provides, among other things, terms and
conditions reasonably consistent with the provisions of Schedule 5.4.1 to the
Marketing Agreement; provided, however, that with respect to any IXC Customer
for which IXC is not in privity of contract with, IXC shall use reasonable best
efforts to cause the IXC Reseller to require that such IXC Customer enter into
an agreement that provides, among other things, terms and conditions reasonably
consistent with the provisions of Schedule 5.4.1 to the Marketing Agreement. The
parties shall be permitted to make appropriate substitutions to reflect the
identity and uniqueness of the providing party so long as the contract
provisions set forth on Schedule 5.4.1 remain in substantially the form attached
thereto and do not impose any greater liability, obligation or commitment on the
part of PSI. Such agreement shall also provide that, except to the extent caused
by PSI's gross negligence, recklessness or willful misconduct, (i) such IXC
Customer shall defend, indemnify and hold harmless PSI and its respective
directors, officers, employees and agents from any claim asserted by any IXC
Customer or any Third Party to or arising out of use by the IXC Customer or
Third Party of the Services or products provided hereunder, (ii) that PSI shall
not be liable to IXC Customer for indirect, consequential, incidental or special
damages even if advised of the possibility in advance, and (iii) that PSI's
liability for damages to any IXC Customer for any cause whatsoever, regardless
of form of action, shall be limited to the greater of (A) $25,000 for each site
provisioned for Services under this Agreement or (B) the amounts paid by such
IXC Customer for Services during the twelve (12) month period preceding the
incident giving rise to the claim for damages. The foregoing requirements may be
waived or modified with the consent of PSI and shall be modified automatically
to the extent PSI waives such provisions, or imposes less restrictive
provisions, on its customers under its standard terms and conditions and normal
business practices (including where exceptions are routinely granted to
customers), or for any other reseller or distributor. Each Party agrees to
consider such modifications to the foregoing requirements as are reasonably
required in light of market conditions. In situations in which PSI enters into
an agreement directly with the IXC Customer for the provision of the Services,
as contemplated under Section 5.4.2 of the Marketing Agreement, PSI agrees to
include corresponding provisions in its agreements with IXC Customers for the
benefit of IXC.



                                    Schedule 5.4.2
                                     Page 1 of 1



<PAGE>


                                  SCHEDULE 6.2
                                           
                             PSI POINTS OF PRESENCE
                                           
                                    [CHART]
                                           















                                  Schedule 6.2
                                  Page 1 of 1

<PAGE>


                                  SCHEDULE 7.1

                          PRICES FOR OPTIONAL SERVICES


    The following are Optional Prices by Service, not including taxes and
postage, etc.:

Wholesale Dial-up Internet Access                                    $$$$

    1.   Fulfillment (mailer, labeling, inserts, etc.)         *
    2.   Software, Netscape software                           *

*

    3.   Diskette Duplication                                  *
    4.   CD Duplication                                        *
    5.   Printing                                              *
    6.   Customer Support for individuals                      *
    7.   Email services                                        *
    8.   Usenet news                                           *


Dedicated Internet Access Service

    1.   Welcome Letters (setup and print merged)               *
    2.   Materials                                              *
    3.   Printing                                               *
    4.   Fulfillment (mailer, labeling, insert, etc.)           * 
    5.   Usenet news                                            *
    6.   News Feeds                                             *
    7.   RouteWaller Internet Security (w/5 free cards)         *
         plus a monthly charge                                  *
    8.   Cold spare router                                      *
    9.   SecureEnterprise                                       *
         (w/5 free access control cards)                        *
         Cold spare redundancy option                           *
    10.  Additional Access Cards & authentication service       *


Lan on Demand

    1.   Welcome Letters (setup and print merged)               *
    2.   Materials                                              *
    3.   Printing                                               *
    4.   Fulfillment (mailer, labeling, insert, etc.)           *


InterMan 

    1.   Security Filtering                                     *



*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission 



                                  Schedule 7.1
                                  Page 1 of 3


<PAGE>




Web Business Services 

    1.   Web Start base site templates used                     *


Field Services, available only in Iman Cities 

    1.   On-site Field Service visits                           *


DNS Services

    1.   Additional Domain Name                                 *
    2.   Additional 1 IP network number                         *


Value Added Reseller 

    1.   PSI Master VAR agreement commissions on Services       *
         (Not including any circuit charges or 
         installation fees) 
         Subject to an agreement on activity to be 
         performed by both Parties


Network Monthly usage reports                                   TBD

Off-hours Helpline Support (other than 8am to 8pm)              TBD












*   Confidential material has been omitted and filed separately with the
    Securities and Exchange Commission


                                  Schedule 7.1
                                  Page 2 of 3


<PAGE>


                                 APPENDIX 1 TO
                                  SCHEDULE 7.1
                                           
                                          *

                 (Confidential and Proprietary to PSINet, Inc.)

                       Retail Price     IXC Cost      Margin         Margin
                       ------------     --------      ------         ------
                        NRC    MRC     NRC    MRC   NRC    MRC     NRC    MRC
                        ---    ---     ---    ---   ---    ---     ---    ---

LAN-DIAL                   *      *       *      *     *      *      *      *

LAN-ISDN                   *      *       *      *     *      *      *      *

InterFrame 56              *      *       *      *     *      *      *      *

InterFrame 128             *      *       *      *     *      *      *      *

InterFrame 256             *      *       *      *     *      *      *      *

InterFrame 512             *      *       *      *     *      *      *      *

InterFrame T1              *      *       *      *     *      *      *      *

InterMAN T1                *      *       *      *     *      *      *      *

InterMAN 4M                *      *       *      *     *      *      *      *

InterMAN 10M               *      *       *      *     *      *      *      *

InterMAN 16M               *      *       *      *     *      *      *      *

InterMAN 25M               *      *       *      *     *      *      *      *

InterMAN T3 (SMDS)         *      *       *      *     *      *      *      *

InterMAN T3 (ATM)          *      *       *      *     *      *      *      *

PSIWebt T1                 *      *       *      *     *      *      *      *

PSIWebt 10M                *      *       *      *     *      *      *      *

PSIWebt T3                 *      *       *      *     *      *      *      *

InterRamp Remote Access*   *      *       *      *     *      *      *      *


*  Price is per unit






*  Confidential material has been omitted and filed separately with the 
   Securities and Exchange Commission



                                  Schedule 7.1
                                  Page 3 of 3