<PAGE>   1
                                                                    EXHIBIT 10.8

                             CAPACITY IRU AGREEMENT


                                 by and between


               360AMERICAS NETWORK (BERMUDA) LTD., as 360americas


                                       and


                    IMPSAT FIBER NETWORKS, INC., as Customer


                          dated as of February _, 2001



<PAGE>   2

                                TABLE OF CONTENTS


<TABLE>
<CAPTION>
ARTICLE      TITLE                                                     PAGE
<S>          <C>                                                       <C>
1            Exhibits; Definitions                                      2
2            IRU                                                        8
3            Payment                                                    9
4            Acceptance Testing and Delivery                            14
5            Term                                                       14
6            Interconnection and Colocation                             15
7            Maintenance and Repair                                     16
8            Use of the Capacity                                        18
9            Indemnification                                            18
10           Limitation of Liability; Disclaimer of Warranties          19
11           Insurance                                                  21
12           Notices                                                    22
13           Confidentiality                                            23
14           Default                                                    24
15           Termination                                                25
16           Force Majeure Events                                       25
17           Dispute Resolution                                         26
18           Assignment and Transfer Restrictions                       27
19           Representations                                            27
20           General                                                    28
</TABLE>

<PAGE>   3

                             CAPACITY IRU AGREEMENT

        THIS CAPACITY IRU AGREEMENT (this "Agreement") is made and entered into
as of February _, 2001 (the "Effective Date"), by and between 360americas
network (Bermuda) ltd., a Bermuda corporation on behalf of itself and its
designated Affiliates ("360americas"), and Impsat Fiber Networks, Inc., a
Delaware corporation ("Customer").


                                    RECITALS

        A.      360americas has entered into a certain Project Development and
Construction Contract, dated the 16th day of June, 1999 (the "Supply Contract")
with Alcatel Submarine Networks, Inc. ("Alcatel") for the design, manufacture,
construction, installation and delivery of a fiber optic communications system
(and related contracts for the maintenance and operation thereof), between
Tuckerton, New Jersey; Boca Raton, Florida; St. David's, Bermuda; Maiquetia,
Venezuela; Fortaleza, Brazil; Bandeirantes, Brazil and Las Toninas, Argentina.
360americas is constructing and/or acquiring rights in a terrestrial fiber optic
communications system between Las Toninas, Argentina and Bandeirantes, Brazil.
The entire communications system shall be referred to as the "360americas
System", and is illustrated on Exhibit A.

        B.      Customer desires to receive from 360americas and 360americas
desires to provide Customer certain telecommunications capacity on the
360americas System.

        C.      Affiliates of 360americas, 360networks (USA) inc. and
360networks services ltd. (collectively "360networks"), either directly or
indirectly, are constructing a fiber optic communications network, including
optronics and other facilities in North America (the "360networks System"),
which is intended to connect 360networks' points of presence or facilities in
the United States and Canada and as such points of presence may be amended from
time to time by 360networks.

        D.      Customer may desire to purchase from 360networks
telecommunications capacity along certain dedicated communications paths on the
360networks System connecting certain endpoints. More or less contemporaneously
herewith, the Parties are entering into that certain Master Services Agreement
governing the purchase and provision of communications capacity on the
360networks System (the "Master Services Agreement"), should Customer require
such capacity for its business. The parties intend that telecommunications
capacity purchased under the Master Services Agreement will contribute toward
satisfaction of the Minimum Commitment set forth in Section 3.7 of this
Agreement.

        Accordingly, in consideration of the mutual promises set forth in this
Agreement, and other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the Parties hereby agree as
follows:


* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
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                                    ARTICLE 1

                              EXHIBITS; DEFINITIONS

        1.1     Exhibits. The following exhibits are attached hereto,
incorporated herein and made a part of this Agreement by this reference:

        Exhibit A:  Schematic of 360americas System/Target RFCS Dates
        Exhibit B:  360americas System Capacity RFCS Standard; Testing Standards
        Exhibit C:  Technical Specification
        Exhibit D:  IRU Fees
        Exhibit E:  O&M Fees
        Exhibit F:  Service Level Agreement
        Exhibit G:  Colocation

        1.2     Definitions. As used in this Agreement, the capitalized terms
listed in this Section 1.2 and derivatives thereof shall have the meanings
respectively ascribed to them in this Section 1.2.

                "360americas" has the meaning set forth in the introductory
                paragraph.

                "360americas Indemnitees" has the meaning set forth in Section
                9.2.

                "360americas System" has the meaning set forth in Recital A.

                "360networks" has the meaning set forth in Recital C.

                "360networks System" has the meaning set forth in Recital C.

                "AAA" has the meaning set forth in Section 17.1.

                "Alcatel" has the meaning set forth in Recital A.

                "Acceptance Date" has the meaning set forth in Section 4.2.

                "Affiliate" means, with respect to any Person, any other Person,
                who directly or indirectly controls, is controlled by, or is
                under common control with that Person. As used in this
                definition, "control" means (i) ownership, directly or
                indirectly, of


                                       2

* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
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                at least 50% of the securities entitled to vote on the affairs
                of a Person or (ii) the possession, directly or indirectly, of
                the power to direct or cause the direction of the management or
                policies of a Person, whether by way of equity ownership,
                contract or otherwise.

                "Agreement" has the meaning set forth in the introductory
                paragraph.

                "Annual Commitment" has the meaning set forth in Section 3.7.
                "First Annual Commitment, "Second Annual Commitment", "Third
                Annual Commitment" and "Fourth Annual Commitment" have the
                meaning ascribed to them in Section 3.7.

                "Background Block Error" or "BBE" has the meaning set forth in
                Exhibit F.

                "Background Block Error Ratio" or "BBER" has the meaning set
                forth in Exhibit F.

                "Cable Station" means the cable stations of the 360americas
                System located at Tuckerton, New Jersey; Boca Raton, Florida;
                Maiquetia, Venezuela; Fortaleza, Brazil; St. David's Bermuda;
                Bandeirantes, Brazil; and Las Toninas, Argentina.

                "Capacity" means communications capacity on the S Segments, the
                T Segments and the Terrestrial Segments purchased by Customer
                under the terms of this Agreement in minimum increments of
                STM-1, STM-4, or STM-16, but not exceeding STM-64 in the
                aggregate, and which capacity features network protection
                equipment provided by or through 360americas. Each accepted
                Circuit Order shall specify the Capacity desired by Customer.

                "Capacity Acceptance Tests" has the meaning set forth in Section
                4.2.

                "Circuit" means individual circuits of Capacity on the entire
                360americas System purchased by Customer pursuant to Section
                2.3.

                "Circuit Order" has the meaning set forth in Section 2.3.1.

                "City-Center POP(s)" means the operating centers of 360americas
                located in Sao Paulo, Brazil and Buenos Aires, Argentina.

                "Commitment Period" has the meaning set forth in Section 3.7.
                The "First Commitment Period", "Second Commitment Period",
                "Third Commitment Period" and "Fourth Commitment Period" have
                the meanings set forth in Section 3.7.

                "Completion Notice" has the meaning set forth in Section 4.1.


                                       3

* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
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                "Confidential Information" has the meaning set forth in Section
                13.1.

                "Costs" means actual, direct costs paid or payable in accordance
                with the established accounting procedures generally used by
                360americas and which 360americas utilizes in billing third
                parties for reimbursable projects, including without limitation
                the following: (i) internal labor costs, including wages,
                salaries and benefits, and overhead allocable to such labor
                costs equal to fifteen percent (15%), and (ii) other direct
                costs and out-of-pocket expenses on a pass-through basis (e.g.,
                equipment, materials, supplies, contract services, etc.).

                "Customer" has the meaning set forth in the introductory
                paragraph.

                "Customer Indemnitees" has the meaning set forth in Section 9.1.

                "Dispute Notice" has the meaning set for thin Section 17.1.

                "Dollars" or "$" means United States of America Dollars.

                "Effective Date" has the meaning set forth in the introductory
                paragraph to this Agreement.

                "Eligible Charges" has the meaning set forth in Section 3.7.

                "Fiber Agreements" means the following agreements entered into
                by Customer and 360americas (or their respective Affiliates)
                more or less contemporaneously herewith: (1) the Service
                Agreement by and among Impsat Comunicacoes Ltda. and 360networks
                do Brasil Ltda.;(2) the IRU Fiber Agreement (Brazil), by and
                among Impsat Comunicacoes Ltda. and 360networks do Brasil Ltda.;
                (3) the IRU Fiber Agreement (Argentina), by and among Impsat
                S.A. and 360networks de Argentina S.A.; and (4) the Telehouse
                Services Agreements for the Buenos Aires Telehouse, the Caracas
                Telehouse, the Rio de Janeiro Telehouse and the Sao Paulo
                Telehouse.

                "Final Payment" has the meaning set forth in Section 3.1(b).

                "Force Majeure Events" has the meaning set forth in Article 16.

                "Full Rack Space" means the entire space available in one free
                standing enclosed cabinet of the total dimensions 24" W x 36" D
                x 84" H, and the corresponding floor space at the Cable Station.
                Except in limited circumstances, the floor space shall be
                sufficient to permit access from the front and the rear of the
                equipment


                                       4

* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
<PAGE>   7

                racks.

                "Income Taxes" shall mean taxes imposed by any national, state,
                provincial or other governmental authority on the income of a
                party to a transaction contemplated by this Agreement, whether
                determined by reference to net income, gross income or otherwise
                and shall include taxes imposed in lieu thereof. Such term shall
                not include Indirect Taxes.

                "Indirect Taxes" shall mean any taxes imposed on any transaction
                contemplated by this Agreement and shall include, without
                limitation, any sales, use, excise, Value Added Taxes ("VAT"),
                Goods and Services Tax ("GST"), gross receipts tax or similar
                type tax imposed by any national, state, provincial or other
                governmental or quasi-governmental authority but, unless stated
                specifically otherwise, shall not include any Income Taxes. For
                purposes of this Agreement, the term Indirect Taxes shall also
                include charges required or permitted by governmental or
                quasi-governmental to collect from or pay to others in support
                of any statutory or regulatory programs, including but not
                limited to the Universal Service Fund charge contemplated by the
                U.S. Telecommunications Act of 1996, as amended from time to
                time, or similar legislation under the laws of any national,
                supranational, state or other political subdivision or
                quasi-governmental authority.

                "Initial Payment" has the meaning set forth in Section 3.1(a).

                "Interest Rate" means [  ]* percent ([  ]*%), per annum, or if
                lower, the highest rate allowed by applicable law.

                "IRU" has the meaning set forth in Section 2.1.

                "IRU Effective Date" has the meaning set forth in Section 5.1.

                "IRU Fee" has the meaning set forth at Section 3.1.

                "Maintenance Window" means certain off-peak transmission hours,
                including without limitation 12:00 a.m. to 7:00 a.m. local time.

                "Master Services Agreement" has the meaning set forth in Recital
                D.

                "Minimum Capacity Unit" or "MCU" means the minimum unit of
                Capacity to be purchased by Customer under any submitted Circuit
                Order. An STM-1 is designated as the MCU for purposes of this
                Agreement.

                "Minimum Commitment" has the meaning set forth in Section 3.7.


                                       5

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filed separately with the Commission.
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                "Network Availability" has the meaning set forth in Exhibit F.

                "O&M Fees" has the meaning set forth in Section 7.3

                "O&M Fee Commencement Date" has the meaning set forth in Section
                7.3.

                "Party" means either 360americas or Customer and "Parties" shall
                mean 360americas and Customer.

                "Permitted Assignee" has the meaning set forth in Section 18.2.

                "Person" means any individual, corporation, partnership, limited
                liability company, joint venture, association, joint-stock
                company, trust, unincorporated organization, government or any
                agency or political subdivision thereof or any other entity.

                "RFCS" means the operation of the Capacity substantially in
                conformity with the standards set forth in Exhibit B.

                "Ring" means the S Segments comprising the North Ring or the
                Central Ring of the 360americas System, and the S Segments and
                Terrestrial Segment comprising the South Ring of the 360americas
                System, as depicted in Exhibit A.

                "S Segment" means the collective reference to Segment S1, S2,
                S3, S4, S5, S6, S7, and S8, each as depicted in Exhibit A.

                "Scheduled Maintenance" means any work on the 360americas System
                planned by 360americas or its maintenance contractor in order to
                preserve the operation of the 360americas System in accordance
                with the System RFCS standards set forth in Exhibit B or to
                prevent or correct any condition which 360americas or its
                maintenance contractor determines could impact the integrity of
                the 360americas System.

                "Segment" means any of the S Segments, T Segments or Terrestrial
                Segments as depicted in Exhibit A.

                "Service Level Agreement" has the meaning set forth in Section
                10.4.

                "Service Outage" has the meaning set forth in Exhibit F.

                "Severely Errored Second" or "SES" has the meaning set forth in
                Exhibit F.


                                       6

* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
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                "Severely Errored Second Ratio" or "SESR" has the meaning set
                forth in Exhibit F.

                "STM-1" means a digital signal having a line rate of 155.52 Mb/s
                and a format as described by the International
                Telecommunications Union Recommendation G.709.

                "STM-4" means a digital signal having a line rate of 622.08
                Mb/s.

                "STM-16" means a digital signal having a line rate of 2488.32
                Mb/s.

                "Supply Contract" has the meaning set forth in Recital A.

                "System Interface" means the optical input/output ports on the
                optical distribution frame in the various Cable Stations and the
                City-Center POPs (including the optical distribution frame
                itself) where the 360americas System connects with other
                transmission facilities or equipment.

                "T Segment" means the collective reference to Segments T1, T2,
                T3, T4, T5, T6 and T7, each as depicted in Exhibit A.

                "Target RFCS Date" means the dates on which 360americas
                anticipates the Segments will be installed and RFCS, in
                accordance with the chart set forth in Exhibit A.

                "Term" has the meaning set forth at Section 5.1.

                "Terrestrial Segments" means those Segments of the 360americas
                System as depicted in Exhibit A.

                "Use Agreement" has the meaning set forth in Section 9.4.

                "Wavelength" means a ten (10) gigabit per second (10 Gbps) of
                communications capacity derived from an individual lambda on the
                360americas System or any Segment thereof which capacity shall
                be provided without network protection equipment.


                                       7

* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
<PAGE>   10

                                    ARTICLE 2

                                       IRU

        2.1     As of the IRU Effective Date with respect to each applicable
Circuit, 360americas, directly or through certain of its Affiliates, shall grant
and provide to Customer and Customer shall purchase and receive from 360americas
or its Affiliates, an exclusive and indefeasible right to use the Capacity
associated with such Circuit on the terms and conditions set forth in this
Agreement (each, an "IRU"). Notwithstanding the foregoing sentence, this
Agreement shall not in any way convey title, interest or salvage rights in the
360americas System, or other infrastructure, systems, equipment, facilities or
other property of 360americas.

        2.2     Except as provided in Section 2.1, 360americas shall have no
right to sell, lease, transfer or use the Capacity or any portion thereof in
which it has granted Customer an IRU. Notwithstanding the foregoing, Customer
acknowledges that 360americas may derive additional communications capacity from
the same fiber or equipment from which the Capacity is derived and sell such
capacity to third parties.

        2.3     Capacity Provisioning.

        2.3.1   From time to time during the Commitment Periods, Customer may
request an IRU in Capacity on the 360americas System by submitting a complete
order to 360americas for such Capacity pursuant to 360americas' then current
service order form (such completed order being called a "Circuit Order"). Each
Circuit Order shall be signed by an authorized representative of Customer.
360americas shall accept or reject a Circuit Order by providing written notice
to the Customer within ten (10) days of receipt of such Circuit Order from the
Customer. Provided that a Circuit Order is complete and consistent with the
provisions of this Agreement, 360americas shall not reject a Circuit Order if
the requested Capacity is available. If 360americas rejects a Circuit Order,
then 360americas must provide to Customer a reasonably detailed basis for such
rejection. [  ]*. A rejected Circuit Order shall be of no force or effect and
any capacity or services so requested by Customer shall not be considered a
"Circuit" or "Capacity".

        2.3.2   (a)     Provided that the 360americas System is RFCS,
360americas shall use commercially reasonable efforts to deliver a Completion
Notice for the applicable Circuit within [  ]* days after Customer submits a
Circuit Order (unless such Circuit Order is rejected pursuant to 2.3.1),
provided that, in the event 360americas cannot deliver a Completion Notice for
the bandwidth level requested in the Circuit Order because the 360americas
System requires an upgrade to accommodate the requested bandwidth, then
360americas shall use commercially reasonable efforts to deliver a Completion
Notice for the requested Circuit within [  ]* of submission of the applicable
Circuit Order.


                                       8

* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
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        If 360americas does not have Capacity available for purchase by Customer
during any Commitment Period because a system upgrade is required, then such
Commitment Period shall be extended by the total number of days it takes for
360americas to complete the required upgrade.

        (b)     In the event that 360americas fails to deliver a Completion
Notice for the requested Circuit within the applicable [  ]* period described
above, as such periods may be extended by Force Majeure Events, then during the
[  ]* period following expiration of the applicable [  ]* period, Customer may,
as its sole remedy for such failure, may either: (1)(A) terminate the delayed
Circuit and require 360americas to refund the Initial Payment made in respect of
the delayed Circuit with interest at the Interest Rate from the date 360americas
received such Initial Payment and (B) in the event of such termination, the
Annual Commitment for the Commitment Period in which the termination occurs
shall be reduced by the IRU Fee applicable to the terminated Circuit; or (2) if
Customer does not terminate under item (1), it may elect that 360americas issue
Customer an invoice credit calculated as [  ]*% of the applicable IRU Fee for
such Circuit, for each day that delivery of the Circuit is delayed past the
applicable [  ]* period until the Acceptance Date for such Circuit, provided
that in no event shall the aggregate amount of such credit exceed [  ]*% of the
IRU Fee applicable to the delayed Circuit.

        2.3.3   Except as provided in this Section 2.3.3, the Capacity provided
under this Agreement shall have protection switching capability. In the event
Customer submits a Circuit Order for linear capacity on a portion of the
360americas System prior to the date on which the entire 360americas System is
RFCS, 360americas will review such Circuit Order and may provide the requested
Capacity, subject to the provisions of this Section 2.3 and subject to
availability. The Capacity on any such Circuit shall be linear and shall not
have protection switching capability.

        2.4     Notwithstanding anything to the contrary contained in this
Agreement, 360americas may elect, at its option, to procure and deliver any
portion of Capacity from third parties in lieu of constructing and installing
the 360americas System, provided 360americas remains liable for such Capacity
under the terms of this Agreement and such Capacity complies with the technical
specifications of this Agreement.


                                    ARTICLE 3

                                     PAYMENT

        3.1     In consideration of the grant of the IRU by 360americas to
Customer with respect to each Circuit, Customer agrees to pay to 360americas the
applicable fee for such Circuit as set forth in Exhibit D (the "IRU Fee") and
all such payments of the IRU Fee shall be non-refundable, except as expressly
provided otherwise. The IRU Fee for each Circuit shall be paid


                                       9

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<PAGE>   12

in accordance with this Article 3 and as follows:

                (a) [  ]*% of the IRU Fee for such Circuit is due and payable
                upon 360amercias' acceptance of each Circuit Order in accordance
                with the provisions of Section 2.3 (the "Initial Payment"); and

                (b) [  ]*% of the IRU Fee for such Circuit is due and payable
                within two (2) days of the Acceptance Date for such Circuit (the
                "Final Payment").

        [  ]*

        [  ]*

        3.2     All payments made by Customer hereunder in excess of $100,000
shall be made by wire transfer of immediately available funds to the account
designated by 360americas from time to time. Payments of all other amounts by
Customer hereunder may be made by wire transfer of immediately available funds
or by company check payable to 360americas or a designated 360americas
Affiliate. 360americas network (Bermuda) ltd. reserves the right to invoice all
or any portion of any charges under this Agreement in its own name or in the
name of one or more of its Affiliates and to direct payment remittance
accordingly.

        3.3     If Customer fails to make any payment under this Agreement when
due, then, in addition to such sum and to any other rights and remedies that
360americas may have, Customer shall pay interest on such unpaid amount at the
Interest Rate until such sum is paid in full and such interest shall accrue both
before and after judgment. Notwithstanding the foregoing, no interest shall
accrue on any invoiced amount that Customer has disputed in good faith, in a
reasonably detailed writing to 360americas, while such dispute is pending. If
such dispute is later resolved in favor of 360americas, such amount shall bear
interest at the Interest Rate from the date when due until paid.

        3.4     In addition to the amounts payable under Section 3.1, Customer
shall be responsible to pay directly or reimburse 360americas for all other
sums, costs, fees and expenses that are expressly required to be paid by
Customer under this Agreement. Except for the IRU Fee which shall be paid in
accordance with Section 3.1, and except as specifically provided otherwise,
360americas (in its own name or in the name of one or more of its Affiliates)
will invoice Customer for all sums, costs, fees and expenses owed by Customer
under this Agreement, and Customer shall pay such invoices within [  ]* days of
the invoice date.

        3.5     (a)     The IRU Fee, O&M Fees and any other amounts due from and
payable by Customer under this Agreement are exclusive of any Indirect Taxes.
360americas shall be entitled to include on any invoice, and Customer shall pay,
any Indirect Tax lawfully imposed on any transaction contemplated by this
Agreement.


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                (b)     Except as set forth in this paragraph (b), all payments
made by Customer under this Agreement shall be made without any deduction or
withholding for or on account of any Income Taxes, except where required by law.
If Customer is required by law to make any deduction or withholding from any
payment due to 360americas under this Agreement, then, notwithstanding anything
to the contrary contained in this Agreement, the gross amount payable by
Customer shall be increased so that after any such deduction or withholding for
Income Taxes, the net amount received by such 360americas will not be less than
360americas would have received had no deduction or withholding been required.
This 'grossing-up' provision shall not apply (i) to the extent the deduction or
withholding merely constitutes a prepayment of 360americas' or its Affiliates'
income tax liability or (ii) to the extent such withholding results from an
assignment by 360americas to a foreign Affiliate of 360americas.

                (c)     360americas and Customer shall undertake commercially
reasonable efforts on behalf of themselves and their respective Affiliates to
cooperate to minimize the incidence of taxation with respect to taxes lawfully
imposed, provided that no Party shall be obliged to so cooperate if and to the
extent that such cooperation would result in an increase in that Party's (or an
Affiliate of such Party's) own liability for taxes. Subject to the foregoing,
each Party shall undertake commercially reasonable efforts to pursue and
implement the benefits of any available tax exemptions, reductions or treaties.

        3.6     Customer's obligation to pay the IRU Fee, O&M Fees and other
amounts under this Agreement shall not be subject to any rights of set-off,
counterclaim, deduction, defense or other right that Customer may have against
360americas.

        3.7     During the Commitment Periods, Customer shall purchase and pay
360americas, in the aggregate, a minimum amount of $46,000,000 (the "Minimum
Commitment") for IRUs in Capacity on the 360americas System, or for capacity on
the 360networks System, and such Minimum Commitment shall be satisfied as
follows:

        3.7.1           Customer shall make an initial payment of $[  ]* upon
        execution of this Agreement (the "Deposit"). The Deposit shall be
        applied toward the IRU Fees for Circuits on the 360americas System only
        as such IRU Fees are incurred.

        3.7.2   During the period commencing on the Effective Date and ending on
        the date that is [  ]* (the "First Commitment Period"), Customer shall
        pay to 360americas for Eligible Charges an amount no less than $[  ]*
        (the "First Annual Commitment"). The Deposit, at Customer's election,
        may be counted toward satisfaction of the First Annual Commitment.

        3.7.3   During the consecutive [  ]* period commencing on the first day
        following the First Commitment Period (the "Second Commitment Period"),
        Customer shall pay to


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        360americas for Eligible Charges an amount no less than $[  ]* (the
        "Second Annual Commitment").

        3.7.4   During the consecutive [  ]* commencing on the first day
        following the Second Commitment Period (the "Third Commitment Period"),
        Customer shall pay to 360americas for Eligible Charges an amount no less
        than $[  ]* (the "Third Annual Commitment").

        3.7.5   During the consecutive [  ]* commencing on the first day
        following the Third Commitment Period (the "Fourth Commitment Period"),
        Customer shall pay to 360americas for Eligible Charges an amount no lees
        than $[  ]* (the "Fourth Annual Commitment").

The First Annual Commitment, Second Annual Commitment, Third Annual Commitment,
and Fourth Annual Commitment shall be referred to individually as an "Annual
Commitment" and collectively as the "Annual Commitments". The First Commitment
Period, Second Commitment Period, Third Commitment Period, and Fourth Commitment
Period shall be referred to individually as a "Commitment Period" and
collectively as the "Commitment Periods".

Only IRU Fees with respect to the 360americas System paid to 360americas (or its
Affiliates) and the monthly recurring fees paid to 360networks for services on
the 360networks System purchased pursuant to the Master Services Agreement shall
contribute toward the satisfaction of the Minimum Commitment (said fees shall be
called the "Eligible Charges"). The Eligible Charges shall not include other
fees, including but not limited to: (i) the amount of any Indirect Tax, (ii)
charges for equipment and colocation, or (iii) O&M Fees or maintenance or
installation fees.

        3.8     To the extent that Customer pays 360americas or its applicable
Affiliates for Eligible Charges during any Commitment Period in excess of the
Annual Commitment for such Commitment Period, then such excess payments shall be
applied to reduce the Annual Commitments for the next Commitment Periods in
direct order until such excess payment is fully applied.

        3.9     In the event that the entire 360americas System is not RFCS by
[  ]* and such event is not caused by Force Majeure Events, a default by
Customer (or its Affiliate) under any of the Fiber Agreements or any other act
or omission of Customer, its Affiliates or contractors, then Customer shall not
be obligated to pay any Annual Commitment that is due and payable after [  ]*.
If the RFCS date for the Central Ring is delayed past [  ]*, then the
commencement of the Second, Third and Fourth Commitment Periods shall be delayed
for each day that the RFCS date for the Central Ring is delayed past [  ]*.

        3.10    The Parties agree that Customer or its Affiliates may submit
Circuit Orders under


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filed separately with the Commission.
<PAGE>   15

this Agreement. In the event Customer's Affiliates submit Circuit Orders for
Capacity hereunder, such Affiliates shall be liable for the applicable fees.
Such Affiliates will be invoiced in accordance with the provisions of Article 3.
Customer hereby guarantees and shall remain primarily liable for any amounts due
and payable by such Affiliates for IRU Fees, O&M Fees and fees for colocation or
any other services provided to such Affiliates under this Agreement. All
Capacity, operations and maintenance, and colocation services provided to any
Customer Affiliate shall be subject to the terms of this Agreement. Customer
agrees further that the acts and omissions of any Affiliate receiving services
under this Agreement shall be imputed to the Customer for the purposes of
Article 14 and all other purposes under this Agreement and 360americas' rights
under this Agreement against Customer shall apply with respect to the acts and
omissions of any such Affiliate. Eligible Charges paid by Customer and any
applicable Customer Affiliate under this Agreement shall be applied toward
satisfaction of the Minimum Commitment. Notwithstanding the foregoing, either
Party may request and the other Party shall (by themselves or through their
local affiliates) enter into separate capacity purchase agreements for those
portions of the Capacity to be provided within the territorial limits of either
Venezuela, Brazil or Argentina, provided that, any such separate agreement shall
be on terms identical to those set forth in this Agreement, except as to such
modifications (mutually agreed between the Parties) as may be required to be
conform to local law.

        3.11    In the event Customer fails to satisfy the Annual Commitment
applicable to any Commitment Period, then Customer shall pay 360americas in cash
at the end of the Commitment Period an amount equal to [  ]*. In the event this
Agreement is terminated in accordance with its terms prior to expiration of the
Commitment Periods (except for any termination caused by 360americas' default
under Article 14), then Customer shall pay to 360americas, in addition to any
other amounts due to as of the date of such termination, an amount equal to
[  ]*.


                                    ARTICLE 4

                         ACCEPTANCE TESTING AND DELIVERY

        4.1     When 360americas has determined that the Capacity with respect
to a Circuit is RFCS, 360americas shall promptly provide Customer written notice
of the same (a "Completion Notice") and, upon Customer's request, will forward
the results of the 360americas System Testing Requirements described in Exhibit
B.

        4.2     Within seven (7) days of Customer's receipt of the Completion
Notice, 360americas shall determine a time for the performance of the acceptance
tests for the applicable Circuit identified in Exhibit B (the "Capacity
Acceptance Tests"). Within seven (7) days of completion of the Capacity
Acceptance Tests, 360americas shall provide the test results in writing to the
Customer. Within five (5) days of receipt of results of the Capacity Acceptance
Tests, Customer shall provide 360americas a written notice accepting or
rejecting the Circuit,


                                       13

* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
<PAGE>   16

specifying in reasonable detail, if rejected, the defect or failure in the
Capacity based on the results of the Capacity Acceptance Tests. If Customer
fails to notify 360americas of its acceptance or rejection of the Capacity
within five (5) days following receipt of the results of the Capacity Acceptance
Tests, Customer shall be deemed to have accepted such Circuit. Any use of such
Capacity by Customer other than for testing purposes shall be deemed to
constitute acceptance of the Circuit. The date of such notice of acceptance or
deemed acceptance of the Circuit shall be the "Acceptance Date." In the event of
any good-faith rejection by Customer, 360americas shall take such action as
reasonably necessary, and as expeditiously as practicable, to correct or cure
such defect or failure in accordance with the applicable specifications.
Customer shall not have any right to use the Capacity with respect to a Circuit
and 360americas shall have no obligation to provide such Capacity to Customer,
until 360americas has received payment in full of the applicable IRU Fee for
such Capacity and any applicable O&M Fees.


                                    ARTICLE 5

                                      TERM

        5.1     This Agreement shall become effective on the Effective Date and
shall continue in force and effect until the expiration of the Term with respect
to the last Circuit purchased hereunder. The term of the IRU with respect to
each Circuit shall commence on the date when both the Acceptance Date and
receipt of the Final Payment has occurred with respect to such Circuit (the "IRU
Effective Date") and shall continue in force and effect until the date which is
twenty (20) years from the RFCS date for the 360americas System (the "Term").

        5.2     [  ]*

[  ]*

        5.3     At the expiration or other termination of this Agreement, the
IRU with respect to each Circuit shall immediately terminate, and all rights of
Customer to use any Capacity shall cease. The expiration or termination of this
Agreement shall not relieve either Party from any liabilities arising prior to
such termination.


                                    ARTICLE 6

                         INTERCONNECTION AND COLOCATION

        6.1     To the extent technically feasible, where the Customer does not
wish to install equipment at the Cable Stations or City-Center POPs, Customer
shall be permitted to make direct optical connections (by "patching through"
from the incoming demarcation point to the


                                       14

* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
<PAGE>   17

outgoing demarcation point) to the System Interfaces in respect of the Capacity.
360americas shall perform any such interconnection work and Customer shall
reimburse and pay 360americas for its Costs to perform such work plus a
management fee equal to [  ]* percent ([  ]*%) of such Costs.

        6.2     With respect to any interconnections that involve the
installation of any transmission equipment at the Cable Stations or City-Center
POPs, 360americas shall perform all such work and Customer shall reimburse and
pay 360americas for its Costs to perform such work plus a management fee equal
to [  ]* percent ([  ]*%) of such Costs. Such payment shall be due and payable
within 30 days of receiving an invoice therefor.

        6.3     In the event Customer desires to make an optical connection to
the System Interface by way of a cable originating from facilities located
outside of the Cable Stations or City-Center POPs, the Customer shall provide
suitable optical fiber facilities as required to connect to the System
Interfaces. In such event, 360americas agrees to grant reasonable supervised
access to the Cable Stations for connection of the Customer's fiber optic
facilities to the System Interfaces. The distance between the Cable Station or
City-Center POP and Customer's facility for the purposes of the above described
optical connection shall be limited as described in the Technical Description
set forth in Exhibit C. 360americas shall perform any such work and Customer
shall reimburse and pay 360americas for its Costs to perform such work plus a
management fee equal to [  ]* percent ([  ]*%) of such Costs.

        6.4     Customer may add or drop communications traffic at any Cable
Station subject to a one time charge per add/drop, per STM-1, of $[  ]*.

        6.5     360americas will provide Customer 1 Full Rack Space at each
Cable Station for each STM-1 activated, subject to a maximum of four (4) Full
Rack Spaces per Cable Station, for installation of the Customer's transmission
equipment, at no additional charge. Provision of such Full Rack Space shall be
subject to the Parties' execution of a colocation license agreement (or
agreements, as the Parties shall mutually determine) in a form substantially
similar to that set forth in Exhibit G. 360americas will notify Customer
promptly when such space is ready for installation of Customer's termination
equipment. Additional Full Rack Space may be provided by 360americas on an as
available basis and is subject to execution of an agreement with terms and
conditions substantially similar to those set forth in Exhibit G and at
360americas' then current market pricing.


                                    ARTICLE 7

                             MAINTENANCE AND REPAIR

                7.1     During the Term of each Circuit, 360americas shall
maintain the Capacity (not to include any third-party networks connected to the
360americas System) in good working


                                       15

* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
<PAGE>   18

order, and in accordance with the standards set forth on Exhibit C and in
accordance with standard industry practices. 360americas shall use commercially
reasonably efforts to perform (or cause to be performed) all Scheduled
Maintenance (which includes without limitation substituting, changing and
reconfiguring the equipment and facilities with respect to the Capacity) during
a Maintenance Window. In the event 360americas determines it necessary to
interrupt the Capacity for the performance of routine maintenance, 360americas
will notify Customer reasonably in advance of the interruption. In no event
shall interruption for Scheduled Maintenance performed in accordance with this
Agreement constitute a failure of performance by 360americas or a failure of the
Capacity in any manner.

                7.2     Prior to commencing Scheduled Maintenance that will
cause a break in transmission on any Segment of a Ring, 360americas will cause
Customer's telecommunications traffic to be switched to the other Segments of
such Ring. In the event a Segment on any Ring is cut or damaged with the result
that there is a break in transmission of Customer's telecommunications traffic
on that Segment, then 360americas agrees that it will not commence any Scheduled
Maintenance on the other Segments comprising such Ring which would result in a
break in transmission on the Ring, unless 360america determines that continued
performance of such Scheduled Maintenance is required to maintain the integrity
of the 360americas System. In the event 360americas is performing Scheduled
Maintenance on a Segment of any Ring (which results in a break in transmission
on that Segment) and during the performance of such Scheduled Maintenance
another Segment on such Ring is cut or damaged with the result that there is a
break in transmission of Customer's telecommunications traffic on the damaged
Segment, then 360americas shall discontinue performance of such Scheduled
Maintenance as soon as reasonably practicable (unless 360americas determines
that completion of such maintenance is required to maintain the integrity of the
360americas System) in order for Customer's telecommunications traffic to resume
transmission on the undamaged Segments of the Ring. For the purposes of this
paragraph, a "break in transmission" shall have the meaning provided in the
definition of "Service Outage", set forth in Exhibit F.

                7.3     In consideration of the maintenance services to be
provided hereunder, Customer shall pay 360americas the fees set forth in Exhibit
E with respect to each Circuit (the "O&M Fees"). The first such payment of O&M
Fees with respect to each Circuit shall be due within 2 days of the Acceptance
Date for such Circuit (each, the "O&M Fee Commencement Date"), provided, if the
O&M Fee Commencement Date is a day other than the first day of any calendar
quarter, then the applicable O&M Fee shall be prorated. Thereafter, for O&M Fees
with respect to each Circuit, 360americas will invoice Customer at the beginning
of each calendar quarter for the applicable O&M Fee. Each payment of O&M Fees
made by Customer shall be non-refundable.

                7.4     [  ]*

                7.5     360americas may substitute, change or reconfigure the


                                       16

* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
<PAGE>   19

telecommunications equipment and facilities used in providing the Capacity as
long as the quality and type of Capacity is not materially impaired or changed.
In such event, the Parties shall work together in good faith to minimize any
disruption of service in connection with such substitution, change or
reconfiguration.



                                    ARTICLE 8

                               USE OF THE CAPACITY

        Customer represents, warrants and covenants that during the Term of each
Circuit (a) it will use the Capacity in compliance with and subject to all
applicable government codes, ordinances, laws, rules and regulations and will
require its customers to do the same, (b) it shall secure, prior to the IRU
Effective Date with respect to each Circuit, and maintain in full force and
effect during the Term with respect to such Circuit, any and all necessary
approvals, consents, rights of way, permits, franchises, licenses or similar
approvals from all governmental and other authorities which are necessary or
required to be obtained by Customer for the receipt, use and operation of the
Capacity by Customer, and (c) Customer shall not use its systems or the Capacity
in a way that interferes in any way with, causes degradation of or adversely
affects (i) the 360americas System (including equipment, systems or facilities
of 360americas) or the equipment, facilities, systems or networks of any third
party, or (ii) the use of the 360americas System or any services thereon by any
Person or use of the equipment, systems, networks, facilities or services of any
Person connected to the 360americas System. Customer shall have no right to
physically access in any manner the 360americas System or any components
thereof.



                                    ARTICLE 9

                                 INDEMNIFICATION

        9.1     Subject to the provisions of Article 10, 360americas hereby
agrees to indemnify, defend, protect and hold harmless Customer and its
Affiliates and their respective employees, officers, agents and directors (the
"Customer Indemnitees"), from and against, and assumes liability for all suits,
actions, damages or claims of any character (i) brought against the Customer
Indemnitees because of any injuries or damage received or sustained by any
persons or tangible property which in whole or in part are proximately caused by
the negligent acts or omissions of 360americas in the performance or
non-performance of its obligations under this Agreement, and (ii) brought
against the Customer Indemnitees under the workers compensation laws arising out
of the acts or omissions of 360americas, except to the extent caused by the
negligence or willful


                                       17

* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
<PAGE>   20

misconduct of the Customer Indemnitees.

        9.2     Subject to the provisions of Article 10, Customer hereby agrees
to indemnify, defend, protect and hold harmless 360americas and its Affiliates,
and their respective employees, officers, agents and directors (the "360americas
Indemnitees"), from and against, and assumes liability for all suits, actions,
damages or claims of any character (i) brought against the 360americas
Indemnitees because of any injuries or damage received or sustained by any
persons or tangible property which in whole or in part are proximately caused by
the negligent acts or omissions of Customer in the performance or
non-performance of its obligations under this Agreement, (ii) brought against
the 360americas Indemnitees under the workers compensation laws arising out of
the acts or omissions of Customer, except to the extent caused by the negligence
or willful misconduct of the 360americas Indemnitees, (iii) brought against the
360americas Indemnitees because of any damage arising out of or resulting from
Customer's use of the Capacity, and (iv) brought against the 360americas
Indemnitees and arising out of, caused by, related to or based upon a
contractual or other relationship between such claiming party and the Customer
as it relates to the Capacity or this Agreement.

        9.3     Nothing contained herein shall operate as a limitation on the
right of any Party hereto to bring an action for damages against any
non-Affiliate third party.

        9.4     Notwithstanding the foregoing provisions of this Article 9, to
the extent 360americas is required under the terms and provisions of any permit,
supply contract, agreement, right-of-way, lease or indefeasible right of use
agreement relating to the provisioning of the Capacity hereunder (collectively,
"Use Agreements") to indemnify the grantor or provider thereof from and against
any and all claims, demands, suits, judgments, liabilities, losses or expenses
arising out of or related to such Use Agreements, regardless of the cause,
Customer hereby releases, and waives any claims against such grantor or provider
from the same.

        9.5     Notwithstanding the termination of this Agreement for any
reason, the provisions in this Article 9 shall survive such termination.



                                   ARTICLE 10

                LIMITATION OF LIABILITY; DISCLAIMER OF WARRANTIES

        10.1    NOTWITHSTANDING ANY PROVISION OF THIS AGREEMENT TO THE CONTRARY,
NO PARTY SHALL BE LIABLE TO ANY OTHER PARTY FOR ANY SPECIAL, INCIDENTAL,
INDIRECT, PUNITIVE OR CONSEQUENTIAL COSTS, LIABILITIES OR DAMAGES, WHETHER
FORESEEABLE OR NOT, ARISING OUT OF, OR IN CONNECTION WITH, SUCH PARTY'S
PERFORMANCE OR NON-


                                       18

* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
<PAGE>   21

PERFORMANCE OF ITS OBLIGATIONS UNDER THIS AGREEMENT OR OTHERWISE RELATED TO THIS
AGREEMENT.

        10.2    EXCEPT AS EXPRESSLY SET FORTH IN THIS AGREEMENT, 360AMERICAS
MAKES NO WARRANTY, EXPRESS OR IMPLIED, WITH RESPECT TO THE CAPACITY, OR ANY
SERVICES PERFORMED UNDER THIS AGREEMENT AND 360AMERICAS HEREBY SPECIFICALLY
DISCLAIMS ALL OTHER WARRANTIES, INCLUDING ANY AND ALL WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR PARTICULAR PURPOSE OR USE. THE WARRANTIES SET
FORTH IN THIS AGREEMENT, IF ANY, CONSTITUTE THE ONLY WARRANTIES MADE BY
360AMERICAS TO CUSTOMER WITH RESPECT TO THIS AGREEMENT OR THE CAPACITY AND ARE
MADE IN LIEU OF ALL OTHER WARRANTIES, WRITTEN OR ORAL, STATUTORY, EXPRESS OR
IMPLIED.

        10.3    The Parties expressly agree that no claim for losses or damages
whatsoever in connection with this Agreement or a claim for indemnity under the
provisions of Article 9 shall be made more than two (2) years after the date
that the event giving rise to such claim is known or reasonably should have been
known to the Party making such claim.

        10.4    360americas will provide the Capacity purchased under this
Agreement subject to the provisions of the service level agreement attached
hereto in Exhibit F (the "Service Level Agreement"). [  ]*

        10.5    NOTWITHSTANDING ANY PROVISION OF THIS AGREEMENT TO THE CONTRARY,
THE MAXIMUM LIABILITY (IF ANY) OF ANY PARTY TO THE OTHER PARTY IN CONNECTION
WITH THIS AGREEMENT SHALL BE LIMITED, IN THE AGGREGATE, TO $[  ]*, PROVIDED,
HOWEVER, THAT THIS LIMITATION SHALL NOT LIMIT IN ANY WAY CUSTOMER'S OBLIGATION
TO PAY 360AMERICAS ANY FEES DUE UNDER THIS AGREEMENT AND SHALL NOT RESTRICT
EITHER PARTY'S RIGHT TO PROCEED FOR INJUNCTIVE RELIEF.

        10.6    360americas represents that it has entered into the Supply
Contract to obtain plant, equipment and services necessary to allow the Capacity
to be placed into operation by the Target RFCS Dates. Neither 360americas nor
any of its Affiliates warrants or guarantees that the RFCS Date for any Segment
of the 360americas System will occur and 360america and its Affiliates will have
no obligation under this Agreement or otherwise unless and until the applicable
RFCS date occurs. Notwithstanding any other provision of this Agreement,
Customer acknowledges and agrees that 360americas and its Affiliates shall not
be liable for any failure to perform on the part of Alcatel and its successors
as contractors under the Supply Contract.


                                       19

* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
<PAGE>   22

                                   ARTICLE 11

                                    INSURANCE

        Following the Acceptance Date for the first Circuit ordered under this
Agreement, and throughout the remaining term of this Agreement, each Party shall
procure and maintain in force, at its own expense, insurance coverage in amounts
that a reasonably prudent business Person would maintain considering the
obligations of the Parties hereunder, but in no event less than coverage of the
following types and limits:

                (a)     Workers' compensation as required by applicable law;

                (b)     Employer's liability with minimum limits of $1,000,000;

                (c)     General liability with minimum limits of $2,000,000; and

                (d)     Automobile liability with minimum limits of $2,000,000.

Each Party shall maintain the required insurance coverage with insurers
reasonably acceptable to the other and licensed to conduct business in the
applicable jurisdictions.


                                       20

* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
<PAGE>   23

                                   ARTICLE 12

                                     NOTICES

        All notices and other communications required or permitted under this
Agreement shall be in writing and shall be given by first class mail, postage
prepaid, registered or certified, return receipt requested, transmitted by
facsimile (provided the original immediately follows by mail) or by hand
delivery (including by means of a professional messenger service or overnight
mail) addressed as follows:

        If to Customer:      Impsat Fiber Networks, Inc.
                             Alferez Pareja 256 (1107)
                             Buenos Aires, Argentina
                             Fax:  54 (114) 4363-3578
                             Attention:  Alexander F. Rivelis


        with a copy to:      Latham & Watkins
                             1001 Pennsylvania Avenue
                             Washington, D.C.  20004
                             Fax: (202) 637-2201
                             Attention: James R. Hanna, Esq.

        If to 360americas:

                             360americas network (Bermuda) ltd.
                             2 Carter's Bay Road, Southside
                             St. David's DDBX, Bermuda
                             Attn:   General Counsel
                             Fax No.: (441) 296-9010

        With a copy to:

                             360americas network (Bermuda) ltd.
                             c/o 360atlantic sales (USA) inc.
                             13900 Lincoln Park Drive
                             Suite 230
                             Herndon, Virginia  20171
                             Attn: Legal Counsel
                             Fax No.:  571-203-6566

                             360americas network (Bermuda) ltd.


                                       21

* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
<PAGE>   24

                             c/o 360networks inc.
                             1500, 1066 West Hastings Street
                             Vancouver, BC  V6E 3X1
                             Fax No. (604) 648-7747

        Any such notice or other communication shall be deemed to be effective
when actually received or refused. Either Party may by similar notice given
change the address to which future notices or other communications shall be
sent.


                                   ARTICLE 13

                                 CONFIDENTIALITY

        13.1    This Agreement and all materials, data, and other documents
which are disclosed by one Party to the other in fulfilling the provisions and
intent of this Agreement, are and shall be confidential (the "Confidential
Information"). No Party shall divulge or otherwise disclose the Confidential
Information to any third party without the prior written consent of the other
Parties, except that a Party may make disclosure to its Affiliates and its
employees required for the implementation or performance of this Agreement, to
its attorneys, and to its auditors, financial advisors, lenders and prospective
lenders, funding partners and prospective funding partners provided that in each
such case the permitted recipient is bound by the confidentiality provisions set
forth in this section. In addition, a Party may make disclosure as required by a
court order, in connection with one's (or its Affiliates') obligations as a
public company or as otherwise required by law or in any legal or arbitration
proceeding relating to this Agreement. If a Party is required by law or by
interrogatories, requests for information or documents, subpoena, civil
investigative demand or similar process to disclose the Confidential
Information, it will provide the other Party with prompt prior written notice of
such request or requirement so that such other Party may seek an appropriate
protective order and/or waive compliance with this Section. The Party whose
consent to disclose information is requested shall respond to such request, in
writing, within five (5) working days of the request by either authorizing the
disclosure or advising of its election to seek a protective order, or if such
Party fails to respond within the prescribed period the disclosure shall be
deemed approved. The provisions of this Section 13.1 shall not apply to
information which a recipient Party can show to a disclosing Party's reasonable
satisfaction: (a) was known to the recipient Party (without obligation to keep
the same confidential) at the date of its disclosure; (b) is after the date of
disclosure lawfully acquired by the recipient Party in good faith from an
independent third party who is not subject to any obligation of confidentiality
in respect of such Confidential Information; (c) in its entirety was at the time
of disclosure or has subsequently become public knowledge other than by reason
of the recipient Party's neglect or breach of the restrictions set out in this
or any other agreement; or (d) is independently developed by the recipient Party
without access to any or all of the Confidential Information.


                                       22

* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
<PAGE>   25

        13.2    Upon termination of this Agreement for any reason or upon
request of a Party, the other Party shall return all Confidential Information,
together with any copies of same. The requirements of confidentiality set forth
herein shall survive the return of such Confidential Information.

        13.3    Nothing herein shall be construed as granting any right or
license under any copyrights, inventions, patents or other rights referred to as
intellectual property now or hereafter owned or controlled by any Party. No
Party shall, without first obtaining the written consent of such other Party,
use any trademark or trade name of such other Party or refer to the subject
matter of this Agreement or the other Party in any promotional activity or
otherwise, nor disclose to others any specific information about the subject
matter of this Agreement.

        13.4    The provisions of this Article 13 shall survive expiration or
other termination of this Agreement for a period of two (2) years.


                                   ARTICLE 14

                                     DEFAULT

        14.1    A default shall be deemed to have occurred under this Agreement
if:

                (a)     in the case of a failure to pay any amount when due
under this Agreement, Customer fails to pay such amount within [  ]* days after
receipt of written notice specifying such breach, or

                (b)     in the case of any other material breach of this
Agreement, a Party fails to cure such material breach within [  ]* days after
receipt of written notice specifying such breach, provided that if the breach is
of a nature that cannot be cured within [  ]*days, a default shall not have
occurred so long as the breaching Party has commenced to cure within said time
period and thereafter pursues such cure with due diligence, the time for curing
such failure shall be extended for such period of time as may be necessary to
complete such cure, up to a maximum of [  ]* days.

                (c)     either of the following occur (i) a Party makes a
general assignment for the benefit of its creditors, files a voluntary petition
in bankruptcy or any petition or answer seeking, consenting to, or acquiescing
in reorganization, arrangement, adjustment, composition, liquidation,
dissolution or similar relief; or (ii) an involuntary petition in bankruptcy,
other insolvency protection against either Party is filed and not dismissed
within one hundred twenty days (120) days.


                                       23

* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
<PAGE>   26

        14.2    In the event of any default under this Agreement the
non-defaulting Party may avail itself of one or more of the following remedies:
(a) take such actions as it determines, in its sole discretion, to correct the
default; (b) pursue any legal remedies it may have under applicable law or
principles of equity, including without limitation specific performance; (c)
upon ten (10) days written notice specifying the intention to terminate this
Agreement, terminate this Agreement in its entirety, unless Customer has paid
360americas all IRU Fees due and payable, in which case 360americas shall only
be entitled to suspend provisioning of the Capacity and associated maintenance
services with respect to such Circuits and/or to the remedies set forth in
clauses (a) and (b) above. Without limiting the foregoing, if the default
consists of a failure of Customer to pay to 360americas any part of the IRU
Fees, O&M Fees, or any other amounts due and payable by Customer to 360americas
under this Agreement or a violation of the provisions of Article 8, then
360americas may suspend the provision of services (including but not limited to
suspending the Capacity and any maintenance and repair services and rejecting
any Circuit Orders) until Customer cures the default.

        14.3    A waiver by either Party at any time of any of its rights as to
anything herein contained shall not be deemed to be a waiver of any breach of
covenant or other matter subsequently occurring.


                                   ARTICLE 15

                                   TERMINATION

        Upon the expiration of the Term with respect to a Circuit or other
termination of this Agreement, the IRU with respect to such Circuits shall
immediately terminate and all rights of Customer to use the Capacity shall
cease, all such rights shall revert to 360americas, and 360americas shall owe
Customer no further duties, obligations or consideration. Expiration or
termination of this Agreement shall not affect the rights or obligations of a
Party that have arisen before the date of termination or expiration. This
Agreement shall not be construed to vest in Customer any salvage rights in the
360americas System.


                                   ARTICLE 16

                              FORCE MAJEURE EVENTS

        Except for any payment obligations of Customer under this Agreement, no
Party shall be in default under this Agreement if and to the extent that any
failure or delay in such Party's performance of one or more of its obligations
hereunder is caused by any of the following conditions, and such Party's
performance of such obligation or obligations shall be excused and extended for
and during the period of any such delay: act of God; weather, fire; material
failures,


                                       24

* CONFIDENTIAL TREATMENT REQUEST - Confidential portion has been omitted and
filed separately with the Commission.
<PAGE>   27

shortages or unavailability or other delay in delivery (except for fiber or
fiber cable) not resulting from the responsible Party's failure to timely place
orders therefor; lack of or delay in transportation; government or
quasi-governmental codes, ordinances, laws, rules, regulations or restrictions;
war or civil disorder; strikes or other labor disputes; permitting delays beyond
the reasonable control of such Party or any other cause beyond the reasonable
control of such Party, including but not limited to any failure of 360americas
to perform its obligations under this Agreement resulting from Customer's (or
its Affiliate's) default under any of the Fiber Agreements (collectively, "Force
Majeure Events"). The Party claiming relief under this Article shall notify the
other in writing as soon as reasonably practicable after the Force Majeure
Event, but in no event later than thirty (30) days of the existence of the event
relied on and promptly of the cessation or termination of said event, and the
Party claiming relief shall exercise commercially reasonable efforts to minimize
the time of any such delay. The unavailability or shortages of, delays in the
delivery of, fiber, cable or other materials, standing alone, shall not
constitute a force majeure event. As of the Effective Date, neither Party is
aware of a Force Majeure Event.


                                   ARTICLE 17

                               DISPUTE RESOLUTION

        17.1    Application. In the event of a disagreement or dispute with
respect to this Agreement that is not resolved to the satisfaction of the
Parties such dispute shall be notified to the other party in writing (such
notice, a "Dispute Notice"). Within seven (7) days of receipt of such Dispute
Notice, the respective senior officers of the Parties with the authority to
settle such disputes shall attempt in good faith to settle such dispute. If the
dispute is not settled within that period of time, the dispute shall be settled
by American Arbitration Association ("AAA") Arbitration in accordance with
Section 17.2 below.

        17.2    Arbitrator. Three (3) arbitrators who are knowledgeable about
the subject matter of this Agreement shall conduct the arbitration under the
then current rules of the AAA Arbitration. Each party shall choose one
arbitrator and the chosen arbitrators shall mutually agree on a third
arbitrator. The arbitration shall be conducted in New York, and all expedited
procedures prescribed by the AAA rules shall apply. The language to be used in
the arbitral proceedings shall be English.

        17.3    Discovery. There shall be no discovery other than the exchange
of information that is provided to the arbitrator by the Parties. The arbitrator
shall have authority only to award compensatory damages and shall not have
authority to award punitive damages, other noncompensatory damages or any other
form of relief; and the Parties hereby waive all rights to any claims for relief
other than compensatory damages. The arbitrators' fees and other costs of the
arbitration shall be borne by the party against whom the award is rendered,
except as the arbitrator may otherwise provide in a written opinion.


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        17.4    Enforcement. If any party files a judicial or administrative
action asserting claims subject to arbitration as prescribed herein, and another
party successfully stays such action or compels arbitration of said claims, the
party filing said action shall pay the other party's costs and expenses incurred
in seeking such stay or compelling arbitration, including reasonable attorneys'
fees.

                                   ARTICLE 18

                      ASSIGNMENT AND TRANSFER RESTRICTIONS

        18.1    Except as provided in Section 18.2, Customer shall not transfer
or assign all or any part of its interest under this Agreement, or delegate any
duties, burdens, or obligations arising hereunder, without 360americas' written
consent, which may be withheld in 360americas' sole discretion. A transfer or
assignment in violation of this Article 18 shall constitute a material breach of
this Agreement and shall be null and void from its inception. If any such
consent is given, the assignor nevertheless shall remain fully and primarily
liable for all obligations under this Agreement. Notwithstanding any provision
of this Article 18, Customer may grant an IRU, lease, or resell its interest in
the Capacity, or any communications circuits, capacity or other services derived
from the Capacity to third parties without obtaining 360americas' consent.

        18.2    Customer may assign this Agreement in whole or in part to a
Permitted Assignee. The term "Permitted Assignee" shall mean (a) any Affiliate
of Customer, (b) any Person that purchases all or substantially all of the
assets of Customer, or any other Person formed by or surviving the merger or
consolidation of Customer and any other person or (c) any bona fide lender to
whom this Agreement is assigned as collateral security for any indebtedness of
Customer or any Affiliate of Customer, provided that such collateral assignment
is subject to the terms of this Agreement and such assignment is in connection
with the collateral assignment of other material assets of Customer to such bona
fide lender. Upon any assignment to a Permitted Assignee, the assignor shall
remain responsible for performance under this Agreement. Any Permitted Assignee
pursuant to subparagraph (a) or (b) above shall expressly assume all obligations
and liabilities with respect to the Agreement which arise after the effective
date of assignment or transfer, prior to or upon the effectiveness of such
assignment and in the case of an assignment as provided in subparagraph (c) of
this Section 18.2, in the event the institutional lender exercises its rights
with respect to this Agreement, it shall expressly assume all obligations and
liabilities with respect to the Agreement which arise thereafter.

        18.3    360americas may assign this Agreement in whole or in part to its
Affiliates.


                                   ARTICLE 19


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                                 REPRESENTATIONS

        By execution of this Agreement, each Party represents to the other
Party: (a) that the representing Party has full right and authority to enter
into and perform this Agreement in accordance with the terms hereof and thereof,
and that by entering into or performing this Agreement, the representing Party
is not in violation of its charter or bylaws, or any law, regulation or
agreement by which it is bound or to which it is subject; (b) that the
execution, delivery and performance of this Agreement by such Party has been
duly authorized by all requisite corporate action, that the signatories for such
Party hereto are authorized to sign this Agreement, and that the joinder or
consent of any other Party, including a court or trustee or referee, is not
necessary to make valid and effective the execution, delivery and performance of
this Agreement by such Party, (c) that the representing Party is a corporation
duly incorporated and organized and validly existing and in good standing under
the laws of its jurisdiction of organization, and (d) that, as of the Effective
Date, there are no actions, suits or proceedings pending or, to the best of its
knowledge, threatened against the representing Party before any court or
administrative agency that would materially impair such Party's performance
under this Agreement.


                                   ARTICLE 20

                                     GENERAL

        20.1    Binding Effect. This Agreement and each of the Parties'
respective rights and obligations under this Agreement, shall be binding on and
shall inure to the benefit of the Parties hereto and each of their respective
permitted successors and assigns.

        20.2    Waiver. The failure of either Party hereto to enforce any of the
provisions of this Agreement, or the waiver thereof in any instance, shall not
be construed as a general waiver or relinquishment on its part of any such
provision, but the same shall nevertheless be and remain in full force and
effect.

        20.3    Governing Law. This Agreement shall be governed by and construed
in accordance with the domestic laws of the state of New York, United States of
America.

        20.4    Rules of Construction. The captions or headings in this
Agreement are strictly for convenience and shall not be considered in
interpreting this Agreement or as amplifying or limiting any of its content.
Words in this Agreement which import the singular connotation shall be
interpreted as plural, and words which import the plural connotation shall be
interpreted as singular, as the identity of the parties or objects referred to
may require.


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                (a)     Unless expressly defined herein, words having well known
technical or trade meanings shall be so construed. All listing of items shall
not be taken to be exclusive, but shall include other items, whether similar or
dissimilar to those listed, as the context reasonably requires.

                (b)     Except as set forth to the contrary herein, any right or
remedy of a Party shall be cumulative and without prejudice to any other right
or remedy, whether contained herein or not.

                (c)     This Agreement has been fully negotiated between and
jointly drafted by the Parties.

                (d)     All actions, activities, consents, approvals and other
undertakings of the Parties shall be performed in a reasonable and timely
manner, it being expressly acknowledged and understood that time is of the
essence in the performance of obligations required to be performed by a date
expressly specified herein. Except as specifically set forth herein, for the
purpose of this Agreement the standards and practices of performance within the
telecommunications industry in the relevant market shall be the measure of a
Party's performance.

        20.5    Entire Agreement. This Agreement constitutes the entire and
final agreement and understanding between the Parties with respect to the
subject matter hereof and supersedes all prior agreements relating to the
subject matter hereof, which are of no further force or effect. The Exhibits
referred to herein are integral parts hereof and are hereby made a part of this
Agreement. This Agreement may only be modified or supplemented by an instrument
in writing executed by each Party and delivered to the Party relying on the
writing.

        20.6    No Personal Liability. Each action or claim against any Party
arising under or relating to this Agreement shall be made only against such
Party as a corporation, and any liability relating thereto shall be enforceable
only against the corporate assets of such Party. No Party shall seek to pierce
the corporate veil or otherwise seek to impose any liability relating to, or
arising from, this Agreement against any shareholder, employee, officer or
director of the other Party. Each of such persons is an intended beneficiary of
the mutual promises set forth in this Article and shall be entitled to enforce
the obligations of this Article.

        20.7    Relationship of the Parties. As a result of this Agreement, the
relationship between the Parties shall not be that of partners, agents, or joint
venturers for one another, and nothing contained in this Agreement shall be
deemed to constitute a partnership or agency agreement between them for any
purposes, including, but not limited to federal income tax purposes. Customer
and 360americas in performing any of their obligations hereunder, shall be
independent contractors or independent parties and shall discharge their
contractual obligations at their own risk subject, however, to the terms and
conditions hereof. Notwithstanding anything


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contained in this Agreement to the contrary, 360networks and 360americas owe
each other no duties or obligations under this Agreement and this Agreement
shall not be deemed to have created such duties or obligations.

        20.8    Performance. 360americas may perform its obligations under this
Agreement (including but not limited to single point and local currency
invoicing, interconnection, colocation, operations and maintenance) directly or
through its Affiliates or using agents or independent contractors it chooses in
its sole discretion.

        20.9    No Third Party Beneficiaries. This Agreement does not provide
and is not intended to provide any third party (including but not limited to
customers of Customer) with any remedy, claim, liability, reimbursement, cause
of action, or any other right.

        20.10   Severability. If any term, covenant or condition contained
herein is, to any extent, held invalid or unenforceable in any respect under the
laws governing this Agreement, the remainder of this Agreement shall not be
affected thereby, and each term, covenant or condition of this Agreement shall
be valid and enforceable to the fullest extent permitted by law.

        20.11   Export Control. The Parties hereto acknowledge that to the
extent any services, products, software or technical information provided under
this Agreement are, or may be, subject to any applicable export laws and
regulations, the Parties hereto agree that they will not use, distribute,
transfer or transmit the services, products, software or technical information
(even if incorporated into other products) except in compliance with such export
laws and regulations (or licenses or orders issued pursuant thereto). If
requested by either Party hereto the other Party agrees to sign all necessary
export related documents as may be required to comply therewith.

        20.12   Waiver of Immunity. The Parties hereto acknowledge that this
Agreement is commercial in nature, and each Party hereto expressly and
irrevocably waives any claim or right which it may have to immunity (whether
sovereign immunity, act of state or otherwise) for itself or with respect to any
of its assets in connection with an arbitration, arbitral award or other
proceeding to enforce this Agreement, including, without limitation, immunity
from service of process, immunity of any of its assets from pre or postjudgment
attachment or execution and immunity from the jurisdiction of any court or
arbitral tribunal.

        20.13   Counterparts. This Agreement may be executed in one or more
counterparts and by facsimile signature, all of which taken together shall
constitute one and the same instrument.

                            [SIGNATURE PAGE FOLLOWS]


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        In confirmation of their mutual consent and agreement to the terms and
conditions contained in this Agreement and intending to be legally bound hereby,
the Parties have executed this Agreement as of the date first above written.

                Impsat Fiber Networks, Inc.

                By:
                       ----------------------------------------------------


                Name:
                       ----------------------------------------------------
                                             printed


                Title:
                       ----------------------------------------------------



                360americas network (Bermuda) ltd. ("360americas")


                By:
                       ----------------------------------------------------


                Name:
                       ----------------------------------------------------
                                             printed


                Title:
                       ----------------------------------------------------


                360americas network (Bermuda) ltd. ("360americas")


                By:
                       ----------------------------------------------------


                Name:
                       ----------------------------------------------------
                                             printed

                Title:
                       ----------------------------------------------------



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