<PAGE>   1
                                                                   EXHIBIT 10.10

                                SERVICE AGREEMENT




                                     BETWEEN


                            IMPSAT COMUNICACOES LTDA.


                                       AND


                           360NETWORKS DO BRASIL LTDA.


                               FEBRUARY ___, 2001




<PAGE>   2



                                TABLE OF CONTENTS



<TABLE>
<S>                                                                                       <C>
ARTICLE 1 DEFINITIONS........................................................................1

        1.01   Defined Terms.................................................................1
        1.02   Construction..................................................................4
ARTICLE 2 PROVISION OF THE CAPACITY..........................................................4

        2.01   Capacity Rights...............................................................4
        2.02   No Ownership Interest.........................................................5
        2.03   Description of Segments.......................................................5
        2.04   Power and Authority...........................................................5
        2.05   Shelters......................................................................5
        2.06   Completion of Construction....................................................5
        2.07   Specification of Equipment by 360americas.....................................6
ARTICLE 3 CONSIDERATION......................................................................6

        3.01   Amount of Total Fee...........................................................6
        3.02   Payment of Fee................................................................6
        3.03   Method of Payment.............................................................6
        3.04   Late Payment..................................................................6
        3.05   Disputed Amounts..............................................................6
        3.06   Indirect Taxes................................................................7
        3.07   Income Taxes..................................................................7
ARTICLE 4 ACCEPTANCE AND TESTING.............................................................8

        4.01   Acceptance Testing............................................................8
ARTICLE 5 TERM...............................................................................8

        5.01   Length of Term................................................................8
        5.02   Ownership of Impsat System....................................................8
ARTICLE 6 NETWORK ACCESS.....................................................................8

        6.01   Grant of Access...............................................................9
        6.02   Reimbursement; Scheduling.....................................................9
ARTICLE 7 MAINTENANCE AND REPAIR.............................................................9

        7.01   Capacity Maintenance..........................................................9
        7.02   Subcontracting................................................................9
ARTICLE 8 INDEMNIFICATION....................................................................9

        8.01   Indemnification by 360americas................................................9
        8.02   Indemnification by Impsat.....................................................9
        8.03   Notice........................................................................9
        8.04   Use Agreements...............................................................10
ARTICLE 9 LIABILITY.........................................................................10
</TABLE>

<PAGE>   3

<TABLE>
<S>                                                                                       <C>
        9.01   Limitation on Types of Damages...............................................10
        9.02   Disclaimer of Warranty.......................................................10
        9.03   Limitation on Amount of Damages..............................................11
        9.04   Limitation on Time for Claim.................................................11
        9.05   Survival.....................................................................11
ARTICLE 10 CONFIDENTIALITY..................................................................11

        10.01  Proprietary Information......................................................11
        10.02  Permitted Disclosure.........................................................12
        10.03  No Intellectual Property Transfer............................................12
        10.04  Internal Disclosures.........................................................12
        10.05  Public Announcements.........................................................12
        10.06  Survival.....................................................................12
ARTICLE 11 DEFAULT..........................................................................12

        11.01  Events of Default by 360americas.............................................12
        11.02  Remedies of Impsat Upon 360americas Event of Default.........................13
        11.03  Events of Default by Impsat..................................................13
        11.04  Remedies of 360americas Upon Impsat Event of Default.........................14
ARTICLE 12 TERMINATION......................................................................14

ARTICLE 13 FORCE MAJEURE....................................................................14

ARTICLE 14 ASSIGNMENT.......................................................................15

        14.01  Assignment by Impsat.........................................................15
        14.02  Assignment by 360americas....................................................15
        14.03  Binding Effect...............................................................16
        14.04  No Third Party Beneficiary...................................................16
ARTICLE 15 REPRESENTATIONS, WARRANTIES AND ACKNOWLEDGMENTS..................................16

        15.01  Representations and Warranties of 360americas................................16
        15.02  Representations and Warranties of Impsat.....................................17
        15.03  Quiet Use and Enjoyment......................................................18
        15.04  Survival.....................................................................18
ARTICLE 16 NOTICES..........................................................................18

ARTICLE 17 GENERAL..........................................................................19

        17.01  Waiver.......................................................................19
        17.02  Governing Law................................................................19
        17.03  Expenses.....................................................................19
        17.04  Rules of Construction........................................................20
        17.05  Entire Agreement.............................................................20
        17.06  Relationship of the Parties..................................................20
        17.07  Severability.................................................................20
        17.08  Counterparts.................................................................21
        17.09  Further Assurances...........................................................21
        17.10  Translation..................................................................21
</TABLE>


<PAGE>   4



                                SERVICE AGREEMENT


              This SERVICE AGREEMENT (this "Agreement"), made and entered into
as of February ___, 2001 (the "Effective Date") in the City of Sao Paulo,
Brazil, is by and between Impsat Comunicacoes Ltda., a Brazil sociedade por
quotas de responsabilidade limitada with head office at Avenida Eid Mansur, No.
666, Parque Sao George, Sao Paulo, SP, CNPJ no. 72.843.212/0001-41 ("Impsat"),
and 360networks do Brasil Ltda., a Brazil sociedade por quotas de
responsabilidade limitada with head offices at Av. Bernardino de Campos No. 98,
3(0) Andar, sala 23, Paraiso 04004-040 Sao Paulo, SP, CNPJ no. 04090.647/0001-02
("360americas") (and its branch offices).

                                    RECITALS


              WHEREAS, Impsat is duly authorized by the Brazilian National
Telecommunications Agency - Anatel to render circuit and networks
telecommunications services in Brazil; and

              WHEREAS, Impsat has acquired certain licenses to provide network
telecommunications services in Brazil including: Servico Limitado Especializado,
Submodalidade Redes Especializadas, Servico Limitado Especializado and
Submodalidade Circuitos Especializados; and

              WHEREAS, 360americas desires to acquire from Impsat, and Impsat
desires to provide to 360americas, Capacity Rights and certain Associated
Services with respect thereto, on the Impsat System from Curitiba, Brazil to Rio
de Janeiro, Brazil through the following major cities: Sao Paulo and Belo
Horizonte, all as more specifically set forth on Exhibit A (such route, the
"Route");

              NOW, THEREFORE, in consideration of the mutual covenants contained
in this Agreement, and for other good and valuable consideration, the receipt
and sufficiency of which are hereby acknowledged, the parties hereto do hereby
agree as follows:

                                    ARTICLE 1
                                   DEFINITIONS

       1.01   Defined Terms. Unless otherwise defined in this Agreement, when
used in this Agreement, the following terms shall have the following meanings:

              "Acceptance Date" means the date of 360americas' notice accepting
the Segment or the date of 360americas' deemed acceptance if the Acceptance
Testing for a Segment shows that the Segment meets industry standards and
360americas does not object to the results of the Acceptance Testing or fails to
notify Impsat of any failure of such Segment to satisfy industry standards
(which shall be the date of the Acceptance Testing); provided, however, that for
the purposes of Section 13.03(A), such date shall be the date that 360americas
receives test results demonstrating that the Segment meets industry standards.

                                       1
<PAGE>   5

              "Acceptance Testing" has the meaning set forth in Section 4.01.

              "Affiliate" means, with respect to any entity, any other entity
controlled by or under common control with such entity; provided, however, that
this definition shall not include any entity under common control with Impsat
Fiber Networks, Inc., a Delaware corporation ("IFN"), but shall include any
entities controlled by IFN. For purposes of this definition, "control"
(including the terms "controlling," "controlled by" and "under common control
with") means the possession, direct or indirect, of the power (i) to vote 50.1%
or more of the securities (on a fully diluted basis) having ordinary voting
power for the election of directors, managing general partners or managing
members or (ii) to direct or cause the direction of the management and policies
of a party, whether by contract or otherwise.

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

              "Ancillary Services Fee" means the price for the use of the
Associated Services as set forth on Exhibit D.

              "Associated Services" means the tangible and intangible property
needed for the use of the Capacity on the Impsat System to provide
communications services, including but not limited to, the Shelters and Impsat's
rights in all Underlying Rights.

              "Route" has the meaning set forth in the Recitals.

              "Business Day" means a day other than a Saturday, Sunday or other
day on which commercial banks in Rio de Janeiro, Brazil, or New York, New York
are authorized or required to close.

              "Cable" when used in this Agreement as a capitalized term means
the fiber optic cable, the individual fibers contained therein, and the
associated splicing connections, splice boxes, and vaults installed or to be
installed by Impsat as part of the Impsat System. When not a capitalized term,
cable means only the fiber optic cable together with the individual fibers
contained therein.

              "Capacity" means [    ]* on the Impsat System as described on
Exhibit G [     ]*.

              "Capacity Fee" means the price for the Capacity Rights as set
forth on Exhibit D.

              "Capacity Maintenance" has the meaning set forth in Section 7.01.

              "Capacity Maintenance Fee" has the meaning set forth in Section
7.02.

              "Capacity Rights" means an exclusive and indefeasible right of use
or IRU in the Capacity Services and the Capacity, provided that the applicable
IRUs granted hereunder do not provide 360americas with any ownership interest in
or other rights to physical access to, control of, modification of, encumbrance
in any manner except as expressly set forth in this Agreement.

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


                                       2
<PAGE>   6

              "Capacity Services" means the services that Impsat will render to
360americas in order to provide the Capacity, all on the terms and conditions in
this Agreement.

              "Connecting Point" has the meaning set forth in Section 6.01.

              "Dispute Account" has the meaning set forth in Section 3.05(A).

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

              "Estimated Delivery Date" means, with respect to each Segment, the
date set forth in Exhibit B with respect to such Segment, as any such date may
be extended for and during (1) the period of any delay described in Article 19
and (2) a period equal to the duration of any 360americas Event of Default.

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

              "Impsat Event of Default" has the meaning set forth in Section
11.03.

              "Impsat System" means the fiber optic telecommunications system
along the Impsat Route, constructed or to be constructed or acquired by Impsat
and comprised of fiber optic cables, cable stations, node sites, telehouses,
amplification/regeneration facilities and similar sites and facilities and other
rights associated with the property and equipment utilized therein.

              "Income Taxes" means 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" means transactional 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"), including but not limited to Tax on Distribution of Goods
and Services of Telecommunications and Transportation ("ICMS"), Tax on Services
("ISS"), gross receipts, or any similar type tax imposed by any governmental or
quasi-governmental authority but, unless stated specifically otherwise, shall
not include any Income Taxes or Impositions. For the purposes of this Agreement,
the term Indirect Taxes shall also include charges required or permitted by
governmental or quasi-governmental authorities to collect from or pay to others
in support of any statutory or regulatory programs, including but not limited to
the Telecommunications Inspection Fund (Fundo de Fiscalizacao das
Telecomunicacoes - FISTEL) and the Universal Service Fund (Fundo de
Universalizacao dos Servicos de Telecomunicacoes - FUST) charge contemplated by
Law No. 9.998 of August 17, 2000, 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.

                                       3
<PAGE>   7

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

              "Payment Escrow Agreement" has the meaning set forth in Section
3.05(A).

              "Planned System Work Period" means a prearranged period of time
reserved for performing certain work on any part of the Impsat System.

              "Proprietary Information" has the meaning set forth in Section
10.01.

              "Reais" means Brazilian Reais.

              "Shelters" has the meaning set forth in Section 2.05(A).

              "Segment" means the connections identified as separate segments as
set forth on Exhibit B.

              "360americas" has the meaning set forth in the preamble.

              "360americas Event of Default" has the meaning set forth in
Section 11.01.

              "Telecommunication Authorizations" has the meaning set forth in
Section 8.01.

              "Term" has the meaning set forth in Section 5.01.

              "Total Fee" means the Capacity Fee and the Ancillary Services Fee.

              "Underlying Rights" has the meaning set forth in Section 8.01.

              "Underlying Rights Requirements" has the meaning set forth in
Section 9.01.

              "Use Agreements" has the meaning set forth in Section 10.04.

       1.02   Construction. Unless otherwise defined in this Agreement, all
terms used in this Agreement which are commonly used in the terrestrial
telecommunications industry shall have the meanings commonly given such terms in
the industry.

                                    ARTICLE 2
                            PROVISION OF THE CAPACITY

       2.01   Capacity Rights. For each particular Segment delivered by Impsat
to 360americas hereunder and with respect to which an Acceptance Date has
occurred, effective as of the Acceptance Date of a Segment, Impsat shall grant
to 360americas, and 360americas shall accept from Impsat, on the terms and
subject to the covenants and conditions set forth in this Agreement:

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


                                       4
<PAGE>   8


              A.     Capacity Rights for the Term and for the purposes described
                     in this Agreement, along such Segment of the Route; and

              B.     The right to collocate, as necessary, additional equipment
                     for the Term and for the purposes described in this
                     Agreement, in the Shelters along such Segment of the Route.

On each Acceptance Date with respect to a Segment, each party shall execute such
documentation as the other reasonably may require to evidence such grant and
acceptance.

       2.02   No Ownership Interest. The parties acknowledge and agree that the
Capacity Rights to be provided by Impsat to 360americas do not imply any sharing
of any infrastructure of any nature.

       2.03   Description of Segments. The Segments included in this Agreement
and the Estimated Delivery Date for each Segment are set forth in Exhibit B.

       2.04   Power and Authority. Each party represents and warrants that it
has the power and authority to perform its obligations under this Agreement.

       2.05   Shelters.

              A.     Exhibit C sets forth the sites along the Route at which
                     regeneration facilities and optical amplification
                     facilities currently are located or are to be installed in
                     accordance with the specifications set forth on Exhibit C
                     and industry standards and practices in the country
                     (collectively, the "Shelters") and the status of the
                     Shelters sites as of the date of this Agreement.

              B.     Associated Services shall include for 360americas the right
                     to collocate additional equipment, subject to the terms of
                     this Agreement, in each Shelter. 360americas acknowledges
                     that the sites for the Shelters may be shared with Impsat
                     and other entities, but that 360americas shall have
                     exclusive access to its Shelters for its sole use.

              C.     Upon reasonable prior notification to Impsat, 360americas
                     (and its supplier and agents) shall be given a right to
                     unescorted access to the Shelter sites to maintain the
                     additional equipment and to add or upgrade equipment as it
                     may consider necessary.

              D.     Impsat shall provide the services set forth in Exhibit C
                     for the Shelters including, without limitation, power, air
                     conditioning, security and fire suppression.

       2.06   Completion of Construction. Impsat shall complete the construction
and satisfactorily perform the Acceptance Testing of each of the Segments,
including the provision of such Shelters on such Segment as are required to be
provided pursuant to Section 2.05, by the applicable Estimated Delivery Date
respecting such Segment.

                                       5
<PAGE>   9

       2.07   Specification of Equipment by 360americas. 360americas shall
deliver to Impsat a list of equipment (the "Specified Equipment"), including
without limitation, brand, model number, technical specifications and part
numbers to be used by Impsat to activate the Capacity and instructions for
installation, testing and operation of the Specified Equipment. The list of
Specified Equipment shall be incorporated into this Agreement as Exhibit H.

                                   ARTICLE 3
                                  CONSIDERATION

       3.01   Amount of Total Fee. The Total Fee shall be the amount set forth
in Exhibit D.

       3.02   Payment of Fee. In consideration for the granting of Capacity
Rights hereunder by Impsat to 360americas, 360americas shall pay to Impsat a fee
in the amount determined pursuant to Section 3.01 above payable in accordance
with the following payment schedule:

              A.     [   ]* percent ([   ]*%) of the Total Fee within five (5)
                     Business Days after the Effective Date; and

              B.     [   ]* percent ([   ]*%) of the Capacity Fee allocable to
                     each Segment, as set forth in Exhibit D, within five (5)
                     Business Days of the Acceptance Date for such Segment.

              C.     [   ]* percent ([   ]*%) of the Ancillary Services Fee
                     shall be payable based on Impsat's inspection, acceptance
                     and payment for materials for the Associated Services, and
                     the remaining [   ]* percent ([   ]*%) of the Ancillary
                     Services Fee shall be payable within five (5) Business Days
                     of the Acceptance Date of the applicable Segment containing
                     such Associated Services.

       3.03   Method of Payment. All payments to be made to Impsat under this
Agreement shall be made by wire transfer of immediately available funds to the
account or accounts designated by Impsat.

       3.04   Late Payment. Except as set forth in Section 3.05, if either party
fails to make any payment under this Agreement when due, such amount shall
accrue interest from the date such payment is due until it is paid, such
interest to be payable along with the amount due on the date the underlying
payment is due, compounded monthly at a rate per annum equal to the Interest
Rate.

       3.05   Disputed Amounts.

              A.     In the event that 360americas has an objection to any
                     payment obligation hereunder including Indirect Taxes
                     pursuant to Section 3.06, 360americas shall promptly notify
                     Impsat of such objection and such amount, and Impsat and
                     360americas shall make every reasonable effort to settle

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

                                       6
<PAGE>   10

                     promptly the dispute concerning the payment(s) in question.
                     In the event such dispute cannot be settled, Impsat and
                     360americas shall promptly execute and deliver a Payment
                     Escrow Agreement substantially in the form of Exhibit E
                     attached hereto (the "Payment Escrow Agreement"), with such
                     changes as the Payment Escrow Agent may reasonably request,
                     and 360americas will have the right to withhold payment of
                     the disputed amount(s) so long as it deposits, in full,
                     such disputed amount into the Dispute Account created
                     pursuant to the Payment Escrow Agreement (the "Dispute
                     Account").

              B.     Provided such disputed amount is placed into the Dispute
                     Account in a timely manner and 360americas has acted in
                     good faith, 360americas shall not be deemed to be in breach
                     of or in default for failing to pay Impsat.

              C.     The Payment Escrow Agent will distribute the disputed
                     amount in accordance with the terms of the Payment Escrow
                     Agreement.

              D.     In addition, the prevailing party shall be entitled to
                     receive from the Dispute Account an amount equal to the
                     interest earned by the Payment Escrow Agent on the
                     distributed, disputed amount, which shall be distributed by
                     the Payment Escrow Agent under clause (C) above. Impsat and
                     360americas will equally share the costs and expenses of
                     the Payment Escrow Agent.

              E.     360americas shall make timely payments for that portion of
                     any payments owed hereunder or such amount will accrue
                     interest as set forth in Section 3.04 above.

       3.06   Indirect Taxes. The Capacity Fee, the Ancillary Services Fee, the
Capacity Maintenance Fee and any other amounts due from and payable by
360americas under this Agreement are exclusive of any Indirect Taxes. Impsat
shall be entitled to include on any invoice, and 360americas shall pay, any
Indirect Tax lawfully imposed on any transaction contemplated by this Agreement.
The Fees set forth in this Agreement do not include ICMS, and each invoice to
360americas must separately state ICMS.

       3.07   Income Taxes. Each party shall be responsible for its own Income
Taxes. Except as set forth in this Section 3.07, all payments made by
360americas hereunder shall be made without any deduction or withholding for or
on account of any Income Taxes, except where required by law. If 360americas is
required by law to make any deduction or withholding from any payment due
hereunder to Impsat, then, notwithstanding anything to the contrary contained in
this Agreement, the gross amount payable by 360americas shall be increased so
that, after any such deduction or withholding for Income Taxes, the net amount
received by Impsat will not be less than Impsat would have received had no such
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 Impsat's income tax liability or (ii) to the extent such
withholding results from an assignment by Impsat to a foreign Affiliate of
Impsat.

                                       7
<PAGE>   11

                                   ARTICLE 4
                             ACCEPTANCE AND TESTING

       4.01   Acceptance Testing. Acceptance testing shall be conducted for each
Segment pursuant to industry standard procedures for the applicable country
("Acceptance Testing").

                                   ARTICLE 5
                                      TERM

       5.01   Length of Term. The Capacity Rights with respect to each Segment
hereunder shall become effective on the first day when both (a) the Acceptance
Date with respect to such Segment has occurred and (b) Impsat has received
payment in full of the Total Fee with respect to such Segment in accordance with
Article 3. Such grant shall extend with respect to such Segment, or portion
thereof, for the periods set forth in Exhibit B (the "Term").

       5.02   Ownership of Impsat System. It is understood and agreed that
Impsat must and does maintain legal title to the Impsat System subject to the
grant of the Capacity Rights hereunder.

                                    ARTICLE 6
                                 NETWORK ACCESS

       6.01   Grant of Access. Impsat shall provide 360americas with access to,
and 360americas shall have the right to connect 360americas' communications
system with, the Capacity at the network access points at the Shelters and
Telehouses and all splice points along the Impsat System (each such access point
being referred to as a "Connecting Point"), provided such access does not
physically or operationally interfere with, or present a risk of damage to, any
portion of the Impsat System, including the equipment of Impsat or any of its
customers thereon, or any of the Shelters. The specific locations of each such
Connecting Point shall be in 360americas' space on 360americas' optical
distribution frame (ODF), as determined by 360americas, subject to the
Underlying Rights Requirements and 360americas having obtained any other
required permits, authorizations and approvals necessary to permit such
connection.

       6.02   Reimbursement; Scheduling. In order to schedule a connection of
this type, 360americas shall request and coordinate such work not less than
ninety (90) days in advance of the date the connection is requested to be
completed unless otherwise agreed to in writing by the parties. In addition,
Impsat shall prepare a proposal regarding the costs of the provision of such
access which is reasonable compared to prevailing market prices and the parties
shall agree on the price to be paid to Impsat for the provision of such
services, which charges shall be reasonable in accordance with industry
standards. Such work will be restricted to a Planned System Work Period, unless
otherwise agreed to in writing by Impsat for specific projects. Subject to all
applicable Underlying Rights Requirements, 360americas shall also be provided
reasonable access by Impsat to any Connecting Point at all times.

                                   ARTICLE 7
                             MAINTENANCE AND REPAIR



                                       8
<PAGE>   12

       7.01   Capacity Maintenance. Beginning on the Acceptance Date with
respect to any Segment, Impsat shall maintain the Capacity in accordance with
industry standard procedures ("Capacity Maintenance").

       7.02   Subcontracting. In its sole discretion, Impsat may subcontract
provisioning, testing, maintenance, repair, restoration, relocation, or other
operational and technical services it is obligated to provide hereunder or may
have the underlying facility owner or its contractor perform such obligations;
provided, however, such contracting shall not relieve Impsat of any obligations
under this Agreement.



                                   ARTICLE 8
                                 INDEMNIFICATION

       8.01   Indemnification by 360americas. Subject to the provisions of
Article 9, 360americas agrees to indemnify, defend, protect and hold harmless
Impsat and its Affiliates, their respective employees, agents, officers and
directors (the "Impsat Indemnitees"), from and against, and assumes all
liability for, all costs, loss, damage, expense, liability, suits, actions,
damages or claims of any character arising out of, related to, or in connection
with (a) any physical damage to the Impsat System or injury to persons to the
extent proximately caused by the acts or omissions of 360americas or its agents,
(b) 360americas' use of the Capacity Rights and/or the Impsat System, (c) any
breach or violation by 360americas of applicable law or governmental regulation
or other statute, rule or regulation issued by an applicable regulatory
authority, or (d) arising out of or in connection with a contractual or other
relationship between such claiming party and 360americas as it relates to
360americas' use of the Impsat System or this Agreement.

       8.02   Indemnification by Impsat. Subject to the provisions of Article 9,
Impsat agrees to indemnify, defend, protect and hold harmless 360americas and
its Affiliates, their respective employees, agents, officers and directors (the
"360americas Indemnitees"), from and against, and assumes all liability for, all
costs, loss, damage, expense, liability, suits, actions, damages or claims of
any character arising out of, related to, or in connection with (a) any physical
damage to the Impsat System or injury to persons to the extent proximately
caused by the acts or omissions of Impsat or its agents, (b) Impsat's use of the
Impsat System, (c) arising out of or in connection with any negligent acts or
omissions of Impsat in the performance or non-performance of its obligations
under this Agreement, or (d) any breach or violation by Impsat of applicable law
or governmental regulation or other statute, rule or regulation issued by an
applicable regulatory authority.

       8.03   Notice. Each party agrees to promptly notify the other party with
notice of any claim that may result in an indemnification obligation hereunder.
The indemnifying party may defend such claim with counsel of its own choosing,
provided that no settlement or compromise of any such claim shall occur without
the consent of the indemnified party, which consent shall not be unreasonably
withheld or delayed.

                                       9
<PAGE>   13

       8.04   Use Agreements. Notwithstanding the foregoing provisions of this
Article 8, to the extent Impsat is required under the terms and provisions of
any easement, supply contract, agreement, right-of-way, lease or indefeasible
right of use agreement relating to the granting of the Capacity Rights hereunder
(collectively, the "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, 360americas hereby releases, and waives any
claims against such grantor or provider from the same, regardless of whether
such claims, suits, judgments, liabilities, losses or expenses arise from the
sole or partial negligence or willful misconduct or other action or inaction of
such grantor or provider or its employees, servants, agents, contractors,
subcontractors or other persons using the property or asset covered by such Use
Agreements.

                                   ARTICLE 9
                                    LIABILITY

       9.01   Limitation on Types of Damages. NOTWITHSTANDING ANY PROVISION OF
THIS AGREEMENT TO THE CONTRARY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER PARTY
FOR ANY SPECIAL, INCIDENTAL, INDIRECT, PUNITIVE OR CONSEQUENTIAL DAMAGES,
WHETHER FORESEEABLE OR NOT, ARISING OUT OF, OR IN CONNECTION WITH SUCH PARTY'S
PERFORMANCE OR FAILURE TO PERFORM ITS RESPECTIVE OBLIGATIONS OR BREACH OF ITS
RESPECTIVE REPRESENTATIONS HEREUNDER, INCLUDING, BUT NOT LIMITED TO, LOSS OF
USE, PROFITS OR REVENUE, COST OF CAPITAL, COST OF RESTORATION (WHETHER ARISING
OUT OF TRANSMISSION INTERRUPTIONS OR PROBLEMS, ANY INTERRUPTION OR DEGRADATION
OF SERVICE OR OTHERWISE), OR CLAIMS OF CUSTOMERS, IN EACH CASE WHETHER
OCCASIONED BY ANY CONSTRUCTION, RECONSTRUCTION, RELOCATION, REPAIR OR
MAINTENANCE PERFORMED BY, OR FAILED TO BE PERFORMED BY, THE OTHER PARTY OR ANY
OTHER CAUSE WHATSOEVER, WHETHER ARISING UNDER CONTRACT OR TORT, INCLUDING BREACH
OF CONTRACT, BREACH OF WARRANTY, ACTIVE, PASSIVE OR IMPUTED NEGLIGENCE, OR
STRICT LIABILITY, ALL CLAIMS WITH RESPECT SUCH SPECIAL, INCIDENTAL, INDIRECT,
PUNITIVE OR CONSEQUENTIAL DAMAGES ARE HEREBY SPECIFICALLY AND EXPRESSLY
DISCLAIMED, EXCLUDED AND WAIVED.

       9.02   Disclaimer of Warranty. EXCEPT AS SET FORTH IN THIS AGREEMENT,
IMPSAT MAKES NO WARRANTY, EXPRESS OR IMPLIED, WITH RESPECT TO THE CAPACITY
RIGHTS, THE CAPACITY OR THE SEGMENTS DELIVERABLE HEREUNDER, INCLUDING ANY
WARRANTY OF MERCHANTABILITY OR FITNESS FOR PARTICULAR PURPOSE, AND ALL SUCH
WARRANTIES ARE HEREBY EXPRESSLY DISCLAIMED. IT IS EXPRESSLY AGREED THAT IMPSAT'S
SOLE OBLIGATION AND LIABILITY FROM A BREACH OF THIS AGREEMENT AND 360AMERICAS'
EXCLUSIVE REMEDIES FOR ANY CAUSE WHATSOEVER (INCLUDING WITHOUT LIMITATION
LIABILITY ARISING FROM NEGLIGENCE) ARISING OUT OF OR RELATING TO THIS AGREEMENT,
UNDER ANY THEORY OF LAW OR EQUITY ARE LIMITED TO THOSE SET FORTH IN ARTICLES 8
AND 11, AND ALL OTHER RIGHTS AND REMEDIES OF 360AMERICAS, INCLUDING (WITHOUT
LIMITATION) ANY THAT MIGHT OTHERWISE APPLY UNDER ANY UNIFORM

                                       10
<PAGE>   14

COMMERCIAL CODE OR SIMILAR LAW OF ANY KIND, ARE EXPRESSLY EXCLUDED, DISCLAIMED
AND WAIVED. IMPSAT MAKES NO WARRANTY, EXPRESS OR IMPLIED, TO ANY PERSON OR
ENTITY OTHER THAN 360AMERICAS OR ITS AFFILIATES CONCERNING THE IMPSAT SYSTEM.

       9.03   Limitation on Amount of Damages. IN NO EVENT SHALL EITHER PARTY BE
LIABLE TO THE OTHER PARTY UNDER THIS AGREEMENT IN AN AGGREGATE AMOUNT THAT
EXCEEDS THE TOTAL FEE; PROVIDED, HOWEVER, THAT THE LIMITATION OF THIS SECTION
9.03 SHALL NOT APPLY TO ANY LOSS OR DAMAGE CAUSED BY THE WILLFUL MISCONDUCT OF
EITHER PARTY.

       9.04   Limitation on Time for Claim. 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 8 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.

       9.05   Survival. The provisions of this Article 9 shall survive
expiration or termination of this Agreement.

                                   ARTICLE 10
                                 CONFIDENTIALITY

       10.01  Proprietary Information.

              A.     Impsat and 360americas hereby agree that if either party
                     provides (or, prior to the execution hereof, has provided)
                     confidential or proprietary information to the other party
                     that is identified as proprietary or confidential or is
                     clearly of such a nature ("Proprietary Information"), such
                     Proprietary Information shall be held in confidence, and
                     the receiving party shall afford such Proprietary
                     Information the same care and protection as it affords
                     generally to its own confidential and proprietary
                     information (which in any case shall be not less than
                     reasonable care) in order to avoid disclosure to or
                     unauthorized use by any third party.

              B.     As used in this Agreement, Proprietary Information shall
                     mean any and all technical or business information
                     furnished, in whatever form or medium, or disclosed by
                     either party including, but not limited to, product or
                     service specifications, prototypes, computer programs,
                     models, drawings, marketing plans, financial data, and
                     personnel statistics.

              C.     All Proprietary Information, unless otherwise specified in
                     writing, shall remain the property of the disclosing party,
                     shall be used by the receiving party only for the intended
                     purpose, and such written Proprietary Information,
                     including all copies thereof, shall be returned to the
                     disclosing party or destroyed after the receiving party's
                     need for it has expired or upon the request of the
                     disclosing party. Proprietary Information shall not be
                     reproduced except to the extent necessary to

                                       11
<PAGE>   15

                     accomplish the purpose and intent of this Agreement, or as
                     otherwise may be permitted in writing by the disclosing
                     party.

       10.02  Permitted Disclosure. The foregoing provisions of Section 10.01
shall not apply to any Proprietary Information which (a) becomes publicly
available other than through the recipient hereunder; (b) is required to be
disclosed by a governmental or judicial law, order, rule or regulation or the
rules of any securities exchange or NASDAQ, provided that the party availing
itself of this exception has used commercially reasonable efforts to avoid or
limit such disclosure; (c) becomes available to the disclosing party without
restriction from a third party without an obligation to keep confidential such
Proprietary Information; or (d) becomes relevant to the settlement of any
dispute or enforcement of either party's rights under this Agreement in
accordance with the provisions of this Agreement, in which case appropriate
protective measures shall be taken to preserve the confidentiality of such
Proprietary Information as fully as possible within the confines of such
settlement or enforcement process. If any Proprietary Information is required to
be disclosed pursuant to the foregoing clause (b), the party required to make
such disclosure shall promptly inform the other party of the requirements of
such disclosure.

       10.03  No Intellectual Property Transfer. Nothing in this Agreement shall
be construed as granting any right or license under any trademarks, copyrights,
inventions, patents or other intellectual property now or hereafter owned or
controlled by either party.

       10.04  Internal Disclosures. Notwithstanding Sections 10.01 and 10.02,
either party may disclose Proprietary Information to its employees, agents, and
legal, financial, and accounting advisors and providers (including its lenders
and other financing sources) to the extent necessary or appropriate in
connection with the negotiation and/or performance of this Agreement or its
obtaining of financing, provided that each such party is notified of the
confidential and proprietary nature of such Proprietary Information and is
subject to or agrees to be bound by similar restrictions on its use and
disclosure.

       10.05  Public Announcements. All media releases, public announcements,
and public disclosures relating to this Agreement or the subject matter of this
Agreement, including promotional or marketing material, but not including
announcements intended solely for internal distribution or disclosures to the
extent required to meet legal or regulatory requirements, shall be coordinated
with and shall be subject to approval by both parties prior to release.

       10.06  Survival. The provisions of this Article 10 shall survive
expiration or termination of this Agreement.

                                   ARTICLE 11
                                     DEFAULT

       11.01  Events of Default by 360americas. The happening of any one or more
of the following listed events (a "360americas Event of Default") shall
constitute a breach of this Agreement by 360americas:

              A.     If 360americas fails to pay Impsat any amounts owed
                     hereunder (except as set forth in Section 3.05), including,
                     without limitation, payment of any

                                       12
<PAGE>   16

                     portion of the Total Fee and the Capacity Maintenance Fee,
                     and does not cure such non-payment within [   ]* days after
                     written notice of the same.

              B.     If 360americas breaches any of its material nonpayment
                     obligations and fails to cure such breach within [   ]*
                     days of written notice thereof by Impsat; provided,
                     however, that where such failure cannot reasonably be cured
                     within such [   ]*-day period and is susceptible to
                     cure, if 360americas shall proceed promptly to cure the
                     same and prosecute 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.     If 360americas files a petition in bankruptcy, concordata,
                     makes an assignment for the benefit of creditors, is
                     adjudicated insolvent or bankrupt, petitions or applies for
                     a receiver or trustee for a substantial part of its
                     property, commences any proceeding under any reorganization
                     arrangement, dissolution or liquidation law or statute of
                     any jurisdiction, or if there is commenced against the
                     other party any such proceeding which has not been
                     dismissed 120 days after commencement.

       11.02  Remedies of Impsat Upon 360americas Event of Default. Subject to
the limitations of Article 9, upon any 360americas Event of Default, Impsat may
(a) take such action as it determines, in its sole discretion, to be necessary
to correct the default, (b) pursue any remedies it may have under this Agreement
or applicable law, (c) upon 10 days written notice specifying the intention to
terminate this Agreement, terminate this Agreement in its entirety, unless
360americas has paid all amounts due in respect of the Total Fee, in which case
Impsat shall not be entitled to terminate this Agreement in its entirety and
shall only be entitled to terminate the portions of this Agreement relating to
the provision of the Maintenance Services and/or to the remedies set forth in
clauses (a) and (b) above.

       11.03  Events of Default by Impsat. The happening of any one or more of
the following listed events (an "Impsat Event of Default") shall constitute a
breach of this Agreement by Impsat:

              A.     If the Acceptance Date for any Segment does not occur
                     within [   ]* days after the Estimated Delivery Date with
                     respect to such Segment.

              B.     If Impsat breaches any of its other material obligations
                     and fails to cure such breach within [   ]* ([   ]*) days
                     of written notice thereof by 360americas; provided,
                     however, that where such failure cannot reasonably be cured
                     within such [   ]* ([   ]*)-day period and is susceptible
                     to cure, if Impsat shall proceed promptly to cure the same
                     and prosecute such cure with due diligence, the time for
                     curing such failure


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


                                       13
<PAGE>   17



                     shall be extended for such period of time as may be
                     necessary to complete such cure, up to a maximum of [   ]*
                     days.

              C.     If Impsat files a petition in bankruptcy, concordata, makes
                     an assignment for the benefit of creditors, is adjudicated
                     insolvent or bankrupt, petitions or applies for a receiver
                     or trustee for a substantial part of its property,
                     commences any proceeding under any reorganization
                     arrangement, dissolution or liquidation law or statute of
                     any jurisdiction, or if there is commenced against the
                     other party any such proceeding which has not been
                     dismissed 120 days after commencement.

       11.04  Remedies of 360americas Upon Impsat Event of Default. Subject to
the limitations of Article 9, upon an Impsat Event of Default, 360americas may
(a) upon 10 days written notice specifying the intention to terminate this
Agreement, terminate this Agreement in its entirety and/or (b) pursue the
specific remedies it may have under this Agreement or applicable law; provided,
however, that in the event any Segment is not completed and not available to be
accepted by 360americas on or before the Estimated Delivery Date with respect to
such Segment, the sole remedy of 360americas under this Agreement shall be the
right to terminate this Agreement.

                                   ARTICLE 12
                                   TERMINATION

              This Agreement shall become effective on the date hereof and,
unless earlier terminated pursuant to Article 11 above, shall terminate on the
date when all the Terms of the Segments shall have expired or terminated. Upon
the expiration of the Term with respect to any Segment or other termination of
this Agreement, the granting of the Capacity Rights with respect to such Segment
shall immediately terminate and all rights of 360americas to use the Impsat
System, the Associated Services or any part thereof relating to such Segment,
shall cease and Impsat shall have no further obligations to 360americas with
respect to such Segment. Promptly thereupon, 360americas shall remove all of
360americas' electronics, equipment, and other 360americas property from such
Segment and any related Impsat facilities at 360americas' sole cost, under
Impsat's supervision. 360americas shall repair such Segment to its original
condition before the installation of such equipment and property.
Notwithstanding the foregoing, no termination or expiration of this Agreement
shall affect the rights or obligations of any party hereto (a) with respect to
any then existing defaults or the obligation to make any payment hereunder for
services rendered prior to the date of termination or expiration, and (b) with
respect to those provisions of this Agreement that are expressly provided in
this Agreement to survive such termination.

                                   ARTICLE 13
                                  FORCE MAJEURE

              Neither 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 one or more of its obligations shall be excused and
extended for and during the period of any such delay: act of

                                       14
<PAGE>   18

God; weather; fire; material failures, 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. The party claiming
relief under this Article 15 shall notify the other in writing as soon as
reasonably practicable after the force majeure event, but in any event, no 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 reasonable commercial efforts to minimize the time of any such delay.
The unavailability or shortages of, or delays in delivery of, fiber, cable or
other materials, standing alone, shall not constitute a force majeure event. As
of the Effective Date of this Agreement, neither party is aware of any force
majeure event.

                                   ARTICLE 14
                                   ASSIGNMENT

       14.01  Assignment by Impsat. Except as provided in this Section 14.01 and
14.02, Impsat shall not assign, encumber or otherwise transfer this Agreement or
all or any portion of its rights or obligations hereunder to any other party
without the prior written consent of 360americas (which consent may be withheld
in 360americas' sole discretion). Notwithstanding the foregoing, and subject to
the provisions of this Article 14, Impsat shall have the right, without
360americas' consent, to (a) subcontract any of its construction, maintenance or
testing obligations hereunder, or (b) assign or otherwise transfer this
Agreement in whole or in part (1) to any Affiliate of Impsat or (2) to any
corporation or other entity into which Impsat and its Affiliates may be merged
or consolidated or which purchases all or substantially all of the stock or
assets of Impsat and its Affiliates; provided that the assignee or transferee in
any such circumstance shall continue to be subject to all of the provisions of
this Agreement, including without limitation, this Section 14.01. Promptly
following any such permitted assignment or transfer, Impsat shall give
360americas written notice identifying the assignee or transferee. In the event
of any permitted partial assignment of any rights hereunder, Impsat shall remain
the sole point of contact with 360americas. No permitted partial or complete
assignment shall release or discharge Impsat from its duties and obligations
hereunder.

       14.02  Assignment by 360americas. Except as provided below, 360americas
shall not assign, encumber or otherwise transfer this Agreement or all or any
portion of its rights or obligations hereunder to any other party without the
prior written consent of Impsat (which consent, prior to payment of the Total
Fee hereunder, may be withheld in Impsat's sole discretion, and after such
payment, may not be unreasonably withheld). 360americas shall have the right,
without Impsat's consent, to assign or otherwise transfer this Agreement (1) in
whole or in part, as collateral to any institutional lender to 360americas (or
institutional lender to any permitted transferee or assignee of 360americas
subject to the prior rights and obligations of the parties hereunder), (2) in
whole or in part, to any Affiliate of 360americas, (3) in whole but not in part,
to any other corporation or other entity into which 360americas and its
Affiliates may be merged or consolidated or which purchases all or substantially
all of the stock or assets of 360americas and its Affiliates; provided, however,
that the assignee or transferee in any such circumstance shall continue to be
subject to all of the provisions of this Agreement (except that

                                       15
<PAGE>   19

any lender referred to in clause (1) above shall not incur any obligations under
this Agreement, nor shall it be restricted from exercising any right of
enforcement or foreclosure with respect to any related security interest or
lien, so long as the purchaser in foreclosure is subject to the provisions of
this Agreement, including, without limitation, this Section 14.02. Promptly
following any such assignment or transfer, 360americas shall give Impsat written
notice identifying the assignee or transferee. In the event of any permitted
partial assignment of any rights hereunder, 360americas shall remain the sole
party and point of contact with Impsat hereunder. No permitted partial or
complete assignment shall release or discharge 360americas from its duties and
obligations hereunder. Impsat acknowledges and agrees that 360americas intends
to collaterally assign its interest in this Agreement to its institutional
lenders.

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

       14.04  No Third Party Beneficiary. Except as otherwise provided in this
Article 14, nothing in this Agreement will be construed to give any person other
than the parties to this Agreement any legal or equitable right under or with
respect to this Agreement or any provision of this Agreement.

                                   ARTICLE 15
                 REPRESENTATIONS, WARRANTIES AND ACKNOWLEDGMENTS

       15.01  Representations and Warranties of 360americas. 360americas
represents and warrants as follows:

              A.     360americas is a sociedade por quotas de responsabilidade
                     limitada duly incorporated, validly existing and in good
                     corporate standing under the laws of its jurisdiction of
                     incorporation.

              B.     360americas has the corporate power and authority to
                     execute and deliver this Agreement and to perform its
                     obligations hereunder. Such execution, delivery and
                     performance have been duly authorized by all necessary
                     corporate action on the part of 360americas. This Agreement
                     has been duly executed and delivered by 360americas and
                     constitutes the valid and legally binding obligation of
                     360americas enforceable against 360americas in accordance
                     with its terms.

              C.     Neither the execution and delivery of this Agreement nor
                     the performance or consummation of the transactions
                     contemplated hereunder will cause 360americas to be in
                     violation of (i) its governing documents or any agreement
                     by which it is bound or to which it is subject, or, (ii) to
                     the knowledge of 360americas, any law or regulation to
                     which it is subject.

              D.     To the knowledge of 360americas, no material consent,
                     order, approval or authorization or other action by, and no
                     notice to or filing with, any governmental authority or
                     regulatory body is required for the due

                                       16
<PAGE>   20

                     execution, delivery and performance by 360americas of the
                     Agreement and the consummation of the transactions
                     contemplated hereby.

              E.     There is no action, suit, proceeding or investigation
                     pending or, to the best knowledge of 360americas,
                     threatened, against or affecting 360americas or its
                     properties, assets or business, in any court or before or
                     by any governmental department, board, agency or
                     instrumentality, or any arbitrator, that materially affects
                     or impairs 360network's ability to enter into this
                     Agreement, or to consummate the transactions contemplated
                     hereby.

       15.02  Representations and Warranties of Impsat. Impsat represents and
warrants as follows:

              A.     Impsat is a sociedade por quotas de responsabilidade
                     limitada duly incorporated, validly existing and in good
                     corporate standing under the laws of its jurisdiction of
                     incorporation.

              B.     Impsat has the corporate power and authority to execute and
                     deliver this Agreement and to perform its obligations
                     hereunder. Such execution, delivery and performance have
                     been duly authorized by all necessary corporate action on
                     the part of Impsat. This Agreement has been duly executed
                     and delivered by Impsat and constitutes the valid and
                     legally binding obligation of Impsat enforceable against
                     Impsat in accordance with its terms.

              C.     Neither the execution and delivery of this Agreement nor
                     the performance or consummation of the transactions
                     contemplated hereunder will cause Impsat to be in violation
                     of (i) its governing documents or any agreement by which it
                     is bound or to which it is subject, or (ii) to the
                     knowledge of Impsat, any law or regulation to which it is
                     subject, or (iii) any agreement, license, permit or other
                     authorization with respect to the underlying rights
                     necessary for the construction and installation of the
                     Impsat System, or occupancy of the rights of way, or to
                     otherwise perform Impsat's obligations under this
                     Agreement, including without limitation the grant of the
                     Capacity Rights.

              D.     To the knowledge of Impsat, no material consent, order,
                     approval or authorization or other action by, and no notice
                     to or filing with, any governmental authority or regulatory
                     body is required for the due execution, delivery and
                     performance by Impsat of any of the Agreement and the
                     consummation of the transactions contemplated hereby.

              E.     There is no action, suit, proceeding or investigation
                     pending or, to the best knowledge of Impsat, threatened,
                     against or affecting Impsat or its properties, assets or
                     business, in any court or before or by any governmental
                     department, board, agency or instrumentality, or any


                                       17
<PAGE>   21

                     arbitrator, that materially affects or impairs Impsat's
                     ability to enter into this Agreement, or to consummate the
                     transactions contemplated hereby.

       15.03  Quiet Use and Enjoyment. So long as no 360americas Event of
Default is continuing, 360americas shall be entitled to quiet use and enjoyment
of the Capacity Rights granted hereunder free from interference by Impsat or any
person other than any person claiming through 360americas. In addition to any
other warranties in this Agreement, Impsat further represents and warrants that
[     ]*; provided 360americas shall keep any and all parts of the Impsat System
free from any liens, rights or claims of any third party attributable to
360americas.

       15.04  Survival. The foregoing representations and warranties shall
survive the execution and delivery of this Agreement.

                                   ARTICLE 16
                                     NOTICES

              All notices and communications concerning this Agreement shall be
addressed to the other party as follows:

                     If to Impsat:

                     Impsat Comunicacoes Ltda.
                     Avenida Eid Mansur, No. 666
                     Parque Sao George, Cotia
                     Sao Paulo, Brazil
                     Attention: General Manager

                     with a copy to:

                     Impsat S.A.
                     Alferez Pareja 256 (1107)
                     Buenos Aires, Argentina
                     Fax: 54 (114) 4363-3758
                     Attention: Alexander F. Rivelis

                     with a copy to:

                     Latham & Watkins
                     1001 Pennsylvania Avenue
                     Washington, DC 20004
                     Fax: (202) 637-2201
                     Attention: James R. Hanna

                     If to 360americas:

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

                                       18
<PAGE>   22

                     360networks do Brasil Ltda.
                     Av. Bernardino de Campos No. 98
                     3(0) Andar, Sala 23
                     Paraiso
                     04004-040 Sao Paulo, SP
                     Brazil
                     Fax: 55(11) 3889-0569

                     with a copy to:

                     360networks do Brasil Ltda.
                     c/o 360networks inc.
                     1066 West Hastings Street, Suite 1500
                     Vancouver, British Columbia V6E 3XI
                     Canada
                     Fax: (604) 648-7747
                     Attention:  Vice President and General Counsel

                     360networks do Brasil Ltda.
                     c/o 360networks (USA) inc.
                     13900 Lincoln Park Drive
                     Suite 230
                     Herndon, VA  20171
                     Fax: (571) 203-6566
                     Attention:  Legal Counsel

or at such other address as either party may designated from time to time in
writing to the other party.

              Notices shall be hand delivered or sent by commercial overnight
delivery service, and shall be deemed served or delivered to the addressee or
its office when actually received or refused.

                                   ARTICLE 17
                                     GENERAL

       17.01  Waiver. No failure to exercise, and no delay in exercising, on the
part of either party, any privilege, any power or any right hereunder will
operate as a waiver thereof, nor will any single or partial exercise of any
privilege, right or power hereunder preclude further exercise of any privilege,
right or power hereunder.

       17.02  Governing Law. This Agreement shall be governed by and construed
in accordance with the laws of Brazil.

       17.03  Expenses. Except as otherwise expressly provided in this
Agreement, each party to this Agreement shall bear its respective expenses
incurred in connection with the preparation,

                                       19
<PAGE>   23

execution and performance of this Agreement and the transactions contemplated
hereby, including all fees and expenses of its representatives.

       17.04  Rules of Construction.

              A.     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. All words used in this Agreement will be construed
                     to be of such gender or number as the context requires.

              B.     Unless expressly defined in this Agreement, 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.

              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 in this Agreement shall be
                     performed in a reasonable and timely manner. Except as
                     specifically set forth in this Agreement, 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.

       17.05  Entire Agreement. This Agreement and all other related documents
executed in connection herewith constitute the entire and final agreement and
understanding between the parties with respect to the subject matter hereof and
supersede all prior agreements relating to the subject matter hereof. The
Exhibits referred to in this Agreement are integral parts hereof and are hereby
made a part of this Agreement; provided, however, that to the extent that any of
the provisions of any Exhibit hereto are inconsistent with the express terms of
this Agreement, the terms of this Agreement shall prevail. This Agreement may
only be modified or supplemented by an instrument in writing executed by a duly
authorized representative of each party and delivered to the party relying on
the writing.

       17.06  Relationship of the Parties. The relationship between 360americas
and Impsat 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.

       17.07  Severability. If any term, covenant or condition contained in this
Agreement 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. The parties
further agree that if any provision contained in this Agreement is, to any
extent, held invalid or unenforceable in any respect under the laws governing
this Agreement, they shall take any actions necessary to render the remaining
provisions of this

                                       20