Document:

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                                                                   Exhibit 10.42

                  NETWORK OPERATING CENTER SERVICES AGREEMENT

THIS AGREEMENT Dated For Reference the _____ day of April, 2000

BETWEEN:

           360NETWORKS INC.

           ("360")

AND:

           WORLDWIDE FIBER NETWORKS SERVICES LTD.

           ("Services")

AND:

           WFI URBANLINK LTD.

           ("Urbanlink")

WHEREAS:

A.    Urbanlink has agreed to provide network operating center services to
Services on the terms and subject to the conditions specified in this Agreement.

IN CONSIDERATION of the mutual agreements in this Agreement and subject to the
terms and conditions specified in this Agreement, the parties agree as follows:

                                   ARTICLE 1
                                  DEFINITIONS

1.1   DEFINITIONS

In this Agreement, including the recitals and the schedules, the following words
and expressions have the following meanings unless the context otherwise
requires:

"Affiliate" of any Person means any other Person which, directly or indirectly,
controls or is controlled by or is under common control with such Person, and
for the purposes of this definition "control" (including correlative meanings of
the terms "controlled by" and "under common control with") means the power to
direct or cause the direction of the management and policies of any Person,
whether through the ownership of shares or by contract or otherwise.

"Person" means an individual, partnership, corporation (including a business
trust), joint stock company, trust, unincorporated association, joint venture or
other entity or a foreign state or political subdivision thereof or any agency
of such state or subdivision.

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"Services Confidential Information" has the meaning provided in Section 5.1.

"Subsidiary" has the meaning provided in the CANADA BUSINESS CORPORATIONS ACT in
effect on the date hereof.

"Urbanlink Confidential Information" has the meaning provided in Section 5.3.

"NOC Services" has the meaning provided in Section 2.1.

                                   ARTICLE 2
                                    SERVICES

2.1   THE SERVICES

Services hereby retains Urbanlink to provide network operating center services
including, without limitation, the monitoring, alarm and surveillance functions,
relating to all networks of Services and of 360 and its Subsidiaries in Canada
and relating to such other networks of 360 Subsidiaries as 360 may request from
time to time (the "NOC Services") by notice in writing to Urbanlink, Urbanlink
agrees to provide the NOC Services to Services. The NOC Services shall be
provided in accordance with the terms and conditions contained in this
Agreement.

2.2   STANDARDS

Urbanlink shall provide the NOC Services in accordance with telecommunications
industry standards for such services and in accordance with such policies and
procedures, and to such standards, as may be specified from time to time by
notice in writing from Services to Urbanlink. The NOC Services provided by
Urbanlink shall be coordinated with the similar functions performed by other
network operating centers operated by 360 Subsidiaries in other countries.

2.3   PROJECT DIRECTORS

Each of Urbanlink and Services will appoint a Project Director whose duties will
be to act as the liaison between Urbanlink and Services.

2.4   SERVICES' ASSISTANCE

Services will provide to Urbanlink full, good faith co-operation to assist
Urbanlink in providing the NOC Services. In particular, and without limiting the
generality of the foregoing, Services will:

      (a)   supply free of charge all pertinent data and information and give
            such assistance as may reasonably be requested by Urbanlink to
            provide the NOC Services and in particular to provide Urbanlink with
            such specific and detailed information regarding Services' systems,
            procedures and equipment as Urbanlink may reasonably request; and

      (b)   make available to Urbanlink such employees of Services as Urbanlink
            may reasonably request.

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                                   ARTICLE 3
                                  COMPENSATION

3.1   FEES

In consideration of Urbanlink providing the NOC Services, Services will pay to
Urbanlink fees for the NOC Services in an amount equal to Urbanlink's operating
costs of providing such services, plus a margin as agreed to between Services
and Urbanlink.

3.2   INTEREST

Unless otherwise agreed between Urbanlink and Services, Urbanlink will invoice
Services for such fees and expenses monthly in arrears. All such invoices will
be payable by Services within 30 days of the date of each such invoice. If
payment is not made when due, Services will pay to Urbanlink interest on the
balance unpaid at a rate of 1.5% per month, compounded monthly (equivalent to
19.56% per annum) until paid.

3.3   TAXES

The amounts specified in this Agreement are exclusive of any federal or
provincial tariffs, duties, sales, use or goods and services taxes or duties,
all of which will be paid by Services.

                                   ARTICLE 4
                     WARRANTIES AND LIMITATION OF LIABILITY

4.1   WARRANTY

Urbanlink will perform the NOC Services to the same reasonable standards of
professional skill and competence applicable to generally recognized providers
of similar services.

4.2   OTHER WARRANTIES EXCLUDED

THE FOREGOING WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES OR CONDITIONS.
URBANLINK MAKES NO OTHER WARRANTY OR CONDITION, EXPRESS OR IMPLIED, AND THERE
ARE EXPRESSLY EXCLUDED ALL IMPLIED OR STATUTORY WARRANTIES OR CONDITIONS OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR TITLE OR NONINFRINGEMENT
AND THOSE ARISING BY STATUTE OR OTHERWISE IN LAW OR FROM A COURSE OF DEALING OR
USAGE OF TRADE. THE STATED EXPRESS WARRANTY IS IN LIEU OF ALL LIABILITIES OR
OBLIGATIONS FOR DAMAGES ARISING OUT OF OR IN CONNECTION WITH THE PERFORMANCE OF
THE NOC SERVICES.

4.3   NO CONSEQUENTIAL DAMAGES

IN NO EVENT WHATSOEVER SHALL URBANLINK BE LIABLE FOR INDIRECT, CONSEQUENTIAL,
EXEMPLARY, INCIDENTAL, SPECIAL, INDIRECT OR OTHER SIMILAR DAMAGES INCLUDING BUT
NOT LIMITED TO LOST PROFITS, LOST BUSINESS REVENUE, FAILURE TO REALIZE EXPECTED
SAVINGS, OTHER

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COMMERCIAL OR ECONOMIC LOSS OF ANY KIND OR ANY CLAIM AGAINST SERVICES BY ANY
PARTY ARISING OUT OF OR IN CONNECTION WITH THE PERFORMANCE OF THE NOC SERVICES
EVEN IF URBANLINK HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

LIMITATION OF LIABILITY BENEFITS EMPLOYEES

Every exemption from liability, limitation and condition contained in this
Agreement for the benefit of Urbanlink and every defence and immunity of
whatsoever nature applicable to Urbanlink or to which Urbanlink is entitled
under this Agreement will also be available and will extend to protect every
director, officer, employee, agent or independent contractor from time to time
of Urbanlink and, for the purpose of all such provisions and this section,
Urbanlink is and will be deemed to be acting as agent and trustee on behalf of
and for the benefit of all such subsidiaries, affiliates, employees, agents and
independent contractors.

                                   ARTICLE 5
                                CONFIDENTIALITY

5.1   SERVICES CONFIDENTIAL INFORMATION

During the course of its relationship with Urbanlink, Services or its
subsidiaries or affiliates or their employees or agents may disclose certain
proprietary or confidential information to Urbanlink or its subsidiaries or
affiliates or their employees or agents. The proprietary or confidential
information may be oral or written, may be of a technical or commercial nature,
may take the form of plans, drawings, processes, formulae, schedules, reports,
projections, analyses, programs, prints, recordings, lists or other compilations
of information, and may relate to Services, its suppliers, employees,
stockholders or customers. All of such proprietary information and confidential
information is herein collectively called the "Services Confidential
Information".

5.2   CONFIDENTIALITY OF SERVICES CONFIDENTIAL INFORMATION

All Services Confidential Information obtained by Urbanlink will be considered
confidential and will not be disclosed by Urbanlink to any person without the
prior written consent of Services. Urbanlink will use the Services Confidential
Information only for the purposes contemplated by this Agreement. Urbanlink will
not obtain any interest in any Services Confidential Information by reason of
this Agreement or by reason of the disclosure of such Services Confidential
Information pursuant to this Agreement. Urbanlink will take the steps reasonably
necessary to protect the confidentiality of the Services Confidential
Information. Urbanlink will provide at least the same level of protection that
it provides for its own proprietary information. Any copies of the Services
Confidential Information which are made by Urbanlink will include all copyright
notices and any other propriety notices contained in such Services Confidential
Information, and will display such notices not less prominently than such
notices are displayed in such Services Confidential Information.

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5.3   URBANLINK CONFIDENTIAL INFORMATION

During the course of its relationship with Services, Urbanlink or its
subsidiaries or affiliates or their employees or agents may disclose certain
proprietary or confidential information to the Services or its subsidiaries or
affiliates or their employees or agents. The proprietary or confidential
information may be oral or written, may be of a technical or commercial nature,
may take the form of programs, design documentation, manuals, plans, drawings,
processes, formulae, schedules, reports, projections, analyses, programs,
prints, recordings, lists or other compilations of information, and may relate
to the Urbanlink, its suppliers, employees, stockholders or customers. All of
such proprietary information and confidential information is herein collectively
called the "Urbanlink Confidential Information".

5.4   CONFIDENTIALITY OF URBANLINK CONFIDENTIAL INFORMATION

All Urbanlink Confidential Information obtained by Services will be considered
confidential and will not be disclosed by Services to any person without the
prior written consent of Urbanlink. Services will use the Urbanlink Confidential
Information only for the purposes contemplated by this Agreement. Services will
not obtain any interest in any Urbanlink Confidential Information by reason of
this Agreement or by reason of the disclosure of such Urbanlink Confidential
Information pursuant to this Agreement. Services will take the steps reasonably
necessary to protect the confidentiality of the Urbanlink Confidential
Information. Services will provide at least the same level of protection that it
provides for its own propriety information. Any copies of the Urbanlink
Confidential Information which are made by Services will include all copyright
notices and any other propriety notices contained in such Urbanlink Confidential
Information, and will display such notices not less prominently than such
notices are displayed in such Urbanlink Confidential Information.

5.5   EXCEPTIONS

The foregoing restrictions do not apply to:

      (a)   information which at the time of disclosure was in the public domain
            as evidenced by a printed publication or otherwise;

      (b)   information which after disclosure becomes part of the public domain
            by publication or otherwise, other than by an action in breach of
            this Agreement;

      (c)   information which was in the possession of a party at the time of
            disclosure by the other party and was not acquired, directly or
            indirectly, from the other party;

      (d)   information which the disclosing party rightfully receives from an
            independent third party who did not receive such information,
            directly or indirectly, from the other party with limitation or
            restriction on its use;

      (e)   information which is independently developed by employees or agents
            of a party who had not had access to the other party's confidential
            information;

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      (f)   any information which is required to be disclosed pursuant to the
            timely disclosure requirements imposed by law or by stock exchange
            policies applicable to the receiving party and, in such cases, only
            where the other party has been given a reasonable opportunity to
            review such proposed disclosure and the other party has maintained
            confidentiality to the greatest extent permissible under such laws
            and policies; or

      (g)   such information as a party may be required to disclose by order of
            a court, administrative agency or other governmental body with
            jurisdiction over such party, provided that such party first
            provides to the other party prompt notice of such required
            disclosure and takes such steps as may be reasonable in the
            circumstances to allow the other party to seek a protective order
            with respect to the confidentiality of the information required to
            be disclosed.

                                   ARTICLE 6
                              TERM AND TERMINATION

6.1   TERM

The term of this Agreement will commence on the date hereof, and will continue
until April 30, 2005.

6.2   TERMINATION FOR DEFAULT

Without limiting the remedies otherwise available under this Agreement or at
law, either Services or Urbanlink (referred to in this section as the
"Terminating Party") may terminate this Agreement by notice in writing to the
other (the "Defaulting Party") on the occurrence of any one or more of the
following events:

      (a)   if the Defaulting Party is in breach of any material term of this
            Agreement and such breach is not cured within 30 days of the
            Defaulting Party receiving written notice from the Terminating Party
            specifying the breach in reasonable detail, or within such longer
            period of time as may be reasonably necessary to cure such breach
            provided that the Defaulting Party is acting in good faith and with
            all reasonable diligence to cure such breach;

      (b)   if the Defaulting Party makes an assignment for the benefit of its
            creditors, is declared bankrupt, or otherwise takes advantage of
            provisions for relief under the Bankruptcy and Insolvency Act, the
            Companies Creditors Arrangement Act or similar legislation in any
            jurisdiction, or makes an authorized assignment, or makes a proposal
            under the Bankruptcy and Insolvency Act or initiates proceedings
            under similar legislation in any jurisdiction;

      (c)   if a receiver, receiver and manager or receiver-manager of all or
            any part of the assets of the Defaulting Party is appointed and such
            receiver, receiver and manager or receiver-manager is not discharged
            within 30 days of such appointment;

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      (d)   if an order is made or an effective resolution is passed for the
            winding-up or liquidation of the Defaulting Party; or

      (e)   if the Defaulting Party ceases to carry on its business.

6.3   SURVIVAL OF TERMS

Articles 4 and 5 and such other provisions as may reasonably be expected to
remain in force will survive the expiration or termination of this Agreement and
will remain in full force and effect following such expiration or termination.
The expiration or termination of this Agreement will not affect the rights of
any party to make a claim for damages arising from a breach of any provision of
this Agreement which occurred prior to such expiration or termination.

                                   ARTICLE 7
                                    GENERAL

7.1   GOVERNING LAW AND ATTORNMENT

This Agreement will be governed by and construed in accordance with the
substantive laws of British Columbia and the federal laws of Canada applicable
in British Columbia, without regard to the conflict of law rules of British
Columbia. The parties irrevocably submit to and accept generally and
unconditionally the exclusive jurisdiction of the courts and appellate courts of
British Columbia with respect to any legal action or proceeding which may be
brought at any time relating in any way to this Agreement. Each of the parties
irrevocably waives any objection it may now or in the future have to the venue
of any such action or proceeding, and any claim it may now or in the future have
that any such action or proceeding has been brought in an inconvenient forum.

7.2   TIME OF THE ESSENCE OF THE AGREEMENT

Unless otherwise specifically provided in this Agreement, time will be of the
essence of this Agreement and of the transactions contemplated by this
Agreement.

7.3   REMEDIES NOT EXCLUSIVE

The remedies provided to the parties under this Agreement are cumulative and not
exclusive to each other, and any such remedy will not be deemed or construed to
affect any right which any of the parties is entitled to seek at law, in equity
or by statute.

7.4   NOTICES

Any notice, direction, request or other communication required or contemplated
by any provision of this Agreement will be given in writing and will be given by
delivering or faxing or emailing the same to the parties as follows:

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      (a)   To 360 at:

            Suite 1510, 1066 West Hastings Street
            Vancouver, B.C.  V6E 3X1

            Attention:      Catherine McEachern
            Fax No.:        (604) 681-0994
            Email:          catherine.meachern@wwfiber.com

      (b)   To Services at:

            Suite 1510, 1066 West Hastings Street
            Vancouver, B.C.  V6E 3X1

            Attention:      Catherine McEachern
            Fax No.:        (604) 681-0994
            Email:          catherine.meachern@wwfiber.com

      (c)   To Urbanlink at:

            Suite 1000, 1066 West Hastings Street
            Vancouver, B.C.  V6E 3X1

            Attention:      Bill Ramsey
            Fax No.:        (604) 681-5372
            Email:          bill.ramsey@wwfiber.com

Any such notice, direction, request or other communication will be deemed to
have been given or made on the date on which it was delivered or, in the case of
fax or email, on the next business day after receipt of transmission. Any party
may change its fax number or address for service or email address from time to
time by written notice in accordance with this section.

7.5   ASSIGNMENT

      (a)   This Agreement is not assignable by Urbanlink in whole or in part
            without the prior written consent of 360, such consent not to be
            unreasonably delayed. This Agreement is not assignable by 360 or
            Services without the prior written consent of Urbanlink, such
            consent not to be unreasonably delayed. Any attempt by any party to
            assign any of the rights or to delegate any of the duties or
            obligations of this Agreement without such prior written consent is
            void.

      (b)   Notwithstanding the foregoing, the interests of any party may be
            assigned by such party to an Affiliate, provided that such Affiliate
            delivers to the other parties a written undertaking to be bound by
            the provisions of this Agreement in all respects and to the same
            extent as the assignor is bound and provided further that the
            assignor will continue to be bound by all the obligations hereunder
            as if such assignment had not occurred and shall perform such
            obligations to the extent that such Affiliate fails to do so.

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      (c)   Notwithstanding the foregoing, the interests of a party under this
            Agreement (including, without limitation, in the case of Urbanlink,
            the right to receive any and all amounts payable to Urbanlink under
            this Agreement) may be assigned by such party by way of collateral
            security to a lender without the consent of the other parties,
            provided however that any such lender agrees in writing that:

            (i)   the rights and interest of the lender are subject to the
                  rights and interests of the parties other than the assignor
                  under this Agreement;

            (ii)  prior to realizing on such collateral security it will provide
                  notice to the other parties giving them the opportunity to
                  cure the default; and

            (iii) should such security be realized with the result that the
                  title or interest of the assignor, as the case may be, is
                  vested in an assignee, acquirer or other successor in title or
                  interest (including the lender if such is the case)
                  ("Successor"), then the lender will cause such Successor to
                  enter into a written agreement with the other parties to be
                  bound by the provisions of this Agreement in all respects and
                  to the same extent as the assignor was bound and this from the
                  date the title or interest is transferred and provided further
                  that the assignor will continue to be bound by all the
                  obligations under this Agreement as if such transfer of title
                  or interest had not occurred and will perform such obligations
                  to the extent that the Successor fails to do so.

7.6   FORCE MAJEURE

The failure or delay of any party to this Agreement to perform any obligation
under this Agreement solely by reason of acts of God, acts of civil or military
authority, civil disturbance, war, strikes or other labour disputes or
disturbances, fire, transportation contingencies, shortage of facilities, fuel,
energy, labour or materials, or laws, regulations, acts or orders of any
governmental agency or official, other catastrophes, or any other circumstance
beyond its reasonable control ("Force Majeure") will be deemed not to be a
breach of this Agreement so long as the party so prevented from complying with
this Agreement has not contributed to such Force Majeure, has used reasonable
efforts to avoid such Force Majeure or to ameliorate its effects, and continues
to take all actions within its power to comply as fully as possible with the
terms of this Agreement. In the event of any such Force Majeure, performance of
the obligations will be deferred until the Force Majeure ceases. This section
will not apply to excuse a failure to make any payment when due.

7.7   COUNTERPARTS

This Agreement may be executed in any number of counterparts with the same
effect as if all parties had signed the same document. All of these counterparts
will for all purposes constitute one agreement, binding on the parties,
notwithstanding that all parties are not signatories to the same counterpart. A
fax transcribed copy or photocopy of this Agreement executed by a party in
counterpart or otherwise will constitute a properly executed, delivered and
binding agreement or counterpart of the executing party.

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7.8   WAIVER

No failure or delay on the part of any party in exercising any power or right
under this Agreement will operate as a waiver of such power or right. No single
or partial exercise of any right or power under this Agreement will preclude any
further or other exercise of such right or power. No modification or waiver of
any provision of this Agreement and no consent to any departure by any party
from any provision of this Agreement will be effective until the same is in
writing. Any such waiver or consent will be effective only in the specific
instance and for the specific purpose for which it was given. No notice to or
demand on any party in any circumstances will entitle such party to any other or
further notice or demand in similar or other circumstances.

7.9   FURTHER ASSURANCES

Each of the parties will promptly execute and deliver to the other at the cost
of the other such further documents and assurances and take such further actions
as the other may from time to time request in order to more effectively carry
out the intent and purpose of this Agreement and to establish and protect the
rights, interests and remedies intended to be created in favour of the other.

7.10  ENTIRE AGREEMENT

This Agreement and any documents and agreements to be delivered pursuant to this
Agreement supersede all previous invitations, proposals, letters,
correspondence, negotiations, promises, agreements, covenants, conditions,
representations and warranties with respect to the subject matter of this
Agreement. There is no representation, warranty, collateral term or condition or
collateral agreement affecting this Agreement, other than as expressed in
writing in this Agreement. No trade terms or trade usages are to be incorporated
by reference implicitly or otherwise into this Agreement, unless expressly
referred to in this Agreement.

7.11  AMENDMENTS

No change or modification of this Agreement will be valid unless it is in
writing and signed by each party to
this Agreement.

7.12  INVALIDITY OF PARTICULAR PROVISION

If any provision of this Agreement or any part of any provision (in this section
called the "Offending Provision") is declared or becomes unenforceable, invalid
or illegal for any reason whatsoever including, without limiting the generality
of the foregoing, a decision by any competent courts, legislation, statutes,
bylaws or regulations or any other requirements having the force of law, then
the remainder of this Agreement will remain in full force and effect as if this
Agreement had been executed without the Offending Provision.

7.13  CURRENCY

Unless otherwise specified all sums of money expressed in this Agreement are in
the lawful money of Canada.

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7.14  NUMBER AND GENDER

Unless the context of this Agreement otherwise requires, to the extent necessary
so that each clause will be given the most reasonable interpretation, the
singular number will include the plural and vice versa, the verb will be
construed as agreeing with the word so substituted, words importing the
masculine gender will include the feminine and neuter genders, words importing
persons will include firms and corporations and words importing firms and
corporations will include individuals.

7.15  HEADINGS AND CAPTIONS

The headings and captions of sections and paragraphs contained in this Agreement
are all inserted for convenience of reference only and are not to be considered
when interpreting this Agreement.

7.16  ACKNOWLEDGEMENT OF RECEIPT

Each of the parties acknowledges receiving an executed copy of this Agreement.

7.17  ENUREMENT

Subject to the restrictions on transfer contained in this Agreement, this
Agreement will enure to the benefit of and be binding on the parties and their
respective heirs, executors, administrators, successors and assigns.

                     [THE NEXT PAGE IS THE EXECUTION PAGE.]

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IN WITNESS WHEREOF the parties have executed this Agreement as of the date
stated on the first page.

360NETWORKS INC.                            WORLDWIDE FIBER NETWORKS
                                            SERVICES LTD.

Per:                                        Per:

------------------------------------        ------------------------------------
Signature                                                     Signature

WFI URBANLINK LTD.

Per:

------------------------------------
Signature

                                      -12-<PAGE>

                                                                   Exhibit 10.43

THIS AGREEMENT is made effective as of the ______ day of April, 2000.

BETWEEN:

                         WORLDWIDE FIBER HOLDINGS LTD.

                                 (the "Vendor")

                                                               OF THE FIRST PART

                                    - and -

                            URBANLINK HOLDINGS LTD.

                               (the "Purchaser")

                                                              OF THE SECOND PART

                              ROLL-OVER AGREEMENT

                                    (SHARES)

A.    The Vendor is the beneficial owner of the Shares.

B.    The Vendor wishes to sell and the Purchaser wishes to purchase all of the
Vendor's interest in the Shares as at the Effective Date for a total purchase
price equal to the aggregate of the fair market values of the Shares all on the
terms and conditions and subject to the representations and warranties set forth
in this Agreement.

      IN CONSIDERATION of the foregoing premises and of the mutual covenants
herein contained the parties agree as follows:

                      ARTICLE 1: INCORPORATION OF RECITALS
                         AND SCHEDULES AND DEFINITIONS

1.1   The Recitals and all Schedules annexed to this Agreement are expressly
incorporated into, and form an integral part of, this Agreement.

                             ARTICLE 2: DEFINITIONS

2.1   In this Agreement:

      (a)   "Act" means the Income Tax Act (Canada), as it read on the Effective
            Date;

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      (b)   "Adjusted Cost Base" means the aggregate cost base of the Shares
            determined by the Vendor in accordance with the Act, where "adjusted
            cost base" is as defined in subsection 248(1) of the Act;

      (c)   "Adjusted Elected Amount" means the amount that, for tax purposes,
            is to be the Vendor's "proceeds of disposition" and the Purchaser's
            "cost of acquisition" of the Shares, determined in accordance with
            section 6.3 to be a greater or lesser amount than the Elected
            Amount;

      (d)   "Articles" means the articles of incorporation of the Purchaser
            together with all amendments thereto as registered with the
            Registrar of Corporations for the Province of Alberta as at the
            Effective Date;

      (e)   "Closing Date" means the Effective Date;

      (f)   "Corporation" means 360networks inc.;

      (g)   "Effective Date" means the date of this Agreement;

      (h)   "Elected Amount" means the amount agreed upon by the parties in
            accordance with section 6.2 hereof which, for tax purposes, is to be
            the Vendor's "proceeds of disposition" and the Purchaser's "cost of
            acquisition" of the Shares;

      (i)   "Election" means the election made by the parties in prescribed form
            and within the time prescribed by subsection 85(6) of the Act that
            the rules set forth in subsection 85(1) of the Act shall apply to
            the purchase and sale of the Shares;

      (j)   "Fair Market Value" means the actual fair market value of the Shares
            determined as of the Effective Date by agreement of the Vendor and
            Purchaser;

      (k)   "Revised Adjusted Cost Base" means the adjusted cost base of the
            Shares determined in accordance with section 6.3 to be greater or
            lesser amounts than the Adjusted Cost Base;

      (l)   "Schedules" means any schedules which are attached to this
            Agreement;

      (m)   "Share Consideration" means the number, series and class of shares
            of the capital of the Purchaser having attached thereto only those
            rights, privileges, restrictions and limitations set forth in the
            Articles, which shares are more particularly described in Schedule
            "B";

      (n)   "Shares" means those shares in the capital of the Corporation owned
            by the Vendor, more particularly described in Schedule "A";

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      (o)   "Stated Capital Addition" means the aggregate stated capital for the
            shares constituting the Share Consideration that is to be added to
            the stated capital account maintained for such shares, which shall
            be equal to the Elected Fair Market Value; and

      (p)   "Taxing Authority" means the Minister of National Revenue for Canada
            or any other competent authority having jurisdiction that is
            authorized by law to issue an assessment or reassessment in respect
            of the transactions herein contemplated.

                          ARTICLE 3: PURCHASE AND SALE

3.1   Subject to the terms and conditions, and based upon the representations
and warranties, contained in this Agreement, the Vendor shall sell, transfer and
assign and the Purchaser shall purchase as of the Effective Date all of the
Vendor's interest in the Shares.

                           ARTICLE 4: EFFECTIVE DATE

4.1   It is acknowledged and agreed to by the parties that the purchase and sale
of the Shares is deemed to have occurred as of the Effective Date.

                           ARTICLE 5: PURCHASE PRICE

5.1   The total purchase price for the Shares is equal to the Fair Market Value
and shall be paid and satisfied by the Purchaser issuing to the Vendor the Share
Consideration.

5.2   The Purchaser shall add the Stated Capital Addition to the stated capital
account being maintained for the class of shares of which the Share
Consideration forms a part.

5.3   The parties' determination of the Fair Market Value is final and binding
upon the parties.

                 ARTICLE 6: JOINT ELECTION AND ELECTED AMOUNTS

6.1   The Vendor and Purchaser shall jointly make the Election.

6.2   Subject to the provisions of this Agreement, for purposes of the Election
the parties agree that the Elected Amount shall be the Adjusted Cost Base of the
Shares, which determination is final and binding on the parties.

6.3   If:

      (a)   the Taxing Authority proposes to issue, or does issue, any
            assessment or reassessments that impose, or would impose, any
            liability for tax of any

                                      -3-
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            nature or kind on either of the parties on the basis that the
            adjusted cost base of the Shares is the Revised Adjusted Cost Base;

      (b)   the parties agree, or a Court or tribunal of competent jurisdiction
            finally adjudges, that the adjusted cost base of the Shares is the
            Revised Adjusted Cost Base; and

      (c)   the Taxing Authority will accept as effective, an amended Election
            of the parties;

then:

      (d)   the Adjusted Cost Base shall be deemed to have always been, and the
            Adjusted Cost Base wherever referred to in this Agreement, shall be
            read as meaning the Revised Adjusted Cost Base;

      (e)   the Elected Amount shall be deemed to have always been, and the
            Elected Amount wherever referred to in this Agreement shall be read
            as meaning, an amount equal to the Adjusted Elected Amount; and

      (f)   the parties shall take all such steps and jointly execute all such
            documents and elections as may be required and allowed so that the
            aggregate of the amounts elected for purposes of subsection 85(1) of
            the Act with respect to the purchase and sale of the Shares shall be
            equal to the Adjusted Elected Amount.

               ARTICLE 7: VENDOR'S REPRESENTATIONS AND WARRANTIES

7.1   The Vendor represents and warrants to the Purchaser that:

      (a)   on the Closing Date the Shares shall be beneficially owned by the
            Vendor free and clear of all restrictions, options, liens, charges
            and encumbrances, whatsoever, excepting those restrictions set forth
            in the articles of continuance (as amended) of the Corporation, the
            restrictions set forth in the Shareholders Agreement respecting the
            issued and outstanding shares in the capital of the Corporation and
            the restrictions set forth in the Amended and Restated Option
            Agreement dated August 1, 1999, to which the Corporation and the
            Vendor are parties;

      (b)   no person, firm or corporation has any written or verbal agreement,
            option, understanding or commitment or any right or privilege
            capable of becoming an agreement for the purchase of the Shares from
            the Vendor other than as set out in this Agreement, in the articles
            of continuance (as amended) of the Corporation, in the Shareholders
            Agreement respecting the issued and outstanding shares in the
            capital of the Corporation and in

                                      -4-
<PAGE>

            the Amended and Restated Option Agreement dated August 1, 1999 to
            which the Corporation and the Vendor are parties;

      (c)   on the Closing Date the Vendor shall not be a non-resident of Canada
            within the meaning of the Act; and

      (d)   all requisite approvals of the Corporation and its directors and
            shareholders, as applicable, have been obtained so as to permit the
            transfer of the shares from the Vendor to the Purchaser in
            accordance with the terms hereof.

7.2   The representations and warranties contained in section 7.1 shall survive
the completion of the purchase and sale of the Shares and shall continue in full
force and effect for the benefit of the Purchaser; provided always that no claim
with respect to the representations and warranties shall be made by the
Purchaser unless written notice shall have been given to the Vendor within one
(1) year from the Closing Date.

             ARTICLE 8: PURCHASER'S REPRESENTATIONS AND WARRANTIES

8.1   The Purchaser represents and warrants to the Vendor that:

      (a)   the Purchaser is a corporation duly incorporated, validly existing
            and qualified to carry on business under the laws of the Province of
            Alberta;

      (b)   the authorized capital of the Purchaser consists of an unlimited
            number of:

            (i)   Class "A" Common Voting Non-Participating Shares

            (ii)  Class "B" Common Non-Voting Participating Shares

            (iii) Class "C" Common Non-Voting Participating Shares,

            having attached thereto only those rights, privileges, restrictions
            and conditions set forth in the Articles;

      (c)   the issuance to the Vendor of the Share Consideration is valid and
            in accordance with the laws of the Province of Alberta; and

      (d)   this Agreement constitutes a valid and binding obligation of the
            Purchaser and the transactions contemplated by this Agreement are
            not in violation of any terms and conditions of the Articles or any
            agreement to which the Purchaser is a party or by which the
            Purchaser is bound.

8.2   The representations and warranties contained in section 8.1 shall survive
the completion of the purchase and sale of the Shares and shall continue in full
force and effect for the benefit of the Vendor; provided always that no claim
with respect to the representations and

                                      -5-
<PAGE>

warranties shall be made by the Vendor unless written notice shall have been
given to the Purchaser within one (1) year from the Closing Date.

            ARTICLE 9: CLOSING, BENEFICIAL OWNERSHIP AND POSSESSION

9.1   Upon or prior to the Closing Date, or so soon thereafter as the parties
agree upon:

      (a)   the Vendor shall deliver to the Purchaser, share certificates
            representing the Shares, duly endorsed in blank for transfer and
            shall cause transfers of such Shares to be duly recorded in the
            books of the Corporation in the name of the Purchaser or its
            nominee;

      (b)   the Purchaser shall:

            (i)   issue and deliver to the Vendor the Share Consideration; and

            (ii)  at the request of the Vendor, deliver to the Vendor a copy of
                  the resolution of the board of directors of the Purchaser
                  adding the Stated Capital Addition to the stated capital
                  account maintained for the shares forming the Share
                  Consideration, certified by the secretary of the Purchaser as
                  a true and exact copy, where required by the Vendor.

9.2   If the corporate proceedings required to duly and validly record the
Shares in the name of the Purchaser or its nominee have not been completed on
the Closing Date, the Vendor agrees that, until such time as the Shares shall be
recorded in the name of the Purchaser or its nominee, the Vendor shall stand as
owner of the Shares as bare trustee for and on behalf of the Purchaser as the
beneficial owner, and in such capacity the Vendor shall:

      (a)   receive on behalf of, account to and forthwith pay over to the
            Purchaser, any and all dividends and other amounts received by the
            Vendor as the recorded owner of the Shares; and

      (b)   transfer and deal with the Shares in such manner as the Purchaser
            may direct.

The Purchaser shall at all times hereafter indemnify and keep indemnified the
Vendor against all liabilities which the Vendor may incur by reason of the
Shares being held in trust in the name of the Vendor for the benefit of the
Purchaser.

                    ARTICLE 10: FURTHER ACTS AND ASSURANCES

10.1  Each of the parties shall, upon the reasonable request of the other party,
make, do, execute or cause to be made, done, or executed all such further and
other lawful acts, deeds,

                                      -6-
<PAGE>

things, documents and assurances of whatsoever nature and kind for the better
performance of the terms and conditions of this Agreement.

                              ARTICLE 11: NOTICES

11.1  Any notice, direction or other instrument required or permitted to be
given under the provisions of this Agreement shall be in writing and either
delivered personally, sent by prepaid registered mail or sent by facsimile to
the party to be notified. The addresses of the parties for such purpose shall
respectively be:

      (a)   to the Vendor at its registered office address; and

      (b)   to the Purchaser at its registered office address;

or to such other address in Canada of which either party may from time to time
notify the other.

11.2  Any notice, direction or other instrument shall:

      (a)   if delivered, be deemed to have been given or received on the day on
            which it was so delivered and if not on a business day then on the
            business day next following the day of delivery;

      (b)   if sent by facsimile shall be deemed to have been given or received
            on the same business day as it was sent, provided facsimile
            confirmation of receipt is received by the sender;

      (c)   if mailed, shall be deemed to have been given or received on the
            third day following the day on which it was mailed; and

      (d)   if mailed at a time when there is an interruption or an anticipated
            interruption of mail service affecting the delivery of such mail,
            shall be deemed to have been given or received on the fifth business
            day after the date that normal postal service is restored.

                          ARTICLE 12: ENTIRE AGREEMENT

12.1  This Agreement constitutes and contains the entire agreement between the
parties respecting the subject matter of this Agreement and supersedes any prior
agreements whether written or verbal.

                                      -7-
<PAGE>

                             ARTICLE 13: ENUREMENT

13.1  This Agreement shall enure to the benefit of and be binding upon the
parties and their respective successors, personal representatives and assigns.

                            ARTICLE 14: COUNTERPART

14.1  This Agreement may be executed in counterparts with the same effect as if
all of the parties hereto had signed the same document. All counterparts shall
be construed together and shall constitute one and the same agreement. A
facsimile transmitted copy of this Agreement signed by a party, in counterpart
or otherwise, shall be deemed to be evidence of a properly executed, delivered
and binding agreement of the party so signing, notwithstanding any variation in
the actual dates of execution. The parties each agree to promptly return an
original duly executed counterpart of this Agreement following the transmission
of the facsimile transcribed copy thereof.

      IN WITNESS WHEREOF the parties have properly executed this Agreement, as
of the Effective Date.

                                            WORLDWIDE FIBER HOLDINGS LTD.

                                            PER:
                                                --------------------------------

                                            URBANLINK HOLDINGS LTD.

                                            PER:
                                                --------------------------------

                                      -8-
<PAGE>

                                  SCHEDULE "A"
                                  ------------

           TO THAT CERTAIN ROLL-OVER AGREEMENT MADE BETWEEN WORLDWIDE
          FIBER HOLDINGS LTD. (AS VENDOR) AND URBANLINK HOLDINGS LTD.
                                 (AS PURCHASER)
          -----------------------------------------------------------

                                     SHARES
                                     ------

Share Certificate # _____ representing ___________________________ Subordinate
Voting Shares of 360networks inc.

<PAGE>

                                  SCHEDULE "B"
                                  ------------

           TO THAT CERTAIN ROLL-OVER AGREEMENT MADE BETWEEN WORLDWIDE
          FIBER HOLDINGS LTD. (AS VENDOR) AND URBANLINK HOLDINGS LTD.
                                 (AS PURCHASER)
          -----------------------------------------------------------

                              SHARE CONSIDERATION
                              -------------------

Share Certificate # 1C representing 490,000 Class "C" Common Non-Voting
Participating Shares in the capital of URBANLINK HOLDINGS Ltd.

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00008-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00008-of-00352.parquet"}]]