<PAGE>
 
                                  EXHIBIT 10.22




                                   Page 135
<PAGE>
 
               THIS INDENTURE made this 23rd day of April, 1997.

BETWEEN:

                       KANATA RESEARCH PARK CORPORATION

                       (Hereinafter called the "Landlord")

                                                               OF THE FIRST PART

AND:

                       NEWBRIDGE NETWORKS CORPORATION

                       (Hereinafter called the "Tenant")

                                                              OF THE SECOND PART



        WITNESSETH that in consideration of the rents, covenants, conditions and
agreements herein contained, the Landlord and the Tenant covenant and agree as
follows:

1.00    LEASED PREMISES

        The Landlord hereby leases to the Tenant all those premises consisting
        of the building known municipally as 349 Terry Fox Drive and comprising
        approximately two hundred and forty-two thousand eight hundred and 
        fifty-six point six seven (242,856.67) square feet (herein called either
        the "Leased Premises" or the "Building") in the City of Kanata which
        said building is erected on the lands (herein called the "Lands")
        described in Schedule "A" annexed hereto. The Leased Premises are more
        particularly outlined on the floor plan annexed hereto and marked
        Schedule "B".

1.01    ADDITIONAL DEFINITIONS

        For the purposes of this Lease and any additions or amendments thereto:

        (a)    "Improvements" means all improvements located on the Lands,
               including the Building, the parking lot or structure servicing
               the Building and other facilities and physical structures which
               are for the exclusive use of occupants of the Building;

        (b)    "Common Areas" means at any time those portions of the Lands and
               Building not leased or designated for lease to tenants but
               provided to be used in common by (or by the sublesses, agents,
               employees, customers or licensees of) Landlord, Tenant and other
               tenants of the Building, whether or not they are open to general
               public and shall include any fixtures, chattels, systems, decor,
               signs, facilities or landscaping contained in those areas or
               maintained or used in connection with them, and shall be deemed
               to include the city sidewalks adjacent to the Lands and any
               pedestrian walkway system (either above or below ground), park,
               or other public facility in respect of which Landlord is from
               time to time subject to obligations arising from the Lands and
               Building.

                                   Page 136
<PAGE>
 
        (c)    "Tenant's Proportionate Share" means one hundred percent (100%)
               provided the said percentage may be varied based on the actual
               area of the Leased Premises as certified by the Landlord.

2.00    TERM

        To have and to hold the Leased Premises for and during the Term,
        (hereinafter called the "Term") of five (5) years to be computed from
        the 1st day of June, l997 or from the date the Tenant takes occupancy of
        the Leased Premises, whichever is sooner, and from thenceforth next
        ensuing and fully to be completed and ended on the 31st day of May 2002.

2.01    INABILITY TO GIVE OCCUPANCY

        It is hereby agreed that if the Landlord is unable to deliver vacant
        possession of the Leased Premises on the date of commencement of the
        Term by reason of the Leased Premises or the Building being uncompleted
        or by reason of any previous tenant or occupant overholding (but not by
        reason of circumstances beyond the Landlord's control or by reason of
        the failure of the Tenant to complete Tenant's Work herein or by reason
        of the Tenant failing on or before the date occurring six (6) weeks
        prior to the commencement of the Term herein to supply all necessary
        approvals and specifications which the Landlord requires in order to
        complete the Leasehold Improvements herein,) the Landlord shall
        diligently exercise all of its rights to obtain completion and vacant
        possession of the Leased Premises and the rent payable hereunder shall
        abate at a rental per day equal to 1/365th of the Annual Rent payable
        until such completion or vacant possession is obtained but the Landlord
        shall not be liable to the Tenant for damages of any nature whatsoever
        and this Lease shall continue in full force and effect subject only to
        the abatement of rent as aforesaid.

2.02    EARLY OCCUPANCY

        If the Tenant occupies the Leased Premises prior to the commencement of
        the Term, then during the period up to the date of commencement the
        Tenant shall be a tenant of the Landlord subject to all the covenants,
        conditions and agreements set out in this Lease and at a rental per day
        equal to 1/365th of the Annual Rent and Additional Rent and such rental
        shall be paid on or before the commencement of the Term.

2.03    OVERHOLDING

        If the Tenant shall continue to occupy the Leased Premises after the
        expiration of this Lease with or without the consent of the Landlord and
        without any further written agreement, the Tenant shall be a monthly
        tenant at a rent equivalent to 150% of the Monthly Rent and Additional
        Rent hereby reserved and subject to all the terms and conditions herein
        set out except as to length of tenancy.

3.00    RENT - Basic Rent

        In each year during the Term of this Lease the Tenant covenants and
        agrees to pay without any set-off or deduction whatsoever, to the
        Landlord, as rent for the Leased Premises the following:

                                   Page 137
<PAGE>
 
<TABLE> 
<CAPTION> 
               Years     Rate/sq foot          Leased Premises
               -----     ------------          ---------------
               <S>       <C>                   <C> 
                1-5             $9.40            $2,282,852.60
</TABLE> 

        herein called "Annual Rent". The Annual Rent will be adjusted
        proportionately for any lease year which is other than twelve months.

3.01    MONTHLY RENTAL

        The Annual Rent shall be payable in equal monthly installments of One
        Hundred and Ninety Thousand Two Hundred and Thirty-Seven Dollars and
        Seventy-Two Cents ($190,237.72) (hereinafter called the "Monthly Rent")
        in advance on the first day of each calendar month during the Term. If
        the Term commences on any day other than the first (1st) or ends on any
        day other than the last of a calendar month, rent for the fraction of a
        month at the commencement and at the end of the Term shall be prorated
        at a rate per day equal to 1/365th of the Annual Rent payable.

3.02    ADDITIONAL RENT

        The Tenant covenants to pay as additional rent all sums to be paid to
        the Landlord hereunder including, without limiting the generality of the
        foregoing, all tax on the Tenant's leasehold improvements, Goods and
        Services Tax and the Tenant's Proportionate Share of the Tax, Capital
        Tax, Landlord's Business Tax and Operating Costs (herein called
        "Additional Rent").

3.03    ESTIMATED ADDITIONAL RENTALS

        During the Term, the Tenant shall pay to the Landlord monthly in advance
        on the 1st day of each and every month during the Term, one-twelfth
        (1/12) of the amount of such annual Additional Rent as reasonably
        estimated by the Landlord to be due from the Tenant. Such estimates may
        be adjusted from time to time and re-adjusted by the Landlord and the
        Tenant shall pay to the Landlord monthly installments of Additional Rent
        according to such estimates, as so adjusted.

3.04    DEFICIENCY OF ADDITIONAL RENT

        If the aggregate amount of such estimated Additional Rent payments made
        by the Tenant in any year should be less than the Additional Rent due
        for such year, then the Tenant shall pay to the Landlord as Additional
        Rent within thirty (30) days of receipt of notice thereof from the
        Landlord the amount of such deficiency.

3.05    EXCESS OF ADDITIONAL RENTAL INSTALLMENTS

        If the aggregate amount of such Additional Rent payments made by the
        Tenant in any year of the Term should be greater than the Additional
        Rent due for such year, then should the Tenant not be otherwise in
        default hereunder, the amount of such excess will be applied by the
        Landlord to the next succeeding installments of such Additional Rent due
        hereunder; and if there be any such excess for the last year of the
        Term, the amount thereof will be refunded by the Landlord to the Tenant
        within thirty (30) days after the completion of the Landlord's year-end
        audit provided the Tenant is not otherwise in default under the terms of
        the Lease.

                                   Page 138
<PAGE>
 
3.06    PRO-RATING OF ADDITIONAL RENT

        If only part of any calendar year is included within the Term the amount
        of the Additional Rent payable by the Tenant for such partial year shall
        be prorated and shall be based upon the estimates made by the Landlord
        and upon a final determination of such Additional Rent, the amount
        remaining unpaid at the termination of this Lease shall, notwithstanding
        such termination, be adjusted and paid within a reasonable time
        thereafter.

3.07    PREPAYMENT OF ADDITIONAL RENT

        Notwithstanding the foregoing, if the Landlord is required to pay any
        amount, which it is entitled to collect from the tenants of the
        Building, more frequently than provided for in this Lease or if the
        Landlord is required to prepay any such amount, the Tenant shall pay to
        the Landlord its portion of such amount calculated in accordance with
        this Lease, forthwith upon demand.

3.08    DISPUTE AS TO AMOUNT OF ADDITIONAL RENT

        In the event of any dispute by the Tenant as to the amount of any
        Additional Rent claimed by the Landlord or the amount of the Tenant's
        Proportionate Share thereof, the opinion of the Landlord's auditors
        shall be conclusive and binding as to the amount thereof for any period
        to which the opinion relates.

3.09    MANNER AND PLACE OF PAYMENT OF RENT

        All rent shall, until further written notice is received from the
        Landlord, be paid by the Tenant without any prior demand therefor to
        Kanata Research Park Corporation, at par in the City of Ottawa at the
        principal office of, Kanata Research Park Corporation, 600 March Road,
        P.O. Box l3600, Kanata, Ontario, Canada K2K 2E6, or at such other place
        in Canada as Kanata Research Park Corporation may designate in writing
        from time to time and shall be payable in lawful money of Canada. The
        Landlord agrees that payments made to Kanata Research Park Corporation
        pursuant to this Lease shall be deemed to be payments made to the
        Landlord and the Tenant shall not be required to see to the application
        thereof.

3.10    DEFAULT

        Any sums received by the Landlord from or for the account of the Tenant
        when the Tenant is in default hereunder may be applied at the Landlord's
        option to the satisfaction, in whole or part, of any of the obligations
        of the Tenant then due hereunder in such manner as the Landlord sees
        fit, and regardless of any designation or instructions of the Tenant to
        the contrary.

3.11    ACCRUAL OF RENT

        Rent shall be considered as annual and accruing from day to day, and
        where it becomes necessary for any reason to calculate such rent for an
        irregular period of less than one (1) year an appropriate apportionment
        and adjustment shall be made. Where the calculation of any Additional
        Rent is not made until after the termination of this Lease, the
        obligation of the Tenant to pay such Additional Rent shall survive the
        termination of this Lease and such amounts shall be payable by the
        Tenant upon demand by the Landlord.

                                   Page 139
<PAGE>
 
3.12    NET LEASE

        The Tenant acknowledges and agrees that it is intended that this Lease
        shall be a completely carefree net lease for the Landlord and that the
        Landlord shall not be responsible during the Term for any costs,
        charges, expenses or outlays of any nature whatsoever arising from or
        relating to the Leased Premises, whether foreseen or unforeseen and
        whether or not within the contemplation of the parties at the
        commencement of the Term except as shall be otherwise expressly provided
        for in this Lease and other than Income Tax due by the Landlord, the
        Tenant shall be responsible for any business transfer tax, value added
        tax, multi-stage sales tax, goods and services tax or any other tax or
        levy on rental income that may be charged, levied or assessed by any
        government or other applicable taxing authority against the Landlord
        whether known as a goods and services tax or any other name ("Goods and
        Services Tax").

4.00    TENANT'S BUSINESS TAX

        In each and every year during the Term the Tenant covenants to pay and
        discharge prior to the same becoming due and payable all taxes, rates,
        duties and assessments and other charges that may be levied, rated,
        charged or assessed against or in respect of the Tenant's or other
        occupant's use and occupancy of the Leased Premises or in respect of the
        Tenant's or other occupant's leasehold improvements, equipment,
        machinery, trade fixtures and facilities situate or installed on or in
        the Leased Premises and every tax and license fee in respect of any and
        every business carried on in the Leased Premises or in respect of the
        use or occupancy thereof by the Tenant (and any and every subtenant,
        licensee or occupant thereof) whether such taxes, rates, duties,
        assessments and license fees are charged by any municipal,
        parliamentary, school or other body during the term hereby demised. The
        Tenant will indemnify and keep indemnified the Landlord from and against
        payment of all loss, costs, charges and expenses occasioned by, or
        arising from any and all such taxes, rates, duties, assessments, license
        fees, and any and all taxes which may in future be levied or charged in
        lieu of such taxes; and any such loss, costs, charges and expenses
        suffered by the Landlord may be collected by the Landlord as rent with
        all rights of distress and otherwise as reserved to the Landlord in
        respect of rent in arrears. The Tenant further covenants and agrees that
        upon written request of the Landlord, the Tenant will promptly deliver
        to the Landlord for inspection receipts for payment of all such taxes,
        rates, duties, assessments, license fees and other charges in respect of
        all improvements, equipment and facilities of the Tenant on or in the
        Leased Premises or in respect of any business carried on in the Leased
        Premises which were due and payable up to one (1) month prior to such
        request.

4.01    LANDLORD'S BUSINESS TAX

        In the event that there are any taxes, rates, duties, assessments or
        charges levied, rated, charged or assessed against the Landlord by any
        municipal or other governmental authority with respect to the Landlord's
        use or occupancy of any part of the Building or the Land which the
        Tenant is entitled to use in common with other persons or with respect
        to any other part of the Building which the Landlord uses or occupies
        for the purpose of supplying services to the Leased Premises (such
        taxes, rates, duties, assessments or charges hereinafter called the
        "Landlord's Business Tax"), then it is agreed that in addition to all
        other sums, the Tenant is required to pay pursuant to this Lease, the
        Tenant shall pay to the Landlord as Additional Rent, the Tenant's
        Proportionate Share of such Landlord's Business Tax.

                                   Page 140
<PAGE>
 
4.02    TAX ON TENANT'S LEASEHOLD IMPROVEMENTS

        The Tenant shall pay to the Landlord as Additional Rent, in respect of
        each applicable tax year, an amount equal to that portion of the Tax for
        such tax year, as determined by the Landlord, which may reasonably be
        regarded as being attributable to the fixtures, improvements,
        installations, alterations, additions and equipment from time to time
        made, erected or installed by or on behalf of the Tenant in the Leased
        Premises.

4.03    PROPERTY TAX

        "Tax" in this Lease means an amount equivalent to all taxes, rates,
        duties, levies and assessments whatsoever levied, rated, charged or
        assessed by any municipal, parliamentary, educational, school or other
        governmental authority charged upon the Building, the Lands, the
        property and all improvements now or hereafter appurtenant thereto or
        upon the Landlord on account thereof including all taxes, rates, duties,
        levies and assessments for local improvements and including any tax
        which has been attracted by the Tenant's leasehold improvements and
        equipment and for which the Tenant is responsible hereunder and
        excluding any portion of Tax payable solely by any other tenant and
        excluding any Tax charged against or applicable to the other office
        buildings constructed on the Lands and the parking spaces (excluding
        visitor parking) applicable to such buildings and excluding such taxes
        as corporate income, capital gains, profits or excess profits, taxes
        assessed upon the income of the Landlord, and shall also include any and
        all taxes which may in future be levied in lieu of Tax as hereinbefore
        defined.

4.04    ALLOCATION OF TAX

        If the Tax or any portion thereof that may be payable by the Tenant by
        reason of this Lease, depends upon an assessment or an approximation of
        an assessment which has not been made by the taxing authority or
        authorities having jurisdiction, the Landlord shall determine the same;
        any such determination made by the Landlord shall be binding upon the
        Tenant unless shown to be unreasonable or erroneous in some substantial
        respect. The Landlord shall have the right from time to time to
        reasonably allocate and re-allocate Taxes not charged separately to the
        various buildings (including the Building) and the parking garages
        located on the Lands.

4.05    SEPARATE SCHOOL TAXES

        If the Tenant or any subtenant or licensee of the Tenant or any occupant
        of the Leased Premises shall elect to have the Leased Premises or any
        part thereof assessed for separate school taxes, the Tenant shall pay to
        the Landlord, as additional rent, as soon as the amount of the separate
        school taxes is ascertained, any amount by which the amount of separate
        school taxes exceeds the amount which would have been payable for Tax
        had such election not been made and if the Tenant or any subtenant or
        licensee of the Tenant shall elect to have the Leased Premises or any
        part thereof assessed for separate school taxes as aforesaid and if such
        separate school taxes are less than the taxes which would have been
        payable for school taxes had such election not been made, then and in
        that event, the Tenant shall be entitled to deduct from the rent for the
        first month of the year following which such taxes were payable, the
        amount by which the separate school taxes were less than the amount
        which would have been payable for school taxes in the year prior to such
        month.

                                   Page 141
<PAGE>
 
4.06    TAX APPEAL

        Any expense incurred by the Landlord in obtaining or attempting to
        obtain a reduction in the amount of the Tax or the assessment upon which
        the Tax may be based, shall be added to and included in the amount of
        the Tax and if the Tenant shall have paid its Proportionate Share of the
        Tax and the Landlord shall thereafter receive a refund of any portion of
        the Tax, the Landlord shall make an appropriate refund to the Tenant.

4.07    CAPITAL TAX

        "Capital Tax" means the tax or excise imposed or capable of being
        imposed upon the Landlord by any government authority having
        jurisdiction which is measured or based in whole or in part upon the
        taxable capital employed by the Landlord, which said taxable capital
        shall be deemed to be the cost to the Landlord of said Building and
        Lands computed as if the amount of such tax were that amount due if the
        Building and the Lands were the only property of the Landlord, the
        Landlord was entitled to no capital deduction, investment allowance or
        any other deduction whatsoever. For the purpose of this paragraph the
        Term "investment allowance" and "capital deduction" shall be defined by
        reference to the applicable taxing statute.

5.00    OPERATING COSTS

        "Operating Costs" in this Lease means the total charges, expenses,
        costs, fees, rentals, disbursements or outlays incurred, accrued, paid,
        payable or attributable whether by the Landlord or others on behalf of
        the Landlord for complete repair, maintenance, operation, cleaning and
        management of the Building, Lands and all the improvements thereon and
        the components of each of them (herein collectively called the
        "Property") such as are in keeping with maintaining the standard of a
        first class commercial Property so as to give it high character and
        distinction; and including, without limiting the generality of the
        foregoing, the cost of all repairs and replacements required for such
        operation and maintenance, the cost of maintaining and repairing the
        heating, air-conditioning, ventilating and mechanical systems and
        equipment in the Building, the cost of operating and maintaining any
        elevators, (including the cost of service contracts); the costs of
        providing hot and cold water; the costs of providing electricity not
        otherwise chargeable to tenants; the costs of all fuel, gas and steam
        used in heating, ventilating and air-conditioning; the cost of energy
        conservation devices or equipment; the cost of snow removal; landscape
        maintenance including the cost of replacing any landscaping on the
        Lands; the cost of window cleaning; the cost of insurance premiums for
        fire, casualty, liability, rental and any other insurance coverage
        maintained by the Landlord in connection with the Property; telephone
        and other utility costs; the amount paid or payable for all salaries,
        wages and benefits and other payments paid to or on behalf of persons
        engaged in the cleaning, supervision, maintenance and repair of the
        Property (including wages of the on site Property Manager); the cost of
        accounting services necessary to prepare the statements and opinions for
        the tenants and to compute the rents and other charges payable by the
        tenants of the Building and the reasonable cost of collecting and
        enforcing payment of all amounts payable by the tenants; the cost of
        porters, guards and other protection services; the cost of providing
        security services; the cost of garbage or refuse removal from the
        Building not otherwise chargeable to tenants; the cost of repair and
        maintenance of the roadways, curbs, paving, walkways, pools,
        landscaping, lighting and other common facilities and outside areas;
        cost of services provided for the common use of the tenants; building
        management (not exceeding the going rate charged by trust companies for
        building management in the Regional Municipality of Ottawa-Carleton for
        similar buildings); the cost of service contracts with independent

                                   Page 142
<PAGE>
 
        contractors and all other expenses, paid or payable by the Landlord in
        connection with the operation of the Property together with an
        administration fee equal to fifteen percent of Operating Costs, but such
        Operating Costs shall not include any interest on any debt or capital;
        retirement of any debt; any amounts directly chargeable by the Landlord
        to any tenant or tenants of the Building and the cost of any repairs
        paid for by insurance proceeds or for which the Landlord was reimbursed
        by insurance proceeds.

5.01    ALLOCATION OF OPERATING COSTS

        In determining the Operating Costs attributable to the Building, the
        Landlord shall have the right from time to time to reasonably allocate
        and re-allocate such Operating Costs which represent operating costs
        incurred for facilities or services shared by the Building and such
        other buildings as are owned or operated by the Landlord and which are
        not charged or allocated separately against the Building and any such
        other building or buildings. Any such determination made by the Landlord
        shall be binding upon the Tenant unless shown to be unreasonable or
        erroneous in some substantive respect. The Tenant shall have the right
        to reasonable access to the books and records of the Landlord to conduct
        an examination and to ascertain whether allocations of Operating Costs
        made by the Landlord have been made reasonably.

5.02    FULL OCCUPANCY

        If in any year the Building has not been fully occupied for the whole
        year, the amount of the Operating Costs for such year may be adjusted by
        the Landlord, acting reasonably, to an amount which reflects what the
        amount of the Operating Costs would be if the Building had been fully
        occupied for the whole year.

5.03    USE OF ELECTRICITY

        The Tenant shall not, without the Landlord's prior written consent in
        each instance, connect any additional fixtures, appliances or equipment
        to the Building's electric distribution system or make any alteration or
        addition to the electrical system of the Leased Premises existing at the
        commencement of the Term. If the Landlord grants such consent, the cost
        of all additional risers and other equipment required therefor shall be
        paid as Additional Rent by the Tenant to the Landlord upon demand. As a
        condition to granting such consent, the Landlord may require the Tenant
        to agree to pay an increase in the Additional Rent for Operating Costs
        by an amount which will reasonably reflect the increased cost of the
        Landlord of the additional electrical services to be furnished to the
        Leased Premises by the Landlord.

5.04    METERS

        The Tenant covenants to pay for the cost of any additional metering
        which may be required by the Landlord to be installed in the Building
        for the purpose of determining the amount of electricity consumed by the
        Tenant in the Leased Premises.

6.00    ASSIGNING OR SUBLETTING

        The Tenant covenants that it will not assign or sublet the Leased
        Premises or any part thereof without the prior written consent of the
        Landlord, which consent shall not be unreasonably withheld save and
        except in the event of any of the following, in which case the Landlord
        may arbitrarily withhold its consent:

                                   Page 143
<PAGE>
 
        (a)    an assignment or sublet of the whole of the Leased Premises, the
               terms of which have a net present value that are less or more
               than the net present value of the terms of the Lease (not
               including the value of initial leasehold improvements, leasing
               commissions or inducements of any kind under the Lease) and in
               the latter event if the Landlord consents to such assigned or
               sublet the Tenant shall pay the increased value to the Landlord
               as Additional Rent.;

        (b)    a sublet of a part of the Leased Premises;

        (c)    where the assignee or subtenant is then a tenant of the Landlord
               at the Building and the Landlord has or will have during the next
               following six (6) months, vacant space for rent in the Building.

6.01    REQUEST TO ASSIGN OR SUBLET

        If the Tenant requests the Landlord's consent to an assignment of this
        Lease or to a subletting of the whole or any part of the Leased
        Premises, the Tenant shall submit to the Landlord the name and address
        of the proposed assignee or subtenant together with a copy of an offer
        or agreement to assign or sublet or the sublease or assignment and such
        additional information as to the nature of its business and its
        financial responsibility and standing (including financial statements)
        as the Landlord may reasonably require ("required information").

6.02    ASSIGNMENT

        The Landlord's consent to any assignment may be conditional upon the
        assignee entering into an assignment in form and content satisfactory to
        the Landlord, to perform, observe and keep each and every covenant,
        condition and agreement in this Lease on the part of the Tenant to be
        performed, observed and kept including the payment of rent and all other
        sums and payments agreed to be paid or payable under this Lease on the
        days and times and in the manner specified.

6.03    CONSENT NOT TO RELEASE TENANT

        In no event shall any assignment or subletting to which the Landlord may
        have consented release or relieve the Tenant from his obligations fully
        to perform all the terms, covenants and conditions of this Lease to be
        performed.

6.04    NOTICE OF CHANGE OF CONTROL

        Where there is a change in corporate control of the Tenant, the Tenant
        shall forthwith so advise the Landlord in writing.

6.05    COST OF CONSENT

        The Tenant further agrees that prior to any consent for assignment,
        subletting or change in control being effective and binding upon the
        Landlord, the Tenant shall pay on demand the Landlord's reasonable costs
        (including the Landlord's own administrative costs) incurred in
        connection with the Tenant's request for such consent.

7.00    TENANT'S COVENANTS

        The Tenant further covenants with the Landlord as follows:

                                   Page 144
<PAGE>
 
7.01    TENANT REPAIRS

        To repair, maintain and keep the Leased Premises and all trade fixtures
        and improvements therein in good and substantial repair subject only to
        defects in construction of the structural members of the Building,
        reasonable wear and tear and damage by fire, lightning and tempest or
        other casualty against which the Landlord is insured (herein
        collectively referred to as "Tenant Repair Exceptions"); and that the
        Landlord may enter and view state of repair and that the Tenant will
        repair according to notice in writing, except for Tenant Repair
        Exceptions and that the Tenant will leave the Leased Premises in good
        repair, except for Tenant Repair Exceptions. Notwithstanding anything
        hereinbefore contained, the Landlord may in any event make repairs to
        the Leased Premises without notice if such repairs are, in the
        Landlord's opinion, necessary for the protection of the Building and the
        Tenant covenants and agrees with the Landlord that if the Landlord
        exercises any such option to repair, the Tenant will pay to the Landlord
        together with the next instalment of Monthly Rent which shall become due
        after the exercise of such option all sums which the Landlord shall have
        expended in making such repairs and that such sums, if not so paid
        within such time, shall be recoverable from the Tenant as rent in
        arrears. Provided further that in the event that the Landlord from time
        to time makes any repairs as hereinbefore provided, the Tenant shall not
        be deemed to have been relieved from the obligation to repair and leave
        the Leased Premises in a good state of repair.

7.02    RULES AND REGULATIONS

        That the Tenant and his employees and all persons visiting or doing
        business with him on the Leased Premises shall be bound by and shall
        observe rules and regulations annexed hereto or as may hereafter be
        reasonably set by the Landlord of which notice in writing shall be given
        to the Tenant and upon such notice being delivered all such rules and
        regulations shall be deemed to be incorporated into and form part of
        this Lease. Such rules and regulations shall not be inconsistent with
        nor derogate from the terms of this Lease and in any event shall apply
        equally to all tenants of the Building and be non-discriminatory in
        their application.

7.03    USE OF PREMISES

        The Leased Premises shall be used only for office and hi-technology
        manufacturing purposes.

7.04    INCREASE IN INSURANCE PREMIUMS

        That it will not keep, use, sell or offer for sale in or upon the Leased
        Premises any article which may be prohibited by any insurance policy in
        force from time to time covering the Building including any regulations
        made by any fire insurance underwriters applicable to such policies. In
        the event the Tenant's occupancy or conduct or business in, or on the
        Leased Premises, whether or not the Landlord has consented to the same,
        results in any increase in premiums for the insurance carried from time
        to time by the Landlord with respect to the Building, the Tenant shall
        pay any such increase in premiums as Additional Rent within ten (10)
        days after bills for such additional premiums shall be rendered by the
        Landlord. In determining whether increased premiums are a result of the
        Tenant's use or occupancy of the Leased Premises, a schedule issued by
        the organization computing the insurance rate on the Building showing
        the various components of such rate, shall be conclusive evidence of

                                   Page 145
<PAGE>
 
        the several items and charges which make up such rate. The Tenant shall
        promptly comply with all reasonable requirements of the insurance
        authority or of any insurer now or hereafter in effect relating to the
        Leased Premises.

7.05    CANCELLATION OF INSURANCE

        If any policy of insurance upon the Building or any part thereof or upon
        the Lands or any part thereof shall be cancelled or rendered voidable by
        the insurer by reason of any act, omission or occupation of the Leased
        Premises or any part thereof by the Tenant, any assignee or subtenant of
        the Tenant or by anyone permitted by the Tenant to be upon the Leased
        Premises, and the Tenant, after receipt of notice from the Landlord,
        shall have failed to immediately reinstate such insurance policies or
        avoid cancellation of such insurance policies, the Landlord may at its
        option determine this Lease forthwith by leaving upon the Leased
        Premises notice in writing of its intention so to do and thereupon rent
        and any other payments for which the Tenant is liable under this Lease
        shall be apportioned and paid in full to the date of such determination
        and the Tenant shall immediately deliver up possession of the Leased
        Premises to the Landlord and the Landlord may re-enter and take
        possession of the same or the Landlord shall pay any increased cost of
        such insurance and the Tenant shall pay as Additional Rent, on demand,
        the amount by which the premiums for such insurance are so increased.

7.06    OBSERVANCE OF LAW

        To comply promptly at its own expense with all provisions of law
        including without limitation, federal and provincial legislative
        enactments, building by-laws, and any other governmental or municipal
        regulations which relate to the partitioning, equipment, operation and
        use of the Leased Premises, and to the making of any repairs,
        replacements, alterations, additions, changes, substitutions or
        improvements of or to the Leased Premises. And to comply with all
        police, fire and sanitary regulations imposed by any federal, provincial
        or municipal authorities or made by fire insurance underwriters, and to
        observe and obey all governmental and municipal regulations and other
        requirements governing the conduct of any business conducted in the
        Leased Premises. Provided that in default of the Tenant so complying the
        Landlord may at its option where possible comply with any such
        requirement and the cost of such compliance shall be payable on demand
        by the Tenant to the Landlord as Additional Rent.

7.07    WASTE AND OVERLOADING OF FLOORS

        Not to do or suffer any waste or damage, disfiguration or injury to the
        Leased Premises or the fixtures and equipment thereof or permit or
        suffer any overloading of the floors thereof; and not to place therein
        any safe, heavy business machine or other heavy thing without first
        obtaining the consent in writing of the Landlord; and not to use or
        permit to be used any part of the Leased Premises for any dangerous,
        noxious or offensive trade or business and not to cause or permit any
        nuisance in, at or on the Leased Premises; and without the prior consent
        in writing of the Landlord, the Tenant will not bring onto or use in the
        Leased Premises or permit any person subject to the Tenant to bring onto
        or use on the Leased Premises any fuel or combustible material for
        heating, lighting or cooking nor will it allow onto the Leased Premises
        any stove, burner, kettle, apparatus or appliance for utilizing the same
        and the Tenant will not purchase, acquire or use electrical current or
        gas for consumption on the Leased Premises except from such supplier
        thereof as shall have been approved in writing by the Landlord.

                                   Page 146
<PAGE>
 
7.08    INSPECTION

        To permit the Landlord, its servants or agents to enter upon the Leased
        Premises at any time and from time to time for the purpose of inspection
        and of making repairs, alterations or improvements to the Leased
        Premises or to the Building and the Tenant shall not be entitled to
        compensation for any inconvenience, nuisance or discomfort occasioned
        thereby. The Landlord, its servants or agents may at any time and from
        time to time enter upon the Leased Premises to remove any article or
        remedy any condition which, in the opinion of the Landlord, reasonably
        arrived at, would be likely to lead to cancellation of any policy of
        insurance and such entry by the Landlord shall not be deemed to be a re-
        entry. The Tenant shall, upon written request of the Landlord, produce
        audited Financial Statements of the Tenant, which statements shall
        include a Balance Sheet, Income Statement, Statement of Retained
        Earnings, Statement of Source and Application of Funds.

7.09    INDEMNITY TO LANDLORD

        To promptly indemnify and save harmless the Landlord for any and all
        liabilities, damages, costs, claims, suits or actions of any nature or
        kind including the full cost to the Landlord in resisting or defending
        the same to which the Landlord shall or may become liable or suffer
        arising out of or by reason of:

        (a)    any breach, violation or non-performance by the Tenant of any of
               its covenants and obligations under this Lease;

        (b)    any damage to property while said property shall be in or about
               the Leased Premises including the systems, furnishings and
               amenities thereof, as a result of the negligence, misuse or
               wilful act of the Tenant, its express or implied invitees,
               licensees, agents, servants or employees; and

        (c)    any injury to any invitee, licensee, agent, servant or employee
               of the Tenant, including death resulting at any time therefrom,
               occurring on or about the Leased Premises, the Property or the
               Lands;

        and this indemnity shall survive the expiry or sooner determination of
        this Lease.

7.10    DAMAGE BY TENANT

        That if the Building including the Leased Premises, the elevators,
        boilers, engines, pipes and other apparatus (or any of them) used for
        the purpose of heating, ventilating or air-conditioning the Building or
        operating the elevators, or if the water pipes, drainage pipes, electric
        lighting or other equipment of the Building or the roof or outside walls
        or other parts of the Building will not function properly or become
        damaged or destroyed through the negligence, carelessness or misuse of
        the Tenant, or of any of its invitees, licensees, agents, servants,
        employees, clients, customers or contractors, or through it or them in
        any way stopping up or injuring any heating, ventilating or air-
        conditioning apparatus, elevators, water pipes, drainage pipes or other
        equipment or parts of the Building, the expense of the necessary
        repairs, replacements or alterations shall be borne by the Tenant and
        paid forthwith on demand to the Landlord as Additional Rent.

                                   Page 147
<PAGE>
 
7.11    TENANT INSURANCE

        (a)    To maintain in force during currency of this Lease at the
               Tenant's expense insurance policies to cover the following:

               (i)      comprehensive general liability insurance with limits of
                        not less than Five Million Dollars ($5,000,000.00)
                        (including bodily injury and property damage, tenant's
                        legal liability, cross liability and contractual
                        liability) to cover all responsibilities assumed by the
                        Tenant with respect to the use or occupancy of and the
                        business carried on, in or from the Leased Premises, in
                        amounts acceptable to the Landlord;
                       
               (ii)     all risk insurance covering leasehold improvements made
                        or installed by or on behalf of the Tenant in an amount
                        equal to the full replacement value thereof; and
                       
               (iii)    any other insurance that the Landlord (or the Landlord's
                        mortgagee, if any) may reasonably require from time to
                        time in form and amounts and for insurance risks against
                        which a prudent Tenant would protect itself;
                    
        (b)    That all Tenant's insurance required hereunder shall be with
               insurers and upon terms and conditions to which the Landlord has
               no reasonable objection. Copies of all policies, or certificates
               evidencing the insurance or its renewal shall be delivered to the
               Landlord at the Landlord's request;

        (c)    That all policies of insurance to be maintained by the Tenant
               shall, in the case of general liability insurance, include the
               Landlord (and, where applicable, the Landlord's mortgagee) as
               additional insured and, in the case of all other insurance
               coverage, contain a waiver by the insurer and Tenant of any
               rights of subrogation or indemnity or any other claim to which
               the insurer might otherwise be entitled against the Landlord (and
               mortgagee) or the agents or employees of the Landlord. All such
               insurance policies shall also contain a provision prohibiting the
               insurer from cancelling or altering the insurance coverage
               without first giving the Landlord thirty (30) days prior written
               notice thereof;

        (d)    That if the Tenant fails to take out or maintain in force such
               insurance, the Landlord may take out the necessary insurance and
               pay the premium therefor and the Tenant shall pay to the Landlord
               the amount of such premium immediately on demand as Additional
               Rent; and

        (e)    That if both the Landlord and the Tenant have claims to be
               indemnified under any such insurance, the indemnity shall be
               applied first to the settlement of the claim of the Landlord and
               the balance, if any, to the settlement of the claim of the
               Tenant.

7.12    NO ABATEMENT OF RENT

        That there shall be no abatement or reduction of rent and that the
        Landlord shall not be liable for any damage howsoever caused to property
        of the Tenant or of any person subject to the Tenant which is in or upon
        or being brought to or from the Lease Premises or the Building or for
        personal injury (including death) sustained in any

                                   Page 148
<PAGE>
 
          manner by the Tenant or any person subject to the Tenant while the
          Tenant or any such person is on or upon entering or leaving the Leased
          Premises or Building unless such property damage or personal injury
          may have been attributable to fault or neglect on the part of the
          Landlord or of any person for whom the Landlord is at law responsible,
          and that the Tenant will indemnify and save harmless the Landlord from
          and against all claims and demands made against the Landlord by any
          person for or arising out of any such property damage or personal
          injury. 


7.13      EXHIBITING PREMISES

          To permit the Landlord or its agents or servants to enter and show the
          Leased Premises, during normal business hours, to prospective
          purchasers of the Building and may after notice of termination of this
          Lease has been given or within the last six (6) months of the Term,
          enter and show the Leased Premises to prospective tenants and erect
          signs stating that the premises are "To Let".

7.14      TENANT MAINTENANCE

          That the Tenant will maintain in good repair all plate and window
          glass, all electrical fixtures, outlets and wiring, all plumbing and
          plumbing fixtures, all heating equipment and all water and gas piping
          and outlets within the Leased Premises and that he will make good any
          damage caused by or resulting from breakage of glass, interference
          with the electrical, plumbing, heating, water or gas systems of the
          Building or misuse of any of the equipment, outlets, piping or wiring
          of any such system by the Tenant or any person subject to the Tenant
          and the Tenant agrees that he shall prior to taking possession of the
          Leased Premises inspect the entire Leased Premises and shall be
          satisfied they are clean and in good order and in a good state of
          repair, and that all plate and window glass is whole and that the
          sanitary arrangements in the Building are in satisfactory condition.


7.15      SIGNS

          The Tenant shall not paint, display, inscribe or place any sign,
          symbol, notice or lettering of any kind anywhere outside the Leased
          Premises within the Leased Premises so as to be visible from the
          outside of the Building with the exception only of an identification
          sign (which sign shall be subject to the Landlord's written approval
          as to size, design and location).

7.16      NAME OF BUILDING

          Not to refer to the Building by any name other than that designated
          from time to time by the Landlord and the Tenant shall use the name of
          the Building for the business address of the Tenant but for no other
          purpose.

7.17      KEEP TIDY

          The Tenant shall provide its own cleaning and janitorial services. At
          the end of each business day, the Tenant shall leave the Leased
          Premises in a tidy condition.

7.18      DELIVERIES

          The Tenant shall receive, ship, take delivery of and allow and require
          suppliers or others to deliver or take delivery of merchandise,
          supplies, fixtures, equipment,

                                   Page 149
<PAGE>
 
          furnishings, wares or merchandise only through the loading entrance
          and other facilities provided for that purpose and at the times set by
          the Landlord.

7.19      NOTICE OF DAMAGE

          To notify the Landlord promptly of any damage to or defect in the
          Leased Premises or the Building or any part thereof including any
          electrical, plumbing, heating, ventilating, air-conditioning, water,
          sprinkler or gas systems or equipment, or the water pipes, gas pipes,
          telephone lines or electrical apparatus within or leading to the
          Leased Premises, and in case of fire to give immediate notice thereof
          to the Fire Department.

7.20      ALTERATIONS, ETC

          The Tenant will not make or erect in or to the Leased Premises any
          installations, alterations, additions or partitions or remove or
          change the location or style of any installations, alterations,
          equipment, outlets, piping or wiring relating to the electrical,
          plumbing, water, gas, air-conditioning, heating or ventilating systems
          without submitting drawings and specifications to the Landlord and
          obtaining the Landlord's prior written consent in each instance. The
          Tenant must further obtain the Landlord's prior written consent to any
          change or changes in such drawings and specifications submitted as
          aforesaid. The Tenant's request for such consent shall be in writing
          and accompanied by an adequate description of contemplated work and
          with appropriate working drawings and specifications thereof. The
          Landlord's cost of having its architects or engineers examine such
          drawings and specifications shall be payable by the Tenant. The
          Landlord may require that any and all work be performed by the
          Landlord's contractors or workmen or by contractors or workmen engaged
          by the Tenant but in each case only under written contract approved in
          writing by the Landlord and subject to all reasonable conditions which
          the Landlord may impose and subject to inspection by and reasonable
          supervision of the Landlord. The Landlord may at its option require
          that only the Landlord's contractors be engaged for any mechanical,
          electrical, plumbing, structural or sprinkler work to be done in the
          Leased Premises. Any work performed by or for the Tenant shall be
          performed by competent workmen whose labour union affiliations are not
          incompatible with those of any workmen who may be employed in the
          Building by the Landlord, its contractors or subcontractors. The cost
          of all such work and of all materials, labour and services involved
          therein and of all services, necessitated thereby shall be at the sole
          cost and expense of the Tenant and shall be completed in a good and
          workmanlike manner and with reasonable diligence in accordance with
          the description of the work approved by the Landlord. Any such
          alterations, additions, and fixtures shall, when made or installed, be
          and become the property of the Landlord without payment being made
          therefor; provided that upon the determination of this Lease the
          Landlord may at its option require the Tenant, or itself at the
          Tenant's expense, to remove the same and to restore the Leased
          Premises to the condition in which they were at the commencement of
          this Lease.

7.21      CONSTRUCTION LIENS

          The Tenant covenants that he will not suffer or permit during the Term
          hereof any construction or other liens for work, labour, services or
          material ordered by him or for the cost of which he may be in any way
          obligated to attach to the Leased Premises or the Building or the Land
          and that whenever and so often as any such liens shall attach or
          claims therefor shall be filed, the Tenant shall within twenty (20)
          days after the 

                                   Page 150
<PAGE>
 
          Tenant has notice of the claim for lien, procure the
          discharge thereof by payment or by giving security or in such manner
          as is or may be required or permitted by law.

7.22      SECURITY

          The Tenant will maintain on the Leased Premises sufficient moveable
          property to guarantee the payment of one (1) year's Annual Rent and
          Additional Rent.

7.23      HAZARDOUS SUBSTANCES

          (a)   The Tenant shall not cause or permit any Hazardous Substances to
                be brought onto, created in, released or discharged from, placed
                or disposed of, at or near the Building or Lands;

          (b)   The Tenant shall not cause or permit to occur any violation of
                any federal, provincial, municipal or local law, ordinance, or
                regulation, now or hereinafter enacted (the "Laws"), relating to
                environmental conditions on, under, at, near or about the
                Building or Lands, or relating to the Landlord, the Tenant or
                the Building, air, soil or ground water condition, including
                without limitation, the generation, storage or disposal of
                Hazardous Substances;

          (c)   For the purposes of this section, "Hazardous Substances" means
                any substance, or class of substance or mixture of substances
                which may be detrimental to the environment, plant or animal
                life, or human health and includes, without limitation,
                flammable, explosives, or radioactive materials, asbestos,
                polychlorinated biphenyls (PCBs), chemicals believed to cause
                cancer or reproductive toxicity, pollutants, contaminants,
                hazardous wastes, toxic substances and related materials,
                petroleum and petroleum products, any substance that, if added
                to water, may degrade or alter or form part of a process of
                degradation or alteration of the quality or temperature of that
                water to the extent that it is detrimental to its use by man or
                by any animal, fish or plant, and substances declared to be
                hazardous or toxic under any law or regulation now or hereafter
                enacted or promulgated by any governmental authority having
                jurisdiction over the Landlord, the Tenant, the Leased Premises
                or the Building (the "Authorities");


          (d)   The Tenant shall, at its own expense, comply with the Laws;

          (e)   The Tenant shall, at its own expense, make all submissions to,
                provide all information required by, and comply with all
                requirements of the Authorities under the Laws;

          (f)   The Tenant shall indemnify, defend and hold harmless the
                Landlord, the Landlord's mortgagees, any manager of the
                building, and their respective officers, directors,
                beneficiaries, shareholders,

                                   Page 151
<PAGE>
 
                partners, agents and employees, from all fines, suits,
                procedures, claims and actions of every kind, and all costs
                associated therewith (including legal fees on a solicitor and
                his own client basis and consultants' fees) arising out of or in
                any way connected with any deposit, spill, discharge, or other
                release of Hazardous Substances that occurs during the Term or
                any renewal or extension period, at or from the Premises, or
                which arises at any time from the Tenant's use or occupancy of
                the Premises, or from the Tenant's failure to provide all
                information, make all submissions, and take all steps required
                by this Section or by the Authorities;


          (g)   Notwithstanding any other provision of this Lease, if the Tenant
                creates or brings to the Leased Premises any Hazardous
                Substances or if the conduct of the Tenant's business shall
                cause there to be any Hazardous Substances at or near the Leased
                Premises, or discharged or released on, under or about the
                Premises, the building or the lands upon which the building is
                constructed, the air, soil or ground water, then,
                notwithstanding any rule of law to the contrary, such Hazardous
                Substances shall be and remain the sole and exclusive property
                of the Tenant and shall not become the property of the Landlord,
                notwithstanding the degree of affixation to the Premises of the
                Hazardous Substances or the goods containing the Hazardous
                Substances. This affirmation of the Tenant's interest in the
                Hazardous Substances or the goods containing the Hazardous
                Substances shall not however prohibit the Landlord from dealing
                with such material as otherwise provided for in this Lease.

7.24      NUISANCE

          The Tenant shall not cause or maintain any nuisance in or about the
          Leased Premises, and shall keep the Leased Premises free of debris,
          rodents, vermin and anything of a dangerous noxious or offensive
          nature or which could create a fire hazard (through undue load on
          electrical circuits or otherwise) or undue vibration, heat or noise.

8.00      LANDLORD'S COVENANTS

          The Landlord further covenants with the Tenant:

8.01      QUIET ENJOYMENT

          The Landlord covenants with the Tenant that if the Tenant pays the
          Annual Rent, Additional Rent and all other sums reserved herein and
          observes and performs the covenants, conditions and agreements set out
          in this Lease, the Tenant shall and may peaceably possess and enjoy
          the Leased Premises during the Term without interruption or
          disturbance from the Landlord.

                                   Page 152
<PAGE>
 
8.02      TAXES, ETC

          To pay or cause to be paid all taxes and rates, municipal,
          parliamentary or otherwise, including, without limiting the generality
          of the foregoing, water rates with respect to the Lands, the Building
          or assessed against the Landlord in respect thereof, except those
          directly assessed or charged to or payable by the Tenant or assessed
          or charged with reference to the use or occupation of the Leased
          Premises and except as otherwise provided in this Lease.

8.03      HEATING AND AIR-CONDITIONING

          To provide for heating and air-conditioning 24 hours per day and seven
          (7) days a week so that when heat is reasonably required for the
          reasonable use of the Leased Premises the Landlord will furnish heat
          therefor up to a reasonable temperature and when the heating system is
          not in use and the Landlord considers that air-conditioning is
          reasonably required it will operate the air-conditioning systems in
          the Building. The said heating and air-conditioning systems will be
          maintained by the Landlord during normal business hours except during
          the making of repairs and should the Landlord make default in so
          doing, it shall not be liable for any indirect or consequential
          damages for personal discomfort or illness due to such default. The
          Landlord reserves the right to stop the services of the heating and/or
          air-conditioning equipment when necessary by reason of any accident or
          any repairs, alterations or improvements which, in the judgment of the
          Landlord, are desirable or necessary to be made until such repairs,
          alterations or improvements shall have been completed. The Landlord
          shall have no further responsibility or liability for failure to
          supply the said heating and/or air-conditioning service when prevented
          from doing so, by strikes or by any cause beyond the Landlord's
          reasonable control or by orders or regulations by any body or
          authority having jurisdiction or by other reason of any failure of
          electrical current, steam or water or suitable power supply or
          inability upon the exercise of reasonable diligence to obtain such
          electrical current, steam or water for the operation of the heating or
          air-conditioning equipment.

8.04      REPAIR OF STRUCTURE

          To repair, replace and maintain the structural parts of the Building,
          and to perform such repairs, replacements and maintenance with
          reasonable dispatch, and in a good and workmanlike manner, at any time
          and from time to time, and notwithstanding anything contained herein
          to the contrary, the Tenant shall not be entitled to compensation for
          any inconvenience, nuisance or discomfort occasioned thereby.

8.05      DELAYS IN PROVISION OF SERVICES

          It is understood and agreed that whenever and to the extent that the
          Landlord shall be unable to fulfil, or shall be delayed or restricted
          in the fulfilment of any obligation hereunder in respect of the supply
          or provision of any service or utility or the doing of any work or the
          making of any repairs by reason of being unable to obtain the
          material, goods, equipment, service, utility or labour required to
          enable it to fulfil such obligation or by reason of any statute, law
          or order-in-council or any regulation or order passed or made pursuant
          thereto or by reason of the order or direction of any administrator,
          controller or board, or any governmental department or officer or
          other authority, or by reason of not being able to obtain any
          permission or authority required thereby, or by reason of any other
          cause beyond its control whether of the foregoing character or not,
          the Landlord shall be entitled to extend the time for fulfilment of
          such obligation by a time equal to the duration of such delay or
          restriction, and the Tenant 

                                   Page 153
<PAGE>
 
          shall not be entitled to compensation for any inconvenience, nuisance,
          discomfort, direct or indirect or consequential damage or damages
          thereby occasioned.

9.00      TENANT'S FIXTURES

          The Tenant may install its usual trade fixtures in the usual manner,
          provided such installation does not damage the structure of the Leased
          Premises or the Building and provided further that the Tenant shall
          have submitted detailed plans and specifications for such trade
          fixtures to the Landlord and obtained its written consent thereto
          which consent shall not be unreasonably withheld.

9.01      REMOVAL OF TENANT'S FIXTURES

          Provided that the Tenant may remove his trade or tenant's fixtures;
          provided further, however, that all installations, alterations,
          additions, partitions, and fixtures other than trade or tenant's
          fixtures in or upon the Leased Premises, whether placed there by the
          Tenant or the Landlord, shall immediately upon such placement, be the
          Landlord's property without compensation therefor to the Tenant and,
          except as hereinafter mentioned in this paragraph shall not be removed
          from the Leased Premises by the Tenant at any time either during or
          after the term. Notwithstanding anything herein contained, the
          Landlord shall be under no obligation to repair or maintain the
          Tenant's installations, alterations, additions, partitions and
          fixtures or anything in the nature of a leasehold improvement made or
          installed by the Tenant or Landlord or third party; and further,
          notwithstanding anything herein contained, the Landlord shall have the
          right upon termination of this Lease by affluxion of time or otherwise
          or within six (6) months thereafter to require the Tenant to remove,
          or require the Tenant to pay to the Landlord the cost to remove, any
          installations, alterations, additions, partitions and fixtures or
          anything in the nature of a leasehold improvement made or installed by
          the Tenant, the Landlord or a third party, whether for the Tenant or a
          previous occupant, and make good any damage caused to the Leased
          Premises by such installation or removal.

10.00     DAMAGE OR DESTRUCTION OF LEASED PREMISES

          Provided that if during the continuation of this Lease, the Building
          or the Leased Premises are destroyed or damaged by any cause
          whatsoever, then the following provisions shall apply:

10.01     PARTIAL DAMAGE

          If damage shall occur to the Building or the Leased Premises so that
          all or part of the Leased Premises are rendered untenantable by damage
          from fire or other casualty which, in the reasonable opinion of the
          Landlord's architect, can be substantially repaired under applicable
          laws and governmental regulations within ninety (90) days from the
          date of such casualty (employing normal construction methods without
          overtime or other premium), the Landlord shall cause such damage to be
          repaired with all reasonable speed.

10.02     TOTAL DAMAGE

          If the Building or the Leased Premises are damaged to such an extent
          that the Leased Premises are rendered untenantable by damage from fire
          or other casualty which, in the reasonable opinion of the Landlord's
          architect, cannot be substantially repaired under applicable laws and
          governmental regulations within ninety (90) days from the 

                                   Page 154
<PAGE>
 
          date of such casualty (employing normal construction methods without
          overtime or other premium), then either the Landlord or Tenant may
          elect to terminate this Lease as of the date of such casualty by
          written notice delivered to the other not more than ten (10) days
          after receipt of such architect's opinion (failing which the Landlord
          shall cause such damage to be repaired at its own expense with all
          reasonable speed).

10.03     OBLIGATION TO REPAIR

          The Landlord's obligation to repair as set forth in the preceding two
          paragraphs hereof is conditional upon the Landlord receiving adequate
          proceeds from policies of insurance maintained in respect of such
          casualties or, if such proceeds are not made available to the
          Landlord, the Landlord electing to obtain its own financing for such
          repairs. In the event that no such proceeds of insurance are available
          to the Landlord and if the Landlord elects not to obtain its own
          financing for such repairs, then the Landlord shall, by notice in
          writing to the Tenant delivered within ten (10) days after receipt of
          the opinion of the Landlord's architect, notify the Tenant that the
          Lease is terminated, which termination shall be effective as of the
          date of such casualty. In calculating the amount of insurance proceeds
          available, the Landlord will be deemed to have received the deductible
          portion of any insurance policy.

10.04     ABATEMENT OF RENT

          If the Landlord is required to repair the damage pursuant to the
          provisions hereof and does not elect to terminate the Lease, the
          Annual Rent and Additional Rent payable by the Tenant under this Lease
          shall be proportionately reduced to the extent that the Leased
          Premises are thereby rendered unusable by the Tenant in its business
          from the date of such casualty until completion by the Landlord of the
          repairs to the Leased Premises and the Building so that the Leased
          Premises are thereafter fully usable by the Tenant in its business.

10.05     DAMAGE TO 50% OF BUILDING

          Notwithstanding anything otherwise contained in this Lease, if fifty
          percent (50%) or more of the rentable area of the Building is damaged
          or destroyed and if, in the reasonable opinion of the Landlord's
          Architect, the said rentable area cannot be rebuilt or made fit for
          the purposes of the tenants thereof within ninety (90) days of the
          date of such casualty, the Landlord may, at its option, terminate this
          Lease by giving notice of termination to the Tenant within thirty (30)
          days of the date of such casualty and the Tenant shall, with
          reasonable dispatch and expedition, but in any event within sixty (60)
          days after delivery of the notice of termination, deliver up
          possession of the Leased Premises to the Landlord and the rent and
          other payments for which the Tenant is liable hereunder shall be
          apportioned and paid to the date possession is so delivered up.

10.06     COMPLETION OF REPAIR

          Provided that, if, upon the completion by the Landlord of any repairs
          required as a result of any such destruction or damage, a dispute
          shall arise between the Landlord and the Tenant as to whether or not
          the Leased Premises have been made fit for the purposes of the Tenant
          under this Lease, the Landlord may, at its option, terminate this
          Lease by giving thirty (30) days notice to the Tenant and if such
          notice shall be given this Lease shall, at the expiration of such
          period, be at an end and the Tenant shall deliver up the Leased
          Premises to the Landlord or whom it may appoint and the Landlord may,
          on demand, recover the full rental hereby reserved computed from the

                                   Page 155
<PAGE>
 
          date on which such repairs were completed up to the date on which the
          Tenant is required to vacate.

11.00     LIABILITY FOR DAMAGE TO PROPERTY

          In the absence of negligence or wilful act or default on the part of
          the Landlord, its servants, agents or workmen, the Landlord shall not
          be liable or responsible in any way for any loss, damage or injury to
          any person or for any loss of or damage to any property belonging to
          the Tenant, to employees of the Tenant or to any other person while
          such property is in the Leased Premises or in the Building or in or on
          the surrounding, Lands and buildings owned by the Landlord, the
          areaways, the parking garages, the parking areas, lawns, sidewalks,
          reflective pools, steps, platforms, corridors, stairways or elevators
          whether or not any such property has been entrusted to employees of
          the Landlord and without limiting the generality of the foregoing, the
          Landlord shall not be liable for any damage to any such property
          caused by theft or breakage or by steam, water, rain or snow which may
          leak into, issue or flow from any part of the Building or from the
          water, steam or drainage pipes or plumbing works of the Building or
          from any other place or quarter or for any damage caused by or
          attributable to the condition or arrangement of any electric or other
          wiring or for any damage caused by smoke or anything done or omitted
          by any other tenant in the Building or for any other loss whatsoever
          with respect to the Leased Premises, goods placed therein or any
          business carried on therein.

12.00     DEFAULT OF TENANT

          Provided and it is hereby expressly agreed that if and whenever the
          Annual Rent or Additional Rent hereby reserved or any part thereof
          shall not be paid on the day appointed for payment thereof, whether
          lawfully demanded or not, or in case of breach or non-observance or
          non-performance of any of the covenants, agreements, provisos,
          conditions or Rules and Regulations on the part of the Tenant to be
          kept, observed or performed, or in case the Leased Premises shall be
          vacated or remain unoccupied for fifteen (15) days or in case the Term
          shall be taken in execution or attachment for any cause whatever, then
          and in every such case, it shall be lawful for the Landlord thereafter
          to enter into and upon the Leased Premises or any part thereof in the
          name of the whole and the same to have again, repossess and enjoy as
          of its former estate, anything in this Lease contained to the contrary
          notwithstanding other than the proviso to this paragraph; PROVIDED
          that the Landlord shall not at any time have the right to re-enter and
          forfeit this Lease by reason of the Tenant's default in the payment of
          the rent reserved by this Lease, unless and until the Landlord shall
          have given to the Tenant written notice setting forth the default
          complained of and the Tenant shall have the right during five (5)
          business days next following the date on such notice to cure any such
          default in payment of rent. In case without the written consent of the
          Landlord, the Leased Premises shall be used by any other person than
          the Tenant or for any other purpose than that for which the same were
          let or in case the Term or any of the goods and chattels of the Tenant
          shall be at any time seized in execution or attachment by any creditor
          of the Tenant or if the Tenant makes any bulk sale, then in any such
          case this lease shall, at the option of the Landlord, cease and
          determine and the Term shall immediately become forfeited and void in
          accordance with the provisions of Section 15, RIGHT OF TERMINATION,
          herein.

13.00     BANKRUPTCY

          Provided further that, in case without the written consent of the
          Landlord, the Leased Premises shall be used by any other person than
          the Tenant or for any other purposes

                                   Page 156
<PAGE>
 
          than that for which the same were let or in case the Term or any of
          the goods and chattels of the Tenant shall be at any time seized in
          execution or attachment by any creditor of the Tenant or by the Tenant
          making any assignment for the benefit of creditors or any bulk sale or
          become bankrupt or insolvent or take the benefit of any act now or
          hereafter in force for bankrupt or insolvent debtors, or, if the
          Tenant is a corporation and any order shall be made for the winding up
          of the Tenant, or other termination of the corporate existence of the
          Tenant, then in any such case this Lease shall, at the option of the
          Landlord, cease and determine and the Term shall immediately become
          forfeited and void and the then current month's rent and the next
          ensuing three (3) months rent shall immediately become due and be paid
          and the Landlord may re-enter and take possession of the Leased
          Premises as though the Tenant or other occupant or occupants of the
          Leased Premises was or were holding over after the expiration of the
          Term without any right whatever.

14.00     RE-ENTRY BY LANDLORD

          The Tenant further covenants and agrees that on the Landlord's
          becoming entitled to re-enter upon the Leased Premises under any of
          the provisions of this Lease, the Landlord, in addition to all other
          rights, shall have the right to enter the Leased Premises as the agent
          of the Tenant either by force or otherwise, without being liable for
          any prosecution therefor and to relet the Leased Premises as the agent
          of the Tenant, and to receive the rent therefor and as the agent of
          the Tenant, to take possession of any furniture or other property on
          the Leased Premises and to sell the same at public or private sale
          without notice and to apply the proceeds of such sale and any rent
          derived from reletting the Leased Premises upon account of the rent
          under this Lease, and the Tenant shall be liable to the Landlord for
          the deficiency, if any.

15.00     RIGHT OF TERMINATION

          The Tenant further covenants and agrees that on the Landlord becoming
          entitled to re-enter upon the Leased Premises under any of the
          provisions of this Lease, the Landlord, in addition to all other
          rights, shall have the right to determine forthwith this Lease and the
          Term by leaving upon the Leased Premises notice in writing of its
          intention so to do, and thereupon, rent shall be computed, apportioned
          and paid in full to the date of such determination of this Lease and
          any other payments for which the Tenant is liable under this Lease
          shall be paid and the Tenant shall immediately deliver up possession
          of the Leased Premises to the Landlord, and the Landlord may re-enter
          and take possession of the same.

16.00     DISTRESS

          The Tenant waives and renounces the benefit of any present or future
          statute taking away or limiting the Landlord's right of distress, and
          covenants and agrees that notwithstanding any such statute, none of
          the goods and chattels of the Tenant on the Leased Premises at any
          time during the Term shall be exempt from levy by distress for rent in
          arrears. In the event that the Tenant shall remove or permit the
          removal of any of its goods or chattels from the Leased Premises, the
          Landlord may within thirty (30) days thereafter and if the Tenant is
          in arrears of rent, seize such goods and chattels wherever the same
          may be found and may sell or otherwise dispose of the same as if they
          had actually been distrained upon the Leased Premises by the Landlord
          for arrears of rent.

                                   Page 156
<PAGE>
 
17.00     NON-WAIVER

          No condoning, excusing or overlooking by the Landlord of any default,
          breach or non-observance by the Tenant at any time or times in respect
          of any covenant, proviso or condition herein contained shall operate
          as a waiver of the Landlord's rights hereunder in respect of any
          continuing or subsequent default, breach or non-observance, or so as
          to defeat or affect in any way the rights of the Landlord herein in
          respect of any such continuing or subsequent default or breach, and no
          waiver shall be inferred from or implied by anything done or omitted
          by the Landlord save only express waiver in writing. All rights and
          remedies of the Landlord in this Lease contained shall be cumulative
          and not alternative.

18.00     CHANGES TO BUILDING

          The Landlord hereby reserves the right at any time and from time to
          time to make changes in, additions to, subtractions from or
          rearrangements of the Building including, without limitation, all
          improvements at any time thereon, all entrances and exits thereto, and
          to grant, modify and terminate easements or other agreements
          pertaining to the use and maintenance of all or parts of the Building
          and to make changes or additions to the pipes, conduits, utilities and
          other necessary building services in the Leased Premises which serve
          other premises, provided that prior to the commencement of the Term,
          the Landlord may alter or relocate the Leased Premises to the extent
          found necessary by the Landlord to accommodate changes in construction
          design or facilities including major alterations and relocations. The
          Landlord agrees that in performing such alterations, it shall do so in
          a manner so as to minimize any material interference with the Tenant's
          use and enjoyment of the Leased Premises.

19.00     SEVERANCE OF LAND

          The Landlord shall have the right from time to time to sever (for
          purposes of sale, lease, mortgage, charge or otherwise) any part or
          parts of the Land or any buildings or improvements thereon, including
          the creation of rights-of-way, easements and parking arrangements
          which the Landlord deems necessary and the Tenant hereby consents to
          any such severance and agrees to execute, at no cost to the Landlord,
          any documents or consents which the Landlord may request for these
          purposes. If any part or parts of the Land or the buildings or
          improvements on the lands are so severed and are deemed by the
          Landlord to no longer form part of the property, such part or parts
          shall be excluded from the Lands and the property for the purposes of
          this Lease at the time designated by the Landlord and the Tenant shall
          when requested by the Landlord, execute, at no cost to the Landlord, a
          release of any interest in the Lands so excluded.

20.00     COSTS OF COLLECTION

          The Tenant shall pay, as Additional Rent, all costs, expenses and
          legal fees (on a solicitor and his client basis) that may be incurred
          or paid by or on behalf of the Landlord in enforcing the covenants and
          provisions of this Lease.


21.00     PROFITS AND REMEDIES BY LANDLORD

          In addition to all rights and remedies available to the Landlord under
          the provisions of this Lease or by statute or the general law in the
          event of any default by the Tenant of the provisions of this Lease:

                                   Page 158
<PAGE>
 
21.01     PAYMENTS TO THIRD PARTIES

          The Landlord shall have the right at all times to remedy or attempt to
          remedy any default of the Tenant, and in so doing, may make any
          payments due or alleged to be due by the Tenant to third parties and
          may enter upon the Leased Premises to do any work or other things
          therein, and in any such event, all costs and expenses of the Landlord
          in remedying or attempting to remedy such default shall be payable by
          the Tenant to the Landlord forthwith upon demand as Additional Rent.

21.02     NON-PAYMENT OF ADDITIONAL RENT

          The Landlord shall have the same rights and remedies in the event of
          any non-payment by the Tenant of any amounts payable by the Tenant
          under any provision of this Lease and the parking agreement as in the
          case of non-payment of rent and may be recovered by the Landlord as
          rent by any and all remedies available to the Landlord for the
          recovery of rent in arrears.

21.03     INTEREST ON ARREARS

          The Landlord shall, if the Tenant shall fail to pay any Monthly Rent,
          Additional Rent or other amounts from time to time payable by it to
          the Landlord hereunder promptly when due, be entitled to interest on
          all such Annual Rent, Additional Rent and other amounts which are
          unpaid and overdue under this Lease and the parking agreement, such
          interest to be compounded monthly thereon and to be computed at a rate
          equal to two percent (2%) per annum in excess of the minimum lending
          rate to prime commercial borrowers from time to time charged by the
          Royal Bank of Canada or such other chartered bank as the Landlord may
          designate, from the date upon which such Monthly Rent, Additional Rent
          and other amounts was due until actual payment thereof.

22.00     NOTICE

          Any notice required or contemplated by any provisions of this Lease
          shall be given in writing, enclosed in a sealed envelope addressed, in
          the case of notice to the Landlord c/o Kanata Research Park
          Corporation, 600 March Road, P.O. Box l3600, Kanata, Ontario, Canada,
          K2K 2E6 and in the case of notice to the Tenant, to it at the Leased
          Premises in the event of a notice of distress and otherwise to it at
          600 March Road, P.O. Box l3600, Kanata, Ontario, Canada, K2K 2E6 and
          mailed by registered mail, postage prepaid or telefaxed. The time of
          giving of such notice shall be conclusively deemed to be, if mailed
          the third (3rd) business day after the day of such mailing, if
          telefaxed, the next business day following the date sent as evidenced
          by the sender's transmittal record. Such notice shall also be
          sufficiently given if and when the same shall be delivered, in the
          case of notice to the Landlord, to an executive officer of the
          Landlord, and in the case of notice to the Tenant, to him personally
          or to an executive officer, manager or a person who appears to be in
          charge, of the Tenant if the Tenant is a corporation. Such notice, if
          delivered, shall be conclusively deemed to have been given and
          received at the time of such delivery. If, in this Lease, two or more
          persons are named as Tenant, such notice shall also be sufficiently
          given if and when the same shall be delivered personally to any one of
          such persons. Provided that either party may, by notice to the other,
          from time to time, designate another address in Canada to which
          notices mailed more than ten (10) days thereafter shall be addressed.
          The word "notice" in this paragraph shall include any request, demand,
          direction, or statement in this Lease provided or permitted to be
          given by the Landlord to the Tenant or by the Tenant to the Landlord.

                                   Page 159
<PAGE>
 
23.00     SUBORDINATION, POSTPONEMENT, ATTORNMENT

          The Tenant shall promptly upon the written request of the Landlord,
          enter into an agreement:

          (a)   subordinating the Term and the rights of the Tenant hereunder to
                any mortgage, charge, ground lease, trust deed or debenture
                present or future and all renewals, modifications, replacements
                or extensions thereof, which may affect the Leased Premises, the
                Property, the Lands or the Building;

          (b)   agreeing that the Term hereof shall be subsequent in priority to
                any such mortgage, charge, ground lease, trust deed or
                debenture;

          provided that the Tenant's obligations under this paragraph shall be
          conditional upon any such mortgagee or secured party entering into a
          non-disturbance agreement with the Tenant under which the Tenant's
          continued possession of the Leased Premises is ensured notwithstanding
          any act taken by the mortgagee or secured party.

23.01     TENANT'S RIGHT TO POSSESSION

          Notwithstanding any postponement or subordination referred to herein,
          the Tenant acknowledges that its obligations under this Lease shall
          remain in full force and effect notwithstanding any action at any time
          taken by a mortgagee, chargee or ground lessor to enforce the security
          of any mortgage charge, ground lease, trust deed or debenture;
          provided, however, that any postponement or subordination given
          hereunder shall reserve to the Tenant the right to continue in
          possession of the Leased Premises under the terms of this Lease so
          long as the Tenant shall not be in default hereunder.

23.02     ATTORNMENT BY TENANT

          The Tenant, whenever requested by any mortgagee (including any trustee
          under a deed of trust and mortgage), chargee or ground lessor, shall
          attorn to such mortgagee, chargee or ground lessor as a tenant upon
          all the terms of this Lease.

24.00     CERTIFICATE

          The Tenant agrees that he will at any time and from time to time upon
          not less than five (5) days' prior notice execute and deliver to the
          Landlord or any mortgagee of the Lands (including a deed of trust and
          mortgage) a statement in writing certifying that this Lease is
          unmodified and in full force and effect (or, if modified, stating the
          modifications and that the same is in full force and effect as
          modified), the amount of the Annual Rental then being paid hereunder,
          the dates to which the same, by instalments or otherwise, and other
          charges hereunder have been paid, and whether or not there is any
          existing default on the part of the Landlord of which the Tenant has
          notice.

25.00     REGISTRATION

          The Tenant covenants and agrees with the Landlord that the Tenant will
          not register this Lease in this form in any Registry Office or the
          Land Titles Office. If the Tenant desires to make a registration for
          the purposes only of giving notice of this Lease, then the parties
          hereto shall contemporaneously with the execution of this Lease
          execute a

                                   Page 160
<PAGE>
 
          short form thereof solely for the purpose of supporting an
          application for registration of notice thereof.

26.00     PLANNING ACT

          Where applicable, this Lease shall be subject to the condition that it
          is effective only if The Planning Act, 1983, as amended is complied
          with. Pending such compliance the Term and any renewal thereof shall
          be deemed to be for a total period of one (1) year less than the
          maximum lease Term permitted by law without such compliance.

27.00     TRANSFER BY LANDLORD

          In the event of a sale, transfer or lease by the Landlord of the
          Building, the Lands or a portion thereof containing the Leased
          Premises or the assignment by the Landlord of this Lease or any
          interest of the Landlord hereunder, the Landlord shall, without
          further written agreement, to the extent that such purchaser,
          transferee or lessee has become bound by the covenants and obligations
          of the Landlord hereunder, be freed, released and relieved of all
          liability or obligations under this Lease incurred or arising after
          the date of such sale, transfer or lease.

28.00     NO ADVERTISING OF LEASED PREMISES

          The Tenant shall not print, publish, post, display or broadcast any
          notice or advertisement to the effect that the whole or any part of
          the Leased Premises are for rent, and it shall not permit any broker
          or other person to do so without the consent in writing of the
          Landlord.

29.00     TIME OF ESSENCE

          Time shall be of the essence of this Lease.

30.00     LAWS OF ONTARIO

          This Lease shall be deemed to have been made in and shall be construed
          in accordance with the Laws of the Province of Ontario.

31.00     SEVERABILITY OF COVENANTS

          The Landlord and the Tenant agree that all of the provisions of this
          Lease are to be construed as covenants and agreements as though the
          words importing such covenants and agreements were used in each
          separate paragraph hereof. Should any provision or provisions of this
          Lease be illegal or not enforceable it or they shall be considered
          separate and severable from the Lease and its remaining provisions
          shall remain in force and be binding upon the parties hereto as though
          the said provision or provisions had never been included.

32.00     HEADINGS

          The captions appearing in the margin or the headings contained in this
          Lease have been inserted as a matter of convenience and for reference
          only and in no way define, limit or enlarge the scope or meaning of
          this Lease or of any provision hereof.

                                   Page 161
<PAGE>
 
33.00     SCHEDULES

          The following Schedules attached hereto form part of this Lease: 
          Schedules: "A", "B", "C", "D", "E" and "F"

34.00     LEASE ENTIRE AGREEMENT

          The Tenant acknowledges that there are no covenants, representations,
          warranties, agreements or conditions expressed or implied, collateral
          or otherwise forming part of or in any way affecting or relating to
          this Lease save as expressly set out in this Lease and that this Lease
          constitutes the entire agreement between the Landlord and the Tenant
          and may not be modified except as herein explicitly provided or except
          by subsequent agreement in writing of equal formality hereto executed
          by the Landlord and the Tenant.

35.00     INTERPRETATION

          IN THIS INDENTURE:

          (a)    "herein", "hereof", "hereby", "hereunder", "hereto",
                 "hereinafter", and similar expressions refer to this indenture
                 and not to any particular paragraph, section or other portion
                 thereof, unless there is something in the subject matter or
                 context inconsistent therewith.

          (b)    "business day(s)" means any of the days from Monday to Friday
                 of each week inclusive unless such day is a statutory holiday
                 or public holiday.

          (c)    "normal business hours" means the hours from 8:00 a.m. to 6:00
                 p.m. on business days.

36.00     SUCCESSORS

          This indenture and everything herein contained shall enure to the
          benefit of and be binding upon the respective heirs, executors,
          administrators, permitted successors and assigns, of the Tenant and
          other legal representatives as the case may be, of each and every of
          the parties hereto, and every reference herein to any party hereto
          shall include the heirs, executors, administrators, permitted
          successors, assigns and other legal representatives of such party, and
          where there is more than one tenant or there is a female party or a
          corporation, the provisions hereof shall be read with all grammatical
          and gender changes thereby rendered necessary and all covenants shall
          be deemed joint and several.

                                   Page 162
<PAGE>
 
37.00     JOINT AND SEVERAL COVENANT

          If more than one person executes this Lease as Tenant, each such
          person shall be bound jointly and severally with the other(s), waiving
          the benefit of division and discussion, for the fulfilment of all of
          the obligations of Tenant hereunder.


          IN WITNESS WHEREOF the parties hereto have hereunto affixed
their corporate seals duly attested to by the hands of their proper signing
officers authorized in that behalf.


SIGNED, SEALED AND DELIVERED )
in the presence of:          )        KANATA RESEARCH PARK
                             )        CORPORATION
                             )
                             )
                             )                                            c/s
                             ) Per: /s/   Bronwen A. Heins
                                   ------------------------------------------
                             ) Name:      Bronwen A. Heins
                             ) Title:     Corporate Secretary
                             ) I have the authority to bind the corporation
                             )
                             )        NEWBRIDGE NETWORKS
                             )        CORPORATION
                             )
                             )
                             )                                             c/s
                             ) Per: /s/ Donald Mills
                                   ---------------------------------------
                             ) Name:    Donald Mills
                             ) Title:   Vice President, Administration
                             )
                             )
                             ) Per: /s/ Peter Nadeau
                                   ----------------------------------------
                             ) Name:    Peter Nadeau
                             ) Title:   Vice President, Legal Services
                             )
                             )I/We have the authority to bind the corporation.


                                   Page 163
<PAGE>
 
                                 SCHEDULE "A"
                                 ------------

                               LEGAL DESCRIPTION
                               -----------------

     Swansea Building - 349 Terry Fox Drive

     FIRSTLY:  Part of Forced Road, Also being a Quarter Sessions Road, known
     locally as Sandhill Road being formerly in the Township of March, now in
     the City of Kanata, designated as Parts 20 & 21 on Plan 4R-12934
     (Part of PIN 04517-0585)

     SECONDLY:  Parcel 8-2, Section March 4, Part Lot 8, Concession 4,
     designated as Parts 22, 23, 24 and 25 on Plan 4R-12934     (PIN 04517-0469)

     THIRDLY:  Parcel 2-1, Section 4M-642, Part of Block 2, Registered Plan
     4M-642, City of Kanata, designated as Parts 8, 9, 10, 11, 12, 13, 14, 15,
     16, 17, 18 & 19 on Plan 4R-12934

     Subject to an easement as in Instrument Number LT911185 over the said Parts
     16, 17 and 19 on Plan 4R-12934 and

     Subject to an easement as in Instrument Number LT623394 over the said Part 
     10 on Plan 4R-12394

     (Part of PIN 04517-0489)

     Regional Municipality of Ottawa Carleton, Land Titles Office of Ottawa
     Carleton No. 4

                                   Page 164
<PAGE>
 
                                 SCHEDULE "B"
                                 ------------

                                  FLOOR PLAN
                                  ----------


                                   Page 165
<PAGE>
 
                                 SCHEDULE "C"
                                 ------------

                             RULES AND REGULATIONS
                             ---------------------



The Tenant and its invitees and employees shall observe the following rules and
regulations (as added to, amended or modified from time to time by the
Landlord).


1.   The sidewalks, entrances, elevators, stairways, passageways, shipping areas
     and corridors of the Building shall not be obstructed or used for any other
     purpose by the Tenant than for ingress and egress to and from the Leased
     Premises; the Tenant shall not place or allow to be placed in such areas or
     facilities any waste paper, garbage, refuse or anything that shall tend to
     make them appear unclean or untidy.

2.   The Tenant and its employees shall use washrooms only for the purpose for
     which they were designed and nothing shall be placed in toilets that might
     cause them to block.

3.   The Tenant shall not make any noise which might disturb other tenants and
     no animals or bicycles or other vehicles other than appropriate vehicles
     for the Tenant's use shall be brought into the Leased Premises or the
     Building.

4.   The Leased Premises shall not be used as overnight sleeping accommodation,
     for public sales nor for entertaining purposes.
     
5.   The Tenant shall make arrangements with the Landlord ahead of time to
     install any machines or equipment which may substantially increase the load
     on the electrical systems, installations will not be made until the
     Landlord's consent is obtained.

6.   Windows will not be left open so as to admit rain or snow.
     
7.   The Tenant will not alter any existing locks nor will any additional locks
     or similar devices be attached to any door or window without the Landlord's
     written consent.

8.   Keys or other devices which are made available to the Tenant for the
     purpose of providing access to the exterior doors of the Building shall not
     be duplicated and shall be returned to the Landlord immediately upon
     termination of the Lease.

9.   All adjustments to mechanical equipment such as thermostats, radiators,
     diffusers, etc. shall be made by the Landlord's staff and no one else.

10.  It shall be the responsibility of the Tenant to prevent any person from
     throwing objects out of windows or into the ducts or stairwells of the
     Building, and the Tenant shall pay for any cost, damage or injury resulting
     from any such acts.

11.  The Tenant shall provide adequate receptacles for garbage, refuse and waste
     paper and all such garbage, refuse and waste paper shall be placed in such
     containers. The Leased Premises shall be kept in a tidy, healthy and clean
     condition.
          
12.  The Tenant shall not bring upon the Leased Premises any safes, heavy
     equipment, motors or any other thing which might overload floors or damage
     the Leased Premises or the Building.

                                   Page 166
<PAGE>
 
13.  The Tenant shall not use or keep inflammable materials in the Leased
     Premises.

14.  The Landlord shall have the right to establish rules and regulations
     governing the use of the parking facilities from time to time and the
     Tenant hereby agrees to observe and abide by all such rules and
     regulations.

15.  Smoking is prohibited in all common areas of the Building.


The foregoing rules and regulations, as from time to time amended, are not
necessarily of uniform application, but may be waived in whole or in part in
respect of other tenants without affecting their enforceability with respect to
the Tenant or the Leased Premises. There is no obligation on the Landlord to
enforce the rules and regulations, and the Landlord shall not be liable by
reason of their non-enforcement.

                                   Page 167
<PAGE>
 
                                 SCHEDULE "D"
                                 ------------

                                    PARKING
                                    -------



1.   During the Term the Landlord hereby agrees to allow the Tenant, its
     employees, agents and invitees shall park their vehicles in the parking
     facilities located on the Lands ("parking facilities").

2.   The Landlord shall not be responsible for any theft, loss or damage to the
     Tenant's vehicles whatsoever, or for injury to the Tenant or others in the
     parking facilities.

3.   The Landlord shall have the right to establish rules and regulations
     governing the use of the parking facilities from time to time and the
     Tenant hereby agrees to observe and abide by all such rules and
     regulations.

                                   Page 168
<PAGE>
 
                                 SCHEDULE "E"
                                 ------------

                                OPTION TO RENEW
                                ---------------

1.     Provided the Tenant is in good standing, during the Term has not been in
       substantial default under this Lease and has not assigned this Lease or
       sublet all or a portion of the Leased Premises, the Tenant shall have and
       is hereby granted an option to renew this Lease for a further term of
       five (5) years provided that in order to exercise this option, the Tenant
       shall be required to give to the Landlord notice of the exercise of such
       option in writing not less than six (6) months prior to the date of
       expiry of the initial Term.
     
2.     Any renewal pursuant to this proviso shall be on the same terms and
       conditions contained in this Lease except:

       (a)    there shall be no additional right of renewal, and no Leasehold
              Improvements;
     
       (b)    the Annual Rent payable by the Tenant for such renewal period
              shall be in accordance with rates for similar premises in a
              similar location and as agreed upon by the Landlord and Tenant and
              shall in no event be less than the Annual Rent paid during the
              last year of the Term; such agreement to be reached not later than
              three (3) months prior to the expiry of the original Term. Failing
              such agreement, either party shall submit the matter to
              arbitration in accordance with the following terms:

                 The dispute shall be submitted to a single arbitrator to be
                 agreed upon by the parties, provided that if a single
                 arbitrator cannot be agreed upon by the parties hereto within
                 ten (10) days after the appointment of a single arbitrator has
                 been requested by one of the parties in writing, then the
                 dispute shall be referred to a board of three arbitrators, one
                 to be appointed by each of the Landlord and the Tenant and a
                 third arbitrator to be appointed by the first two arbitrators
                 in writing; and if either the Landlord or the Tenant shall
                 refuse or neglect to appoint an arbitrator within ten (10) days
                 after the other party shall have appointed an arbitrator and
                 shall have served a written notice upon the party so refusing
                 or neglecting to appoint an arbitrator requiring such party to
                 make such appointment, then the arbitrator first appointed
                 shall, at the request of the party appointing him, proceed to
                 hear and determine the dispute as if he were a single
                 arbitrator appointed by both the Landlord and the Tenant for
                 that purpose. If two arbitrators are so named within the time
                 prescribed and they do not agree within a period of ten (10)
                 days upon the appointment of the third arbitrator, then upon
                 the application of either the Landlord or the Tenant, the third
                 arbitrator shall be appointed by a Judge of the Ontario Court
                 (General Division). The determination which shall be made by
                 the said arbitrators or a majority of them, or by the single
                 arbitrator, as the case may be, shall be final and binding upon
                 the parties hereto and the costs of the arbitration and
                 remuneration of the third arbitrator, if any, shall be borne
                 equally between the parties hereto, each of the parties bearing
                 the remuneration of the arbitrator appointed by it. The
                 provisions of this paragraph shall be deemed to be submission
                 to arbitration within the provisions of The Arbitration Act of
                                                         ----------------------
                 Ontario and any statutory modification or re-enactment thereof;
                 -------
                 provided that any limitation on the remuneration of arbitrators
                 imposed by such legislation shall not have application to any
                 arbitration proceeding commenced pursuant to this paragraph.

                                   Page 169
<PAGE>
 
                                 SCHEDULE "F"
                                 ------------

                            LEASEHOLD IMPROVEMENTS
                            ----------------------


The Landlord shall, construct on behalf of the Tenant and install on a turnkey
basis those leasehold improvements agreed upon by both Landlord and Tenant as
chosen from the Landlord's samples. The turnkey cost shall include the
Landlord's administrative costs which relate to the work. The Tenant shall pay
to the Landlord on or before the commencement of the Term the sum of One Million
Nine Hundred Thousand Dollars ($1,900,000.00) towards the costs of such
leasehold improvements.

                                   Page 170
<PAGE>
 
                      DATED the 23rd day of April, 1997.




BETWEEN:



                      KANATA RESEARCH PARK CORPORATION


                                                               OF THE FIRST PART

AND:

                      NEWBRIDGE NETWORKS CORPORATION


                                                              OF THE SECOND PART



-------------------------------------------------------------------------------

                                    L E A S E

-------------------------------------------------------------------------------









Prepared by:          Bronwen A. Heins
Date Edited:
Disk Reference:       Swansea.lse

                                   Page 171
<PAGE>
 
                       KANATA RESEARCH PARK CORPORATION

                                      AND

                        NEWBRIDGE NETWORKS CORPORATION

<TABLE> 
<C>  <S>                                                                     <C>
1.00 LEASED PREMISES.........................................................
1.01 ADDITIONAL DEFINITIONS..................................................
2.00 TERM....................................................................
2.01 INABILITY TO GIVE OCCUPANCY.............................................
2.02 EARLY OCCUPANCY.........................................................
2.03 OVERHOLDING.............................................................
3.00 RENT - Basic Rent.......................................................
3.01 MONTHLY RENTAL..........................................................
3.02 ADDITIONAL RENT.........................................................
3.03 ESTIMATED ADDITIONAL RENTALS............................................
3.04 DEFICIENCY OF ADDITIONAL RENT...........................................
3.05 EXCESS OF ADDITIONAL RENTAL INSTALLMENTS................................
3.06 PRO-RATING OF ADDITIONAL RENT...........................................
3.07 PREPAYMENT OF ADDITIONAL RENT...........................................
3.08 DISPUTE AS TO AMOUNT OF ADDITIONAL RENT.................................
3.09 MANNER AND PLACE OF PAYMENT OF RENT.....................................
3.10 DEFAULT.................................................................
3.11 ACCRUAL OF RENT.........................................................
3.12 NET LEASE...............................................................
4.00 TENANT'S BUSINESS TAX...................................................
4.01 LANDLORD'S BUSINESS TAX.................................................
4.02 TAX ON TENANT'S LEASEHOLD IMPROVEMENTS..................................
4.03 PROPERTY TAX............................................................
4.04 ALLOCATION OF TAX.......................................................
4.05 SEPARATE SCHOOL TAXES...................................................
4.06 TAX APPEAL..............................................................
4.07 CAPITAL TAX.............................................................
5.00 OPERATING COSTS.........................................................
5.01 ALLOCATION OF OPERATING COSTS...........................................
5.02 FULL OCCUPANCY..........................................................
5.03 USE OF ELECTRICITY......................................................
5.04 METERS..................................................................
6.00 ASSIGNING OR SUBLETTING.................................................
6.01 REQUEST TO ASSIGN OR SUBLET.............................................
6.02 ASSIGNMENT AGREEMENT....................................................
6.03 CONSENT NOT TO RELEASE TENANT...........................................
6.04 NOTICE OF CHANGE OF CONTROL.............................................
6.05 COST OF CONSENT.........................................................
</TABLE> 

                                   Page 172
<PAGE>
 
<TABLE> 
<C>  <S>                                                                     <C>
7.00 TENANT'S COVENANTS......................................................
7.01 TENANT REPAIRS..........................................................
7.02 RULES AND REGULATIONS...................................................
7.03 USE OF PREMISES.........................................................
7.04 INCREASE IN INSURANCE PREMIUMS..........................................
7.05 CANCELLATION OF INSURANCE...............................................
7.06 OBSERVANCE OF LAW.......................................................
7.07 WASTE AND OVERLOADING OF FLOORS.........................................
7.08 INSPECTION..............................................................
7.09 INDEMNITY TO LANDLORD...................................................
7.10 DAMAGE BY TENANT........................................................
7.11 TENANT INSURANCE........................................................
7.12 NO ABATEMENT OF RENT....................................................
7.13 EXHIBITING PREMISES.....................................................
7.14 TENANT MAINTENANCE......................................................
7.15 SIGNS...................................................................
7.16 NAME OF BUILDING........................................................
7.17 KEEP TIDY...............................................................
7.18 DELIVERIES..............................................................
7.19 NOTICE OF DAMAGE........................................................
7.20 ALTERATIONS, ETC........................................................
7.21 CONSTRUCTION LIENS......................................................
7.22 SECURITY................................................................
7.23 HAZARDOUS SUBSTANCES....................................................
7.24  NUISANCE...............................................................
8.00 LANDLORD'S COVENANTS....................................................
8.01 QUIET ENJOYMENT.........................................................
8.02 TAXES, ETC..............................................................
8.03 HEATING AND AIR-CONDITIONING............................................
8.04 REPAIR OF STRUCTURE.....................................................
8.05 DELAYS IN PROVISION OF SERVICES.........................................
9.00 TENANT'S FIXTURES.......................................................
9.01 REMOVAL OF TENANT'S FIXTURES............................................
10.00 DAMAGE OR DESTRUCTION OF LEASED PREMISES...............................
10.01 PARTIAL DAMAGE.........................................................
10.02 TOTAL DAMAGE...........................................................
10.03 OBLIGATION TO REPAIR...................................................
10.04 ABATEMENT OF RENT......................................................
10.05 DAMAGE TO 50% OF BUILDING..............................................
10.06 COMPLETION OF REPAIR...................................................
11.00 LIABILITY FOR DAMAGE TO PROPERTY.......................................
12.00 DEFAULT OF TENANT......................................................
13.00 BANKRUPTCY.............................................................
14.00 RE-ENTRY BY LANDLORD...................................................
15.00 RIGHT OF TERMINATION...................................................
16.00 DISTRESS...............................................................
</TABLE> 

                                   Page 173
<PAGE>
 
<TABLE> 
<C>   <S>                                                                    <C>
17.00 NON-WAIVER.............................................................
18.00 CHANGES TO BUILDING....................................................
19.00 SEVERANCE OF LAND......................................................
20.00 COSTS OF COLLECTION....................................................
21.00 PROFITS AND REMEDIES BY LANDLORD.......................................
21.01 PAYMENTS TO THIRD PARTIES..............................................
21.02 NON-PAYMENT OF ADDITIONAL RENT.........................................
21.03 INTEREST ON ARREARS....................................................
22.00 NOTICE.................................................................
23.00 SUBORDINATION, POSTPONEMENT, ATTORNMENT................................
23.01 TENANT'S RIGHT TO POSSESSION...........................................
23.02 ATTORNMENT BY TENANT...................................................
24.00 CERTIFICATE............................................................
25.00 REGISTRATION...........................................................
26.00 PLANNING ACT...........................................................
27.00 TRANSFER BY LANDLORD...................................................
28.00 NO ADVERTISING OF LEASED PREMISES......................................
29.00 TIME OF ESSENCE........................................................
30.00 LAWS OF ONTARIO........................................................
31.00 SEVERABILITY OF COVENANTS..............................................
32.00 HEADINGS...............................................................
33.00 SCHEDULES..............................................................
34.00 LEASE ENTIRE AGREEMENT.................................................
35.00 INTERPRETATION.........................................................
36.00 SUCCESSORS.............................................................
37.00 JOINT AND SEVERAL COVENANT.............................................
</TABLE> 
<TABLE> 
<S>                                                                          <C>
SCHEDULE "A".................................................................
------------
SCHEDULE "B".................................................................
-----------
SCHEDULE "C".................................................................
------------
SCHEDULE "D".................................................................
------------
SCHEDULE "E".................................................................
------------
SCHEDULE "F".................................................................
------------
</TABLE> 
                                   Page 174