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                                                                     EXHIBIT 4.5

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                                  IBASIS, INC.

                               IBASIS GLOBAL, INC.

                       IBASIS SECURITIES CORPORATION, INC.

                               SECURITY AGREEMENT


                          Dated as of January 30, 2003


               U.S. BANK NATIONAL ASSOCIATION, as COLLATERAL Agent

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                                TABLE OF CONTENTS

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<S>                                                                                       <C>
1.  Reference to Exchange Agreement; Definitions; Certain Rules of Construction............1
2.  Certain Exhibits.......................................................................2
       2.1.  Agreements Relating to Financing Debt, Real Property, etc.....................2
       2.2.  Organization and Business.....................................................3
       2.3.  Quarterly Updates.............................................................3
3.  Security...............................................................................3
       3.1.  Credit Security...............................................................3
       3.2.  Additional Credit Security....................................................6
       3.3.  Certain Covenants with Respect to Credit Security.............................7
       3.4.  Administration of Credit Security............................................11
       3.5.  Right to Realize upon Credit Security........................................12
       3.6.  Custody of Credit Security...................................................15
4.  Defeasance............................................................................16
5.  Successors and Assigns................................................................16
6.  Notices...............................................................................16
7.  Reimbursement of Expenses.............................................................17
8.  Venue; Service of Process. Each of the Borrower, the Guarantor and the Agent:.........17
9.  WAIVER OF JURY TRIAL..................................................................17
10.  General..............................................................................18
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                                  IBASIS, INC.

                               IBASIS GLOBAL, INC.

                               SECURITY AGREEMENT

     This Agreement, dated as of January 30, 2003, is among iBasis, Inc., a
Delaware corporation (the "COMPANY"), iBasis Global, Inc., a Delaware
corporation, ("iBASIS GLOBAL", and collectively with the Company, the
"BORROWER"), iBasis Securities Corporation, a Massachusetts Corporation (the
"Guarantor") and U.S. Bank National Association, as Collateral Agent (the
"AGENT") for the Holders under the Exchange Agreement (as defined below). The
parties agree as follows:

1. REFERENCE TO EXCHANGE AGREEMENT; DEFINITIONS; CERTAIN RULES OF CONSTRUCTION.
Reference is made to the Securities Exchange Agreement dated as of the date
hereof, as from time to time in effect (the "EXCHANGE AGREEMENT"), among the
Borrower, the Guarantor, the Symphony Funds (as defined therein) and the
Collateral Agent. Capitalized terms defined in the Exchange Agreement and not
otherwise defined herein are used herein with the meanings so defined. Certain
other capitalized terms are used in this Agreement as specifically defined below
in this Section 1. Except as the context otherwise explicitly requires, (a) the
capitalized term "Section" refers to sections of this Agreement, (b) the
capitalized term "Exhibit" refers to exhibits to this Agreement, (c) references
to a particular Section shall include all subsections thereof, (d) the word
"including" shall be construed as "including without limitation", (e) terms
defined in the UCC and not otherwise defined herein have the meaning provided
under the UCC, (f) references to a particular statute or regulation include all
rules and regulations thereunder and any successor statute, regulation or rules,
in each case as from time to time in effect and (g) references to a particular
Person include such Person's successors and assigns to the extent not prohibited
by this Agreement and the other Credit Documents. References to "the date
hereof" mean the date first set forth above.

     "ACCOUNTS" is defined in Section 3.1.2.

     "AGREEMENT" means this Security Agreement as from time to time in effect.

     "FINANCING DEBT" means indebtedness (a) for borrowed money, (b) evidenced
by notes, debentures or similar instruments, (c) associated with capitalized
lease obligations and synthetic lease obligations, (d) associated with the
deferred purchase price of assets, services or securities, including related
noncompetition, consulting and stock repurchase obligations (other than ordinary
trade accounts payable on customary terms in the ordinary course of business),
and any long-term contractual obligations for the payment of money, (e)
associated with mandatory redemption, repurchase or dividend rights on capital
stock (or other equity), including provisions that require the exchange of such
capital stock (or other equity) for Indebtedness from the issuer, (f) associated
with reimbursement obligations, whether contingent or matured, with respect to
letters of credit, bankers acceptances, surety bonds, other financial
guarantees, foreign currency hedge agreements and interest rate protection
agreements (without duplication of other

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indebtedness supported or guaranteed thereby), and (g) any guarantees of any of
the foregoing items.

     "INTELLECTUAL PROPERTY" is defined in Section 3.3.8.

     "OBLIGORS" means the Borrower and the Guarantor.

     "PLEDGED INDEBTEDNESS" is defined in Section 3.1.6.

     "PLEDGED RIGHTS" is defined in Section 3.1.5.

     "PLEDGED SECURITIES" means the Pledged Stock, the Pledged Rights and the
Pledged Indebtedness, collectively.

     "PLEDGED STOCK" is defined in Section 3.1.4.

     "UCC" means the Uniform Commercial Code as in effect in Massachusetts on
the date hereof; PROVIDED, HOWEVER, that with respect to the perfection of the
Agent's Lien on the Credit Security and the effect of nonperfection thereof, the
term "UCC" means the Uniform Commercial Code as in effect in any jurisdiction
the laws of which are made applicable by section 9-301 of the Uniform Commercial
Code as in effect in Massachusetts.

2. CERTAIN EXHIBITS. In order to induce the Symphony Funds to enter into the
Credit Documents, including this Agreement, each of the Obligors jointly and
severally represents and warrants as follows:

     2.1. AGREEMENTS RELATING TO FINANCING DEBT, REAL PROPERTY, ETC. Exhibit
2.1, as from time to time hereafter supplemented in accordance with Section 2.3,
sets forth, as of the later of the date hereof or the end of the most recent
fiscal quarter:

          2.1.1. The amounts (as of the dates indicated in Exhibit 2.1, as so
     supplemented) of all Financing Debt of the Company and its Subsidiaries and
     all agreements, Liens and guarantees which relate to such Financing Debt.

          2.1.2. All real property owned by the Company or any of its
     Subsidiaries or leased from an Affiliate of the Company.

          2.1.3. Material license agreements with respect to the products of the
     Company and its Subsidiaries, including the parties thereto and the
     expiration dates thereof.

          2.1.4. All trademarks, tradenames, service marks, service names and
     patents owned by the Company and its Subsidiaries that are registered with
     the federal Patent and Trademark Office (or with respect to which
     applications for such registration have been filed).

          2.1.5. All copyrights owned by the Company and its Subsidiaries that
     are registered with the federal Copyright Office.

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          2.1.6. All internet domain names owned by the Company and its
     Subsidiaries and the related registry information.

          2.1.7. All commercial tort claims owned by the Company and its
     Subsidiaries and related information with respect to the status of the
     proceedings.

          2.1.8. All bank and deposit accounts owned by the Company and its
     Subsidiaries.

The Company has furnished the Symphony Funds correct and complete copies of any
agreements described above in this Section 2.1 requested by the Symphony Funds.

     2.2. ORGANIZATION AND BUSINESS.

          2.2.1. Exhibit 2.2, as from time to time hereafter supplemented in
     accordance with Section 2.3, sets forth, as of the later of the date hereof
     or the end of the most recent fiscal quarter, (i) the jurisdiction of
     organization, the organizational identification number issued by such
     jurisdiction and the federal taxpayer identification number of the
     Borrower, (ii) the address of the Borrower's principal executive office and
     chief place of business, (iii) each name, including any trade name, under
     which the Borrower conducts its business and (iv) the jurisdictions in
     which the Borrower owns real or tangible personal property and, in the case
     of real property, whether such real property is owned or leased by the
     Borrower.

          2.2.2. Exhibit 2.2, as from time to time hereafter supplemented in
     accordance with Section 2.3, sets forth, as of the later of the date hereof
     or the end of the most recent fiscal quarter, (i) the name, jurisdiction of
     organization, the organizational identification number issued by such
     jurisdiction and the federal taxpayer identification number of each
     Subsidiary of the Borrower, (ii) the address of the chief executive office
     and principal place of business of each such Subsidiary, (iii) each name
     under which each such Subsidiary conducts its business, (iv) each
     jurisdiction in which each such Subsidiary owns real or tangible personal
     property, and, in the case of real property, whether such real property is
     owned or leased by such Subsidiary and (v) the number of authorized and
     issued equity interests and ownership of each such Subsidiary.

     2.3. QUARTERLY UPDATES. The Borrower shall furnish to the Holders as soon
as available, but in any event, within 45 days after the end of the fiscal
quarter of the Borrower in which any material changes in the information set
forth in such exhibits occurs, supplements to Exhibits 2.1 and 2.2 showing such
changes in the information set forth in such exhibits not previously furnished
to the Holders in writing, which supplements must be reasonably satisfactory to
the Agent, as well as any changes in the Charter, Bylaws or incumbency of
officers of the Obligors from those previously certified to the Agent.

3. SECURITY.

     3.1. CREDIT SECURITY. As security for the payment and performance of the
Obligations, each Obligor party hereto mortgages, pledges and collaterally
grants and assigns to the Agent for the benefit of

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the Holders, and creates a security interest in favor of the Agent for the
benefit of the Holders in, all of such Obligor's right, title and interest in
and to (but none of its obligations or liabilities with respect to) the items
and types of present and future property described in Sections 3.1.1 through
3.1.14 (subject, however, to Section 3.1.15), whether now owned or hereafter
acquired, all of which shall be included in the term "CREDIT SECURITY":

          3.1.1. TANGIBLE PERSONAL PROPERTY. All goods, machinery, equipment,
     inventory and all other tangible personal property of any nature
     whatsoever, wherever located, including raw materials, work in process,
     finished parts and products, supplies, spare parts, replacement parts,
     merchandise for resale, computers, tapes, disks and computer equipment.

          3.1.2. RIGHTS TO PAYMENT OF MONEY. All rights to receive the payment
     of money, including accounts and receivables, health care insurance
     receivables, rights to receive the payment of money under contracts,
     franchises, licenses, permits, subscriptions or other agreements (whether
     or not earned by performance), and rights to receive payments from any
     other source (all such rights, other than Financing Debt, being referred to
     herein as "ACCOUNTS").

          3.1.3. INTANGIBLES. All of the following (to the extent not included
     in Section 3.1.2): (a) contracts, franchises, licenses, permits,
     subscriptions and other agreements and all rights thereunder; (b) rights
     granted by others which permit such Obligor to sell or market items of
     personal property; (c) United States and foreign common law and statutory
     copyrights and rights in literary property and rights and licenses
     thereunder; (d) trade names, United States and foreign trademarks, service
     marks, internet domain names, registrations of any of the foregoing and
     related good will; (e) United States and foreign patents and patent
     applications; (f) computer software, designs, models, know-how, trade
     secrets, rights in proprietary information, formulas, customer lists,
     backlog, orders, subscriptions, royalties, catalogues, sales material,
     documents, good will, inventions and processes; (g) judgments, causes in
     action, commercial tort claims set forth from time to time on Exhibit 2.1
     or any supplements thereto provided pursuant to Section 2.3 or otherwise
     and other claims, whether or not inchoate, and (h) all other general
     intangibles, payment intangibles and intangible property and all rights
     thereunder, including such items set forth from time to time on Exhibit 2.1
     or any supplements thereto provided pursuant to Section 2.3 or otherwise.

          3.1.4. PLEDGED STOCK. (a) All shares of capital stock or other
     evidence of beneficial interest in any corporation, business trust or
     limited liability company, (b) all limited partnership interests in any
     limited partnership, (c) all general partnership interests in any general
     or limited partnership, (d) all joint venture interests in any joint
     venture and (e) all options, warrants and similar rights to acquire such
     capital stock or such interests. All such capital stock, interests,
     options, warrants and other rights are collectively referred to as the
     "PLEDGED STOCK".

          3.1.5. PLEDGED RIGHTS. All rights to receive profits or surplus of, or
     other distributions (including income, return of capital and liquidating
     distributions) from, any partnership, joint venture or limited liability
     company, including any distributions by any

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     such Person to partners, joint venturers or members. All such rights are
     collectively referred to as the "PLEDGED RIGHTS".

          3.1.6. PLEDGED INDEBTEDNESS. All Financing Debt from time to time
     owing to such Obligor from any Person (all such Financing Debt being
     referred to as the "PLEDGED INDEBTEDNESS").

          3.1.7. CHATTEL PAPER, INSTRUMENTS, ETC. All chattel paper (whether
     tangible or electronic), non-negotiable instruments, negotiable
     instruments, documents, securities and investment property.

          3.1.8. LEASES. All leases of personal property, whether such Obligor
     is the lessor or the lessee thereunder.

          3.1.9. DEPOSIT ACCOUNTS. All general or special deposit accounts,
     including any demand, time, savings, passbook or similar account maintained
     by such Obligor with any bank, trust company, savings and loan association,
     credit union or similar organization, and all money, cash and cash
     equivalents of such Obligor, whether or not deposited in any such deposit
     account.

          3.1.10. CREDIT SUPPORT. All collateral granted by third parties to, or
     held by, such Obligor, and all letter of credit rights (whether or not the
     letter of credit is evidenced in writing) and other supporting obligations
     of such Obligor.

          3.1.11. BOOKS AND RECORDS. All books and records, including books of
     account and ledgers of every kind and nature, all electronically recorded
     data (including all computer programs, disks, tapes, electronic data
     processing media and software used in connection with maintaining such
     Obligor's books and records), all files, correspondence and all containers
     for the foregoing.

          3.1.12. INSURANCE. All insurance policies which insure against any
     loss or damage to any other Credit Security or which are otherwise owned by
     such Obligor.

          3.1.13. ALL OTHER PROPERTY. All other property, assets and items of
     value of every kind and nature, tangible or intangible, absolute or
     contingent, legal or equitable.

          3.1.14. PROCEEDS AND PRODUCTS. All proceeds, including insurance
     proceeds, and products of the items of Credit Security described or
     referred to in Sections 3.1.1 through 3.1.13 and, to the extent not
     included in the foregoing, all distributions with respect to the Pledged
     Securities.

          3.1.15. EXCLUDED PROPERTY. Notwithstanding Sections 3.1.1 through
     3.1.14, the payment and performance of the Obligations shall not be secured
     by:

          (a) any contract, license, permit or franchise that validly prohibits
     the creation by such Obligor of a security interest in such contract,
     license, permit or franchise (or in any rights or property obtained by such
     Obligor under such contract, license, permit or

                                      -5-
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     franchise); PROVIDED, HOWEVER, that the provisions of this Section 3.1.15
     shall not prohibit the security interests created by this Agreement from
     extending to the proceeds of such contract, license, permit or franchise
     (or such rights or property) or to the monetary value of the good will and
     other general intangibles of the Obligors relating thereto;

          (b) any rights or property to the extent that any valid and
     enforceable law or regulation applicable to such rights or property
     prohibits the creation of a security interest therein; PROVIDED, HOWEVER,
     that the provisions of this Section 3.1.15 shall not prohibit the security
     interests created by this Agreement from extending to the proceeds of such
     rights or property or to the monetary value of the good will and other
     general intangibles of the Obligors relating thereto;

          (c) any rights or property to the extent that such rights or property
     secure purchase money financing therefor permitted by the Exchange
     Agreement and the agreements providing such purchase money financing
     prohibit the creation of a further security interest therein; PROVIDED,
     HOWEVER, that the provisions of this Section 3.1.15 shall not prohibit the
     security interests created by this Agreement from extending to the proceeds
     of such rights or property or to the monetary value of the good will and
     other general intangibles of the Obligors relating thereto;

          (d) more than 66% of the outstanding voting stock or other voting
     equity in any Foreign Subsidiary to the extent that the pledge of voting
     stock or other voting equity above such amount would result in a
     repatriation of a material amount of foreign earnings under the Code
     (including the "deemed dividend" provisions of section 956 of the Code); or

          (e) Margin Stock unless the applicable requirements of Regulations T,
     U and X of the Board of Governors of the Federal Reserve System have been
     satisfied; or

          (f) the items described in Section 3.2 (but only in the event and to
     the extent the Agent has not specified that such items be included in the
     Credit Security pursuant thereto).

     In addition, in the event any Obligor disposes of assets to third parties
in a transaction permitted by section 4.3 of the Exchange Agreement, such
assets, but not the proceeds or products thereof, shall be released from the
Lien of the Credit Security.

     3.2. ADDITIONAL CREDIT SECURITY. As additional Credit Security, each
Obligor covenants that it will mortgage, pledge and collaterally grant and
assign to the Agent for the benefit of the Holders, and will create a security
interest in favor of the Agent for the benefit of the Holders in all of its
right, title and interest in and to (but none of its obligations with respect
to) such of the following present or future items as the Agent may from time to
time specify by notice to such Obligor, whether now owned or hereafter acquired,
and the proceeds and products thereof, except to the extent consisting of rights
or property of the types referred to in Section 3.1.15(a) through (f), subject
only to Liens permitted by Section 3.3.3, all of which shall thereupon be
included in the term "CREDIT SECURITY":

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     3.2.1. MOTOR VEHICLES AND AIRCRAFT. All motor vehicles and aircraft.

     3.3. CERTAIN COVENANTS WITH RESPECT TO CREDIT SECURITY. Each Obligor
covenants that:

          3.3.1. PLEDGED STOCK. All shares of capital stock, limited partnership
     interests, membership interests and similar securities included in the
     Pledged Stock shall be at all times duly authorized, validly issued, fully
     paid and (in the case of capital stock and limited partnership interests)
     nonassessable. Subject to 3.3.13., each Obligor will deliver to the Agent
     (or an agent on its behalf) certificates representing any Pledged Stock
     held by such Obligor, accompanied by a stock transfer power executed in
     blank, all in form and manner reasonably satisfactory to the Agent. Pledged
     Stock that is not evidenced by a certificate held by such Obligor will be
     described in appropriate control statements and UCC financing statements
     provided to the Agent, all in form and substance reasonably satisfactory to
     the Agent. In the event the Pledged Stock includes uncertificated equity
     interests in a limited liability company, limited partnership, general
     partnership or other entity, except with the prior written consent of the
     Agent, which consent shall not be unreasonably withheld, the Obligors shall
     use reasonable efforts to take all action within their power to prevent
     such limited liability company, limited partnership, general partnership or
     other entity from (a) opting to have such uncertificated equity interests
     treated as "securities" for purposes of Article 8 of the UCC or (b) issuing
     certificates for such uncertificated equity interests. Upon the occurrence
     and during the continuance of an Event of Default, the Agent may transfer
     into its name or the name of its nominee any Pledged Stock. In the event
     the Pledged Stock includes any Margin Stock, the Obligors will furnish to
     the Holders Federal Reserve Form U-1 and take such other action as the
     Agent may reasonably request to ensure compliance with applicable laws.

          3.3.2. ACCOUNTS AND PLEDGED INDEBTEDNESS. Subject to 3.3.13., each
     Obligor will, immediately upon the receipt thereof, deliver to the Agent
     (or an agent on its behalf) any promissory note or similar instrument
     representing any Account or Pledged Indebtedness, after having endorsed
     such promissory note or instrument in blank.

          3.3.3. NO LIENS OR RESTRICTIONS ON TRANSFER OR CHANGE OF CONTROL. All
     Credit Security shall be free and clear of any Liens and restrictions on
     the transfer thereof, including contractual provisions which prohibit the
     assignment of rights under contracts, except for Permitted Liens (as such
     term is defined in the Exchange Agreement) or by this Section 3.3.3.
     Without limiting the generality of the foregoing, each Obligor will in good
     faith attempt to exclude from agreements, instruments, deeds or leases to
     which it becomes a party after the date hereof provisions that would
     prevent such Obligor from creating a security interest in such agreement,
     instrument, deed or lease or any rights or property acquired thereunder as
     contemplated hereby. None of the Pledged Stock shall be subject to any
     option to purchase or similar rights of any Person. Except with the written
     consent of the Required Holders, which consent will not be unreasonably
     withheld, each Obligor will in good faith attempt to exclude from any
     agreement, instrument, deed or lease provisions that would restrict the
     change of control or ownership of the Borrower or any of its Subsidiaries,
     or the creation of a security interest in the ownership of the Borrower or
     any of its Subsidiaries.

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          3.3.4. JURISDICTION OF ORGANIZATION. Each Obligor shall at all times
     maintain its jurisdiction of organization as set forth in Exhibit 2.2 as in
     effect on the date hereof or, so long as such Obligor shall have taken all
     steps reasonably necessary to perfect the Holders' security interest in the
     Credit Security with respect to such new jurisdiction, in such other
     jurisdiction as such Obligor may specify by notice delivered to the Agent
     not less than 10 Business Days prior to such change of jurisdiction of
     organization.

          3.3.5. LOCATION OF CREDIT SECURITY. Each Obligor shall at all times
     keep its records concerning the Accounts at its chief executive office and
     principal place of business, which office and place of business shall be as
     set forth in Exhibit 2.2 (as from time to time supplemented in accordance
     with Section 2.3) or, so long as such Obligor shall have taken all steps
     reasonably directed by the Agent to perfect the Holders' security interest
     in the Credit Security with respect to such new address, at such other
     address as such Obligor may specify by notice delivered to the Agent not
     less than 10 Business Days prior to such change of address. No Obligor
     shall at any time keep tangible personal property of the type referred to
     in Section 3.1.1 in any jurisdiction other than the jurisdictions specified
     in such Exhibit 2.2 (as so supplemented) or, so long as such Obligor shall
     have taken all steps reasonably directed by the Agent to perfect the
     Holders' security interest in the Credit Security with respect to such
     other jurisdiction, other jurisdictions as such Obligor may specify by
     notice delivered to the Agent not less than 10 Business Days prior to
     moving such tangible personal property into such other jurisdiction.

          3.3.6. TRADE NAMES. No Obligor will adopt or do business under any
     name other than its name or names designated in Exhibit 2.2 (as from time
     to time supplemented in accordance with Section 2.3) or any other name
     specified by notice delivered to the Agent not less than 10 Business Days
     prior to the conduct of business under such additional name. Since its
     inception, no Obligor has changed its name or adopted or conducted business
     under any trade name other than a name specified in such Exhibit 2.2 (as so
     supplemented).

          3.3.7. INSURANCE. Each insurance policy included in, or insuring
     against loss or damage to, the Credit Security, or insuring against
     liabilities of the Borrower and its Subsidiaries, shall name the Agent as
     additional insured party or as loss payee, as the case may be. No such
     insurance policy shall be cancelable or subject to termination or reduction
     in amount or scope of coverage until after at least 30 days' prior written
     notice from the insurer to the Agent. At least 10 days prior to the
     expiration of any such insurance policy for any reason, each Obligor shall
     furnish the Agent with reasonably satisfactory evidence of a renewal or
     replacement policy and payment of the premiums therefor to the extent due.
     Each Obligor grants to the Agent full power and authority as its
     attorney-in-fact, effective upon notice to such Obligor after the
     occurrence and during the continuance of an Event of Default, to obtain,
     cancel, transfer, adjust and settle any such insurance policy and to
     endorse any drafts thereon. Any amounts that the Agent receives under any
     such policy (including return of unearned premiums) when no Event of
     Default has occurred and is continuing shall be delivered to the Obligors
     for the replacement, restoration and maintenance of the Credit Security in
     the case of property insurance or for reimbursing insured liabilities in
     the case of liability insurance. Any such amounts that the Agent receives
     after the occurrence and during the continuance of an Event of Default
     shall, at the Agent's option, be applied to payment of the Obligations or
     to the replacement, restoration and maintenance of the Credit Security in
     the case of property

                                       -8-
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     insurance or to the reimbursement of insured liabilities in the case of
     liability insurance. If any Obligor fails to provide insurance as required
     by this Agreement, the Agent may, at its option, purchase such insurance,
     and such Obligor will on demand pay to the Agent the amount of any payments
     made by the Agent or the Holders for such purpose, together with interest
     on the amounts so disbursed from five Business Days after the date demanded
     until payment in full thereof at the rate specified in section 3.2 of the
     Exchange Agreement.

          3.3.8. INTELLECTUAL PROPERTY. Exhibit 2.1 (as supplemented from time
     to time in accordance with Section 2.3) shall set forth the following items
     (collectively, the "INTELLECTUAL PROPERTY"):

          (a) all copyrights owned by the Obligors that are registered with the
     United States Copyright Office (or any office maintaining registration of
     copyrights in any foreign jurisdiction) and all applications for such
     registration;

          (b) all trademarks, tradenames, service marks, service names and
     patents owned by the Obligors that are registered with the United States
     Patent and Trademark Office (or any office maintaining registration of such
     items in any state of the United States of America or any foreign
     jurisdiction) and all applications for such registration; and

          (c) all internet domain names owned by the Obligors and the registry
     office on which such domain names are registered.

     The Obligors shall duly authorize, execute and deliver to the Agent
     separate memoranda of security interests with respect to the foregoing
     Intellectual Property for filing in the offices described above. Upon the
     registration of any additional Intellectual Property (or the filing of
     applications therefor) in the offices described above, the Obligors shall
     (at least quarterly, as contemplated by Section 2.3) notify the Agent and
     duly authorize, execute and deliver to the Agent separate memoranda of
     security interests covering such additional Intellectual Property for
     filing in such offices. The Obligors hereby appoint and constitute the
     Agent as their attorney with full power and authority, in their place and
     stead, after the occurrence and during the continuance of an Event of
     Default, to register with the Patent and Trademark Office, the U.S.
     Copyright Office or any other applicable governmental authority the
     assignment by the Obligors to the Agent of the Intellectual Property.

          3.3.9. DEPOSIT ACCOUNTS. Each Obligor shall keep all its bank and
     deposit accounts only with the Agent, Holders or the financial institutions
     listed on Exhibit 2.1 (as from time to time supplemented in accordance with
     Section 2.3). Each Obligor shall use reasonable efforts to cause such
     financial institutions (other than the Holders and the

                                       -9-
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     Agent) to enter into account control agreements with the Agent in form and
     substance reasonably satisfactory to the Agent.

          3.3.10. MODIFICATIONS TO CREDIT SECURITY. Except with the prior
     written consent of the Agent, which consent will not be unreasonably
     withheld, no Obligor shall amend or modify, or waive any of its material
     rights under or with respect to, any material Accounts, general
     intangibles, Pledged Securities or leases if the effect of such amendment,
     modification or waiver would be to reduce the amount of any such items or
     to extend the time of payment thereof, to waive any default by any other
     party thereto, or to waive or impair any remedies of the Obligors or the
     Holders under or with respect to any such Accounts, general intangibles,
     Pledged Securities or leases, in each case other than consistent with past
     practice in the ordinary course of business and on an arm's-length basis.
     Each Obligor will promptly give the Agent written notice of any request by
     any Person for any material credit or adjustment with respect to any
     Account, general intangible, Pledged Securities or leases.

          3.3.11. DELIVERY OF DOCUMENTS. Upon the Agent's reasonable request,
     each Obligor shall deliver to the Agent, promptly upon such Obligor's
     receipt thereof, copies of any agreements, instruments, documents or
     invoices comprising or relating to the Credit Security. Pending such
     request, such Obligor shall keep such items at its chief executive office
     and principal place of business (as specified pursuant to Section 3.3.5).

          3.3.12. PERFECTION OF CREDIT SECURITY.

          (a) This Agreement creates and shall create in favor of the Agent, for
     the benefit of the Holders, a legal, valid and enforceable second priority
     security interest in the Credit Security described herein, subject only to
     Permitted Liens.

          (b) The Agent may at any time and from time to time execute and file
     UCC financing statements, continuation statements and amendments thereto
     that the Agent reasonably deems necessary to perfect or maintain its
     security interest granted herein, which UCC financing statements,
     continuation statements and amendments describe the Credit Security and
     contain any information required by the UCC or the applicable filing office
     with respect to any such UCC financing statement, continuation statement or
     amendment thereof.

          (c) The Obligors shall execute and deliver all such instruments,
     including UCC financing statements, collateral assignments of copyrights,
     trademarks and patents, mortgages or deeds of trust, notations on
     certificates of title and written confirmation of the grant of a security
     interest in commercial tort claims, and will take all such other action,
     all as may be necessary or desirable (including as the Agent may reasonably
     request from time to time as the Agent deems reasonably necessary or
     desirable) for perfecting or otherwise confirming to it the Credit Security
     or to carry out any other purpose of this Agreement or any other Credit
     Document.

                                      -10-
<Page>

          (d) In furtherance of the foregoing, the Obligors shall use reasonable
     efforts to obtain (i) a written acknowledgment, in form and substance
     reasonably satisfactory to the Agent, from any bailee having possession of
     any Credit Security that such bailee holds such Credit Security for the
     benefit of the Agent and (ii) control of any investment property, deposit
     accounts, letter of credit rights or electronic chattel paper, with any
     agreements establishing such control to be in form and substance reasonably
     satisfactory to the Agent.

          3.3.13. POSSESSION OF CREDIT SECURITY. The Agent shall not take
     possession of any Credit Security required to be delivered by the Obligors
     hereunder that has been delivered to the lenders under the Senior Loan
     Agreement unless and until the Senior Loan Agreement (as such term is
     defined in the Exchange Agreement) has terminated. Upon termination of the
     Senior Loan Agreement (as such term is defined in the Exchange Agreement),
     the Obligors shall cause the senior lenders to deliver to the Agent such
     Credit Security as is required to be delivered by this Agreement.

     3.4. ADMINISTRATION OF CREDIT SECURITY. The Credit Security shall be
administered as follows, and if an Event of Default shall have occurred and be
continuing, Section 3.5 shall also apply.

          3.4.1. USE OF CREDIT SECURITY. Until the Agent provides written notice
     to the contrary, each Obligor may use, commingle and dispose of any part of
     the Credit Security in the ordinary course of its business, all subject to
     section 4.3 of the Exchange Agreement.

          3.4.2. ACCOUNTS. To the extent specified by prior written notice from
     the Agent after the occurrence and during the continuance of an Event of
     Default, all sums collected or received and all property recovered or
     possessed by any Obligor in connection with any Credit Security shall be
     received and held by such Obligor in trust for and on the Holders' behalf,
     shall be segregated from the assets and funds of such Obligor, and shall be
     delivered to the Agent for the benefit of the Holders. Without limiting the
     foregoing, upon the Agent's request after the occurrence and during the
     continuance of an Event of Default, each Obligor shall institute depository
     collateral accounts, lock-box receipts and similar credit procedures
     providing for the direct receipt of payment on Accounts at a separate
     address, the segregation of such proceeds for direct payment to the Agent
     and appropriate notices to Account debtors. Upon the Agent's request after
     the occurrence and during the continuance of an Event of Default, each
     Obligor will cause its accounting books and records to be marked with such
     legends and segregated in such manner as the Agent may specify.

          3.4.3. DISTRIBUTIONS ON PLEDGED SECURITIES.

          (a) Until an Event of Default shall occur and be continuing, the
     respective Obligors shall be entitled, to the extent permitted by the
     Credit Documents, to receive all distributions on or with respect to the
     Pledged Securities (other than distributions constituting additional
     Pledged Securities or liquidating distributions). All distributions

                                      -11-
<Page>

     constituting additional Pledged Securities or liquidating distributions
     will be retained by the Agent (or if received by any Obligor shall be held
     by such Person in trust and shall be immediately delivered by such Person
     to the Agent in the original form received, endorsed in blank) and held by
     the Agent as part of the Credit Security.

          (b) If an Event of Default shall have occurred and be continuing, all
     distributions on or with respect to the Pledged Securities shall be
     retained by the Agent (or if received by any Obligor shall be held by such
     Person in trust and shall be promptly delivered by it to the Agent in the
     original form received, endorsed in blank) and held by the Agent as part of
     the Credit Security or applied by the Agent to the payment of the
     Obligations in accordance with Section 3.5.6.

          3.4.4. VOTING PLEDGED SECURITIES.

          (a) Until an Event of Default shall occur and be continuing and the
     Agent shall have delivered a notice contemplated by clause (b) below, the
     respective Obligors shall be entitled to vote or consent with respect to
     the Pledged Securities in any manner not inconsistent with the terms of any
     Credit Document, and the Agent will, if so requested, execute appropriate
     revocable proxies therefor.

          (b) If an Event of Default shall have occurred and be continuing, if
     and to the extent that the Agent shall so notify in writing the Obligor
     pledging the Pledged Securities in question, only the Agent shall be
     entitled to vote or consent or take any other action with respect to the
     Pledged Securities (and any Obligor will, if so requested, execute
     appropriate proxies therefor).

     3.5. RIGHT TO REALIZE UPON CREDIT SECURITY. Except to the extent prohibited
by applicable law that cannot be waived, this Section 3.5 shall govern the
Holders' and the Agent's rights to realize upon the Credit Security if any Event
of Default shall have occurred and be continuing. The provisions of this Section
3.5 are in addition to any rights and remedies available at law or in equity and
in addition to the provisions of any other Credit Document. In the case of a
conflict between this Section 3.5 and any other Credit Document, this Section
3.5 shall govern.

          3.5.1. ASSEMBLY OF CREDIT SECURITY; RECEIVER. Each Obligor shall, upon
     the Agent's request, assemble the Credit Security and otherwise make it
     available to the Agent. The Agent may have a receiver appointed for all or
     any portion of the Obligors' assets or business which constitutes the
     Credit Security in order to manage, protect, preserve, sell and otherwise
     dispose of all or any portion of the Credit Security in accordance with the
     terms of the Credit Documents, to continue the operations of the Obligors
     and to collect all revenues and profits therefrom to be applied to the
     payment of the Obligations, including the compensation and expenses of such
     receiver.

          3.5.2. GENERAL AUTHORITY. To the extent specified in written notice
     from the Agent to the Obligor in question, each Obligor grants the Agent
     full and exclusive power and authority, subject to the Agent's commercially
     reasonable judgment and the terms hereof and applicable law, to take any of
     the following actions (for the sole benefit of the

                                      -12-
<Page>

     Agent on behalf of the Holders, the reasonable expenses of which shall be
     at such Obligor's expense):

          (a) To ask for, demand, take, collect, sue for and receive all
     payments in respect of any Accounts, general intangibles, Pledged
     Securities or leases which such Obligor could otherwise ask for, demand,
     take, collect, sue for and receive for its own use.

          (b) To extend the time of payment of any Accounts, general
     intangibles, Pledged Securities or leases and to make any allowance or
     other adjustment with respect thereto.

          (c) To settle, compromise, prosecute or defend any action or
     proceeding with respect to any Accounts, general intangibles, Pledged
     Securities or leases and to enforce all rights and remedies thereunder
     which such Obligor could otherwise enforce.

          (d) To enforce the payment of any Accounts, general intangibles,
     Pledged Securities or leases, either in the name of such Obligor or in its
     own name, and to endorse the name of such Obligor on all checks, drafts,
     money orders and other instruments tendered to or received in payment of
     any Credit Security.

          (e) To notify the third party payor with respect to any Accounts,
     general intangibles, Pledged Securities or leases of the existence of the
     security interest created hereby and to cause all payments in respect
     thereof thereafter to be made directly to the Agent; PROVIDED, HOWEVER,
     that whether or not the Agent shall have so notified such payor, such
     Obligor will at its expense render all reasonable assistance to the Agent
     in collecting such items and in enforcing claims thereon.

          (f) To use, operate, sell, transfer, assign or otherwise deal in or
     with any Credit Security or the proceeds thereof, as fully as such Obligor
     otherwise could do.

          3.5.3. MARSHALING, ETC. Neither the Agent nor the Holders shall be
     required to make any demand upon, or pursue or exhaust any of their rights
     or remedies against, any Obligor or any other guarantor, pledgor or any
     other Person with respect to the payment of the Obligations or to pursue or
     exhaust any of their rights or remedies with respect to any collateral
     therefor or any direct or indirect guarantee thereof. Neither the Agent nor
     the Holders shall be required to marshal the Credit Security or any
     guarantee of the Obligations or to resort to the Credit Security or any
     such guarantee in any particular order, and all of its and their rights
     hereunder or under any other Credit Document shall be cumulative. To the
     extent it may lawfully do so, each Obligor absolutely and irrevocably
     waives and relinquishes the benefit and advantage of, and covenants not to
     assert against the Agent or the Holders, any valuation, stay, appraisement,
     extension, redemption or similar laws now or hereafter existing which, but
     for this provision, might be applicable to the sale of any Credit Security
     made under the judgment, order or decree of any court, or privately under
     the power of sale conferred by this Agreement, or otherwise. Without
     limiting the generality of the foregoing, each Obligor (a) agrees that it
     will not invoke or utilize any law which might prevent, cause a delay in or
     otherwise impede the enforcement of the rights of the Agent or any Holder
     in the Credit Security,

                                      -13-
<Page>

     (b) waives its rights under all such laws, and (c) agrees that it will not
     invoke or raise as a defense to any enforcement by the Agent or any Holder
     of any rights and remedies relating to the Credit Security or the
     Obligations any legal or contractual requirement with which the Agent or
     any Holder may have in good faith failed to comply. In addition, each
     Obligor waives any right to prior notice (except to the extent expressly
     required by this Agreement) or judicial hearing in connection with
     foreclosure on or disposition of any Credit Security, including any such
     right which such Obligor would otherwise have under the Constitution of the
     United States of America, any state or territory thereof or any other
     jurisdiction.

          3.5.4. SALES OF CREDIT SECURITY. All or any part of the Credit
     Security may be sold for cash or other value in any number of lots at
     public or private sale, without demand, advertisement or notice; PROVIDED,
     HOWEVER, that the Agent shall give the Obligor granting the security
     interest in such Credit Security 10 days' prior written notice of the time
     and place of any public sale, or the time after which a private sale may be
     made, which notice each of the Obligors and the Agent agrees to be
     reasonable; and PROVIDED, FURTHER, that any such sale shall otherwise be
     conducted in a commercially reasonable manner. At any sale or sales of
     Credit Security, any Holder or any of its respective officers acting on its
     behalf, or such Holder's assigns, may bid for and purchase all or any part
     of the property and rights so sold, may use all or any portion of the
     Obligations owed to such Holder as payment for the property or rights so
     purchased, and upon compliance with the terms of such sale may hold and
     dispose of such property and rights without further accountability to the
     respective Obligors, except for the proceeds of such sale or sales pursuant
     to Section 3.5.6. The Obligors acknowledge that any such sale will be made
     by the Agent on an "as is" basis with disclaimers of all warranties,
     whether express or implied (including warranties with respect to title,
     possession, quiet enjoyment and other similar warranties). The respective
     Obligors will execute and deliver or cause to be executed and delivered
     such instruments, documents, assignments, waivers, certificates and
     affidavits, will supply or cause to be supplied such further information
     and will take such further action, as the Agent shall reasonably request in
     connection with any such sale.

          3.5.5. SALE WITHOUT REGISTRATION. If, at any time when the Agent shall
     determine to exercise its rights hereunder to sell all or part of the
     securities included in the Credit Security, the securities in question
     shall not be effectively registered under the Securities Act (or other
     applicable law), the Agent may sell such securities by private or other
     sale not requiring such registration in such manner and in such
     circumstances as the Agent may reasonably deem necessary or advisable in
     order that such sale may be effected in accordance with applicable
     securities laws without such registration and the related delays,
     uncertainty and expense. Without limiting the generality of the foregoing,
     in any event the Agent may, in its reasonable discretion, (a) approach and
     negotiate with a single purchaser or one or more possible purchasers to
     effect such sale, (b) restrict such sale to one or more purchasers each of
     whom will represent and agree that such purchaser is purchasing for its own
     account, for investment and not with a view to the distribution or sale of
     such securities and (c) cause to be placed on certificates representing the
     securities in question a legend to the effect that such securities have not
     been registered under the

                                      -14-
<Page>

     Securities Act (or other applicable law) and may not be disposed of in
     violation of the provisions thereof. Each Obligor agrees that such manner
     of disposition is commercially reasonable, that it will upon the Agent's
     request give any such purchaser access to such information regarding the
     issuer of the securities in question as the Agent may reasonably request
     and that the Agent and the Holders shall not incur any responsibility for
     selling all or part of the securities included in the Credit Security at
     any private or other sale not requiring such registration, notwithstanding
     the possibility that a substantially higher price might be realized if the
     sale were deferred until after registration under the Securities Act (or
     other applicable law) or until made in compliance with certain other rules
     or exemptions from the registration provisions under the Securities Act (or
     other applicable law). Each Obligor acknowledges that no adequate remedy at
     law exists for breach by it of this Section 3.5.5 and that such breach
     would not be adequately compensable in damages and therefore agrees that
     this Section 3.5.5 may be specifically enforced.

          3.5.6. APPLICATION OF PROCEEDS. The proceeds of all sales and
     collections in respect of any Credit Security or other assets of any
     Obligor, all funds collected from the Obligors and any cash contained in
     the Credit Security, the application of which is not otherwise specifically
     provided for in the Subordination Agreement (as defined in the Exchange
     Agreement) or herein, shall be applied as follows:

          (a) First, to the payment of the costs and expenses of such sales and
     collections, the reasonable fees and expenses of the Agent then outstanding
     and the reasonable fees and expenses of its special counsel;

          (b) Second, any surplus then remaining to the payment of the
     Obligations in such order and manner as the Agent may in its reasonable
     discretion determine; PROVIDED, HOWEVER, that any such payment shall be
     distributed to the Holders in accordance with the Exchange Agreement and
     the other Credit Documents; and

          (c) Third, any surplus then remaining shall be paid to the Obligors,
     subject, however, to any rights of the holder of any then existing Lien who
     has duly presented to the Agent an authenticated demand for proceeds before
     the Agent's distribution of the proceeds is completed.

     3.6. CUSTODY OF CREDIT SECURITY. Except as provided by applicable law that
cannot be waived, the Agent will have no duty as to the custody and protection
of the Credit Security, the collection of any part thereof or of any income
thereon or the preservation or exercise of any rights pertaining thereto,
including rights against prior parties, except for the use of due care in the
custody and physical preservation of any Credit Security in its possession.
Absent gross negligence or willful misconduct, the Holders will not be liable or
responsible for any loss or damage to any Credit Security, or for any diminution
in the value thereof, by reason of the act or omission of any agent selected by
the Agent acting in good faith.

          3.6.1. In entering into this Agreement, and in performing or observing
     any of the terms of this Agreement, and otherwise in respect of any matter
     arising under or in

                                      -15-
<Page>

     respect of this Agreement, the Agent shall enjoy and shall be protected by
     each of the rights, immunities, indemnities and other protections set forth
     in the Exchange Agreement; and any obligations, duties or liabilities to
     which the Agent may be or become subject under or in respect of this
     Agreement shall be subject to and limited by the terms of the Exchange
     Agreement (including, without limitation, the terms of Section 11 thereof).
     In no event shall the Agent have any liability hereunder that it would not
     have, nor shall the Agent be obligated to take any action hereunder that it
     would not be required to take, under the terms of the Exchange Agreement.

          3.6.2. The Agent is entering into this Agreement pursuant to the terms
     of the Exchange Agreement and the Agent has no responsibility for the terms
     of this Agreement or its sufficiency for any purpose.

4. DEFEASANCE. When all Obligations have been paid, performed and reasonably
determined by the Holders to have been indefeasibly discharged in full, and if
at the time no Holder continues to be committed to extend any credit to the
Borrower under the Exchange Agreement or any other Credit Document, this
Agreement shall terminate and, at the Borrower's written request, the Credit
Security shall immediately revert to the Borrower and the right, title and
interest of the Holders therein shall terminate. Thereupon, on the Borrower's
demand and at its cost and expense, the Agent shall execute proper instruments,
acknowledging satisfaction of and discharging this Agreement, and shall
immediately deliver to the Borrower any Credit Security then in its possession.

5. SUCCESSORS AND ASSIGNS. The provisions of this Agreement shall inure to the
benefit of the Holders and their successors and assigns and shall be binding
upon the Borrower and its respective successors and assigns. The Borrower may
not assign its rights or obligations under this Agreement without the written
consent of the Agent.

6. NOTICES. Except as otherwise expressly provided herein, all notices,
requests, consents, and other communications under this Agreement shall be in
writing and shall be deemed delivered (a) two business days after being sent by
registered or certified mail, return receipt requested, postage prepaid or (b)
one business day after being sent via a reputable nationwide overnight courier
service guaranteeing next business day delivery, in each case to the intended
recipient as set forth below:

     If to the Borrower or an other Obligor, at 20 Second Avenue, Burlington, MA
01803, Attention: Chief Financial Officer, or at such other address or addresses
as may have been furnished in writing by the Borrower to the Holders, with a
copy to Hans Brigham, Bingham McCutchen LLP, 1900 University Avenue, East Palo
Alto, CA 94303-2223; and

     If to the Agent, to it at its address specified in or pursuant to section
13.2 of the Exchange Agreement.

     Any party may give any notice, request, consent or other communication
under this Agreement using any other means (including personal delivery,
messenger service, facsimile, first class mail or electronic mail), but no such
notice, request, consent or other communication

                                      -16-
<Page>

shall be deemed to have been duly given unless and until it is actually received
by the party for whom it is intended. Any party may change the address to which
notices, requests, consents or other communications hereunder are to be
delivered by giving the other parties notice in the manner set forth in this
Section 6.

7. REIMBURSEMENT OF EXPENSES. The Borrower shall promptly pay on demand all
reasonable expenses of the Agent and the Holders (including reasonable attorney
fees and expenses) in connection with the preparation of this Agreement,
operations hereunder and enforcement and collection hereof, whether before or
after bankruptcy or similar proceedings (and whether or not allowed as a claim
therein).

8. VENUE; SERVICE OF PROCESS. Each of the Borrower, the Guarantor and the Agent:

          (a) Irrevocably submits to the nonexclusive jurisdiction of the state
     courts of the Commonwealth of Massachusetts and to the nonexclusive
     jurisdiction of the United States District Court for the District of
     Massachusetts for the purpose of any suit, action or other proceeding
     arising out of or based upon this Agreement or any other Credit Document or
     the subject matter hereof or thereof;

          (b) Waives to the extent not prohibited by applicable law, and agrees
     not to assert, by way of motion, as a defense or otherwise, in any such
     proceeding brought in any of the above-named courts, any claim that it is
     not subject personally to the jurisdiction of such court, that its property
     is exempt or immune from attachment or execution, that such proceeding is
     brought in an inconvenient forum, that the venue of any such proceeding is
     improper, or that this Agreement or any other Credit Document, or the
     subject matter hereof or thereof, may not be enforced in or by such court;

          (c) Irrevocably consents to the service of process out of any of the
     aforementioned courts in any such action or proceeding by the mailing of
     copies thereof by registered or certified mail, postage prepaid, to each
     Obligor at its address for notices pursuant to Section 6, such service to
     become effective 15 days after such mailing. Nothing herein shall affect
     the right of any Holder to serve process in any other manner permitted by
     law or to commence legal proceedings or otherwise proceed against any
     Obligor in any other jurisdiction; and

          (d) Waives to the extent not prohibited by applicable law that cannot
     be waived any right it may have to claim or recover in any such proceeding
     any special, exemplary, punitive or consequential damages.

9. WAIVER OF JURY TRIAL. TO THE EXTENT NOT PROHIBITED BY APPLICABLE LAW THAT
CANNOT BE WAIVED, EACH OF THE PARTIES HERETO WAIVES, AND COVENANTS THAT IT WILL
NOT ASSERT (WHETHER AS PLAINTIFF, DEFENDANT OR OTHERWISE), ANY RIGHT TO TRIAL BY
JURY IN ANY FORUM IN RESPECT OF ANY ISSUE, CLAIM OR PROCEEDING ARISING OUT OF
THIS AGREEMENT OR ANY OTHER DOCUMENT OR THE SUBJECT MATTER HEREOF OR THEREOF OR
ANY OBLIGATION OR IN ANY WAY CONNECTED WITH THE DEALINGS OF THE

                                      -17-
<Page>

HOLDERS OR THE COLLATERAL AGENT, THE BORROWER OR ANY OTHER OBLIGOR IN CONNECTION
WITH ANY OF THE ABOVE, IN EACH CASE WHETHER NOW EXISTING OR HEREAFTER ARISING
AND WHETHER IN CONTRACT, TORT OR OTHERWISE. Each of the parties hereto
acknowledges that the foregoing waiver constitutes a material inducement upon
which each of the parties has relied and will rely in entering into this
Agreement and any other Credit Document. Any party hereto may file an original
counterpart or a copy of this Agreement with any court as written evidence of
the consent of each of the parties hereto to the waiver of their rights to trial
by jury.

10. GENERAL. All covenants, agreements, representations and warranties made in
this Agreement or any other Credit Document or in certificates delivered
pursuant hereto or thereto shall be deemed to have been relied on by each
Symphony Fund, notwithstanding any investigation made by the Agent on its
behalf, and shall survive the execution and delivery to the Symphony Funds and
the Holders hereof and thereof. The invalidity or unenforceability of any
provision hereof shall not affect the validity or enforceability of any other
provision hereof, and any invalid or unenforceable provision shall be modified
so as to be enforced to the maximum extent of its validity or enforceability.
The headings in this Agreement are for convenience of reference only and shall
not limit, alter or otherwise affect the meaning hereof. This Agreement and the
other Credit Documents constitute the entire understanding of the parties with
respect to the subject matter hereof and thereof and supersede all prior and
current understandings and agreements, whether written or oral. This Agreement
is a Credit Document and may be executed in any number of counterparts, which
together shall constitute one instrument. This Agreement shall be governed by
and construed in accordance with the laws (other than the conflict of laws
rules) of the Commonwealth of Massachusetts, except as may be required by the
UCC of other jurisdictions with respect to matters involving the perfection of
the Agent's Lien on the Credit Security located in such other jurisdictions.
Each beneficial holder of the Obligations shall be entitled to the benefits of a
Holder under this Agreement.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

                                      -18-
<Page>

     Each of the undersigned has caused this Agreement to be executed and
delivered by its duly authorized officer as an agreement under seal as of the
date first written above.

                                    iBASIS, INC.


                                    By /s/ Ofer Gneezy
                                       -----------------------------------------
                                       Title: President and CEO


                                    iBASIS GLOBAL, INC.


                                    By /s/ Richard G. Tennant
                                       -----------------------------------------
                                       Title: Treasurer and CFO


                                    iBASIS SECURITES CORPORATION


                                    By /s/ Gordon VanderBrug
                                       -----------------------------------------
                                       Title: Executive Vice President


                                    U.S. BANK NATIONAL ASSOCIATION,
                                     as Agent


                                    By /s/ John A. Brennan
                                       -----------------------------------------
                                       Title: Trust Officer

                                      -19-