Document:

EXHIBIT 10.22
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                             REIMBURSEMENT AGREEMENT

         This REIMBURSEMENT AGREEMENT, dated as of December 27, 2002 (this
"Agreement"), is entered into by and between DSL.NET, INC., a Delaware
corporation ("Obligor"), the guarantors identified on the signature pages hereof
(collectively, the "Guarantors" and each a "Guarantor") and VANTAGEPOINT VENTURE
PARTNERS III (Q), L.P., a Delaware limited partnership as the administrative
agent for the Guarantors ("Agent").

                                    RECITALS
                                    --------

         A.   Obligor has requested that the Guarantors cause to be issued, and
              subject to the terms and condition of this Agreement, the
              Guarantors have agreed to be issued, Guaranties (collectively, as
              amended and in effect from time to time, the "Guaranties" and each
              a "Guaranty") in an aggregate amount up to Six Million Seven
              Hundred Thirty Thousand Dollars ($6,730,000) to support certain
              obligations of Obligor, under a Revolving Credit and Term Loan
              Agreement, dated as of December 13, 2002 (as amended and in effect
              from time to time, the "Credit Agreement"), between Obligor and
              Fleet National Bank ("Bank").

         B.   In order to induce Guarantors to issue the Guaranties, Obligor has
              agreed to enter into this Agreement.

         C.   The obligations under this Agreement are secured by a Security
              Agreement, dated the date hereof, executed by Obligor and certain
              of its Subsidiaries in favor of Agent for itself and the benefit
              of the Guarantors (as amended and in effect from time to time, the
              "Security Agreement"). The obligations under this Agreement have
              been guarantied by certain of the Subsidiaries of Obligor (each a
              "Subsidiary Guarantor") pursuant to a Subsidiary Guaranty, dated
              as of the date hereof (as amended and in effect from time to time,
              the "Subsidiary Guaranty")

         D.   Capitalized terms used and not otherwise defined in this Agreement
              shall have the respective meanings set forth in Section 6 hereof.

                                    AGREEMENT
                                    ---------

         NOW, THEREFORE, in consideration of the above recitals and for other
good and valuable consideration, the receipt and adequacy of which are hereby
acknowledged, Obligor hereby agrees with Guarantors and Agent as follows:

         1.   REIMBURSEMENT. (a) If Guarantors shall at any time or from time to
time be required to make any payment (i) under the Guaranties for any Drawn
Amounts, or (ii) in payment of a Guaranty Expense Amount, then Agent, at the
direction of Required Guarantors (provided, that if the Columbia Entities desire
to take an enforcement action that Required Guarantors have not consented to,
the Agent shall take such enforcement action as the Columbia Entities direct the
Agent to take, provided further, that Agent shall not take such enforcement
action until the earlier of (A) the 120th day after receipt by Agent of written
notice of such enforcement action from the Columbia Entities or (B) such time as
the Required Guarantors have provided their consent to such enforcement
actions), may give Obligor written notice of any such payments and Obligor shall
reimburse Agent within two (2) business days of receipt of such written notice
an amount equal to such Drawn Amounts and/or Guaranty Expense Amount, as
applicable.
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         (b)  Obligor's Obligations hereunder are absolute, unconditional and
irrevocable and shall not be reduced by any set-off or any event or occurrence
including any action or inaction by Agent or Guarantors or any other party or by
any unenforceability of the Credit Agreement. Any Obligations not paid when due
shall bear interest a rate per annum of 10%.

         (c)  All payments by Obligor shall be made to Agent for the account of
all of the Guarantors and shall be made in immediately available funds, no later
than 1:00 p.m. (California time) on the date specified herein. Any payment
received by Agent later than 1:00 p.m. (California time), shall be deemed to
have been received on the following business day and any applicable interest
shall continue to accrue until such following business day.

         (d)  Except as otherwise provided in this Agreement, aggregate payments
made pursuant to this Section 1 shall be apportioned ratably among the
Guarantors and payments of Guaranty Expense Amounts (other than fees or expenses
that are for Agent's separate account) shall be apportioned ratably among the
Guarantors. All payments shall be remitted to Agent and all such payments and
all proceeds of Collateral received by Agent, shall be applied as follows:

                  (i) first, to pay any Guaranty Expense Amounts then due to
         Agent under the Operative Documents, until paid in full;

                  (ii) second, to pay any Guaranty Expense Amount then due to
         the Guarantors under the Operative Documents, on a ratable basis, until
         paid in full;

                  (iii) third, to pay any interest due in respect of Drawn
         Amounts to the Guarantors under this Agreement, on a ratable basis,
         until paid in full; and

                  (iv) fourth, to pay any Drawn Amounts then due to the
         Guarantors under this Agreement, on a ratable basis, until paid in
         full.

         Except as otherwise provided in this Agreement, rights, interests and
obligations of each Guarantor under this Agreement and related Operative
Documents, including security interests in the Collateral under the Security
Agreement, shall be shared by each Guarantor in the ratio of (a) the aggregate
Drawn Amount paid by such Guarantor to Bank pursuant to such Guarantor's
Guaranty to (b) the aggregate Drawn Amounts paid by all Guarantors to Bank
pursuant to such Guarantors' Guaranties; and if no Drawn Amounts have been paid
to Bank, then the ratio of (y) a Guarantor's Guaranty Commitment to (z) the
aggregate Guaranty Commitments of all Guarantors. Any reference in this
Agreement to an allocation between or sharing by Guarantors of any right,
interest or obligation "ratably," "proportionally" or in similar terms shall
refer to this ratio.

         2.   REPRESENTATIONS AND WARRANTIES OF OBLIGOR. Obligor represents and
warrants to Agent and Guarantors that:

              (a) DUE INCORPORATION, QUALIFICATION, ETC. Obligor (i) is a
corporation duly organized, validly existing and in good standing under the laws
of its state of incorporation; (ii) has the corporate power and authority to
own, lease and operate its properties and carry on its business as now
conducted; and (iii) is duly qualified, licensed to do business and in good
standing as a foreign corporation in each jurisdiction where the failure to be
so qualified or licensed could reasonably be expected to have a material adverse
effect on the business, financial condition or results of operations of Obligor.

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              (b) AUTHORITY. The execution, delivery and performance by Obligor
of this Agreement and the other Operative Documents to which it is a party and
the consummation of the transactions contemplated hereby (i) are within the
corporate power and authority of Obligor and (ii) have been duly authorized by
all necessary corporate actions on the part of Obligor.

              (c) ENFORCEABILITY. This Agreement and the other Operative
Documents to which Obligor is a party has been duly executed and delivered by
Obligor and constitutes, or will constitute, a legal, valid and binding
obligation of Obligor, enforceable against Obligor in accordance with its terms,
except as limited by bankruptcy, insolvency or other laws of general application
relating to or affecting the enforcement of creditors' rights generally and
general principles of equity.

              (d) NON-CONTRAVENTION. The execution and delivery by Obligor of
this Agreement and the other Operative Documents and the performance and
consummation of the transactions contemplated hereby do not and will not (i)
violate the articles or certificate of incorporation or bylaws of Obligor or any
material judgment, order, writ, decree, statute, rule or regulation applicable
to Obligor; (ii) violate any provision of, or result in the breach or the
acceleration of, or entitle any other person to accelerate (whether after the
giving of notice or lapse of time or both), any material mortgage, indenture,
agreement, instrument or contract to which Obligor is a party or by which it is
bound; or (iii) result in the creation or imposition of any lien upon any
property, asset or revenue of Obligor (other than those in favor of Agent) or
the suspension, revocation, impairment, forfeiture, or nonrenewal of any
material permit, license, authorization or approval applicable to Obligor, its
business or operations, or any of its assets or properties.

              (e) APPROVALS. Other than those already obtained, no consent,
approval, order or authorization of, or registration, declaration or filing
with, any governmental authority or other person (including, without limitation,
the shareholders of Obligor) is required in connection with the execution and
delivery of this Agreement and the other Operative Documents and the performance
and consummation of the transactions contemplated hereby and thereby.

         3.   DELIVERIES. Simultaneously with the execution and delivery of this
Agreement, the following shall occur:

              (a) Obligor and each Subsidiary Guarantor shall have executed and
delivered to Agent the Security Agreement in the form attached hereto as Exhibit
A;

              (b) Each Subsidiary Guarantor shall have executed and delivered to
Agent the Subsidiary Guaranty in the form attached hereto as Exhibit B;

              (c) Obligor shall have delivered to each Guarantor or their
designee (other than the Additonal Guarantors) a warrant in the form attached
hereto as Exhibit C (collectively, the "Warrants") to purchase that number of
shares of Obligor's common stock as set forth on Schedule 3;

              (d) Obligor and each Subsidiary Guarantor shall have executed and
delivered each financing statement, instrument, agreement and other document as
Agent shall have reasonably requested to perfect its security interest and the
priority thereof;

              (e) Obligor shall have delivered to Agent an opinion of its
counsel in form and substance reasonably satisfactory to Agent;

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<PAGE>
              (f) Obligor shall have delivered to Agent an amendment to
Obligor's Stockholders Agreement, dated as of December 24, 2001, duly executed
by the requisite number of investors party thereto, pursuant to which each
Guarantor or their representative designee receiving a warrant from Obligor in
connection with the transactions described herein shall receive the same
registration rights granted to other investors party to such registration rights
agreement with respect to the shares of common stock issuable upon exercise or
conversion of the warrant referenced in subsection (c) of this Section 3; and

              (g) Except for the Additional Guarantors, each Guarantor, or an
affiliate or designee of such Guarantor, shall have executed and delivered to
Lender a Guaranty in the maximum principal amount set forth opposite such
Guarantor's name on Schedule 2 hereto.

         To the extent any of the foregoing shall not have occurred upon the
execution and delivery of this Agreement, Obligor agrees (as a covenant and not
merely as a condition) to promptly accomplish the same.

         4.   COVENANTS OF OBLIGOR.

              (a) Obligor agrees:

                  (i) To timely perform all of its obligations to Bank under the
Credit Agreement;

                  (ii) To give Agent prompt notice of any default in the
observance of each Obligor's obligations under the Credit Agreement and to use
its commercially reasonable best efforts to cure any such default within the
time periods permitted;

                  (iii) Unless the Required Guarantors provides their prior
written consent, not to make any initial borrowing or otherwise utilize credit
under the Credit Agreement until such time as the unrestricted cash (determined
in accordance with GAAP and excluding Excluded Cash) shown on Obligor's balance
sheet is less than $2,000,000;

                  (iv) Not to amend or otherwise modify the Credit Agreement
without the prior written consent of Agent, and not to enter into any loan or
credit agreement or other credit arrangements with Bank, or any other lender,
outside the Operative Documents;

                  (v) To immediately notify Agent if the unrestricted cash
(determined in accordance with GAAP and excluding Excluded Cash) shown on
Obligor's balance sheet equals or exceeds $11,000,000;

                  (vi) If the unrestricted cash (determined in accordance with
GAAP and excluding Excluded Cash) shown on Obligor's balance sheet equals or
exceeds $11,000,000, then Obligor shall do either of the following at Agent's
request:

                        (1) repay outstanding loans under the Credit Agreement
in increments of $1,000,000 for each such increment in excess of $10,000,000
(excluding any Excluded Cash) (provided that if there is less than $1,000,000 of
outstanding loans due under the Credit Agreement, then Obligor shall repay such
lesser amount to the extent that Obligor retains unrestricted cash balances in
an amount equal to $10,000,000 (excluding any Excluded Cash) after giving effect
to such repayment), and if requested by Agent, permanently reduce the
outstanding commitment under the Credit Agreement in an amount equal to such
repayment amount; or
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                        (2) cause each Guarantor's guarantee requirement under
the Credit Agreement to be eliminated ratably in an aggregate amount equal to
the amount of outstanding loans that would otherwise be required to be repaid
pursuant to Section 4(a)(vi)(1) hereof.

                  (vii) Obligor will cause each of its Subsidiaries (other than
a Regulated Subsidiary and DSLnet Communications Delaware, Inc.) hereafter
formed or acquired, to execute and deliver to Agent a Subsidiary Joinder in the
form of Attachment 1 to the Guaranty, to cause such Subsidiary to become a
Subsidiary Guarantor under the Subsidiary Guaranty and a Grantor under the
Security Agreement. Obligor and such Subsidiary shall fully cooperate with Agent
and perform all additional acts requested by Agent to effect the purposes of
this Section 4(a)(vii), including without limitation, execution and delivery of
agreements, instruments, UCC financing statements, documents, and certificates
all in form and substance satisfactory to Agent.

              (b) Obligor agrees, at all times after Obligor has received notice
of a demand by Bank for payment under the Guaranty and until such demand has
been rescinded by Bank, that without the prior written consent of Agent:

                  (i) INDEBTEDNESS. Neither Obligor nor any of its Subsidiaries
shall create, incur, assume or permit to exist any Indebtedness except Permitted
Indebtedness.

                  (ii) LIENS. Neither Obligor nor any of its Subsidiaries shall
create, incur, assume or permit to exist any Lien on or with respect to any of
its assets or property of any character, whether now owned or hereafter
acquired, except for Permitted Liens.

                  (iii) ASSET DISPOSITIONS. Neither Obligor nor any of its
Subsidiaries shall sell, lease, transfer, license or otherwise dispose of
(collectively, a "Transfer") any of its assets or property, whether now owned or
hereafter acquired, except (i) Transfers in the ordinary course of its business
(A) consisting of the sale of inventory, (B) consisting of sales of excess,
worn-out or obsolete equipment, and (C) consisting of cash payments in a manner
that is not prohibited by the terms of this Agreement or the other Operative
Documents; and (ii) Transfers by Obligor to any Subsidiary which is a Subsidiary
Guarantor and Transfers by any Subsidiary to Obligor or another Subsidiary which
is a Subsidiary Guarantor.

                  (iv) MERGERS, ACQUISITIONS, ETC. Neither Obligor nor any of
its Subsidiaries shall consolidate with or merge into any other Person or permit
any other Person to merge into it, or acquire all or substantially all of the
assets or capital stock of any other Person, except that any Subsidiary may
merge with and into Obligor or another Subsidiary which is a Subsidiary
Guarantor.

                  (v) INVESTMENTS. Neither Obligor nor any of its Subsidiaries
shall make any Investment except for Permitted Investments. Neither Obligor nor
any of its Subsidiaries shall create, acquire or permit to exist any Subsidiary
which is not a Subsidiary Guarantor other than a Regulated Subsidiary or DSLnet
Communications Delaware, Inc. Notwithstanding the foregoing, neither Obligor nor
any of its Subsidiaries shall make any Investment in a Regulated Subsidiary to
the extent that such Investment exceeds amounts necessary for such Regulated
Subsidiary to make payments to its vendors, public utility commissions or the
Federal Communications Commission and any other governmental authorities in the
ordinary course of business.

                  (vi) DIVIDENDS, REDEMPTIONS, ETC. Neither Obligor nor any of
its Subsidiaries shall (i) pay any dividends or make any distributions on its
equity securities; (ii) purchase, redeem, retire, defease or otherwise acquire
for value any of its equity securities, other than equity securities in an
aggregate amount not to exceed $250,000 purchased from terminated employees,

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consultants or directors pursuant to employee stock purchase plans, employee
restricted stock agreements or similar agreements; (iii) return any capital to
any holder of its equity securities; (iv) make any distribution of assets,
Equity Securities, obligations or securities to any holder of its Equity
Securities; or (v) set apart any sum for any such purpose; provided, however,
that any Subsidiary may pay cash dividends to Obligor or any Subsidiary which is
a Subsidiary Guarantor.

                  (vii) INDEBTEDNESS PAYMENTS. Neither Obligor nor any of its
Subsidiaries shall (i) prepay, redeem, purchase, defease or otherwise satisfy in
any manner prior to the scheduled repayment thereof any Indebtedness for
borrowed money (other than amounts due under the Credit Agreement or this
Agreement) or lease obligations, (ii) amend, modify or otherwise change the
terms of any Indebtedness (other than the Obligations) or lease obligations so
as to accelerate the scheduled repayment thereof or (iii) repay any notes to
officers, directors or shareholders.

                  (viii) AFFILIATE TRANSACTIONS. Except for this Agreement and
the other Operative Documents, neither Obligor nor any of its Subsidiaries shall
enter into any contractual obligation with any Affiliate or engage in any other
transaction with any Affiliate (other than transactions pursuant to existing
agreements between Obligor and holders of its Preferred Stock and transactions
which are not material in amount) except upon terms at least as favorable to
Obligor or such Subsidiary as an arms-length transaction with unaffiliated
Persons.

                  (ix) NOTICE OF DEFAULTS. Promptly upon the occurrence thereof,
provide written notice to Agent of the occurrence of any Event of Default
hereunder.

              (c) Notwithstanding anything contained in this Agreement or any of
the Operative Documents within ninety (90) days of the date of this Agreement,
Obligor shall cause the dissolution of DSLnet Communications Delaware, Inc.,
provided that the assets or properties, or proceeds of such assets or properties
of such Subsidiary are transferred to Obligor.

              (d) If The Lafayette Investment Fund, L.P., Charles River
Partnership X, Charles River Partnership X-A, Charles River Friends X-B, LLC, or
Charles River Friends X-C, LLC (collectively, the "Additional Guarantors" and
each an "Additional Guarantor") enter into a Guaranty on or before January 31,
2003, with Bank to guaranty Obligor's obligations under the Credit Agreement,
then each Additional Guarantor, on the date of execution of its Guaranty, shall
be issued a warrant to purchase Obligor's common stock in the form attached
hereto as Exhibit C. Each Additional Guarantor that is entitled to receive a
warrant pursuant to this provision, shall receive the right to purchase that
number of shares equal to its ratable share of Ten Million (10,000,000) shares
of Obligor's common stock as set forth on Schedule 3 hereto. To the extent that
any Excess Warrant Shares have not been issued as of January 31, 2003, then no
later than February 4, 2003, the Obligor shall issue an additional warrant to
each Guarantor (other than the Additional Guarantors that have not entered into
a Guaranty pursuant to this Section 4(d)) in the form of Exhibit C to purchase
such Guarantor's ratable share of the Excess Warrant Shares. The term "Excess
Warrant Shares" shall mean Ten Million (10,000,000) shares minus the aggregate
number of shares of common stock issuable upon exercise or conversion of all
Warrants issued in connection with this Agreement, including any warrants issued
pursuant to this Section 4(d). Each of the Additional Guarantors agree to use
their best efforts to enter into a Guaranty on or before January 31, 2003, in
the maximum principal amount set forth opposite such Additional Guarantor's name
on Schedule 2 hereto.

         5.   DEFAULT AND REMEDIES. Obligor shall be deemed in default under
this Agreement upon the occurrence and during the continuance of any of the
following events (each, an "Event of Default"):

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              (a) Obligor shall default with respect to any payment obligation
hereunder and such default shall continue uncured for a period of five (5)
business days; or

              (b) Any representation or warranty made by Obligor in this
Agreement or in the Credit Agreement, or as an inducement to any of the
Guarantors to cause such Guarantor's Guaranty to be issued, shall be false,
incorrect, incomplete or misleading in any material respect when made or
furnished; or

              (c) Obligor or any of its Subsidiaries shall fail to observe or
perform any other covenant, obligation, condition or agreement contained in this
Agreement or the other Operative Documents (other than those specified in
Sections 5(a)) and (i) such failure shall continue for fifteen (15) days, or
(ii) if such failure is not curable within such fifteen (15) day period, but is
reasonably capable of cure within thirty (30) days, either (A) such failure
shall continue for thirty (30) days or (B) Obligor or any such Subsidiary shall
not have commenced a cure in a manner reasonably satisfactory to Agent within
the initial fifteen (15) day period; or

              (d) Obligor or any of its Subsidiaries shall default in the
observance or performance of any other agreement, term or condition contained in
any bond, debenture, note or other evidence of Indebtedness, and the effect of
such failure or default is to cause, or permit the holder or holders of such
Indebtedness thereof to cause, Indebtedness in an aggregate amount for all such
collective defaults of One Million Dollars ($1,000,000) or more to become due
prior to its stated date of maturity; or

              (e) Obligor shall (i) apply for or consent to the appointment of a
receiver, trustee, liquidator or custodian of itself or of all or a substantial
part of its property, (ii) be unable, or admit in writing its inability, to pay
its debts generally as they mature, (iii) make a general assignment for the
benefit of its or any of its creditors, (iv) be dissolved or liquidated, (v)
become insolvent (as such term may be defined or interpreted under any
applicable statute), (vi) commence a voluntary case or other proceeding seeking
liquidation, reorganization or other relief with respect to itself or its debts
under any bankruptcy, insolvency or other similar law now or hereafter in effect
or consent to any such relief or to the appointment of or taking possession of
its property by any official in an involuntary case or other proceeding
commenced against it, or (vii) take any action for the purpose of effecting any
of the foregoing; or

              (f) Proceedings for the appointment of a receiver, trustee,
liquidator or custodian of any Obligor or of all or a substantial part of its
property, or an involuntary case or other proceedings seeking liquidation,
reorganization or other relief with respect to any Obligor or its debts under
any bankruptcy, insolvency or other similar law now or hereafter in effect shall
be commenced and an order for relief entered or such proceeding shall not be
dismissed or discharged within sixty (60) days of commencement.

              (g) A final judgment or order for the payment of money in excess
of One Hundred Dollars ($100,000) shall be rendered against Obligor or any of
its Subsidiaries and the same shall remain undischarged for a period of ten (10)
days after it is due during which execution shall not be effectively stayed, or
any judgment, writ, assessment, warrant of attachment, or execution or similar
process shall be issued or levied against a substantial part of the property of
Obligor or any of its Subsidiaries and such judgment, writ, or similar process
shall not be released, stayed, vacated or otherwise dismissed within fifteen
(15) days after issue or levy.

         Upon the occurrence and during the continuance of any such Event of
Default, Agent shall have all of the rights set forth under this Agreement, the
other Operative Documents and under applicable law. Upon the occurrence and
during the continuance of any Event of Default under this Agreement at which
time no demand has been made under the Guaranties, Agent shall have the right,
at the direction of the Required Guarantors (provided, that if the Columbia
Entities desire to take an enforcement action that Required Guarantors have not
consented to, the Agent shall take such enforcement action as the Columbia

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Entities direct the Agent to take, provided further, that Agent shall not take
such enforcement action until the earlier of (A) the 120th day after receipt by
Agent of written notice of such enforcement action from the Columbia Entities or
(B) such time as the Required Guarantors have provided their consent to such
enforcement actions), by written notice to Obligor, to require Obligor to post
cash collateral in an amount equal to the maximum amount which may be demanded
under the Guaranty, in which case Obligor shall execute all such documentation
as Agent may reasonably request to perfect Agent's security interest in such
cash collateral.

         6.   DEFINITIONS. As used in this Agreement, the following capitalized
terms have the following meanings

              (a) "Additional Guarantors" has the meaning given in Section 4(d)
hereof.

              (b) "Affiliate," with respect to any Person, means (i) any
director or officer of such Person, (ii) any Person directly or indirectly
controlling or controlled by or under direct or indirect common control with
such Person, and (iii) any Person beneficially owning or holding 5% or more of
any class of voting securities of such Person or any corporation of which such
Person beneficially owns or holds, in the aggregate, 5% or more of any class of
voting securities The term "control" means the possession, directly or
indirectly, of the power to direct or cause the direction of the management and
policies of a Person, whether through the ownership of voting securities, by
contract or otherwise. The term "Affiliate," when used herein without reference
to any Person, shall mean an Affiliate of Obligor.

              (c) "Claim" has the meaning given to such term in the Security
Agreement.

              (d) "Collateral" has the meaning given to such term in the
Security Agreement.

              (e) "Columbia Entities" means Columbia Capital Equity Partners II
(QP), LP, Columbia Capital Equity Partners II (Cayman), LP, Columbia Capital
Equity Partners II LP, Columbia Capital Investors, LLC, Columbia Capital Equity
Partners III (QP), LP, Columbia Capital Equity Partners III (Cayman), LP,
Columbia Capital Equity Partners III (AI), LP and Columbia Capital Investors
III, LLC.

              (f) "Drawn Amount" means any amount required to be paid by a
Guarantor under such Guarantor's Guaranty upon a request for payment by Bank.

              (g) "Equity Securities" of any Person shall mean (a) all common
stock, preferred stock, participations, shares, partnership interests or other
equity interests in and of such Person (regardless of how designated and whether
or not voting or non-voting) and (b) all warrants, options and other rights to
acquire any of the foregoing.

              (h) "Event of Default" has the meaning given in Section 5 hereof.

              (i) "Excess Warrant Shares" has the meaning given in Section 4(d)
hereof.

              (j) "Excluded Cash" means the aggregate amount of cash proceeds of
any issuance of Obligor's securities since the date of this Agreement minus the
aggregate amount of all cash used since the date of this Agreement to fund any
mergers or acquisitions, or to acquire any assets or securities of any other
Person (other than (i) pursuant to agreements existing as of the date of this
Agreement or (ii) in the ordinary course of business), provided that Excluded
Cash shall never be less than zero.

              (k) "GAAP" shall mean generally accepted accounting principles as
in effect in the United States of America from time to time.

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              (l) "Guaranty Commitment" means with respect to each Guarantor,
the amount set forth on Schedule 2 hereto as the maximum principal amount of
such Guarantor's Guaranty.

              (m) "Guaranty Expense Amount" means any costs or expenses (other
than Drawn Amounts) payable by Agent or Guarantors or their affiliates in
connection with the Guaranties whether under the Credit Agreement or otherwise,
including without limitation, fees for the issuance or enforcement or collection
of the Guaranties, and reasonable attorneys fees and costs (including the fees
of attorneys employed by Guarantors), incurred by Agent or Guarantors in
connection with the demand related to a payment under any of the Guaranties or
in connection with the enforcement, collection of, or attempted collection or
enforcement of any of the obligations of Obligor which are not performed as and
when required by this Agreement.

              (n) "Indebtedness" shall mean and include the aggregate amount of,
without duplication (i) all obligations for borrowed money, (ii) all obligations
evidenced by bonds, debentures, notes or other similar instruments, (iii) all
obligations to pay the deferred purchase price of property or services (other
than accounts payable and accrued expenses incurred in the ordinary course of
business determined in accordance with GAAP), (iv) all obligations with respect
to capital leases, (v) all obligations created or arising under any conditional
sale or other title retention agreement with respect to property acquired by
such Person, (vi) all reimbursement and other payment obligations, contingent or
otherwise, in respect of letters of credit and similar surety instruments; and
(vii) all guaranty obligations with respect to the types of Indebtedness listed
in clauses (i) through (vi) above.

              (o) "Investment" of any Person shall mean any loan or advance of
funds by such Person to any other Person (other than advances to employees of
such Person for moving and travel expense, drawing accounts and similar
expenditures in the ordinary course of business), any purchase or other
acquisition of any Equity Securities or Indebtedness of any other Person, any
capital contribution by such Person to or any other investment by such Person in
any other Person (including, without limitation, any Indebtedness incurred by
such Person of the type described in clauses (i) and (ii) of the definition of
"Indebtedness" on behalf of any other Person); provided, however, that
Investments shall not include accounts receivable or other indebtedness owed by
customers of such Person which are current assets and arose from sales or
non-exclusive licensing in the ordinary course of such Person's business.

              (p) "Lien" shall mean, with respect to any property, any security
interest, mortgage, pledge, lien, claim, charge or other encumbrance in, of, or
on such property or the income therefrom, including, without limitation, the
interest of a vendor or lessor under a conditional sale agreement, capital lease
or other title retention agreement, or any agreement to provide any of the
foregoing, and the filing of any financing statement or similar instrument under
the Uniform Commercial Code or comparable law of any jurisdiction.

              (q) "Material Adverse Effect" shall mean a material adverse effect
on (a) the business, assets, operations, prospects or financial or other
condition of Obligor; (b) the ability of Obligor to pay or perform the
Obligations in accordance with the terms of this Agreement and the other
Operative Documents and to avoid an Event of Default, or an event which, with
the giving of notice or the passage of time or both, would constitute an Event
of Default, under any Operative Document; or (c) the rights and remedies of
Agent and the Guarantors under this Agreement, the other Operative Documents or
any related document, instrument or agreement.

              (r) "Obligations" shall mean and include all loans, advances,
debts, liabilities and obligations, arising in connection with this
Reimbursement Agreement or the other Operative Documents and the issuance of,
maintenance of or payment by Guarantors under their respective Guaranties, owed
by Obligor to Guarantors of every kind and description (whether or not evidenced
by any note or instrument and whether or not for the payment of money), now
existing or hereafter arising, including, all interest, fees, charges, expenses,

                                       -9-
<PAGE>
attorneys' fees and costs and accountants' fees and costs chargeable to and
payable by each Obligor hereunder, in each case, whether direct or indirect,
absolute or contingent, due or to become due, and whether or not arising after
the commencement of a proceeding under Title 11 of the United States Code (11
U.S.C. Section 101 et seq.), as amended from time to time (including
post-petition interest) and whether or not allowed or allowable as a claim in
any such proceeding.

              (s) "Operative Documents" shall mean this Agreement, the Security
Agreement, the Subsidiary Guaranty and all other agreements or documents
executed in connection therewith.

              (t) "Permitted Indebtedness" shall mean (a) Indebtedness of
Obligor or any of its Subsidiaries (i) in favor of Bank arising under the Credit
Agreement and (ii) in favor of Agent and Guarantors arising under this Agreement
or any other Operative Document; (b) Indebtedness existing on the date hereof
and disclosed on Schedule 1 hereto; and (c) Indebtedness secured by a Lien that
is otherwise permitted pursuant to subsections (vi), (vii) or (viii) of the
definition of "Permitted Lien."

              (u) "Permitted Investments" shall mean and include: (a) Deposits
accounts with commercial banks organized under the laws of the United States or
a state thereof to the extent Agent has a perfected security interest therein
and such deposits are fully insured by the Federal Deposit Insurance
Corporation; (b) Investments in marketable obligations issued or fully
guaranteed by the United States and maturing not more than one (1) year from the
date of issuance; (c) Investments in open market commercial paper rated at least
"Al " or "PI " or higher by a national credit rating agency and maturing not
more than 270 days from the creation thereof; (d) Investments pursuant to or
arising under currency agreements or interest rate agreements entered into in
connection with bona fide hedging arrangements.

              (v) "Permitted Liens" shall mean and include: (i) Liens for taxes
or other governmental charges not at the time delinquent or thereafter payable
without penalty or being contested in good faith, provided provision is made to
the reasonable satisfaction of Agent for the eventual payment thereof if
subsequently found payable; (ii) Liens of carriers, warehousemen, mechanics,
materialmen, vendors, and landlords incurred in the ordinary course of business
for sums not overdue or being contested in good faith, provided provision is
made to the reasonable satisfaction of Agent for the eventual payment thereof if
subsequently found payable; (iii) deposits under workers' compensation,
unemployment insurance and social security laws or to secure the performance of
bids, tenders, contracts (other than for the repayment of borrowed money) or
leases, or to secure statutory obligations of surety or appeal bonds or to
secure indemnity, performance or other similar bonds in the ordinary course of
business; (iv) easements, reservations, rights of way, restrictions, minor
defects or irregularities in title and other similar charges or encumbrances
affecting real property in a manner not materially or adversely affecting the
value or use of such property; (v) Liens in favor of Agent (vi) Liens securing
obligations under a capital lease if such lease is permitted under this
Agreement and such Liens do not extend to property other than the property
leased under such capital lease; (vii) Liens upon any equipment or other assets
acquired or held by Obligor or any of its Subsidiaries to secure the purchase
price of such equipment or other assets or indebtedness incurred solely for the
purpose of financing the acquisition of such equipment or other assets, so long
as such Lien extends only to the equipment or other assets financed, and any
accessions, replacements, substitutions and proceeds (including insurance
proceeds) thereof or thereto and (viii) Liens on assets acquired from Network
Access Solutions Corporation or its affiliates, or IP Communications, Inc. or
its affiliates, provided that such Liens are limited to such assets so acquired.

              (w) "Person" shall mean and include an individual, a partnership,
a corporation (including a business trust), a joint stock company, a limited
liability company, an unincorporated association, a joint venture or other
entity or a governmental authority.

                                      -10-
<PAGE>
              (x) "Regulated Subsidiary" shall mean any Subsidiary for which
federal, state, provincial, local or other governmental approval would be
required for such Subsidiary to grant a security interest in its assets, issue
any evidence of indebtedness or assume any obligation or liability as guarantor
with respect to any obligation or liability of any other Person.

              (y) "Required Guarantors" shall mean, as of any date, Guarantors
that have paid to Bank more than fifty percent (50%) of the aggregate Drawn
Amounts, and if no Drawn Amounts are outstanding, the Guarantors whose aggregate
Guaranty Commitment constitutes more than fifty percent (50%) of the aggregate
Guaranty Commitments of all Guarantors; provided that "ninety percent (90%)"
shall be substituted in place of the above-referenced percentages in the
following circumstances: (A) appointment of a successor Agent under Section
7(i), (B) executing and delivering a release under Section 7(k) of Liens on
Collateral in the aggregate valued in excess of $1,000,000, and (C) the consent
required pursuant to Section 4(a)(iii) and (D) notwithstanding any provision in
this Agreement or the Operative Documents, engaging in any action or
transaction, including without limitation amendment or modification of this
Agreement or the Operative Documents that (i) materially adversely affects the
rights of any Guarantor in a manner different than any other Guarantor, or (ii)
could reasonably be expected to prejudice or otherwise treat inequitably the
interests of any Guarantor in relation to the rights of any other Guarantor,
which actions or transactions shall require the approval of that percentage of
Guarantors referenced in this proviso.

              (z) "Subsidiary" shall mean (a) any corporation of which more than
50% of the issued and outstanding equity securities having ordinary voting power
to elect a majority of the Board of Directors of such corporation is at the time
directly or indirectly owned or controlled by Obligor, (b) any partnership,
joint venture, or other association of which more than 50% of the equity
interest having the power to vote, direct or control the management of such
partnership, joint venture or other association is at the time directly or
indirectly owned and controlled by Obligor, (c) any other entity included in the
financial statements of Obligor on a consolidated basis.

              (aa) "Warrants" has the meaning given to such term in Section 3(c)
hereof.

         7.   AGENT.

              (a) Appointment and Authorization of Agent. Each Guarantor hereby
designates and appoints VantagePoint Venture Partners III (Q), L. P. as its
representative under this Agreement and the other Operative Documents and each
Guarantor hereby irrevocably authorizes Agent, or any successor Agent to take
such action on its behalf under the provisions of this Agreement and each other
Operative Document and to exercise such powers and perform such duties as are
expressly delegated to Agent by the terms of this Agreement or any other
Operative Document, together with such powers as are reasonably incidental
thereto. Agent agrees to act as representative of the Guarantors on the express
conditions contained in this Section 7 and as set forth in the Operative
Documents. The provisions of this Section 7 are solely for the benefit of Agent,
and the Guarantors, and Obligor shall have no rights as a third party
beneficiary of any of the provisions contained herein. Any provision to the
contrary contained elsewhere in this Agreement or in any other Operative
Document notwithstanding, Agent shall not have any duties or responsibilities,
except those expressly set forth herein or therein, nor shall Agent have or be
deemed to have any fiduciary relationship with any Guarantor, and no implied
covenants, functions, responsibilities, duties, obligations or liabilities shall
be read into this Agreement or any other Operative Document or otherwise exist
against Agent; it being expressly understood and agreed that the use of the word
"Agent" is for convenience only, that Agent is merely the representative of the
Guarantors, and only has the contractual duties set forth herein and in the
Operative Documents. Except as expressly otherwise provided in this Agreement,
Agent shall in good faith and in the best interests of the Guarantors have and
may use its sole discretion with respect to exercising or refraining from
exercising any discretionary rights or taking or refraining from taking any

                                      -11-
<PAGE>
actions that Agent expressly is entitled to take or assert under or pursuant to
this Agreement and the other Operative Documents. Without limiting the
generality of the foregoing, or of any other provision of the Operative
Documents that provides rights or powers to Agent, Guarantors agree that Agent
shall have the right to exercise the following powers as long as this Agreement
remains in effect: (a) maintain, in accordance with its customary business
practices, ledgers and records reflecting the status of the Obligations, the
Collateral and related matters, (b) execute or file any and all financing or
similar statements or notices, amendments, renewals, supplements, documents,
instruments, proofs of claim, notices and other written agreements with respect
to the Operative Documents, (c) exclusively receive, apply, and distribute any
payments received from Obligor or proceeds of Collateral as provided in the
Operative Documents, (d) perform, exercise, and enforce any and all other rights
and remedies of the Guarantors with respect to Obligor, the Obligations, the
Collateral or otherwise related to any of same as provided in the Operative
Documents, and (e) incur and pay such Guaranty Expense Amounts as Agent
reasonably may deem necessary or appropriate for the performance and fulfillment
of its functions and powers pursuant to the Operative Documents.

              (b) Delegation of Duties. Agent may execute any of its duties
under this Agreement or any other Operative Document by or through agents,
employees or attorneys-in-fact and shall be entitled to advice of counsel
concerning all matters pertaining to such duties. Agent shall not be responsible
for the negligence or misconduct of any agent or attorney-in-fact that it
selects as long as such selection was made without gross negligence or willful
misconduct, but Agent covenants to monitor and supervise in a reasonable manner
the conduct of such agents or attorneys-in-fact in furtherance of Agent's duties
hereunder.

              (c) Liability of Agent. Neither the Agent nor any of its partners,
members, managers, officers or employees nor any other Person assisting them in
their duties nor any agent or employee thereof ("Agent-Related Person"), shall
(i) be liable for any action taken or omitted to be taken by any of them under
or in connection with this Agreement or any other Operative Document or the
transactions contemplated hereby (except for its own gross negligence or willful
misconduct), or (ii) be responsible in any manner to any of the Guarantors for
any recital, statement, representation or warranty made by Obligor or any
Subsidiary or Affiliate of Obligor, or any officer or director thereof,
contained in this Agreement or in any other Operative Document, or in any
certificate, report, statement or other document referred to or provided for in,
or received by Agent under or in connection with, this Agreement or any other
Operative Document, or the validity, effectiveness, genuineness, enforceability
or sufficiency of this Agreement or any other Operative Document, or for any
failure of Obligor or any other party to any Operative Document to perform its
obligations hereunder or thereunder. No Agent-Related Person shall be under any
obligation to any Guarantor to ascertain or to inquire as to the observance or
performance of any of the agreements contained in, or conditions of, this
Agreement or any other Operative Document.

              (d) Reliance by Agent. Agent shall be entitled to rely, and shall
be fully protected in relying, upon any writing, resolution, notice, consent,
certificate, affidavit, letter, telegram, facsimile, telex or telephone message,
statement or other document or conversation believed by it to be genuine and
correct and to have been signed, sent, or made by the proper Person or Persons,
and upon advice and statements of legal counsel (including counsel to Obligor or
counsel to any Guarantor), independent accountants and other experts selected by
Agent. Agent shall be fully justified in failing or refusing to take any action
under this Agreement or any other Operative Document unless Agent shall first
receive such advice or concurrence of the Guarantors as it deems appropriate and
until such instructions are received, Agent shall act, or refrain from acting,
as it deems advisable. If Agent so requests, it shall first be indemnified to
its reasonable satisfaction by Guarantors against any and all liability and
expense that may be incurred by it by reason of taking or continuing to take any
such action. Agent shall in all cases be fully protected in acting, or in
refraining from acting, under this Agreement or any other Operative Document in
accordance with a request or consent of the Guarantors and such request and any
action taken or failure to act pursuant thereto shall be binding upon all of the
Guarantors.

                                      -12-
<PAGE>
              (e) Notice of Default or Event of Default. Agent shall not be
deemed to have knowledge or notice of the occurrence of any default or Event of
Default, except with respect to Events of Default of which Agent has actual
knowledge, unless Agent shall have received written notice from a Guarantor or
Obligor referring to this Agreement, describing such default or Event of
Default, and stating that such notice is a "notice of default." Agent promptly
will notify the Guarantors of its receipt of any such notice or of any Event of
Default or incipient Event of Default of which Agent has actual knowledge. If
any Guarantor obtains actual knowledge of any Event of Default, such Guarantor
promptly shall notify the other Guarantors and Agent of such Event of Default or
incipient Event of Default. Subject to Section 7(d), Agent shall take such
action with respect to such default or Event of Default as may be requested by
the Required Guarantors; provided, however, that unless and until Agent has
received any such request, Agent may (but shall not be obligated to) take such
action, or refrain from taking such action, with respect to such default or
Event of Default as it reasonably shall deem advisable.

              (f) Credit Decision. Each Guarantor acknowledges that none of the
Agent-Related Persons has made any representation or warranty to it, and that no
act by Agent hereinafter taken, including any review of the affairs of Obligor
and its Subsidiaries or Affiliates, shall be deemed to constitute any
representation or warranty by any Agent-Related Person to any Guarantor. Each
Guarantor represents to Agent that it has, independently and without reliance
upon any Agent-Related Person and based on public filings of the Obligor and
such other documents and information as it has deemed appropriate, made its own
appraisal of and investigation into the business, prospects, operations,
property, financial and other condition and creditworthiness of Obligor and any
other Person (other than the Guarantors) party to an Operative Document, and all
applicable laws relating to the transactions contemplated hereby, and made its
own decision to enter into this Agreement and to extend credit to Obligor. Each
Guarantor also represents that it will, independently and without reliance upon
any Agent-Related Person and based on such documents and information as it shall
deem appropriate at the time, continue to make its own credit analysis,
appraisals and decisions in taking or not taking action under this Agreement and
the other Operative Documents, and to make such investigations as it deems
necessary to inform itself as to the business, prospects, operations, property,
financial and other condition and creditworthiness of Obligor and any other
Person (other than the Guarantors) party to an Operative Document. Except for
notices, reports, and other documents expressly herein required to be furnished
to the Guarantors by Agent, Agent shall not have any duty or responsibility to
provide any Guarantor with any credit or other information concerning the
business, prospects, operations, property, financial and other condition or
creditworthiness of Obligor and any other Person party to an Operative Document
that may come into the possession of any of the Agent-Related Persons.

              (g) Costs and Expenses; Indemnification. Agent may incur and pay
Guaranty Expense Amounts to the extent Agent reasonably deems necessary or
appropriate for the performance and fulfillment of its functions, powers, and
obligations pursuant to the Operative Documents, including court costs,
reasonable attorneys fees and expenses, costs of collection by outside
collection agencies and auctioneer fees and costs of security guards or
insurance premiums paid to maintain the Collateral, whether or not Obligor are
obligated to reimburse Agent or Guarantors for such expenses pursuant to this
Agreement or otherwise. Agent is authorized and directed to deduct and retain
sufficient amounts from any payments or proceeds of Collateral received by Agent
to reimburse Agent for such out-of-pocket costs and expenses prior to the
distribution of any amounts to Guarantors. In the event Agent is not reimbursed
for such costs and expenses from such payments or proceeds of Collateral
received by Agent, each Guarantor hereby agrees that it is and shall be
obligated to pay to or reimburse Agent for the amount of such Guarantor's
ratable share thereof. Whether or not the transactions contemplated hereby are
consummated, the Guarantors shall indemnify upon demand within five (5) business
days the Agent-Related Persons (to the extent not reimbursed by or on behalf of
Obligor and without limiting the obligation of Obligor to do so), according to
their ratable shares, from and against any and all Claims; provided, however,
that no Guarantor shall be liable for the payment to any Agent-Related Person of
any portion of such Claims resulting solely from such Person's gross negligence

                                      -13-
<PAGE>
or willful misconduct. Without limitation of the foregoing, each Guarantor shall
reimburse Agent upon demand for such Guarantor's ratable share of any costs or
out-of-pocket expenses (including attorneys fees and expenses) incurred by Agent
in connection with the preparation, execution, delivery, administration,
modification, amendment, or enforcement (whether through negotiations, legal
proceedings or otherwise) of, or legal advice in respect of rights or
responsibilities under, this Agreement, any other Operative Document, or any
document contemplated by or referred to herein, to the extent that Agent is not
reimbursed for such expenses by or on behalf of Obligor. The undertaking in this
Section shall survive the payment of all Obligations hereunder and the
resignation or replacement of Agent.

              (h) Agent in Individual Capacity. Agent and its Affiliates may
make loans to, acquire equity interests in, and generally engage in any kind of
other business with Obligors and their Subsidiaries and Affiliates and any other
Person party to any Operative Documents as though Agent were not Agent
hereunder, and, in each case, without notice to or consent of the other
Guarantors; provided that nothing herein is intended to alter obligations of the
parties that may be set forth other than in the Operative Documents.

              (i) Successor Agent. Agent may resign as Agent upon 30 days notice
to the Guarantors. If Agent resigns under this Agreement, the Required
Guarantors shall appoint a successor Agent for the Guarantors. If no successor
Agent is appointed prior to the effective date of the resignation of Agent,
Agent may appoint, after consulting with the Guarantors, a successor Agent. If
Agent has materially breached or failed to perform any material provision of
this Agreement or of applicable law, the Required Guarantors may agree in
writing to remove and replace Agent with a successor Agent from among the
Guarantors. In any such event, upon the acceptance of its appointment as
successor Agent hereunder, such successor Agent shall succeed to all the rights,
powers, and duties of the retiring Agent and the term "Agent" shall mean such
successor Agent and the retiring Agent's appointment, powers, and duties as
Agent shall be terminated. After any retiring Agent's resignation hereunder as
Agent, the provisions of this Section 7 shall inure to its benefit as to any
actions taken or omitted to be taken by it while it was Agent under this
Agreement. If no successor Agent has accepted appointment as Agent by the date
which is 30 days following a retiring Agent's notice of resignation, the
retiring Agent's resignation shall nevertheless thereupon become effective and
the Guarantors shall perform all of the duties of Agent hereunder until such
time, if any, as the Guarantors appoint a successor Agent as provided for above.

              (j) Guarantor in Individual Capacity. Any Guarantor and its
respective Affiliates may make loans to, acquire equity interests in and
generally engage in any kind of other business with Obligors and their
Subsidiaries and Affiliates and any other Person party to any Operative
Documents as though such Guarantor were not a Guarantor hereunder without notice
to or consent of the Guarantors; provided that nothing herein is intended to
alter obligations of the parties that may be set forth other than in the
Operative Documents.

              (k) Collateral Matters.

                  (a)   The Guarantors hereby irrevocably authorize Agent, at
its option and in its sole discretion, to release any Lien on any Collateral (i)
upon the termination of the Guaranty and payment and satisfaction in full by
Obligor of all Obligations, or (ii) constituting property being sold or disposed
of if a release is required or desirable in connection therewith and if Obligor
certifies to Agent that the sale or disposition is permitted pursuant to the
terms of this Agreement or the other Operative Documents (and Agent may rely
conclusively on any such certificate, without further inquiry). Except as
provided above, Agent will not execute and deliver a release of any Lien on any
Collateral without the prior written authorization of the Required Guarantors.
Upon request by Agent or Obligor at any time, the Guarantors will confirm in
writing Agent's authority to release any such Liens on particular types or items
of Collateral pursuant to this Section 7(k); provided, however, that (1) Agent
shall not be required to execute any document necessary to evidence such release

                                      -14-
<PAGE>
on terms that, in Agent's opinion, would expose Agent to liability or create any
obligation or entail any consequence other than the release of such Lien without
recourse, representation, or warranty, and (2) such release shall not in any
manner discharge, affect, or impair the Obligations or any Liens (other than
those expressly being released) upon (or obligations of Obligor in respect of)
all interests retained by Obligor, including, the proceeds of any sale, all of
which shall continue to constitute part of the Collateral.

                  (b)   Agent shall have no obligation whatsoever to any of the
Guarantors to assure that the Collateral exists or is owned by Obligor or is
cared for, protected, or insured or has been encumbered, or that the Agent's
Liens have been properly or sufficiently or lawfully created, perfected,
protected, or enforced or are entitled to any particular priority, or to
exercise at all or in any particular manner or under any duty of care,
disclosure or fidelity, or to continue exercising, any of the rights,
authorities and powers granted or available to Agent pursuant to any of the
Operative Documents, it being understood and agreed that in respect of the
Collateral, or any act, omission, or event related thereto, subject to the terms
and conditions contained herein, Agent may act in any manner it may deem
appropriate, in its sole discretion given Agent's own interest in the Collateral
in its capacity as one of the Guarantors and that Agent shall have no other duty
or liability whatsoever to any Guarantor as to any of the foregoing, except as
otherwise provided herein.

              (l) Restrictions on Actions by Guarantors; Sharing of Payments.

                  (a)   Each of the Guarantors agrees that it shall not, unless
specifically requested to do so by Agent, take or cause to be taken any action,
including, the commencement of any legal or equitable proceedings, to foreclose
any Lien on, or otherwise enforce any security interest in, any of the
Collateral the purpose of which is, or could be, to give such Guarantor any
preference or priority against the other Guarantors with respect to the
Collateral.

                  (b)   If, at any time or times any Guarantor shall receive (i)
by payment, foreclosure, setoff, or otherwise, any proceeds of Collateral or any
payments with respect to the Obligations arising under, or relating to, this
Agreement or the other Operative Documents, except for any such proceeds of
Collateral or payments received by such Guarantor from Agent pursuant to the
terms of this Agreement, or (ii) payments from Agent in excess of such
Guarantor's ratable portion of all such distributions by Agent, such Guarantor
promptly shall turn the same over to Agent, in kind, and with such endorsements
as may be required to negotiate the same to Agent, or in immediately available
funds, as applicable, for the account of all of the Guarantors and for
application to the Obligations in accordance with the applicable provisions of
this Agreement.

              (m) Concerning the Collateral and Related Operative Documents.
Each of the Guarantors authorizes and directs Agent to enter into this Agreement
and the other Operative Documents relating to the Collateral, for the benefit of
the Guarantors. Each of the Guarantors agrees that any action taken by Agent in
accordance with the terms of this Agreement or the other Operative Documents
relating to the Collateral and the exercise by Agent of its powers set forth
therein or herein, together with such other powers that are reasonably
incidental thereto, shall be binding upon all of the Guarantors.

              (n) No Liability. Nothing contained herein shall confer upon any
Guarantor any interest in, or subject any Guarantor to any liability for, or in
respect of, the business, assets, profits, losses, or liabilities of any other
Guarantor. Except as provided in Section 7(g), none of the Guarantors shall have
any liability for the acts or any of the other Guarantors.

         8.   MISCELLANEOUS.

                                      -15-
<PAGE>
              (a) Notices. Except as otherwise provided herein, all notices,
requests, demands, consents, instructions or other communications to or upon
Obligor, Agent or Guarantors under this Agreement shall be in writing and
delivered by facsimile, hand delivery, overnight courier service or certified
mail, return receipt requested, to each party at the address most recently
provided by such party to the other party.

              (b) Nonwaiver. No failure or delay on Agent's or any Guarantor's
part in exercising any right hereunder shall operate as a waiver thereof or of
any other right nor shall any single or partial exercise of any such right
preclude any other further exercise thereof or of any other right.

              (c) Amendments and Waivers. This Agreement may not be amended or
modified, nor may any of its terms be waived, except by written instruments
signed by Obligor and Required Guarantors. Each waiver or consent under any
provision hereof shall be effective only in the specific instances for the
purpose for which given.

              (d) Assignments. This Agreement shall be binding upon and inure to
the benefit of Agent, Guarantors and Obligor and their respective successors and
assigns; provided, however, that Obligor may not assign or delegate rights and
obligations hereunder without the prior written consent of Required Guarantors.

              (e) Cumulative Rights, etc. The rights, powers and remedies of
Agent and Guarantors under this Agreement shall be in addition to all rights,
powers and remedies given to Agent and Guarantors by virtue of any applicable
law, rule or regulation of any governmental authority or any other agreement,
all of which rights, powers, and remedies shall be cumulative and may be
exercised successively or concurrently without impairing Agent's or Guarantor's
rights hereunder.

              (f) Partial Invalidity. If at any time any provision of this
Agreement is or becomes illegal, invalid or unenforceable in any respect under
the law or any jurisdiction, neither the legality, validity or enforceability of
the remaining provisions of this Agreement nor the legality, validity or
enforceability of such provision under the law of any other jurisdiction shall
in any way be affected or impaired thereby.

              (g) Expenses. Each Obligor shall pay on demand all reasonable fees
and expenses, including reasonable attorneys' fees and expenses, incurred by
Agent and Guarantors in connection with any enforcement or attempt to enforce
any of the obligations of any Obligor which are not performed as and when
required by this Agreement.

              (h) Entire Agreement. This Agreement and the other Operative
Documents constitutes and contains the entire agreement of Obligor and Agent and
Guarantors with respect to the subject matter hereof and supersedes any and all
prior agreements, negotiations, correspondence, understandings and
communications among the parties, whether written or oral, respecting the
subject matter hereof, including, without limitation, that certain Guaranty
Agreement, dated as of October 8, 2002, by and between Obligor and VantagePoint
Venture Partners III (Q), L.P.

              (i) Governing Law. This Agreement shall be governed by and
construed in accordance with the laws of the State of California without
reference to conflicts of law rules.

              (j) Jury Trial. OBLIGOR, AGENT AND EACH GUARANTOR, TO THE FULLEST
EXTENT PERMITTED BY APPLICABLE LAW, HEREBY IRREVOCABLY WAIVES ALL RIGHT TO TRIAL
BY JURY AS TO ANY ISSUE RELATING HERETO IN ANY ACTION, PROCEEDING, OR
COUNTERCLAIM ARISING OUT OF OR RELATING TO THIS AGREEMENT.

                                      -16-
<PAGE>
              (k) Release of Additional Guarantors. In the event that an
Additional Guarantor does not enter into a Guaranty on or before January 31,
2003, then such Additional Guarantor's rights and obligations under this
Agreement and the other Operative Documents to which it is a party shall
automatically terminate and such Additional Guarantor shall be deemed released
from this Agreement and such other Operative Documents.

              (l) Right to Terminate Guaranty. In the event that Obligor does
not borrow any loans under the Credit Agreement on or before March 31, 2003,
then the Credit Agreement shall terminate automatically on March 31, 2003
pursuant to its terms and all Guaranties shall automatically terminate on March
31, 2003 pursuant to their respective terms (the "Termination Event"). In the
event of a Termination Event, (i) Guarantor's rights and obligations under each
Operative Document to which it is a party shall automatically terminate and such
Guarantor shall be deemed released from such Operative Document and (ii) any
Warrants issued to Guarantor in connection with the transactions contemplated by
the Operative Documents shall be deemed terminated as of the date of such
Termination Election.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

                                      -17-
<PAGE>

         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed as of the day and year first written above.

                                            DSL.NET, INC.,
                                            AS OBLIGOR

                                            By: /s/ David F. Struwas
                                                ------------------------------
                                            Name:  David F. Struwas
                                                  ----------------------------
                                            Title: Chief Executive Officer
                                                   ---------------------------

AGREED & ACCEPTED:

VANTAGEPOINT VENTURE PARTNERS III (Q), L.P., AS AGENT AND A GUARANTOR

By:  VantagePoint Venture Associates III, L.L.C.

By:   /s/ James D. Marver
      --------------------------------------------------------
       James D. Marver               , Managing Member
      ------------------------------
<PAGE>
AGREED & ACCEPTED:

COLUMBIA CAPITAL EQUITY PARTNERS II (QP), LP, AS A GUARANTOR

By:    Columbia Capital Equity Partners, L.P., its General Partner

By:    /s/ Donald A. Doering
       --------------------------------------------
Name:  Donald A. Doering
       --------------------------------------------
Title: Chief Financial Officer
       --------------------------------------------

COLUMBIA CAPITAL EQUITY PARTNERS II (CAYMAN), LP, AS A GUARANTOR

By:    Columbia Capital Equity Partners, L.P., its General Partner

By:    /s/ Donald A. Doering
       --------------------------------------------
Name:  Donald A. Doering
       --------------------------------------------
Title: Chief Financial Officer
       --------------------------------------------

COLUMBIA CAPITAL EQUITY PARTNERS II LP, AS A GUARANTOR

By:    Columbia Capital Equity Partners, L.P., its General Partner

By:    /s/ Donald A. Doering
       --------------------------------------------
Name:  Donald A. Doering
       --------------------------------------------
Title: Chief Financial Officer
       --------------------------------------------

COLUMBIA CAPITAL INVESTORS, LLC, AS A GUARANTOR

By:    Columbia Capital, LLC, its Manager

By:    /s/ Donald A. Doering
       --------------------------------------------
Name:  Donald A. Doering
       --------------------------------------------
       Title: Chief Financial Officer
       --------------------------------------------
<PAGE>
AGREED & ACCEPTED:

COLUMBIA CAPITAL EQUITY PARTNERS III (QP), LP, AS A GUARANTOR

By:    Columbia Capital Equity Partners III, L.P., its General Partner

By:    /s/ Donald A. Doering
       --------------------------------------------
Name:  Donald A. Doering
       --------------------------------------------
Title: Chief Financial Officer
       --------------------------------------------

COLUMBIA CAPITAL EQUITY PARTNERS III (CAYMAN), LP, AS A GUARANTOR

By:    Columbia Capital Equity Partners III, L.P., its General Partner

By:    /s/ Donald A. Doering
       --------------------------------------------
Name:  Donald A. Doering
       --------------------------------------------
Title: Chief Financial Officer
       --------------------------------------------

COLUMBIA CAPITAL EQUITY PARTNERS III (AI), LP, AS A GUARANTOR

By:    Columbia Capital Equity Partners III, L.P., its General Partner

By:    /s/ Donald A. Doering
       --------------------------------------------
Name:  Donald A. Doering
       --------------------------------------------
Title: Chief Financial Officer
       --------------------------------------------

COLUMBIA CAPITAL INVESTORS III, LLC, AS A GUARANTOR

By:    Columbia Capital III, LLC, its Manager

By:    /s/ Donald A. Doering
       --------------------------------------------
Name:  Donald A. Doering
       --------------------------------------------
Title: Chief Financial Officer
       --------------------------------------------
<PAGE>
AGREED & ACCEPTED:

THE LAFAYETTE INVESTMENT FUND, L.P., AS A GUARANTOR

By:    Layafette Investment Partners, L.P., its sole General Partner

By:    Layafette Private Equities, Inc., its sole General Partner

By:    /s/ Robert Sussman
       --------------------------------------------
Name:  Robert Sussman
       --------------------------------------------
Title: Vice President
       --------------------------------------------

<PAGE>
AGREED & ACCEPTED:

CHARLES RIVER PARTNERSHIP X, A LIMITED PARTNERSHIP, AS A GUARANTOR

By:    Charles River X GP, LLC, General Partner

By:    /s/ Richard M. Burnes, Jr.
       --------------------------------------------
Name:  Richard M. Burnes, Jr.
       --------------------------------------------
Title: Managing Member
       --------------------------------------------

CHARLES RIVER PARTNERSHIP X-A, A LIMITED PARTNERSHIP, AS A GUARANTOR

By:    Charles River X GP, LLC, General Partner

By:    /s/ Richard M. Burnes, Jr.
       --------------------------------------------
Name:  Richard M. Burnes, Jr.
       --------------------------------------------
Title: Managing Member
       --------------------------------------------

CHARLES RIVER FRIENDS X-B, LLC, AS A GUARANTOR

By:    Charles River Friends, Inc., Manager

By:    /s/ Richard M. Burnes, Jr.
       --------------------------------------------
Name:  Richard M. Burnes, Jr.
       --------------------------------------------
Title: Officer
       --------------------------------------------

CHARLES RIVER FRIENDS X-C, LLC, AS A GUARANTOR

By:    Charles River Friends, Inc., Manager

By:    /s/ Richard M. Burnes, Jr.
       --------------------------------------------
Name:  Richard M. Burnes, Jr.
       --------------------------------------------
Title: Officer
       --------------------------------------------

<PAGE>
                                   Schedule 1
                                   ----------

Existing Indebtedness:

Type                      Creditor                                    Amount
----                      --------                                 -----------
Capital Lease             Comdisco, Inc.                           $   194,978
Capital Lease             Copper Mountain Networks, Inc.           $ 4,098,813
Capital Lease             Lucent Technologies/Avaya, Inc.          $   295,546
Capital Lease             Insight Technologies/Verserv, Inc.       $    35,187
Capital Lease             Other                                    $    30,482

Letter of Credit          People's Bank #SB-1199                   $   406,666
Letter of Credit          People's Bank #SB-1187                   $   194,031
Letter of Credit          People's Bank #SB-1222                   $   166,000
Letter of Credit          People's Bank #SB-1240                   $   253,500

<PAGE>
                                   Schedule 2
                                   ----------

                                                          MAXIMUM PRINCIPAL
GUARANTOR                                                 AMOUNT OF GUARANTY
---------                                                 ------------------

VantagePoint Venture Partners III (Q), LP                   $5,000,000.00

Columbia Capital Equity Partners II (QP), LP                   $68,757.63

Columbia Capital Equity Partners II (Cayman), LP               $56,132.51

Columbia Capital Equity Partners II, LP                         $2,899.72

Columbia Capital Investors, LLC                                $12,337.14

Columbia Capital Equity Partners III (QP), LP                 $518,532.22

Columbia Capital Equity Partners III, (Cayman), LP            $284,753.65

Columbia Capital Equity Partners III, (AI), LP                 $28,645.20

Columbia Capital Investors III, LLC                           $127,941.93

The Lafayette Investment Fund, L.P.                           $500,000.00

Charles River Partnership X, a Limited Partnership            $117,661.28

Charles River Partnership X-A, a Limited Partnership            $3,230.00

Charles River Friends X-B, LLC                                  $7,762.14

Charles River Friends X-C, LLC                                  $1,346.58
                                                            -------------
                                            TOTAL:          $6,730,000.00
                                                            =============
<PAGE>
                                   Schedule 3
                                   ----------

GUARANTOR                                                   WARRANT SHARES
---------                                                   --------------

VantagePoint Venture Partners III (Q), LP                      10,379,420(1)

Columbia Capital Equity Partners II (QP), LP                      102,166

Columbia Capital Equity Partners II (Cayman), LP                   83,406

Columbia Capital Equity Partners II, LP                             4,309

Columbia Capital Investors, LLC                                    18,332

Columbia Capital Equity Partners III (QP), LP                     770,479

Columbia Capital Equity Partners III, (Cayman), LP                423,111

Columbia Capital Equity Partners III, (AI), LP                     42,563

Columbia Capital Investors III, LLC                               190,107

The Lafayette Investment Fund, L.P.                               742,942

Charles River Partnership X, a Limited Partnership                174,831

Charles River Partnership X-A, a Limited Partnership                4,799

Charles River Friends X-B, LLC                                     11,534

Charles River Friends X-C, LLC                                      2,001

-----------------------
(1) Includes 2,950,000 warrant shares that Obligor previously agreed to grant
    pursuant to that certain superceded Guaranty Agreement, dated as of October
    8, 2002.EXHIBIT 10.23
                                                                   -------------

                               SUBSIDIARY GUARANTY

              THIS SUBSIDIARY GUARANTY (this "GUARANTY"), dated as of December
27, 2002, is executed by each of the undersigned (each such entity and each
entity which hereafter executes and delivers a Subsidiary Joinder in
substantially the form of Attachment 1 hereto to be referred to herein as a
"SUBSIDIARY GUARANTOR"), in favor of (i) VANTAGEPOINT VENTURE PARTNERS III (Q),
L.P., as administrative agent for itself and the other Guarantors which are or
may become parties to the Reimbursement Agreement ("AGENT") and (ii) each of the
Guarantors.

                                    RECITALS
                                    --------

         A.   Reference is made to that certain Revolving Credit and Term Loan
Agreement, dated as of December 13, 2002 (as amended and in effect from time to
time, the "CREDIT AGREEMENT"), by and between Fleet National Bank ("Lender") and
DSL.net, Inc. ("BORROWER").

         B.   It is a condition precedent to the extension of credit by Lender
under the Credit Agreement that the Guarantors party to the Reimbursement
Agreement enter into guaranties (as amended and in effect from time to time, the
"CREDIT GUARANTIES" and each a "CREDIT GUARANTY") to guaranty certain of the
obligations of Borrower to Lender under the Credit Agreement.

         C.   In order to induce Guarantors to enter into the Credit Guaranty:
(i) Borrower has agreed to enter into a Reimbursement Agreement, dated as of the
date hereof (as amended and in effect from time to time, the "REIMBURSEMENT
AGREEMENT") with the Guarantors and Agent, (ii) Borrower's subsidiaries party
hereto have agreed to enter into this Guaranty to guaranty Borrower's
obligations to Agent and Guarantors under the Reimbursement Agreement and (iii)
Borrower and Subsidiary Guarantors have agreed to enter into a Security
Agreement, dated as of the date hereof, to secure their respective obligations
under the Reimbursement Agreement and this Guaranty.

         D.   Each of the undersigned Subsidiary Guarantors is a subsidiary of
Borrower and expects to derive substantial direct and indirect benefit from the
transactions contemplated by the Credit Agreement.

                                    AGREEMENT
                                    ---------

              NOW, THEREFORE, in consideration of the above recitals and for
other good and valuable consideration, the receipt and adequacy of which are
hereby acknowledged, each Subsidiary Guarantor, each Guarantor and Agent hereby
agree as follows:

1.       DEFINITIONS AND INTERPRETATION.
         -------------------------------

         (a)  Definition. When used in this Guaranty, the following terms shall
have the following respective meanings:

         "ADJUSTED MAXIMUM GUARANTY AMOUNT" shall mean, with respect to any
Subsidiary Guarantor, the maximum liability of such Subsidiary Guarantor under
this Guaranty, limited to the extent provided in Section 2(d) hereof (except
that, for purposes of calculating the Adjusted Maximum Guaranty Amount of a
<PAGE>
Subsidiary Guarantor only, any assets or liabilities of such Subsidiary
Guarantor arising under Section 8 hereof shall be ignored).

         "AGENT" shall have the meaning given to that term in the introductory
paragraph hereof.

         "AGGREGATE GUARANTY PAYMENTS" shall mean, with respect to any
Subsidiary Guarantor at any time, the aggregate net amount of all payments made
by such Subsidiary Guarantor under this Guaranty (including, without limitation,
under Section 8 hereof) at or prior to such time.

         "BORROWER" shall have the meaning given to that term in Recital A
hereof.

         "CLOSING DATE" shall mean the date of this Guaranty.

         "CREDIT AGREEMENT" shall have the meaning given to that term in Recital
A hereof.

         "DISALLOWED POST-COMMENCEMENT INTEREST AND EXPENSES" shall mean
interest computed at the rate provided in the Reimbursement Agreement and claims
for reimbursement, costs, expenses or indemnities under the terms of any of the
Operative Documents accruing or claimed at any time after the commencement of
any Insolvency Proceeding, if the claim for such interest, reimbursement, costs,
expenses or indemnities is not allowable, allowed or enforceable against
Borrower in such Insolvency Proceeding.

         "EXEMPT SUBSIDIARY GUARANTOR" shall mean DSLnet Communications Puerto
Rico, Inc. and DSLnet Communications VA, Inc.

         "FAIR SHARE" shall mean, with respect to any Subsidiary Guarantor at
any time, an amount equal to (i) a fraction, the numerator of which is the
Adjusted Maximum Guaranty Amount of such Subsidiary Guarantor and the
denominator of which is the aggregate Adjusted Maximum Guaranty Amounts of all
Subsidiary Guarantors, multiplied by (ii) the aggregate amount paid by all
Funding Subsidiary Guarantors under this Guaranty at or prior to such time.

         "FAIR SHARE SHORTFALL" shall mean, with respect to any Subsidiary
Guarantor at any time, the amount, if any, by which the Fair Share of such
Subsidiary Guarantor at such time exceeds the Aggregate Guaranty Payments of
such Subsidiary Guarantor at such time.

         "FUNDING SUBSIDIARY GUARANTOR" shall have the meaning given to that
term in Section 8 hereof.

         "GUARANTEED OBLIGATIONS" shall mean the Obligations.

         "INSOLVENCY PROCEEDING" shall mean any case or proceeding under the
United States Bankruptcy Code or any other similar law, rule or regulation of
the United States or any jurisdiction or any other action or proceeding for the
reorganization, liquidation, appointment of a receiver, rearrangement of debts,
marshalling of assets or similar action relating to Borrower or any Subsidiary
Guarantor, their respective creditors or any substantial part of their
respective assets, whether or not any such case, proceeding or action is
voluntary or involuntary.

         "OPERATIVE DOCUMENTS" shall have the meaning given to that term in the
Reimbursement Agreement.

         "PERSON" shall mean and include an individual, a partnership, a
corporation, a business trust, a joint stock company, a limited liability
company, an unincorporated association or other entity and any domestic or

                                       -2-
<PAGE>
foreign national, state or local government, any political subdivision thereof,
and any department, agency, authority or bureau of any of the foregoing.

         "SOLVENT" shall mean, with respect to any Person on any date, that on
such date (a) the present fair saleable value of the assets of such Person is
not less than the amount that will be required to pay the probable liability of
such Person on its debts as they become absolute and matured, and (b) such
Person does not intend to, and does not believe that it will, incur debts or
liabilities beyond such Person's ability to pay as such debts and liabilities
mature.

         "SUBORDINATED OBLIGATIONS" shall have the meaning given to that term in
Section 6 hereof.

         "SUBSIDIARY GUARANTOR" shall have the meaning given to that term in the
introductory paragraph hereof.

         "SUBSIDIARY JOINDER" shall mean an agreement substantially in the form
of Attachment 1 hereto.

         Unless otherwise defined herein, all other capitalized terms used
herein and defined in the Reimbursement Agreement shall have the respective
meanings given to those terms in the Reimbursement Agreement.

         (b)  Other Interpretive Provisions. The rules of construction set forth
in the Reimbursement Agreement shall, to the extent not inconsistent with the
terms of this Guaranty, apply to this Guaranty and are hereby incorporated by
reference. Each Subsidiary Guarantor acknowledges receipt of copies of the
Reimbursement Agreement and the other Operative Documents.

2.       GUARANTY.
         ---------

         (a)  Payment Guaranty. Each Subsidiary Guarantor (jointly and severally
with the other Subsidiary Guarantors) unconditionally guarantees and promises to
pay and perform as and when due, whether at stated maturity, upon acceleration
or otherwise, any and all of the Guaranteed Obligations. If any Insolvency
Proceeding relating to Borrower is commenced, each Subsidiary Guarantor (jointly
and severally with the other Subsidiary Guarantors) further unconditionally
guarantees and promises to pay and perform, upon the demand of Agent, at the
direction of Required Guarantors, any and all of the Guaranteed Obligations
(including any and all Disallowed Post-Commencement Interest and Expenses) in
accordance with the terms of the Operative Documents, whether or not such
obligations are then due and payable by Borrower and whether or not such
obligations are modified, reduced or discharged in such Insolvency Proceeding.
This Guaranty is a guaranty of payment and not of collection.

         (b)  Continuing Guaranty. This Guaranty is an irrevocable continuing
guaranty of the Guaranteed Obligations which shall continue in effect until all
obligations of Lender to extend credit to Borrower have terminated and all of
the Guaranteed Obligations have been fully, finally and indefensibly paid or
until the Credit Guaranties are terminated. If any payment on any Guaranteed
Obligation is set aside, avoided or rescinded or otherwise recovered from Agent,
such recovered payment shall constitute a Guaranteed Obligation hereunder and,
if this Guaranty was previously released or terminated, it automatically shall
be fully reinstated, as if such payment was never made.

         (c)  Independent Obligation. The liability of each Subsidiary Guarantor
hereunder is independent of the Guaranteed Obligations and of the obligations of
each other Subsidiary Guarantor hereunder, and a separate action or actions may
be brought and prosecuted against each Subsidiary Guarantor irrespective of
whether action is brought against Borrower, any other Subsidiary Guarantor or
any other guarantor of the Guaranteed Obligations or whether Borrower, any other
Subsidiary Guarantor or any other guarantor of the Guaranteed Obligations is
joined in any such action or actions.

                                       -3-
<PAGE>
         (d)  Fraudulent Transfer Limitation. If, in any action to enforce this
Guaranty, any court of competent jurisdiction determines that enforcement
against any Subsidiary Guarantor for the full amount of the Guaranteed
Obligations is not lawful under or would be subject to avoidance under Section
548 of the United States Bankruptcy Code or any applicable provision of any
comparable law of any state or other jurisdiction, the liability of such
Subsidiary Guarantor under this Guaranty shall be limited to the maximum amount
lawful and not subject to such avoidance.

         (e)  Termination. Notwithstanding any termination of this Guaranty in
accordance with Section 6 hereof, this Guaranty shall continue to be in full
force and effect and applicable to any Guaranteed Obligations arising thereafter
which arise because prior payments of Guaranteed Obligations are rescinded or
otherwise required to be surrendered by Agent after receipt.

3.       REPRESENTATIONS AND WARRANTIES. Each Subsidiary Guarantor makes the
following representations and warranties to Agent and Guarantors:

         (a)  Due Incorporation, Qualification, etc. Such Subsidiary Guarantor
and its Subsidiaries (i) are duly organized, validly existing and in good
standing under the laws of their state of incorporation or formation; (ii) have
the power and authority to own, lease and operate their properties and carry on
their business as now conducted; and (iii) are duly qualified, licensed to do
business and in good standing as foreign corporations in each jurisdiction where
the failure to be so qualified or licensed could reasonably be expected to have
a Material Adverse Effect.

         (b)  Authority. The execution, delivery and performance by such
Subsidiary Guarantor of each Operative Document to be executed by such
Subsidiary Guarantor and the consummation of the transactions contemplated
thereby (i) are within the power of such Subsidiary Guarantor and (ii) have been
duly authorized by all necessary actions on the part of such Subsidiary
Guarantor.

         (c)  Enforceability. Each Operative Document executed, or to be
executed, by such Subsidiary Guarantor has been, or will be, duly executed and
delivered by such Subsidiary Guarantor and constitutes, or will constitute, a
legal, valid and binding obligation of such Subsidiary Guarantor, enforceable
against such Subsidiary Guarantor in accordance with its terms, except as
limited by bankruptcy, insolvency or other laws of general application relating
to or affecting the enforcement of creditors' rights generally and general
principles of equity.

         (d)  Non-Contravention. The execution and delivery by such Subsidiary
Guarantor of the Operative Documents executed by such Subsidiary Guarantor and
the performance and consummation of the transactions contemplated thereby do not
and will not (i) violate the certificate of incorporation or bylaws or
comparable formation documents of such Subsidiary Guarantor or any material
judgment, order, writ, decree, statute, rule or regulation applicable to such
Subsidiary Guarantor; (ii) violate any provision of, or result in the breach or
the acceleration of, or entitle any other Person to accelerate (whether after
the giving of notice or lapse of time or both), any material mortgage,
indenture, agreement, instrument or contract to which such Subsidiary Guarantor
is a party or by which it is bound; or (iii) result in the creation or
imposition of any Lien upon any property, asset or revenue of such Subsidiary
Guarantor (other than any Lien arising under the Operative Documents) or the
suspension, revocation, impairment, forfeiture, or nonrenewal of any material
permit, license, authorization or approval applicable to such Subsidiary
Guarantor, its business or operations, or any of its assets or properties.

                                       -4-
<PAGE>
         (e)  Approvals. No consent, approval, order or authorization of, or
registration, declaration or filing with, any governmental authority or other
Person (including, without limitation, the shareholders of any Person) is
required in connection with the execution and delivery of the Operative
Documents executed by such Subsidiary Guarantor and the performance and
consummation of the transactions contemplated thereby.

         (f)  No Violation or Default. Neither such Subsidiary Guarantor nor
such Subsidiary Guarantor's Subsidiaries is in violation of or in default with
respect to (i) its certificate of incorporation or bylaws or comparable
formation documents or any material judgment, order, writ, decree, statute, rule
or regulation applicable to such Person; (ii) any material mortgage, indenture,
agreement, instrument or contract to which such Person is a party or by which it
is bound (nor is there any waiver in effect which, if not in effect, would
result in such a violation or default), where, in each case, such violation or
default, individually, or together with all such violations or defaults, could
reasonably be expected to have a Material Adverse Effect. No default under this
Guaranty has occurred and is continuing.

         (g)  Litigation. No actions (including, without limitation, derivative
actions), suits, proceedings or investigations are pending or, to the knowledge
of such Subsidiary Guarantor, threatened against such Subsidiary Guarantor or
such Subsidiary Guarantor's Subsidiaries at law or in equity in any court or
before any other governmental authority which if adversely determined (i) would
(alone or in the aggregate) have a Material Adverse Effect or (ii) seeks to
enjoin, either directly or indirectly, the execution, delivery or performance by
such Subsidiary Guarantor of the Operative Documents or the transactions
contemplated thereby.

         (h)  Other Regulations. Neither such Subsidiary Guarantor nor its
Subsidiaries is subject to regulation under the Investment Company Act of 1940,
the Public Utility Holding Company Act of 1935, the Federal Power Act, the
Interstate Commerce Act, any state public utilities code or to any federal or
state statute or regulation limiting its ability to incur Indebtedness.

         (i)  Governmental Charges. Each of such Subsidiary Guarantor and its
Subsidiaries has filed or caused to be filed all tax returns which are required
to be filed by it. Such Subsidiary Guarantor and such Subsidiary Guarantor's
Subsidiaries have paid, or made adequate reserves (determined in accordance with
GAAP) for the payment of, all taxes and other levies, assessments, fees, claims
or other charges imposed by any governmental authority which have or may have
become due pursuant to said returns, except such taxes, levies, assessments,
fees, claims or other charges, if any, which are being contested in good faith
and as to which adequate reserves (determined in accordance with GAAP) have been
provided or which could not reasonably be expected to have a Material Adverse
Effect if unpaid.

         (j)  Subsidiaries, etc. Except as set forth in the Disclosure Schedule
attached hereto (setting forth the jurisdiction of incorporation or formation,
capital structure and percentage ownership of each shareholder), such Subsidiary
Guarantor has no Subsidiaries, is not a partner in any partnership, a member of
any limited liability company or a joint venturer in any joint venture.

         (k)  Solvency, Etc. Such Subsidiary Guarantor (other than an Exempt
Subsidiary Guarantor) is Solvent and, after the execution and delivery of the
Operative Documents and the consummation of the transactions contemplated
thereby, such Subsidiary Guarantor (other than an Exempt Subsidiary Guarantor)
will be Solvent.

4.       COVENANTS. Until all obligations of Lender to extend credit to Borrower
have terminated and all of the Guaranteed Obligations have been fully, finally
and indefensibly paid, each Subsidiary Guarantor shall comply with the following
covenants:

                                       -5-
<PAGE>
         (a)  Financial Statements, Reports, Etc(i) . Such Subsidiary Guarantor
shall furnish to Agent such financial statements, certificates, opinions,
statements, documents and information relating to the operations or condition
(financial or otherwise) of such Subsidiary Guarantor or its Subsidiaries, and
compliance by Borrower and such Subsidiary Guarantor with the terms of the
Operative Documents as Agent may from time to time reasonably request.

         (b)  Inspections. Such Subsidiary Guarantor and its Subsidiaries shall
permit any Person designated by Agent, upon reasonable prior notice and during
normal business hours, to visit and inspect any of the properties and offices of
such Subsidiary Guarantor and its Subsidiaries, to examine the books and records
of such Subsidiary Guarantor and its Subsidiaries and make copies thereof and to
discuss the affairs, finances and accounts of such Subsidiary Guarantor and its
Subsidiaries with, and to be advised as to the same by, their officers, auditors
and accountants, all at such times and intervals as Agent may reasonably
request.

         (c)  Insurance. Such Subsidiary Guarantor and its Subsidiaries shall
maintain the insurance required to be maintained under the Reimbursement
Agreement.

         (d)  Governmental Charges. To the extent failure to do so could
reasonably be expected to have a Material Adverse Effect, such Subsidiary
Guarantor and its Subsidiaries shall promptly pay and discharge all taxes and
other charges imposed by any government authority upon such Subsidiary Guarantor
or its Subsidiaries or their property as and when they become due.

         (e)  General Business Operations. To the extent failure to do so could
reasonably be expected to have a Material Adverse Effect, such Subsidiary
Guarantor and its Subsidiaries shall (i) maintain its corporate existence and
all rights, privileges and franchises necessary for the conduct of its business
and (ii) comply with any material judgment, order, writ, decree, statute, rule
or regulation applicable to such Person and any material mortgage, indenture,
agreement, instrument or contract to which such Person is a party or by which it
is bound.

5.       AUTHORIZATIONS, WAIVERS, ETC.
         -----------------------------

         (a)  Authorizations. Each Subsidiary Guarantor authorizes Agent and
Guarantors, in their discretion, without prior notice to such Subsidiary
Guarantor, irrespective of any change in the financial condition of Borrower,
such Subsidiary Guarantor, any other Subsidiary Guarantor or any other guarantor
of the Guaranteed Obligations since the date hereof, and without affecting or
impairing in any way the liability of such Subsidiary Guarantor hereunder, from
time to time to:

              (i)  Create new Guaranteed Obligations and renew, compromise,
extend, accelerate or otherwise change the time for payment or performance of,
or otherwise amend or modify the Operative Documents or change the terms of the
Guaranteed Obligations or any part thereof, including increase or decrease of
the rate of interest thereon; and

              (ii) Assign the Guaranteed Obligations, this Guaranty or the other
Operative Documents in whole or in part to the extent provided in the
Reimbursement Agreement and the other Operative Documents.

         (b)  Authorizations. Each Subsidiary Guarantor authorizes Agent, in its
discretion, without prior notice to such Subsidiary Guarantor, irrespective of
any change in the financial condition of Borrower, such Subsidiary Guarantor,
any other Subsidiary Guarantor or any other guarantor of the Guaranteed
Obligations since the date hereof, and without affecting or impairing in any way
the liability of such Subsidiary Guarantor hereunder, from time to time to:

                                       -6-
<PAGE>

              (i)  Take and hold security for the payment or performance of the
Guaranteed Obligations and exchange, enforce, waive or release any such
security; apply such security and direct the order or manner of sale thereof;
and purchase such security at public or private sale;

              (ii) Otherwise exercise any right or remedy they may have against
Borrower, such Subsidiary Guarantor, any other Subsidiary Guarantor, any other
guarantor of the Guaranteed Obligations or any security, including, without
limitation, the right to foreclose upon any such security by judicial or
nonjudicial sale; and

              (iii) Settle, compromise with, release or substitute any one or
more makers, endorsers or guarantors of the Guaranteed Obligations.

         (c)  Waivers. To the extent permitted by applicable law, each
Subsidiary Guarantor hereby waives:

              (i)  Any right to require Agent and Guarantors to (A) proceed
against Borrower, any other Subsidiary Guarantor or any other guarantor of the
Guaranteed Obligations, (B) proceed against or exhaust any security received
from Borrower, such Subsidiary Guarantor, any other Subsidiary Guarantor or any
other guarantor of the Guaranteed Obligations or otherwise marshal the assets of
Borrower, such Subsidiary Guarantor, any other Subsidiary Guarantor or any other
guarantor of the Guaranteed Obligations or (C) pursue any other remedy in
Agent's or Guarantors' power whatsoever;

              (ii) Any defense arising by reason of the application by Borrower
of the proceeds of any borrowing;

              (iii) Any defense resulting from the absence, impairment or loss
of any right of reimbursement, subrogation, contribution or other right or
remedy of Subsidiary Guarantor against Borrower, any other Subsidiary Guarantor,
any other guarantor of the Guaranteed Obligations or any security, whether
resulting from an election by Agent to foreclose upon security by nonjudicial
sale, or otherwise;

              (iv) Any setoff or counterclaim of Borrower or any defense which
results from any disability or other defense of Borrower or the cessation or
stay of enforcement from any cause whatsoever of the liability of Borrower
(including, without limitation, the lack of validity or enforceability of any of
the Operative Documents);

              (v)  Any defense based upon any law, rule or regulation which
provides that the obligation of a surety must not be greater or more burdensome
than the obligation of the principal;

              (vi) Until all obligations of Lender to extend credit to Borrower
have terminated and all of the Guaranteed Obligations have been fully, finally
and indefensibly paid, any right of subrogation, reimbursement, indemnification
or contribution and other similar right to enforce any remedy which Agent or any
Guarantor or any other Person now has or may hereafter have against Borrower on
account of the Guaranteed Obligations, and any benefit of, and any right to
participate in, any security now or hereafter received by Agent or any Guarantor
or any other Person on account of the Guaranteed Obligations;

              (vii) All presentments, demands for performance, notices of
nonperformance, notices delivered under the Operative Documents, protests,
notice of dishonor, and notices of acceptance of this Guaranty and of the
existence, creation or incurring of new or additional Guaranteed Obligations and
notices of any public or private foreclosure sale;

              (viii) The benefit of any statute of limitations to the extent
permitted by law;

                                       -7-
<PAGE>
              (ix) Any appraisement, valuation, stay, extension, moratorium
redemption or similar law or similar rights for marshalling;

              (x)  Any right to be informed by Agent or any Guarantor of the
financial condition of Borrower, any other Subsidiary Guarantor or any other
circumstances bearing upon the risk of nonpayment or nonperformance of the
Guaranteed Obligations;

              (xi) Until all obligations of Lender to extend credit to Borrower
have terminated and all of the Guaranteed Obligations have been fully, finally
and indefensibly paid, any right to revoke this Guaranty;

              (xii) Any defense arising from an election for the application of
Section 1111(b)(2) of the United States Bankruptcy Code which applies to the
Guaranteed Obligations;

              (xiii) Any defense based upon any borrowing or grant of a security
interest under Section 364 of the United States Bankruptcy Code; and

              (xiv) Any right it may have to a fair value hearing to determine
the size of a deficiency judgment following any foreclosure on any security for
the Guaranteed Obligations.

Without limiting the scope of any of the foregoing provisions of this Section 5,
to the extent permitted by applicable law, each Subsidiary Guarantor hereby
further waives (A) all rights and defenses arising out of an election of
remedies by Agent, even though that election of remedies, such as a nonjudicial
foreclosure with respect to security for a Guaranteed Obligation, has destroyed
such Subsidiary Guarantor's rights of subrogation and reimbursement against
Borrower by the operation of Section 580d of the Code of Civil Procedure or
otherwise, (B) all rights and defenses such Subsidiary Guarantor may have by
reason of protection afforded to Borrower with respect to the Guaranteed
Obligations pursuant to the antideficiency or other laws of California limiting
or discharging the Guaranteed Obligations, including, without limitation,
Section 580a, 580b, 580d, or 726 of the California Code of Civil Procedure, and
(C) all other rights and defenses available to such Subsidiary Guarantor by
reason of Sections 2787 to 2855, inclusive, Section 2899 or Section 3433 of the
California Civil Code or Section 3605 of the California Commercial Code.

         (d)  Financial Condition of Borrower, Etc. Each Subsidiary Guarantor is
fully aware of the financial condition and affairs of Borrower. Each Subsidiary
Guarantor has executed this Guaranty without reliance upon any representation,
warranty, statement or information concerning Borrower furnished to such
Subsidiary Guarantor by Agent or any Guarantor and has, independently and
without reliance on Agent or any Guarantor and based on such documents and
information as it has deemed appropriate, made its own appraisal of the
financial condition and affairs of Borrower and of other circumstances affecting
the risk of nonpayment or nonperformance of the Guaranteed Obligations. Each
Subsidiary Guarantor is in a position to obtain, and assumes full responsibility
for obtaining, any additional information about the financial condition and
affairs of Borrower and of other circumstances affecting the risk of nonpayment
or nonperformance of the Guaranteed Obligations and will, independently and
without reliance upon Agent or any Guarantor, and based on such documents and
information as it shall deem appropriate at the time, continue to make its own
appraisals and decisions in taking or not taking action in connection with this
Guaranty.

6.       SUBORDINATION. Each Subsidiary Guarantor hereby subordinates any and
all debts, liabilities and obligations owed to such Subsidiary Guarantor by
Borrower or any Subsidiary of Borrower (the "Subordinated Obligations") to the
Guaranteed Obligations as provided in this Section 6.

         (a)  Prohibited Payments, Etc. Except during the existence of an Event
of Default or any default by any Subsidiary Guarantor hereunder, each Subsidiary
Guarantor and its Subsidiaries may receive regularly scheduled payments from

                                       -8-
<PAGE>
Borrower on account of Subordinated Obligations. During the existence of any
Event of Default or any default by any Subsidiary Guarantor hereunder (including
the commencement and continuation of any Insolvency Proceeding relating to
Borrower), however, unless Agent otherwise requests, such Subsidiary Guarantor
shall not, nor shall it permit any of its Subsidiaries to, demand, accept or
take any action to collect any payment on account of the Subordinated
Obligations.

         (b)  Prior Payment of Guaranteed Obligation. In any Insolvency
Proceeding relating to Borrower, each Subsidiary Guarantor agrees that Agent and
Guarantors shall be entitled to receive payment of all Guaranteed Obligations
(including any and all Disallowed Post-Commencement Interest and Expenses)
before such Subsidiary Guarantor or any of its Subsidiaries receives payment of
any Subordinated Obligations.

         (c)  Turn-Over. During the existence of any Event of Default (including
the commencement and continuation of any Insolvency Proceeding relating to
Borrower), each Subsidiary Guarantor and its Subsidiaries shall, if Agent so
requests, collect, enforce and receive payments on account of the Subordinated
Obligations as trustee for Agent and deliver such payments to Agent on account
of the Guaranteed Obligations (including any and all Disallowed
Post-Commencement Interest and Expenses), together with any necessary
endorsements or other instruments of transfer, but without reducing or affecting
in any manner the liability of such Subsidiary Guarantor under the other
provisions of this Guaranty.

         (d)  Agent Authorization. During the existence of any Event of Default
or any default by a Subsidiary Guarantor hereunder (including the commencement
and continuation of any Insolvency Proceeding relating to Borrower), Agent is
authorized and empowered (but without any obligation to so do), in its
discretion, (i) in the name of each Subsidiary Guarantor and its Subsidiaries,
to collect and enforce, and to submit claims in respect of, Subordinated
Obligations and to apply any amounts received thereon to the Guaranteed
Obligations (including any and all Disallowed Post-Commencement Interest and
Expenses), and (ii) to require each Subsidiary Guarantor (A) to collect and
enforce, and to submit claims in respect of, Subordinated Obligations and (B) to
pay any amounts received on such obligations to Agent for application to the
Guaranteed Obligations (including any and all Disallowed Post-Commencement
Interest and Expenses).

7.       GENERAL PLEDGE; SETOFF.
         -----------------------

         (a)  Pledge. In addition to all liens upon and rights of setoff against
the property of any Subsidiary Guarantor given to Agent or any Guarantor by law
or separate agreement to secure the liabilities of any Subsidiary Guarantor
hereunder, to the extent permitted by law, each Subsidiary Guarantor hereby
grants to Agent for the benefit of the Guarantors and itself, as security for
such Subsidiary Guarantor's obligations hereunder, a security interest in all
monies, securities and other property of such Subsidiary Guarantor now or
hereafter in the possession of Agent or any Guarantor; and Agent shall have all
rights and remedies of a secured party with respect to such property.

         (b)  Setoff. In addition to any rights and remedies of Agent or
Guarantors provided by law, Agent shall have the right, without prior notice to
any Subsidiary Guarantor, any such notice being expressly waived by each
Subsidiary Guarantor to the extent permitted by applicable law, during the
existence of an Event of Default, to set-off and apply against the Guaranteed
Obligations then due and payable any amount owing from Agent or any Guarantor to
such Subsidiary Guarantor.

         (c)  Nonwaiver. No security interest or right of setoff shall be deemed
to have been waived by any act or conduct on the part of Agent or by any failure
to exercise such right of setoff or to enforce such security interest, or by any

                                       -9-
<PAGE>
delay in so doing; and every right of setoff and security interest shall
continue in full force and effect until such right of setoff or security
interest is specifically waived or released by an instrument in writing executed
by Agent.

8.       CONTRIBUTION AMONG SUBSIDIARY GUARANTORS. The Subsidiary Guarantors
desire to allocate among themselves, in a fair and equitable manner, their
rights of contribution from each other when any payment is made by any
Subsidiary Guarantor under this Guaranty. Accordingly, if any payment is made by
any Subsidiary Guarantor under this Guaranty (a "Funding Subsidiary Guarantor"')
that exceeds its Fair Share, the Funding Subsidiary Guarantor shall be entitled
to a contribution from each other Subsidiary Guarantor in the amount of such
other Subsidiary Guarantor's Fair Share Shortfall, so that all such
contributions shall cause each Subsidiary Guarantor's Aggregate Guaranty
Payments to equal its Fair Share. The amounts payable as contributions hereunder
shall be determined by the Funding Subsidiary Guarantor as of the date on which
the related payment or distribution is made by the Funding Subsidiary Guarantor,
and such determination shall be binding on the other Subsidiary Guarantors
absent manifest error. The allocation and right of contribution among the
Subsidiary Guarantors set forth in this Section 8 shall not be construed to
limit in any way the liability of any Subsidiary Guarantor under this Guaranty
or the amount of the Guaranteed Obligations.

9.       MISCELLANEOUS.
         --------------

         (a)  Notices. Except as otherwise provided herein, all notices,
requests, demands, consents, instructions or other communications to or upon any
Subsidiary Guarantor or Agent under this Guaranty or the other Operative
Documents to which a Subsidiary Guarantor is a party shall be in writing and
fixed, mailed or delivered, if to a Subsidiary Guarantor or Agent, at its
respective facsimile number or address set forth below or in the respective
Subsidiary Joinder for such Subsidiary Guarantor (or to such other facsimile
number or address for any party as indicated in any notice given by that party
to the other parties). All such notices and communications shall be effective
(i) when sent by overnight service of recognized standing, on the second
Business Day following the deposit with such service; (ii) when mailed, first
class postage prepaid and addressed as aforesaid through the United States
Postal Service, upon receipt; (iii) when delivered by hand, upon delivery; and
(iv) when faxed, upon confirmation of receipt.

         Subsidiary
         Guarantor:       DSLnet Communications Puerto Rico, Inc.
                          DSLnet Communications VA, Inc.
                          Tycho Networks, Inc.
                          Vector Networks, Inc.
                          c/o DSL.net, Inc.
                          545 Long Wharf Drive
                          5th Floor
                          New Haven, CT 06511
                          Attention:  General Counsel
                          Facsimile:  203-624-3612
                          Telephone:  203-772-1000

         Agent            VANTAGEPOINT VENTURE PARTNERS III (Q), L.P., as Agent
                          101 Bayhill Drive, Suite 300
                          San Bruno, CA  94066
                          Attention:  Geoff Fletcher
                          Telephone:  650-866-3100
                          Facsimile:  650-869-3078

                                      -10-
<PAGE>
         (b)  Payments. Each Subsidiary Guarantor shall make all payments
required hereunder to Agent, or its order, at Agent's office located at the
address set forth in Section 9(a) hereof, or at such other office as Agent may
designate, on demand, in U.S. dollars. If any amounts required to be paid by a
Subsidiary Guarantor under this Guaranty are not paid when due, such Subsidiary
Guarantor shall pay interest on the aggregate, outstanding balance of such
amounts from the date due until those amounts are paid in full at a per annum
rate equal to ten percent (10%).

         (c)  Expenses. Each Subsidiary Guarantor shall pay on demand (i) all
reasonable fees and expenses, including reasonable attorneys' fees and expenses,
incurred by Agent and Guarantors in connection with the preparation, execution
and delivery of, and the exercise of its duties under, this Guaranty and the
preparation, execution and delivery of amendments and waivers hereunder and (ii)
all reasonable fees and expenses, including reasonable attorneys' fees and
expenses, incurred by Agent and Guarantors in connection with the enforcement or
attempted enforcement of this Guaranty or any of the Guaranteed Obligations or
in preserving any of Agent's and Guarantors' rights and remedies (including,
without limitation, all such fees and expenses incurred in connection with any
"workout" or restructuring affecting the Operative Documents or the Guaranteed
Obligations or any bankruptcy or similar proceeding involving Subsidiary
Guarantor, any other Subsidiary Guarantor, Borrower or any of their Affiliates).

         (d)  Waivers, Amendments. This Guaranty may not be amended or modified,
nor may any of its terms be waived, except by written instruments signed by each
Subsidiary Guarantor and Required Guarantors. Each waiver or consent under any
provision hereof shall be effective only in the specific instances for the
purpose for which given. No failure or delay on Agent's or any Guarantors' part
in exercising any right hereunder shall operate as a waiver thereof or of any
other right nor shall any single or partial exercise of any such right preclude
any other further exercise thereof or of any other right.

         (e)  Assignment. This Guaranty shall be binding upon and inure to the
benefit of Agent, each Guarantor and the Subsidiary Guarantors and their
respective successors and assigns; provided, however, that no Subsidiary
Guarantor may assign or transfer any of its rights and obligations under this
Guaranty without the prior written consent of Required Guarantors, and,
provided, further, that Agent may sell, assign and delegate their respective
rights and obligations hereunder only as permitted by the Reimbursement
Agreement. All references in this Guaranty to any Person shall be deemed to
include all permitted successors and assigns of such Person.

         (f)  Cumulative Rights, etc. The rights, powers and remedies of Agent
and Guarantors under this Guaranty shall be in addition to all rights, powers
and remedies given to Agent and Guarantors by virtue of any applicable law, rule
or regulation of any governmental authority, the Reimbursement Agreement, any
other Operative Document or any other agreement, all of which rights, powers,
and remedies shall be cumulative and may be exercised successively or
concurrently without impairing Agent's and Guarantors' rights hereunder. Each
Subsidiary Guarantor waives any right to require Agent or Guarantors to proceed
against any Person or to exhaust any Collateral or to pursue any remedy in
Agent's or Guarantors' power.

         (g)  Payments Free of Taxes, Etc. All payments made by each Subsidiary
Guarantor under this Guaranty shall be made by each Subsidiary Guarantor free
and clear of and without deduction for any and all present and future taxes,
levies, charges, deductions and withholdings. In addition, each Subsidiary
Guarantor shall pay upon demand any stamp or other taxes, levies or charges of
any jurisdiction with respect to the execution, delivery, registration,
performance and enforcement of this Guaranty. If any taxes, levies, charges or
other amounts are required to be withheld from any amounts payable to Agent,
hereunder, the amounts so payable to Agent shall be increased to the extent
necessary to yield to Agent (after payment of all such amounts) any such amounts
payable hereunder in the amounts, specified in this Guaranty. Upon reasonable
request by Agent, each Subsidiary Guarantor shall furnish evidence satisfactory
to Agent that all requisite authorizations and approvals by, and notices to and
filings with, governmental authorities and regulatory bodies have been obtained
and made and that all requisite taxes, levies and charges have been paid.

                                      -11-
<PAGE>
         (h)  Partial Invalidity. If at any time any provision of this Guaranty
is or becomes illegal, invalid or unenforceable in any respect under the law or
any jurisdiction, neither the legality, validity or enforceability of the
remaining provisions of this Guaranty nor the legality, validity or
enforceability of such provision under the law of any other jurisdiction shall
in any way be affected or impaired thereby.

         (i)  Joint and Several Obligation. The obligations of the Subsidiary
Guarantors under this Guaranty are joint and several obligations of each
Subsidiary Guarantor and may be freely enforced against each Subsidiary
Guarantor, for the full amount of the Guaranteed Obligations, without regard to
whether enforcement is sought or available against any other Subsidiary
Guarantor.

         (j)  Governing Law. THIS GUARANTY AND THE RIGHTS AND OBLIGATIONS OF THE
PARTIES HERETO SHALL BE GOVERNED BY AND CONSTRUED AND ENFORCED IN ACCORDANCE
WITH THE LAWS OF THE STATE OF CALIFORNIA (WITHOUT REFERENCE TO ITS CHOICE OF
LAWS PROVISIONS).

         (k)  Jury Trial. EACH SUBSIDIARY GUARANTOR, AGENT AND EACH GUARANTOR,
TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, HEREBY IRREVOCABLY WAIVES ALL
RIGHT TO TRIAL BY JURY AS TO ANY ISSUE RELATING HERETO IN ANY ACTION,
PROCEEDING, OR COUNTERCLAIM ARISING OUT OF OR RELATING TO THIS GUARANTY.

         (l)  Limitation of Liability. NO CLAIM MAY BE MADE BY ANY SUBSIDIARY
GUARANTOR AGAINST AGENT OR ANY GUARANTOR OR THE MEMBERS, AFFILIATES, DIRECTORS,
OFFICERS, EMPLOYEES OR ATTORNEYS OF AGENT OR ANY GUARANTOR FOR ANY SPECIAL,
INDIRECT, CONSEQUENTIAL OR PUNITIVE DAMAGES IN RESPECT OF ANY CLAIM (WHETHER
BASED UPON ANY BREACH OF CONTRACT, TORT, BREACH OF STATUTORY DUTY OR ANY OTHER
THEORY OF LIABILITY) ARISING OUT OF OR RELATED TO THE TRANSACTIONS CONTEMPLATED
BY THIS GUARANTY, OR ANY ACT, OMISSION OR EVENT OCCURRING IN CONNECTION
THEREWITH AND EACH GUARANTOR HEREBY WAIVES, RELEASES AND AGREES NOT TO SUE UPON
ANY CLAIM FOR ANY SUCH DAMAGES, WHETHER OR NOT NOW ACCRUED AND WHETHER OR NOT
KNOWN OR SUSPECTED TO EXIST IN ITS FAVOR.

                                      -12-
<PAGE>

         IN WITNESS WHEREOF, each Subsidiary Guarantor has caused this Guaranty
to be executed as of the day and year first above written.

                                    DSLNET COMMUNICATIONS PUERTO RICO, INC.

                                    By:           /s/ David F. Struwas
                                        -------------------------------------
                                        Name:     David F. Struwas
                                            ---------------------------------
                                        Title:    President
                                               ------------------------------

                                    DSLNET COMMUNICATIONS VA, INC.

                                    By:           /s/ David F. Struwas
                                        -------------------------------------
                                        Name:     David F. Struwas
                                             --------------------------------
                                        Title:    President
                                              -------------------------------

                                    TYCHO NETWORKS, INC.

                                    By:           /s/ David F. Struwas
                                        -------------------------------------
                                        Name:     David F. Struwas
                                             --------------------------------
                                        Title:    President
                                              -------------------------------

                                    VECTOR INTERNET SERVICES, INC.

                                    By:           /s/ David F. Struwas
                                        -------------------------------------
                                        Name:     David F. Struwas
                                             --------------------------------
                                        Title:    President
                                              -------------------------------

                      Signature Page to Subsidiary Guaranty
<PAGE>

                               DISCLOSURE SCHEDULE
                               -------------------

None.

<PAGE>
                                  ATTACHMENT 1
                                  ------------

                               SUBSIDIARY JOINDER
                               ------------------

         THIS SUBSIDIARY JOINDER (this "Agreement"), dated as of __________,
____, is executed by [NEW SUBSIDIARY], a ___________ [corporation] [partnership]
[etc.] ("New Subsidiary"), in favor of VANTAGEPOINT VENTURE PARTNERS III (Q),
L.P. as administrative agent for itself and the other Guarantors which are or
may become parties to the Reimbursement Agreement (the "Agent").

                                    RECITALS
                                    --------

         A. Reference is made to that certain Revolving Credit and Term Loan
Agreement, dated as of ________, 2002 (the "CREDIT AGREEMENT"), by and between
Fleet National Bank ("LENDER") and DSL.net, Inc. ("BORROWER").

         B. Each Guarantor has entered into a Guaranty, dated as of ________,
2002 (the "CREDIT GUARANTY"), to guaranty certain of the obligations of Borrower
under the Credit Agreement.

         C. In order to induce Guarantors to enter into the Credit Guaranty, (i)
Borrower entered into a Reimbursement Agreement, dated as of ________, 2002 (the
"REIMBURSEMENT AGREEMENT") with Agent and Guarantors, (ii) certain of Borrower's
subsidiaries ("SUBSIDIARY GUARANTORS") entered into a Subsidiary Guaranty, dated
as of __________, 2002 (the "GUARANTY"), to guaranty Borrower's obligations to
Agent and Guarantors under the Reimbursement Agreement and (iii) Borrower and
Subsidiary Guarantors entered into a Security Agreement, dated as of _______,
2002 (the "SECURITY AGREEMENT"), to secure their respective obligations under
the Reimbursement Agreement and the Guaranty.

         D. New Subsidiary is a [new] Subsidiary of Borrower and expects to
derive substantial direct and indirect benefit from the transactions
contemplated by the Reimbursement Agreement.

                                    AGREEMENT
                                    ---------

         NOW, THEREFORE, in consideration of the above recitals and for other
good and valuable consideration, the receipt and adequacy of which are hereby
acknowledged, New Subsidiary hereby agrees with Agent and each Guarantor, as
follows:

         1. DEFINITIONS AND INTERPRETATION. Unless otherwise defined herein, all
capitalized terms used herein and defined in the Guaranty shall have the
respective meanings given to those terms in the Guaranty. New Subsidiary
acknowledges receipt of copies of the Guaranty, the Security Agreement, the
Credit Agreement and the other Operative Documents.

         2. REPRESENTATIONS AND WARRANTIES. On and as of the date of this
Agreement (the "Effective Date") and for the benefit of Agent, New Subsidiary
hereby makes each of the representations and warranties made by each Subsidiary
Guarantor in the Guaranty.
<PAGE>

         3. AGREEMENT TO BE BOUND. New Subsidiary agrees that, on and as of the
Effective Date, it shall become a Subsidiary Guarantor under the Guaranty and a
Grantor (as such term is defined in the Security Agreement) under the Security
Agreement and shall be bound by all the provisions of the Guaranty and the
Security Agreement to the same extent as if New Subsidiary had executed the
Guaranty and the Security Agreement on the Closing Date.

         4. WAIVER. Without limiting the generality of the waivers in the
Guaranty, New Subsidiary specifically agrees to be bound by the Guaranty and the
Security Agreement and waives any right to notice of acceptance of its execution
of this Agreement and of its agreement to be bound by the Guaranty and the
Security Agreement.

         5. GOVERNING LAW. This Agreement shall be governed by, and construed in
accordance with, the laws of the State of California.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

                                       -2-
<PAGE>

         IN WITNESS WHEREOF, New Subsidiary has caused this Agreement to be
executed by its duly authorized officer.

                                             [NEW SUBSIDIARY]

                                             By:  ______________________________

                                                  Name:_________________________

                                                  Title:________________________

         Address:

         [_____________________________]

         [_____________________________]

         [_____________________________]

         Attn:
              __________________________
         Telephone:
                   _____________________
         Facsimile:
                   _____________________

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