Document:

EXHIBIT 10.4

                               GUARANTY AGREEMENT

     This GUARANTY AGREEMENT (this  "Guaranty"),  dated effective as of June 30,
2000,  is executed and  delivered  by GLOBAL  NETWORKS  ASSETS,  LLC, a Delaware
limited  liability  company  ("Guarantor"),  to and in favor of NORTEL  NETWORKS
INC., as administrative  agent for itself and the other Lenders (as such term is
hereinafter defined) (in such capacity, together with its successors and assigns
in such capacity, "Administrative Agent").

                              W I T N E S S E T H:

     A. Savvis Communications  Corporation, a Missouri corporation ("Borrower"),
Savvis  Communications  Corporation,  a Delaware corporation  ("Holdings"),  the
lenders named therein  (together with their  successors and assigns,  "Lenders")
and Administrative Agent are, concurrently herewith,  entering into that certain
Credit Agreement dated as of June 30, 2000 (as the same may be amended, renewed,
extended,  restated, replaced,  substituted,  supplemented or otherwise modified
from time to time, the "Credit Agreement") and, in connection  therewith,  inter
alia, Borrower is, concurrently herewith,  executing and delivering that certain
Note  dated June 30,  2000,  in the  original  principal  amount of  $38,000,000
payable to the order of Nortel Networks Inc. (such promissory note, as it may be
amended, renewed, extended,  restated,  replaced,  substituted,  supplemented or
otherwise  modified  from time to time,  the "Note" and, to the extent  there is
more than one promissory note  subsequent to a partial  assignment of the Loans,
the "Notes").

     B. Guarantor has directly and  indirectly  benefitted and will directly and
indirectly  benefit  from  the  loans  evidenced  and  governed  by  the  Credit
Agreement,  the Notes and the other Loan  Documents  and the other  transactions
evidenced by and contemplated in the Loan Documents.

     C. Execution and delivery of this Guaranty is a condition to Administrative
Agent and Lenders  entering  into the Credit  Agreement  and the making of Loans
pursuant thereto.

     NOW,  THEREFORE,  for good and  valuable  consideration,  the  receipt  and
adequacy of which are hereby acknowledged, Guarantor hereby agrees as follows:

     1. Definitions.  Unless otherwise defined in this Guaranty, all capitalized
terms used in this  Guaranty  shall have the meanings  ascribed to such terms in
the Credit Agreement.

     2. Guaranty of Indebtedness,  Liabilities and Obligations. Guarantor hereby
absolutely,   unconditionally   and  irrevocably   guarantees  (a)  payment  and
performance to Administrative Agent and Lenders, as and when the same become due
or performable  strictly in accordance with the terms and provisions of the Loan
Documents,  whether at stated maturity, by acceleration or otherwise, of any and
all  Obligations  (as such  term is  defined  in the  Credit  Agreement),  which
Obligations include,  without limitation,  (i) any and all interest,  penalties,
fees and  expenses  (specifically  including,  but not  limited  to,  reasonable
attorneys'  fees and expenses)  which  Borrower may now or at any time hereafter
owe to  Administrative  Agent  or any  Lender  (whether  or not  such  interest,
penalties,  fees and expenses were  originally  contracted  with  Administrative
Agent or any Lender or

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with  another or others and whether or not such  interest,  penalties,  fees and
expenses are enforceable against Borrower) pursuant to the Credit Agreement, any
Note or any other Loan Document  plus (ii) the  principal  amount of any and all
indebtedness,  liabilities and other  obligations,  whether  primary,  absolute,
secondary,  direct,  indirect,  fixed,  contingent,  liquidated,   unliquidated,
secured or unsecured, matured or unmatured, joint, several or joint and several,
due  or to  become  due  and  whether  arising  by  agreement,  note,  discount,
acceptance,  overdraft  or  otherwise,  which  Borrower  may now or at any  time
hereafter  owe to  Administrative  Agent  or any  Lender  (whether  or not  such
indebtedness,  liabilities  and  obligations  were  originally  contracted  with
Administrative  Agent or any Lender or with another or others and whether or not
such indebtedness,  liabilities or obligations are enforceable against Borrower)
pursuant to the Credit  Agreement,  any Note or any other Loan  Document and (b)
the  faithful,  prompt  and  complete  compliance  by  Borrower  with all terms,
conditions,  covenants, agreements and undertakings of Borrower under the Credit
Agreement,  any  Note  or any  other  Loan  Document  (the  Obligations  and the
interest, penalties, fees, expenses, indebtedness,  liabilities and obligations,
etc.  referred  to in  clauses  (a)  and  (b)  preceding  as to  which  payment,
performance  and  compliance  are  guaranteed  pursuant  to  this  Guaranty  are
hereinafter individually and collectively called the "Guaranteed Obligations").

     Notwithstanding   that   Borrower   may  not  be  liable  or  obligated  to
Administrative  Agent or any Lender for interest  and/or  reasonable  attorneys'
fees and expenses on, or in connection with, the Guaranteed Obligations from and
after the Petition Date (as  hereinafter  defined) as a result of the provisions
of the federal  bankruptcy  laws or otherwise,  the Guaranteed  Obligations  for
which  Guarantor shall be liable and obligated under this Guaranty shall include
(to the extent permitted by law or a court of competent  jurisdiction)  interest
accruing on the  Guaranteed  Obligations at the highest rate provided for in the
Credit  Agreement from and after the date on which Borrower files for protection
under  the  federal  bankruptcy  laws or from  and  after  the  date on which an
involuntary  proceeding is filed against  Borrower under the federal  bankruptcy
laws (herein collectively referred to as the "Petition Date") and all attorneys'
fees and expenses incurred by Administrative  Agent or any Lender from and after
the Petition Date in connection with the Guaranteed Obligations.

     3.  Continuing  Guaranty  of  Payment.  This  Guaranty  is and  shall be an
absolute, unconditional, irrevocable and continuing guaranty of payment, and not
merely  of  collection,  and from  time to time or at any  time  the  Guaranteed
Obligations  may be  increased,  reduced or paid in full without  affecting  the
liability or obligation of Guarantor with respect to  indebtedness,  liabilities
and  obligations of Borrower to  Administrative  Agent or any Lender  thereafter
incurred.  Guarantor  further  agrees that this  Guaranty  shall  continue to be
effective or be reinstated (if a release or discharge has occurred), as the case
may be, if at any time any payment (or any part thereof) to Administrative Agent
or any Lender in respect of the  Guaranteed  Obligations  is  rescinded  or must
otherwise  be restored  by  Administrative  Agent or any Lender  pursuant to any
bankruptcy,  insolvency,  reorganization,  receivership  or other debtor  relief
granted  to  Borrower  or  its   successors  or  assigns.   In  the  event  that
Administrative  Agent or any Lender must rescind or restore any payment received
by  Administrative  Agent or any Lender,  respectively,  in  satisfaction of the
Guaranteed Obligations, as set forth herein, any prior release or discharge from
the terms of this Guaranty  given to Guarantor by  Administrative  Agent or such
Lender, respectively, shall be without effect, and this Guaranty shall remain in
full force and effect. It is the intention of Administrative  Agent, Lenders and
Guarantor that Guarantor's liabilities and obligations hereunder shall not be

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discharged  except  by the full and  complete  payment  and  performance  of the
Guaranteed  Obligations  and  then  only  to the  extent  of  such  payment  and
performance.  This  Guaranty  is  independent  of, and in  addition  and without
modification  to and does not impair or in any way  affect  any other  guaranty,
endorsement or other agreement executed in favor of Administrative  Agent or any
Lender, and this Guaranty and Guarantor's liabilities and obligations under this
Guaranty shall not be impaired or otherwise affected by the execution,  delivery
or  performance  by  Guarantor  or  any  other  Person  of any  other  guaranty,
endorsement or other agreement.

     4. Absolute  Guaranty.  Guarantor's  liabilities and obligations under this
Guaranty  shall be absolute  and  unconditional  irrespective  of,  shall not be
released,  impaired, limited, reduced, conditioned upon or otherwise affected by
and shall  continue in full force and effect  notwithstanding  the occurrence of
any event (other than an event  consisting  of payment and  performance  of such
liabilities  and  obligations  as provided in Paragraph 3 hereof) at any time or
from  time  to  time,  including,  without  limitation,  any  one or more of the
following events specified in clauses (a) through (n) of this Paragraph 4 below,
and neither  Administrative  Agent nor any Lender shall be obligated or required
to take or to refrain  from taking any of such  actions or  inactions  specified
below and shall  not have any  liability,  obligation  or duty  whatsoever  with
respect  to such  actions  or  inactions,  it being  acknowledged  and agreed by
Guarantor  that all of such  liabilities,  obligations  and  duties  (if any) of
Administrative  Agent  or any  Lender  otherwise  existing  and all  rights  and
remedies (if any) of Guarantor with respect thereto  (whether such  liabilities,
obligations,  duties,  rights or remedies  exist by virtue of agreement,  common
law,  equity,  statute or otherwise),  and each and every defense  which,  under
principles of guaranty or suretyship law, would otherwise  operate to eliminate,
impair,  condition or restrict the  liabilities and obligations of Guarantor for
the Guaranteed Obligations, are hereby expressly waived by Guarantor:

          (a) the taking or accepting of any security or other  guaranty for any
     or all of the  Guaranteed  Obligations,  whether  heretofore,  concurrently
     herewith or hereafter;

          (b) any failure to create or perfect or properly create or perfect any
     lien, security interest or assignment intended as security, or any release,
     surrender, exchange, substitution, subordination or loss of any security or
     guaranty  at  any  time  existing  in  connection  with  any  or all of the
     Guaranteed   Obligations  for  any  reason;  or  any  suretyship  defenses,
     including, without limitation, any impairment of collateral;

          (c) any partial or full  release of the  liability  or  obligation  of
     Guarantor under any other guaranty whether or not similar to this Guaranty;

          (d) the entering into,  delivery of,  modification of, amendment to or
     waiver of compliance with the Credit Agreement,  any Note or any other Loan
     Document, or any agreement, document or instrument evidencing,  securing or
     otherwise affecting all or part of the Guaranteed Obligations,  without the
     notification  of  Guarantor,  the right of such  notification  being hereby
     specifically waived by Guarantor;

          (e) the bankruptcy, insolvency, arrangement,  adjustment, composition,
     liquidation,   disability,   dissolution  or  lack  of  authority  (whether
     corporate, partnership or trust

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     or relating to any other  entity or Person) of  Borrower,  Guarantor or any
     other Person at any time liable or obligated  for the payment of any or all
     of the Guaranteed Obligations, whether now existing or hereafter arising;

          (f)  any   increase,   reduction,   renewal,   extension,   amendment,
     modification,  repayment,  refunding and/or rearrangement of the payment or
     any other terms or provisions of any or all of the  Guaranteed  Obligations
     at any time and from time to time, whether on one or more occasions, either
     with or  without  notice to or  consent of  Guarantor,  or any  adjustment,
     indulgence,  forbearance  or  compromise  that might be granted or given by
     Administrative Agent or any Lender to Borrower or Guarantor;

          (g) any neglect, delay, omission, failure or refusal of Administrative
     Agent or any Lender (i) to exercise or properly or diligently  exercise any
     right or remedy with respect to any or all of the Guaranteed Obligations or
     the collection  thereof or any collateral,  security or guaranty  therefor,
     whether under the Credit Agreement,  any Note or any other Loan Document or
     otherwise,  including,  without  limitation,  to ensure compliance with any
     term or provision of the Credit Agreement or any other Loan Document,  (ii)
     to take or prosecute or properly or diligently take or prosecute any action
     for the  collection  of any or all of the  Guaranteed  Obligations  against
     Borrower,  Guarantor or any other guarantor of any or all of the Guaranteed
     Obligations  and/or any other  Person,  (iii) to  foreclose or prosecute or
     properly or diligently foreclose or prosecute any action in connection with
     any agreement,  document or instrument or arrangement evidencing,  securing
     or  otherwise  affecting  all or any  part of the  Guaranteed  Obligations,
     including,  without  limitation,  any  failure  to  conduct a  commercially
     reasonable  foreclosure sale, or (iv) to mitigate damages or take any other
     action to reduce, collect or enforce the Guaranteed Obligations;

          (h) any failure of  Administrative  Agent or any Lender to give notice
     to Borrower  and/or  Guarantor of, or obtain the consent of Borrower and/or
     Guarantor  with  respect to, (i) the  incurrence  of any of the  Guaranteed
     Obligations,  (ii) the occurrence of any "Default" or "Event of Default" as
     such terms are  defined in the  Credit  Agreement  or any of the other Loan
     Document,  (iii) demand,  presentment,  protest,  nonpayment,  intention to
     accelerate,  acceleration,  lack of diligence or delay in collection of all
     or any part of the  Guaranteed  Obligations  or any  other  matter,  or the
     absence  thereof,  (iv)  any  renewal,   extension  or  assignment  of  the
     Guaranteed Obligations or any part thereof, (vi) the disposition or release
     of all or any part of any security for the Guaranteed  Obligations (whether
     or not such  disposition  is  commercially  reasonable)  or (vi) any  other
     action taken or refrained from being taken by  Administrative  Agent or any
     Lender against  Borrower,  it being agreed that (except as may be expressly
     provided in the other Loan Documents) neither  Administrative Agent nor any
     Lender shall be required to give  Borrower or  Guarantor  any notice of any
     kind or to obtain Borrower's or Guarantor's consent under any circumstances
     whatsoever   with  respect  to  or  in  connection   with  the   Guaranteed
     Obligations;

          (i) the unenforceability, illegality or uncollectibility of all or any
     part of the  Guaranteed  Obligations  against  Borrower  by  reason  of (i)
     failure of  consideration,  (ii) breach of warranty,  (iii) fraud, (iv) the
     fact that the interest contracted for, charged, collected or

<PAGE>

     received  in  respect  of the  Guaranteed  Obligations  exceeds  the amount
     permitted by law, (v) the act of creating the Guaranteed Obligations or any
     part  thereof  is ultra  vires,  (vi) the  officers,  directors,  partners,
     trustees or  representatives  creating the Guaranteed  Obligations acted in
     excess  of their  authority  or lacked  legal  capacity,  (vii) the  Credit
     Agreement,  any Note or any other Loan Document  evidencing  the Guaranteed
     Obligations  has been forged or otherwise is irregular or is not genuine or
     authentic,  (viii)  expiration of the applicable  statute of limitations of
     the  Guaranteed  Obligations,  (ix)  failure to comply  with the statute of
     frauds, (x) lender liability, or (xi) accord and satisfaction;

          (j) any payment by Borrower to  Administrative  Agent or any Lender is
     held to constitute a  preferential  transfer or a fraudulent  conveyance or
     transfer under any applicable law, or for any reason  Administrative  Agent
     or any Lender is  required  to refund  such  payment or pay such  amount to
     Borrower or any other Person;

          (k)  any  merger,  reorganization,  consolidation  or  dissolution  of
     Borrower,  any  sale,  lease or  transfer  of any or all of the  assets  of
     Borrower, or any change in name, business, location, composition, structure
     or  any  change  in the  shareholders,  partners  or  members  (whether  by
     accession, secession, death, dissolution,  transfer of assets or otherwise)
     of Borrower;

          (l) any  failure  of  Administrative  Agent or any  Lender  to  notify
     Guarantor of (i) the acceptance of this Guaranty,  (ii) the making of Loans
     by any Lender in reliance on this  Guaranty,  (iii) the failure of Borrower
     to make any payment due by Borrower to Administrative  Agent or any Lender,
     or (iv) any information  regarding the financial  condition or prospects of
     Borrower;

          (m) any full or partial  release of the  liability  of  Borrower,  any
     guarantor  of all or any part of the  Guaranteed  Obligations  or any other
     Person  for  all or  any  part  of the  Guaranteed  Obligations,  it  being
     acknowledged  and agreed by  Guarantor  that it may be  required to pay the
     Guaranteed Obligations in full without assistance or support,  whether from
     Borrower, any other guarantor or any other Person; or

          (n) any other  action taken or omitted to be taken with respect to any
     of  the  Credit  Agreement,  any  Note  or any  other  Loan  Document,  the
     Guaranteed Obligations or the security and collateral therefor,  whether or
     not  such  action  or  omission  prejudices   Guarantor  or  increases  the
     likelihood  that  Guarantor  will be required to pay all or any part of the
     Guaranteed Obligations pursuant to the terms hereof.

Without limiting the foregoing or Guarantor's  liability under this Guaranty, to
the extent that Administrative  Agent and Lenders (or any of them) have advanced
funds or  extended  credit to Borrower  and do not receive  payments or benefits
thereon in the amounts and at the times required or provided by or in connection
with the Credit  Agreement,  any Notes or any other Loan Document,  Guarantor is
absolutely  liable to make such  payments and to confer such benefits on Lenders
on a timely basis.

<PAGE>

     5.  Representations  and  Warranties.  In  connection  with this  Guaranty,
Guarantor  hereby  represents and warrants to  Administrative  Agent and Lenders
that:

          (a)  Guarantor is a Subsidiary  of Borrower and Guarantor has received
     and  will  receive  a  direct  and  indirect   material  benefit  from  the
     transactions  evidenced by and  contemplated in the Credit  Agreement,  the
     Notes and the other Loan Documents;  this Guaranty is given by Guarantor in
     furtherance  of the direct and indirect  business  interests  and corporate
     purposes of  Guarantor,  and is  necessary to the  conduct,  promotion  and
     attainment of the  businesses of Borrower and  Guarantor;  and the value of
     the  consideration  received and to be received by Guarantor is believed by
     Guarantor  to be  reasonably  worth at least as much as the  liability  and
     obligation of Guarantor hereunder;

          (b) The execution and delivery of this Guaranty and the performance of
     and  compliance  with the terms hereof will not constitute a default (or an
     event  which  with  notice  or lapse  of time or both  would  constitute  a
     default)  under,  or  result  in the  breach  of,  any  material  contract,
     agreement  or  instrument  to which  Guarantor  is a party or which  may be
     applicable to Guarantor or any of its assets;

          (c) This  Guaranty,  when executed and  delivered by  Guarantor,  will
     constitute the legal, valid and binding obligation of Guarantor enforceable
     in accordance with its terms,  except as limited by bankruptcy,  insolvency
     or  other  laws of  general  application  relating  to the  enforcement  of
     creditors' rights and general principles of equity;

          (d) As of the date of this  Guaranty,  and after giving effect to this
     Guaranty  and  the  contingent   obligation  evidenced  by  this  Guaranty,
     Guarantor is not, on either an unconsolidated basis or a consolidated basis
     with Borrower and Holdings'  subsidiaries,  insolvent, as such term is used
     or defined in any applicable bankruptcy,  fraudulent conveyance, fraudulent
     transfer or similar  law,  and  Guarantor  has and will have assets  which,
     fairly  valued,  exceed  its  indebtedness,  liabilities  and  obligations;
     Guarantor is not  executing  this  Guaranty  with any  intention to hinder,
     delay or defraud any present or future  creditor or creditors of Guarantor;
     Guarantor is not engaged in any business or transaction (including, without
     limitation, the execution of this Guaranty) which will leave Guarantor with
     unreasonably  small  capital  or  assets  which are  unreasonably  small in
     relation  to the  business or  transactions  engaged in by  Guarantor,  and
     Guarantor  does not intend to engage in any such  business or  transaction;
     Guarantor does not intend to incur, nor does Guarantor believe that it will
     incur, debts beyond Guarantor's ability to repay such debts as they mature;

          (e) All acts and  conditions  required to be performed  and  satisfied
     prior to the creation and issuance of this Guaranty, and to constitute this
     Guaranty  as the  legal,  valid and  binding  obligation  of  Guarantor  in
     accordance  with its terms,  have been  performed  and satisfied in due and
     strict compliance with all applicable laws;

          (f) Guarantor is familiar with, and has  independently  received books
     and records regarding,  the financial condition of Borrower and is familiar
     with the value of any and all  collateral  (if any)  intended to secure the
     Guaranteed Obligations; however, Guarantor is not

<PAGE>

     relying on such financial  condition or any such  collateral (if any) as an
     inducement to enter into this  Guaranty;  Guarantor  has adequate  means to
     obtain from Borrower, on a continuing basis, the information referred to in
     this clause (f) and is not relying on Administrative Agent or any Lender to
     provide any such information at any time;

          (g)  Guarantor has not been induced to enter into this Guaranty on the
     basis of a  contemplation,  belief,  understanding  or  agreement  that any
     Person  other  than   Guarantor  will  be  liable  to  pay  the  Guaranteed
     Obligations;

          (h)  Except  for  the  execution  of  the  Credit  Agreement,  neither
     Administrative  Agent,  any  Lender  nor any  other  Person  has  made  any
     representation, warranty or statement to, or promise, covenant or agreement
     with, Guarantor in order to induce Guarantor to execute this Guaranty;

          (i) Guarantor is a wholly-owned Subsidiary of Borrower; and

          (j)  All  representations  and  warranties  in  the  Credit  Agreement
     relating to the  Guarantor  are true and correct in all  respects as of the
     date  hereof,  except to the extent made only as of a specific  prior date,
     and on each date the representations and warranties thereunder are restated
     pursuant to any of the Loan  Documents with the same force and effect as if
     such  representations  and warranties had been made on and as of such date,
     all of which are incorporated herein by reference.

     6. Default. Upon the occurrence of an Event of Default, Guarantor shall, on
demand by  Administrative  Agent and  without  further  notice of  dishonor  and
without notice of any kind (including,  without limitation, notice of acceptance
by  Administrative  Agent or any Lender of this  Guaranty)  having been given to
Borrower, Guarantor or any other Person previous to such demand, promptly (i.e.,
not later than 1:00 p.m.,  New York,  New York time,  on the date of such demand
or, if such  demand is made after 12:00 noon,  on the next  succeeding  Business
Day)  pay,  in  immediately  available  funds,  the full  unpaid  amount  of the
Guaranteed  Obligations,  or such lesser amount,  if any, as may be specifically
demanded by Administrative  Agent from time to time, to Administrative  Agent at
Administrative Agent's Principal Office located in New York, New York or at such
other place as  Administrative  Agent may specify to  Guarantor  in writing.  If
acceleration  of the time for payment of any amount payable by Borrower under or
with respect to any of the Guaranteed Obligations is stayed or otherwise delayed
upon the insolvency,  bankruptcy or reorganization of Borrower, all such amounts
otherwise subject to acceleration under the terms of the Guaranteed  Obligations
shall  nonetheless  be  payable by  Guarantor  hereunder  promptly  on demand by
Administrative Agent.

     7. Cumulative Remedies;  No Election.  If Guarantor is or becomes liable or
obligated for the Guaranteed  Obligations,  by  endorsement or otherwise,  other
than under this  Guaranty,  such  liability  or  obligation  shall not be in any
manner   impaired  or  affected   hereby,   and  the  rights  and   remedies  of
Administrative  Agent or any Lender hereunder shall be cumulative of any and all
other rights and remedies that Administrative Agent or such Lender may ever have
against  Guarantor.  The exercise by  Administrative  Agent or any Lender of any
right or remedy hereunder or under any other

<PAGE>

agreement,  document or instrument,  or at law or in equity,  shall not preclude
the concurrent or subsequent  exercise of any other right or remedy.  Without in
any way limiting the generality of the foregoing,  it is specifically understood
and agreed that this Guaranty is given by Guarantor as an additional guaranty or
security to any and all other  guaranties or security  heretofore,  concurrently
herewith or hereafter  executed and/or  delivered by Guarantor to or in favor of
Administrative Agent or any Lender relating to the Guaranteed  Obligations,  and
nothing  herein  shall ever be deemed to in any way  negate or replace  any such
other guaranties or security;  provided,  however, that Administrative Agent and
Lenders  shall  have  all of their  rights  and  remedies  under  this  Guaranty
irrespective of anything to the contrary  contained in any such other guaranties
or  security.  This  Guaranty  may be  enforced  from  time to time as  often as
occasion  therefor may arise,  and it is agreed and understood that it shall not
be necessary for  Administrative  Agent or any Lender,  in order to enforce this
Guaranty  against  Guarantor,  first to exercise any rights or remedies  against
Borrower or any other Person or institute  suit or exhaust any available  rights
or  remedies  against  security  in  Administrative   Agent's  or  any  Lender's
possession or under Administrative Agent's or any Lender's control, or to resort
to  any  other  sources  or  means  of  obtaining   payment  of  the  Guaranteed
Obligations.

     8. Joint and Several Obligation. Guarantor agrees that Administrative Agent
and Lenders, in their sole discretion, may (a) bring suit against all guarantors
or other Persons  liable or obligated to  Administrative  Agent or any Lender or
against  any one or more of  them,  for  interest,  penalties,  expenses,  fees,
indebtedness,  liabilities and obligations owed to  Administrative  Agent or any
Lender and apply any amounts obtained by  Administrative  Agent or any Lender in
such a manner as  Administrative  Agent or any Lender may elect,  (b) bring suit
against all  guarantors of the Guaranteed  Obligations  jointly and severally or
against  any one or more of them,  (c)  settle  fully or in part with any one or
more of such guarantors for such  consideration as  Administrative  Agent or any
Lender may deem proper,  and (d)  partially or fully release one or more of such
guarantors from liability under any guaranty agreement,  and that no such action
shall  impair the rights of  Administrative  Agent or any Lender to collect  the
Guaranteed  Obligations  (or the unpaid balance  thereof) from other  guarantors
(including, without limitation, Guarantor), or any of them, not so sued, settled
with or released.

     9.  Release  of  Collateral,  etc.  If all or any  part  of the  Guaranteed
Obligations is at any time secured,  Guarantor agrees that Administrative  Agent
or any Lender may, at any time and from time to time in its  discretion and with
or  without  valuable   consideration,   allow  substitution  or  withdrawal  of
collateral or other security and release  collateral or other  security  without
impairing or diminishing the liabilities or obligations of Guarantor  hereunder.
Guarantor further agrees that, if Borrower or any other Person executes in favor
of Administrative Agent or any Lender any collateral agreement,  mortgage,  deed
of  trust,   collateral   assignment,   security  agreement  or  other  security
instrument,  the exercise by Administrative  Agent or any Lender of any right or
remedy thereby conferred on  Administrative  Agent or any Lender shall be wholly
discretionary with Administrative Agent and such Lender, respectively,  and that
the  exercise  or failure to exercise  any such right or remedy  shall in no way
impair or diminish the  obligation  of Guarantor  hereunder.  Guarantor  further
agrees that (except to the extent  prohibited by applicable law  notwithstanding
an agreement of the parties to the contrary)  neither  Administrative  Agent nor
any Lender  shall be liable  for its  failure  to use  diligence  or care in the
collection of the Guaranteed Obligations, in the creation

<PAGE>

or perfection of any lien,  security interest or assignment intended as security
or in  preserving  the  liability  of any  Person  liable  or  obligated  on the
Guaranteed  Obligations,  and Guarantor  hereby waives  presentment for payment,
notice of nonpayment, protest and notice thereof, and diligence in bringing suit
against any Person liable on the Guaranteed Obligations or any part thereof.

     10.  Binding  Effect.  This  Guaranty is for the benefit of  Administrative
Agent and Lenders and their successors and permitted  assigns,  and in the event
of an  assignment  by  Administrative  Agent or any Lender or its  successors or
assigns  of the  Guaranteed  Obligations,  or any part  thereof,  the rights and
benefits  hereunder,  to the extent applicable to the indebtedness,  liabilities
and  obligations  so  assigned,  may  be  transferred  with  such  indebtedness,
liabilities and obligations.  This Guaranty is binding, not only upon Guarantor,
but upon its successors and assigns.

     11. WAIVER OF SUBROGATION,  CONTRIBUTION AND OTHER RIGHTS.  UPON PAYMENT BY
GUARANTOR  OF ANY  SUMS  IN  RESPECT  OF THE  GUARANTEED  OBLIGATIONS  HEREUNDER
(INCLUDING,  WITHOUT LIMITATION, ANY AMOUNTS ADVANCED TO BORROWER BY GUARANTOR),
ALL  RIGHTS  OF  GUARANTOR  AGAINST  BORROWER  OR  ANY  OTHER  GUARANTOR  OF THE
GUARANTEED  OBLIGATIONS  ARISING  AS A  RESULT  THEREFROM  BY  WAY OF  RIGHT  OF
SUBROGATION,  REIMBURSEMENT,  EXONERATION, CONTRIBUTION,  INDEMNIFICATION AND/OR
OTHERWISE  SHALL IN ALL RESPECTS BE  SUBORDINATE  AND JUNIOR IN RIGHT OF PAYMENT
AND ENFORCEMENT TO THE PRIOR INDEFEASIBLE PAYMENT AND ENFORCEMENT IN FULL OF THE
GUARANTEED OBLIGATIONS. GUARANTOR SHALL NOT HAVE, AND HEREBY IRREVOCABLY WAIVES,
ANY AND ALL RIGHTS AND  REMEDIES  OF  SUBROGATION,  REIMBURSEMENT,  EXONERATION,
CONTRIBUTION,  INDEMNIFICATION  AND/OR OTHERWISE AGAINST OR FROM BORROWER UNLESS
AND UNTIL ALL OF THE  GUARANTEED  OBLIGATIONS  HAVE BEEN PAID AND  PERFORMED  IN
FULL. IN ADDITION TO THE FOREGOING,  GUARANTOR HEREBY IRREVOCABLY WAIVES ANY AND
ALL CLAIMS OR OTHER  RIGHTS AND  REMEDIES IT MAY NOW HAVE OR  HEREAFTER  ACQUIRE
AGAINST  ADMINISTRATIVE  AGENT,  ANY LENDER,  BORROWER OR ANY OTHER PERSON UNDER
CHAPTER 34 OF THE TEXAS  BUSINESS AND COMMERCE  CODE,  UNDER RULES 31 AND 163 OF
THE TEXAS  RULES OF CIVIL  PROCEDURE,  UNDER  SECTION  17.001 OF THE TEXAS CIVIL
PRACTICE  AND  REMEDIES  CODE AND UNDER ANY OTHER  STATUTE OF ANY STATE OR OTHER
JURISDICTION  REQUIRING  RECOURSE  AGAINST THE PRIMARY OBLIGOR OR IMPOSING OTHER
REQUIREMENTS AS A CONDITION TO RECOURSE AGAINST A GUARANTOR IF AND TO THE EXTENT
THAT THE SAME MAY BE APPLICABLE TO THIS GUARANTY.  Except as expressly otherwise
provided in this Paragraph 11,  Guarantor  shall have all rights of subrogation,
reimbursement,  exoneration,  contribution  and  indemnification  that may exist
under currently applicable law.

<PAGE>

     12.  Subordination  of  Indebtedness  and Liens.  In  connection  with this
Guaranty, Guarantor hereby agrees that:

          (a) The  payment  of any  and all  principal  of and  interest  on the
     Subordinated  Indebtedness  (as  defined  below)  shall in all  respects be
     subordinate  and junior in right of payment  and  enforcement  to the prior
     payment and  enforcement in full of all Guaranteed  Obligations as provided
     in this Paragraph 12. The Subordinated  Indebtedness  shall not be payable,
     and no payment of principal,  interest or other amounts on account thereof,
     and no property or guaranty of any nature to secure,  guarantee  or pay the
     Subordinated Indebtedness shall be made or given, directly or indirectly by
     or on behalf of  Borrower  or  received,  accepted,  retained or applied by
     Guarantor unless and until the Guaranteed  Obligations shall have been paid
     and performed in full; except that, prior to the occurrence and continuance
     of an Event of Default, Guarantor shall have the right to receive regularly
     scheduled payments, but not prepayments,  on the Subordinated  Indebtedness
     made in the ordinary  course of business.  After the occurrence of an Event
     of  Default,  no payments of  principal  or interest  may be made or given,
     directly or indirectly, by or on behalf of Borrower or received,  accepted,
     retained  or  applied  by  Guarantor   unless  and  until  the   Guaranteed
     Obligations  shall have been paid and  performed in full. If any sums shall
     be paid to Guarantor or any Affiliate of Guarantor by Borrower or any other
     Person on account of the Subordinated Indebtedness when such payment is not
     permitted hereunder,  such sums shall be held in trust by Guarantor for the
     benefit  of  Administrative  Agent  and  Lenders  and  shall  forthwith  be
     delivered  to  Administrative  Agent  without  affecting  the  liability of
     Guarantor  under this Guaranty and may be applied by  Administrative  Agent
     against the Guaranteed Obligations in accordance with the Credit Agreement.
     Upon the request of Administrative Agent, Guarantor shall execute, deliver,
     and endorse to  Administrative  Agent such  documentation as Administrative
     Agent may request to perfect,  preserve  and enforce its rights  hereunder.
     For  purposes of this  Guaranty  and with  respect to  Guarantor,  the term
     "Subordinated   Indebtedness"  means  all  indebtedness,   liabilities  and
     obligations   of  Borrower  to   Guarantor,   whether  such   indebtedness,
     liabilities and  obligations now exist or are hereafter  incurred or arise,
     or are primary, absolute,  secondary,  direct, indirect, fixed, contingent,
     liquidated,  unliquidated,  secured or  unsecured,  matured  or  unmatured,
     joint,  several,  joint and several,  or  otherwise,  and  irrespective  of
     whether such  indebtedness,  liabilities or obligations  are evidenced by a
     note, contract,  open account or otherwise,  and irrespective of the Person
     or Persons in whose favor such  indebtedness,  obligations  or  liabilities
     may, at their  inception,  have been, or may  hereafter be created,  or the
     manner in which they have been or may hereafter be acquired by Guarantor;

          (b) Any  and  all  Liens  (including  any  judgment  Liens)  upon  any
     Borrower's   property  or  assets  securing  payment  of  any  Subordinated
     Indebtedness  (the  "Subordinated  Liens") shall be and remain inferior and
     subordinate to any and all Liens upon Borrower's assets securing payment of
     the Guaranteed Obligations or any part thereof,  regardless of whether such
     Subordinated  Liens presently  exist or are hereafter  created or when such
     Subordinated Liens were created,  perfected,  filed or recorded.  Guarantor
     shall not exercise or enforce any creditors' rights or remedies that it may
     have  against  Borrower or  foreclose,  repossess,  sequester  or otherwise
     institute any action or proceeding (whether judicial or

<PAGE>

     otherwise,  including,  without limitation, the commencement of, or joinder
     in, any bankruptcy, insolvency,  reorganization,  liquidation, receivership
     or  other  debtor  relief  law) to  enforce  any  Subordinated  Lien on any
     property or assets of Borrower unless and until the Guaranteed  Obligations
     shall have been irrevocably paid and performed in full.

          (c) In the  event  of any  receivership,  bankruptcy,  reorganization,
     rearrangement,  debtor's relief or other  insolvency  proceeding  involving
     Borrower as debtor,  Administrative Agent shall have the right to prove and
     vote any claim under the Subordinated  Indebtedness and to receive directly
     from  the  receiver,  trustee  or  other  court  custodian  all  dividends,
     distributions and payments made in respect of the Subordinated Indebtedness
     until the  Guaranteed  Obligations  have been paid in full.  Administrative
     Agent may apply any such dividends,  distributions and payments against the
     Guaranteed Obligations in accordance with the Credit Agreement;

          (d) All promissory notes, accounts receivable, ledgers, records or any
     other evidence of Subordinated  Indebtedness,  and all mortgages,  deeds of
     trust,  security  agreements,  assignments  and  other  security  documents
     evidencing the Subordinated  Liens, shall contain a specific written notice
     thereon that the indebtedness and Liens evidenced  thereby are subordinated
     under the terms of this Guaranty; and

          (e) The  terms  and  provisions  of this  Paragraph  12 are  given  by
     Guarantor as additional rights,  remedies and benefits to any and all other
     subordination  agreements  heretofore,  concurrently  herewith or hereafter
     executed by Guarantor to or in favor of Administrative Agent or any Lender,
     and nothing in this  Guaranty  shall ever be deemed to in any way negate or
     replace any other such  previous,  concurrent or  subsequent  subordination
     agreements.

     13. Right of Setoff.  Guarantor hereby grants to  Administrative  Agent and
each  Lender a right of  setoff  upon any and all  monies,  securities  or other
property of  Guarantor,  and the proceeds  therefrom,  now or hereafter  held or
received by or in transit to Administrative  Agent or any Lender from or for the
account of Guarantor,  whether for safekeeping,  custody, pledge,  transmission,
collection or otherwise, and also upon any and all deposits (general or special)
and  credits  of  Guarantor,  and  any  and  all  claims  of  Guarantor  against
Administrative  Agent or any  Lender at any time  existing.  The right of setoff
granted  pursuant to this Paragraph 13 shall be cumulative of and in addition to
Administrative Agent's and each Lender's common law right of setoff.

     14. Further  Assurances.  Upon the request of  Administrative  Agent or any
Lender,  Guarantor  will,  at any time and from time to time,  duly  execute and
deliver to Administrative  Agent any and all such further agreements,  documents
and instruments,  and supply such additional information, as may be necessary or
advisable,  in the reasonable opinion of Administrative  Agent or any Lender, to
obtain the full benefits of this Guaranty.

     15.  Invalid  Provisions.  If any  provision of this Guaranty is held to be
illegal,  invalid or unenforceable under present or future laws effective during
the term hereof, such provision shall be fully severable, this Guaranty shall be
construed and enforced as if such illegal, invalid or

<PAGE>

unenforceable  provision  had never  comprised a part hereof,  and the remaining
provisions  hereof  shall  remain  in full  force  and  effect  and shall not be
affected by the illegal,  invalid or unenforceable provision or by its severance
herefrom.  Furthermore,  in lieu  of  such  illegal,  invalid  or  unenforceable
provision  there  shall  be added  automatically  as a part of this  Guaranty  a
provision  as  similar  in  terms  to such  illegal,  invalid  or  unenforceable
provision as may be possible and be legal,  valid and enforceable.  No provision
herein or in any other Loan Document evidencing the Guaranteed Obligations shall
require  the  payment  or permit the  collection  of  interest  in excess of the
maximum permitted by applicable law.

     16. Modification in Writing. No modification,  consent, amendment or waiver
of any provision of this Guaranty,  and no consent to any departure by Guarantor
herefrom, shall be effective unless the same shall be in writing and signed by a
duly authorized officer of Administrative  Agent and Guarantor and then shall be
effective only in the specific  instance and for the specific  purpose for which
given.

     17. No Waiver,  Etc. No notice to or demand on Guarantor or  Administrative
Agent in any case shall entitle Guarantor or Administrative Agent, respectively,
to any other or further notice or demand in similar or other  circumstances.  No
delay or omission by Administrative Agent, any Lender or Guarantor in exercising
any  right or  remedy  hereunder  shall  impair  any such  right or remedy or be
construed  as a waiver  thereof or any  acquiescence  therein,  and no single or
partial  exercise of any such right or remedy  shall  preclude  other or further
exercise thereof or the exercise of any other right or remedy hereunder.

     18. Cumulative Rights. All rights and remedies of Administrative  Agent and
Lenders  hereunder  are  cumulative  of each other and of every  other  right or
remedy which  Administrative Agent or any Lender may otherwise have at law or in
equity or under any other contract or document,  and the exercise of one or more
rights or remedies  shall not  prejudice or impair the  concurrent or subsequent
exercise of other rights or remedies.

     19. Expenses. Guarantor agrees to pay on demand by Administrative Agent all
reasonable costs and expenses incurred by Administrative  Agent or any Lender in
connection  with the  enforcement  of the terms and  provisions of this Guaranty
and, if and to the extent that Borrower is obligated therefor in accordance with
the  Credit  Agreement,  any  and  all  amendments,   modifications,   renewals,
restatements  and/or  supplements hereto from time to time,  including,  without
limitation,  the reasonable fees and expenses of legal counsel to Administrative
Agent.  If  Guarantor  should  breach or fail to perform any  provision  of this
Guaranty, Guarantor agrees to pay to Administrative Agent all costs and expenses
incurred  by  Administrative  Agent or any  Lender  in the  enforcement  of this
Guaranty from time to time, including,  without limitation,  the reasonable fees
and expenses of all legal counsel to Administrative Agent and Lenders.

<PAGE>

     20.  APPLICABLE  LAW. THIS GUARANTY  SHALL BE GOVERNED BY, AND CONSTRUED IN
ACCORDANCE  WITH, THE LAWS OF THE STATE OF NEW YORK (WITHOUT REGARD TO CONFLICTS
OF LAWS PRINCIPLES).

     21. NO ORAL  AGREEMENTS.  THIS  GUARANTY  REPRESENTS  THE  FINAL  AGREEMENT
BETWEEN GUARANTOR AND  ADMINISTRATIVE  AGENT AND LENDERS RELATING TO THE SUBJECT
MATTER  OF THIS  GUARANTY  AND MAY NOT BE  CONTRADICTED  BY  EVIDENCE  OF PRIOR,
CONTEMPORANEOUS  OR SUBSEQUENT  ORAL  AGREEMENTS  OF SUCH PARTIES.  THERE ARE NO
UNWRITTEN ORAL AGREEMENTS BETWEEN OR AMONG GUARANTOR AND ADMINISTRATIVE AGENT OR
ANY LENDER.  THIS GUARANTY  SUPERSEDES ALL PRIOR (IF ANY) ORAL AGREEMENTS,  ORAL
ARRANGEMENTS  OR ORAL  UNDERSTANDINGS  RELATING  TO THE  SUBJECT  MATTER OF THIS
GUARANTY,  AND THIS GUARANTY  SUPERSEDES  ALL PRIOR (IF ANY) WRITTEN  AGREEMENTS
RELATING TO THE SUBJECT  MATTER OF THIS  GUARANTY IF AND TO THE EXTENT THAT SUCH
PRIOR AGREEMENTS ARE INCONSISTENT WITH THIS GUARANTY.

     22. Notices. All notices and other communications  required or permitted to
be given  under this  Guaranty  shall be given or made in  writing  and shall be
delivered in the manner and to the  addresses,  and shall be deemed to have been
duly given when, specified in the Credit Agreement.

     23. Survival. All representations,  warranties, covenants and agreements of
Guarantor in this Guaranty shall survive the execution of this Guaranty.

     24.  Counterparts.   This  Guaranty  may  be  executed  in  any  number  of
counterparts,  each of which shall constitute an original, but all of which when
taken together shall constitute one and the same Guaranty.

     25.  Limitation  on  Interest.  Notwithstanding  anything  to the  contrary
contained or referred to in this  Guaranty,  none of the terms and provisions of
this Guaranty, the Credit Agreement,  the Notes or any other Loan Document shall
ever be construed to create a contract or  obligation  to pay interest at a rate
in excess of the Maximum Rate, and neither  Administrative  Agent nor any Lender
shall ever charge, receive, take, collect,  reserve or apply, as interest on the
Obligations or the Guaranteed  Obligations,  any amount in excess of the Maximum
Rate. The parties hereto agree that any interest,  charge, fee, expense or other
indebtedness,  liability or obligation provided for in this Guaranty, the Credit
Agreement, the Notes or any other Loan Document which constitutes interest under
applicable law shall be, ipso facto and under any and all circumstances, limited
or reduced to an amount equal to the lesser of (a) the amount of such  interest,
charge, fee, expense or other  indebtedness,  liability or obligation that would
be payable  in the  absence of this  Paragraph  25 or (b) an amount,  which when
added to all other interest payable under this Guaranty,  the Credit  Agreement,
the  Notes  and  any  other  Loan   Document,   equals  the  Maximum  Rate.  If,
notwithstanding the foregoing, Administrative Agent or any Lender ever contracts
for, charges,  receives,  takes,  collects,  reserves or applies as interest any
amount  in  excess  of the  Maximum  Rate,  such  amount  which  would be deemed
excessive interest shall be deemed a partial payment or prepayment of

<PAGE>

principal  of  the  Obligations  and  the  Guaranteed  Obligations  and  treated
hereunder as such, and if the  Obligations  and the Guaranteed  Obligations,  or
applicable  portions  thereof,  are paid in full,  any  remaining  excess  shall
promptly be paid to Borrower,  Guarantor or such other Person (as  appropriate).
In  determining  whether  the  interest  paid or  payable,  under  any  specific
contingency, exceeds the Maximum Rate, Guarantor, Borrower, Administrative Agent
and Lenders  shall,  to the maximum  extent  permitted  by  applicable  law, (i)
characterize any nonprincipal  payment as an expense, fee or premium rather than
as interest,  (ii) exclude  voluntary  prepayments and the effects thereof,  and
(iii) amortize, prorate, allocate and spread in equal or unequal parts the total
amount of interest  throughout the entire  contemplated  term of the Obligations
and the Guaranteed  Obligations,  or applicable  portions  thereof,  so that the
interest  rate does not exceed the  Maximum  Rate at any time during the term of
the  Obligations  and the Guaranteed  Obligations;  provided that, if the unpaid
principal  balance  is paid and  performed  in full prior to the end of the full
contemplated term thereof, and if the interest received for the actual period of
existence  thereof  exceeds the Maximum Rate,  Administrative  Agent and Lenders
shall refund to Borrower,  Guarantor or such other Person (as  appropriate)  the
amount of such excess and, in such event,  neither  Administrative Agent nor any
Lender shall be subject to any  penalties  provided by any laws for  contracting
for, charging, receiving, taking, collecting,  receiving or applying interest in
excess of the Maximum Rate.

     26.  Irrevocable  Nature of Guaranty.  This  Guaranty may not be revoked by
Guarantor; provided, however, in the event it shall be determined that Guarantor
shall have the right, in accordance with applicable law and  notwithstanding its
express agreement herein to the contrary, to revoke this Guaranty, Guarantor may
deliver to  Administrative  Agent,  at its  address for notices set forth in the
Credit  Agreement,  written  notice of  Guarantor's  intention  not to be liable
hereunder for any  Guaranteed  Obligations  arising,  created or incurred  after
Administrative  Agent's  receipt of such notice,  whereupon such notice shall be
effective  to the extent (but only to the  extent)  provided  hereinbelow  as to
Guarantor  from and after (but not before) the time when such notice is actually
delivered  to and  received by and  receipted  for in writing by  Administrative
Agent (the "Effective Revocation Time"); provided,  further,  however, that such
notice shall not be effective as to, and shall not in any way  restrict,  limit,
impair,   release  or  otherwise  affect,   the  indebtedness,   liabilities  or
obligations of Guarantor  under this Guaranty with respect to (a) any Guaranteed
Obligations  consisting of  indebtedness,  liabilities or obligations  under the
Credit Agreement, the Notes or any other Loan Document,  whether incurred before
or after the Effective  Revocation  Time  (including,  without  limitation,  any
loans,  advances or  extensions  of credit at any time made or created under the
Credit Agreement, whether or not agreed, committed or contemplated to be made by
Administrative  Agent  or any  Lender  and  whether  or not  discretionary  with
Administrative  Agent or any Lender),  (b) any Guaranteed  Obligations  arising,
created or incurred prior to the Effective  Revocation Time, (c) any amendments,
modifications,  renewals,  extensions,  restatements and/or supplements to or of
the indebtedness,  liabilities or obligations referred to in clauses (a) and (b)
preceding,  whether occurring before or after the Effective  Revocation Time, or
(d) any interest or costs of collection with respect to any of the indebtedness,
liabilities or obligations referred to in clauses (a), (b) or (c) preceding. Any
revocation  or attempted  revocation  of this  Guaranty,  whether in whole or in
part, shall not be effective except under limited circumstances (if any), and to
the limited extent, expressly provided in this Paragraph 26.

<PAGE>

     27. Reinstatement of Guaranteed  Obligations.  Notwithstanding  anything to
the  contrary  contained  in this  Guaranty or any other Loan  Document,  if the
payment of any amount of principal of or interest with respect to the Guaranteed
Obligations,  or any portion thereof, is rescinded,  voided or must otherwise be
refunded by the  Administrative  Agent or any Lender or otherwise for any reason
whatsoever, then the Guaranteed Obligations will be automatically reinstated and
become  automatically  effective and in full force and effect, all to the extent
that and as though such payment so rescinded,  voided or otherwise  refunded had
never been made.

     28. Covenants and Agreements.  Guarantor covenants and agrees that, as long
as the Guaranteed  Obligations or any part thereof are outstanding or any Lender
has any  Commitment  under the Credit  Agreement,  it will  comply,  strictly in
accordance   with  the  terms   thereof,   with  all  covenants  and  agreements
specifically  applicable  to it as set  forth  in any one or more of the  Credit
Agreement and the other Loan Documents,  all of which are incorporated herein by
reference.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

<PAGE>

     IN WITNESS  WHEREOF,  the  undersigned has executed this Guaranty as of the
date first written above.

                                      GUARANTOR:
                                      ---------

                                      GLOBAL NETWORKS ASSETS, LLC

                                      By: /s/ Steven M. Gallant
                                         ---------------------------------------
                                      Name:   Steven M. Gallant
                                      Title:  President

     The  undersigned  has  executed  this  Guaranty  solely for the  purpose of
confirming   receipt  of  this   Guaranty  and  reliance  on  this  Guaranty  by
Administrative Agent and Lenders as of the date first written above.

                                      NORTEL NETWORKS INC.,
                                      as Administrative Agent

                                     By: /s/ Mitchell L. Stone
                                        ---------------------------------------
                                     Name:   Mitchell L. Stone
                                     Title:  Director, Customer Finance AmericasEXHIBIT 10.5

                               GUARANTY AGREEMENT

     This GUARANTY AGREEMENT (this  "Guaranty"),  dated effective as of June 30,
2000, is executed and delivered by SAVVIS COMUNICATIONS  INTERNATIONAL,  INC., a
Delaware corporation ("Guarantor"),  to and in favor of NORTEL NETWORKS INC., as
administrative  agent  for  itself  and  the  other  Lenders  (as  such  term is
hereinafter defined) (in such capacity, together with its successors and assigns
in such capacity, "Administrative Agent").

                              W I T N E S S E T H:
                              - - - - - - - - - -

     A. Savvis Communications  Corporation, a Missouri corporation ("Borrower"),
Savvis  Communications  Corporation,  a Delaware corporation  ("Holdings"),  the
lenders named therein  (together with their  successors and assigns,  "Lenders")
and Administrative Agent are, concurrently herewith,  entering into that certain
Credit Agreement dated as of June 30, 2000 (as the same may be amended, renewed,
extended,  restated, replaced,  substituted,  supplemented or otherwise modified
from time to time, the "Credit Agreement") and, in connection  therewith,  inter
alia, Borrower is, concurrently herewith,  executing and delivering that certain
Note  dated June 30,  2000,  in the  original  principal  amount of  $38,000,000
payable to the order of Nortel Networks Inc. (such promissory note, as it may be
amended, renewed, extended,  restated,  replaced,  substituted,  supplemented or
otherwise  modified  from time to time,  the "Note" and, to the extent  there is
more than one promissory note  subsequent to a partial  assignment of the Loans,
the "Notes").

     B. Guarantor has directly and  indirectly  benefitted and will directly and
indirectly  benefit  from  the  loans  evidenced  and  governed  by  the  Credit
Agreement,  the Notes and the other Loan  Documents  and the other  transactions
evidenced by and contemplated in the Loan Documents.

     C. Execution and delivery of this Guaranty is a condition to Administrative
Agent and Lenders  entering  into the Credit  Agreement  and the making of Loans
pursuant thereto.

     NOW,  THEREFORE,  for good and  valuable  consideration,  the  receipt  and
adequacy of which are hereby acknowledged, Guarantor hereby agrees as follows:

     1. Definitions.  Unless otherwise defined in this Guaranty, all capitalized
terms used in this  Guaranty  shall have the meanings  ascribed to such terms in
the Credit Agreement.

     2. Guaranty of Indebtedness,  Liabilities and Obligations. Guarantor hereby
absolutely,   unconditionally   and  irrevocably   guarantees  (a)  payment  and
performance to Administrative Agent and Lenders, as and when the same become due
or performable  strictly in accordance with the terms and provisions of the Loan
Documents,  whether at stated maturity, by acceleration or otherwise, of any and
all  Obligations  (as such  term is  defined  in the  Credit  Agreement),  which
Obligations include,  without limitation,  (i) any and all interest,  penalties,
fees and  expenses  (specifically  including,  but not  limited  to,  reasonable
attorneys'  fees and expenses)  which  Borrower may now or at any time hereafter
owe to  Administrative  Agent  or any  Lender  (whether  or not  such  interest,
penalties,  fees and expenses were  originally  contracted  with  Administrative
Agent or any Lender or

<PAGE>

with  another or others and whether or not such  interest,  penalties,  fees and
expenses are enforceable against Borrower) pursuant to the Credit Agreement, any
Note or any other Loan Document  plus (ii) the  principal  amount of any and all
indebtedness,  liabilities and other  obligations,  whether  primary,  absolute,
secondary,  direct,  indirect,  fixed,  contingent,  liquidated,   unliquidated,
secured or unsecured, matured or unmatured, joint, several or joint and several,
due  or to  become  due  and  whether  arising  by  agreement,  note,  discount,
acceptance,  overdraft  or  otherwise,  which  Borrower  may now or at any  time
hereafter  owe to  Administrative  Agent  or any  Lender  (whether  or not  such
indebtedness,  liabilities  and  obligations  were  originally  contracted  with
Administrative  Agent or any Lender or with another or others and whether or not
such indebtedness,  liabilities or obligations are enforceable against Borrower)
pursuant to the Credit  Agreement,  any Note or any other Loan  Document and (b)
the  faithful,  prompt  and  complete  compliance  by  Borrower  with all terms,
conditions,  covenants, agreements and undertakings of Borrower under the Credit
Agreement,  any  Note  or any  other  Loan  Document  (the  Obligations  and the
interest, penalties, fees, expenses, indebtedness,  liabilities and obligations,
etc.  referred  to in  clauses  (a)  and  (b)  preceding  as to  which  payment,
performance  and  compliance  are  guaranteed  pursuant  to  this  Guaranty  are
hereinafter individually and collectively called the "Guaranteed Obligations").

     Notwithstanding   that   Borrower   may  not  be  liable  or  obligated  to
Administrative  Agent or any Lender for interest  and/or  reasonable  attorneys'
fees and expenses on, or in connection with, the Guaranteed Obligations from and
after the Petition Date (as  hereinafter  defined) as a result of the provisions
of the federal  bankruptcy  laws or otherwise,  the Guaranteed  Obligations  for
which  Guarantor shall be liable and obligated under this Guaranty shall include
(to the extent permitted by law or a court of competent  jurisdiction)  interest
accruing on the  Guaranteed  Obligations at the highest rate provided for in the
Credit  Agreement from and after the date on which Borrower files for protection
under  the  federal  bankruptcy  laws or from  and  after  the  date on which an
involuntary  proceeding is filed against  Borrower under the federal  bankruptcy
laws (herein collectively referred to as the "Petition Date") and all attorneys'
fees and expenses incurred by Administrative  Agent or any Lender from and after
the Petition Date in connection with the Guaranteed Obligations.

     3.  Continuing  Guaranty  of  Payment.  This  Guaranty  is and  shall be an
absolute, unconditional, irrevocable and continuing guaranty of payment, and not
merely  of  collection,  and from  time to time or at any  time  the  Guaranteed
Obligations  may be  increased,  reduced or paid in full without  affecting  the
liability or obligation of Guarantor with respect to  indebtedness,  liabilities
and  obligations of Borrower to  Administrative  Agent or any Lender  thereafter
incurred.  Guarantor  further  agrees that this  Guaranty  shall  continue to be
effective or be reinstated (if a release or discharge has occurred), as the case
may be, if at any time any payment (or any part thereof) to Administrative Agent
or any Lender in respect of the  Guaranteed  Obligations  is  rescinded  or must
otherwise  be restored  by  Administrative  Agent or any Lender  pursuant to any
bankruptcy,  insolvency,  reorganization,  receivership  or other debtor  relief
granted  to  Borrower  or  its   successors  or  assigns.   In  the  event  that
Administrative  Agent or any Lender must rescind or restore any payment received
by  Administrative  Agent or any Lender,  respectively,  in  satisfaction of the
Guaranteed Obligations, as set forth herein, any prior release or discharge from
the terms of this Guaranty  given to Guarantor by  Administrative  Agent or such
Lender, respectively, shall be without effect, and this Guaranty shall remain in
full force and effect. It is the intention of Administrative  Agent, Lenders and
Guarantor that Guarantor's liabilities and obligations hereunder shall not be

<PAGE>

discharged  except  by the full and  complete  payment  and  performance  of the
Guaranteed  Obligations  and  then  only  to the  extent  of  such  payment  and
performance.  This  Guaranty  is  independent  of, and in  addition  and without
modification  to and does not impair or in any way  affect  any other  guaranty,
endorsement or other agreement executed in favor of Administrative  Agent or any
Lender, and this Guaranty and Guarantor's liabilities and obligations under this
Guaranty shall not be impaired or otherwise affected by the execution,  delivery
or  performance  by  Guarantor  or  any  other  Person  of any  other  guaranty,
endorsement or other agreement.

     4. Absolute  Guaranty.  Guarantor's  liabilities and obligations under this
Guaranty  shall be absolute  and  unconditional  irrespective  of,  shall not be
released,  impaired, limited, reduced, conditioned upon or otherwise affected by
and shall  continue in full force and effect  notwithstanding  the occurrence of
any event (other than an event  consisting  of payment and  performance  of such
liabilities  and  obligations  as provided in Paragraph 3 hereof) at any time or
from  time  to  time,  including,  without  limitation,  any  one or more of the
following events specified in clauses (a) through (n) of this Paragraph 4 below,
and neither  Administrative  Agent nor any Lender shall be obligated or required
to take or to refrain  from taking any of such  actions or  inactions  specified
below and shall  not have any  liability,  obligation  or duty  whatsoever  with
respect  to such  actions  or  inactions,  it being  acknowledged  and agreed by
Guarantor  that all of such  liabilities,  obligations  and  duties  (if any) of
Administrative  Agent  or any  Lender  otherwise  existing  and all  rights  and
remedies (if any) of Guarantor with respect thereto  (whether such  liabilities,
obligations,  duties,  rights or remedies  exist by virtue of agreement,  common
law,  equity,  statute or otherwise),  and each and every defense  which,  under
principles of guaranty or suretyship law, would otherwise  operate to eliminate,
impair,  condition or restrict the  liabilities and obligations of Guarantor for
the Guaranteed Obligations, are hereby expressly waived by Guarantor:

          (a) the taking or accepting of any security or other  guaranty for any
     or all of the  Guaranteed  Obligations,  whether  heretofore,  concurrently
     herewith or hereafter;

          (b) any failure to create or perfect or properly create or perfect any
     lien, security interest or assignment intended as security, or any release,
     surrender, exchange, substitution, subordination or loss of any security or
     guaranty  at  any  time  existing  in  connection  with  any  or all of the
     Guaranteed   Obligations  for  any  reason;  or  any  suretyship  defenses,
     including, without limitation, any impairment of collateral;

          (c) any partial or full  release of the  liability  or  obligation  of
     Guarantor under any other guaranty whether or not similar to this Guaranty;

          (d) the entering into,  delivery of,  modification of, amendment to or
     waiver of compliance with the Credit Agreement,  any Note or any other Loan
     Document, or any agreement, document or instrument evidencing,  securing or
     otherwise affecting all or part of the Guaranteed Obligations,  without the
     notification  of  Guarantor,  the right of such  notification  being hereby
     specifically waived by Guarantor;

          (e) the bankruptcy, insolvency, arrangement,  adjustment, composition,
     liquidation,   disability,   dissolution  or  lack  of  authority  (whether
     corporate, partnership or trust

<PAGE>

     or relating to any other  entity or Person) of  Borrower,  Guarantor or any
     other Person at any time liable or obligated  for the payment of any or all
     of the Guaranteed Obligations, whether now existing or hereafter arising;

          (f)  any   increase,   reduction,   renewal,   extension,   amendment,
     modification,  repayment,  refunding and/or rearrangement of the payment or
     any other terms or provisions of any or all of the  Guaranteed  Obligations
     at any time and from time to time, whether on one or more occasions, either
     with or  without  notice to or  consent of  Guarantor,  or any  adjustment,
     indulgence,  forbearance  or  compromise  that might be granted or given by
     Administrative Agent or any Lender to Borrower or Guarantor;

          (g) any neglect, delay, omission, failure or refusal of Administrative
     Agent or any Lender (i) to exercise or properly or diligently  exercise any
     right or remedy with respect to any or all of the Guaranteed Obligations or
     the collection  thereof or any collateral,  security or guaranty  therefor,
     whether under the Credit Agreement,  any Note or any other Loan Document or
     otherwise,  including,  without  limitation,  to ensure compliance with any
     term or provision of the Credit Agreement or any other Loan Document,  (ii)
     to take or prosecute or properly or diligently take or prosecute any action
     for the  collection  of any or all of the  Guaranteed  Obligations  against
     Borrower,  Guarantor or any other guarantor of any or all of the Guaranteed
     Obligations  and/or any other  Person,  (iii) to  foreclose or prosecute or
     properly or diligently foreclose or prosecute any action in connection with
     any agreement,  document or instrument or arrangement evidencing,  securing
     or  otherwise  affecting  all or any  part of the  Guaranteed  Obligations,
     including,  without  limitation,  any  failure  to  conduct a  commercially
     reasonable  foreclosure sale, or (iv) to mitigate damages or take any other
     action to reduce, collect or enforce the Guaranteed Obligations;

          (h) any failure of  Administrative  Agent or any Lender to give notice
     to Borrower  and/or  Guarantor of, or obtain the consent of Borrower and/or
     Guarantor  with  respect to, (i) the  incurrence  of any of the  Guaranteed
     Obligations,  (ii) the occurrence of any "Default" or "Event of Default" as
     such terms are  defined in the  Credit  Agreement  or any of the other Loan
     Document,  (iii) demand,  presentment,  protest,  nonpayment,  intention to
     accelerate,  acceleration,  lack of diligence or delay in collection of all
     or any part of the  Guaranteed  Obligations  or any  other  matter,  or the
     absence  thereof,  (iv)  any  renewal,   extension  or  assignment  of  the
     Guaranteed Obligations or any part thereof, (vi) the disposition or release
     of all or any part of any security for the Guaranteed  Obligations (whether
     or not such  disposition  is  commercially  reasonable)  or (vi) any  other
     action taken or refrained from being taken by  Administrative  Agent or any
     Lender against  Borrower,  it being agreed that (except as may be expressly
     provided in the other Loan Documents) neither  Administrative Agent nor any
     Lender shall be required to give  Borrower or  Guarantor  any notice of any
     kind or to obtain Borrower's or Guarantor's consent under any circumstances
     whatsoever   with  respect  to  or  in  connection   with  the   Guaranteed
     Obligations;

          (i) the unenforceability, illegality or uncollectibility of all or any
     part of the  Guaranteed  Obligations  against  Borrower  by  reason  of (i)
     failure of  consideration,  (ii) breach of warranty,  (iii) fraud, (iv) the
     fact that the interest contracted for, charged, collected or

<PAGE>

     received  in  respect  of the  Guaranteed  Obligations  exceeds  the amount
     permitted by law, (v) the act of creating the Guaranteed Obligations or any
     part  thereof  is ultra  vires,  (vi) the  officers,  directors,  partners,
     trustees or  representatives  creating the Guaranteed  Obligations acted in
     excess  of their  authority  or lacked  legal  capacity,  (vii) the  Credit
     Agreement,  any Note or any other Loan Document  evidencing  the Guaranteed
     Obligations  has been forged or otherwise is irregular or is not genuine or
     authentic,  (viii)  expiration of the applicable  statute of limitations of
     the  Guaranteed  Obligations,  (ix)  failure to comply  with the statute of
     frauds, (x) lender liability, or (xi) accord and satisfaction;

          (j) any payment by Borrower to  Administrative  Agent or any Lender is
     held to constitute a  preferential  transfer or a fraudulent  conveyance or
     transfer under any applicable law, or for any reason  Administrative  Agent
     or any Lender is  required  to refund  such  payment or pay such  amount to
     Borrower or any other Person;

          (k)  any  merger,  reorganization,  consolidation  or  dissolution  of
     Borrower,  any  sale,  lease or  transfer  of any or all of the  assets  of
     Borrower, or any change in name, business, location, composition, structure
     or  any  change  in the  shareholders,  partners  or  members  (whether  by
     accession, secession, death, dissolution,  transfer of assets or otherwise)
     of Borrower;

          (l) any  failure  of  Administrative  Agent or any  Lender  to  notify
     Guarantor of (i) the acceptance of this Guaranty,  (ii) the making of Loans
     by any Lender in reliance on this  Guaranty,  (iii) the failure of Borrower
     to make any payment due by Borrower to Administrative  Agent or any Lender,
     or (iv) any information  regarding the financial  condition or prospects of
     Borrower;

          (m) any full or partial  release of the  liability  of  Borrower,  any
     guarantor  of all or any part of the  Guaranteed  Obligations  or any other
     Person  for  all or  any  part  of the  Guaranteed  Obligations,  it  being
     acknowledged  and agreed by  Guarantor  that it may be  required to pay the
     Guaranteed Obligations in full without assistance or support,  whether from
     Borrower, any other guarantor or any other Person; or

          (n) any other  action taken or omitted to be taken with respect to any
     of  the  Credit  Agreement,  any  Note  or any  other  Loan  Document,  the
     Guaranteed Obligations or the security and collateral therefor,  whether or
     not  such  action  or  omission  prejudices   Guarantor  or  increases  the
     likelihood  that  Guarantor  will be required to pay all or any part of the
     Guaranteed Obligations pursuant to the terms hereof.

Without limiting the foregoing or Guarantor's  liability under this Guaranty, to
the extent that Administrative  Agent and Lenders (or any of them) have advanced
funds or  extended  credit to Borrower  and do not receive  payments or benefits
thereon in the amounts and at the times required or provided by or in connection
with the Credit  Agreement,  any Notes or any other Loan Document,  Guarantor is
absolutely  liable to make such  payments and to confer such benefits on Lenders
on a timely basis.

<PAGE>

     5.  Representations  and  Warranties.  In  connection  with this  Guaranty,
Guarantor  hereby  represents and warrants to  Administrative  Agent and Lenders
that:

          (a)  Guarantor is a Subsidiary  of Holdings and Guarantor has received
     and  will  receive  a  direct  and  indirect   material  benefit  from  the
     transactions  evidenced by and  contemplated in the Credit  Agreement,  the
     Notes and the other Loan Documents;  this Guaranty is given by Guarantor in
     furtherance  of the direct and indirect  business  interests  and corporate
     purposes of  Guarantor,  and is  necessary to the  conduct,  promotion  and
     attainment of the  businesses of Borrower and  Guarantor;  and the value of
     the  consideration  received and to be received by Guarantor is believed by
     Guarantor  to be  reasonably  worth at least as much as the  liability  and
     obligation of Guarantor hereunder;

          (b) The execution and delivery of this Guaranty and the performance of
     and  compliance  with the terms hereof will not constitute a default (or an
     event  which  with  notice  or lapse  of time or both  would  constitute  a
     default)  under,  or  result  in the  breach  of,  any  material  contract,
     agreement  or  instrument  to which  Guarantor  is a party or which  may be
     applicable to Guarantor or any of its assets;

          (c) This  Guaranty,  when executed and  delivered by  Guarantor,  will
     constitute the legal, valid and binding obligation of Guarantor enforceable
     in accordance with its terms,  except as limited by bankruptcy,  insolvency
     or  other  laws of  general  application  relating  to the  enforcement  of
     creditors' rights and general principles of equity;

          (d) As of the date of this  Guaranty,  and after giving effect to this
     Guaranty  and  the  contingent   obligation  evidenced  by  this  Guaranty,
     Guarantor is not, on either an unconsolidated basis or a consolidated basis
     with Borrower and Holdings'  subsidiaries,  insolvent, as such term is used
     or defined in any applicable bankruptcy,  fraudulent conveyance, fraudulent
     transfer or similar  law,  and  Guarantor  has and will have assets  which,
     fairly  valued,  exceed  its  indebtedness,  liabilities  and  obligations;
     Guarantor is not  executing  this  Guaranty  with any  intention to hinder,
     delay or defraud any present or future  creditor or creditors of Guarantor;
     Guarantor is not engaged in any business or transaction (including, without
     limitation, the execution of this Guaranty) which will leave Guarantor with
     unreasonably  small  capital  or  assets  which are  unreasonably  small in
     relation  to the  business or  transactions  engaged in by  Guarantor,  and
     Guarantor  does not intend to engage in any such  business or  transaction;
     Guarantor does not intend to incur, nor does Guarantor believe that it will
     incur, debts beyond Guarantor's ability to repay such debts as they mature;

          (e) All acts and  conditions  required to be performed  and  satisfied
     prior to the creation and issuance of this Guaranty, and to constitute this
     Guaranty  as the  legal,  valid and  binding  obligation  of  Guarantor  in
     accordance  with its terms,  have been  performed  and satisfied in due and
     strict compliance with all applicable laws;

          (f) Guarantor is familiar with, and has  independently  received books
     and records regarding,  the financial condition of Borrower and is familiar
     with the value of any and all  collateral  (if any)  intended to secure the
     Guaranteed Obligations; however, Guarantor is not

<PAGE>

     relying on such financial  condition or any such  collateral (if any) as an
     inducement to enter into this  Guaranty;  Guarantor  has adequate  means to
     obtain from Borrower, on a continuing basis, the information referred to in
     this clause (f) and is not relying on Administrative Agent or any Lender to
     provide any such information at any time;

          (g)  Guarantor has not been induced to enter into this Guaranty on the
     basis of a  contemplation,  belief,  understanding  or  agreement  that any
     Person  other  than   Guarantor  will  be  liable  to  pay  the  Guaranteed
     Obligations;

          (h)  Except  for  the  execution  of  the  Credit  Agreement,  neither
     Administrative  Agent,  any  Lender  nor any  other  Person  has  made  any
     representation, warranty or statement to, or promise, covenant or agreement
     with, Guarantor in order to induce Guarantor to execute this Guaranty;

          (i) Guarantor is a wholly-owned Subsidiary of Holdings; and

          (j)  All  representations  and  warranties  in  the  Credit  Agreement
     relating to the  Guarantor  are true and correct in all  respects as of the
     date  hereof,  except to the extent made only as of a specific  prior date,
     and on each date the representations and warranties thereunder are restated
     pursuant to any of the Loan  Documents with the same force and effect as if
     such  representations  and warranties had been made on and as of such date,
     all of which are incorporated herein by reference.

     6. Default. Upon the occurrence of an Event of Default, Guarantor shall, on
demand by  Administrative  Agent and  without  further  notice of  dishonor  and
without notice of any kind (including,  without limitation, notice of acceptance
by  Administrative  Agent or any Lender of this  Guaranty)  having been given to
Borrower, Guarantor or any other Person previous to such demand, promptly (i.e.,
not later than 1:00 p.m.,  New York,  New York time,  on the date of such demand
or, if such  demand is made after 12:00 noon,  on the next  succeeding  Business
Day)  pay,  in  immediately  available  funds,  the full  unpaid  amount  of the
Guaranteed  Obligations,  or such lesser amount,  if any, as may be specifically
demanded by Administrative  Agent from time to time, to Administrative  Agent at
Administrative Agent's Principal Office located in New York, New York or at such
other place as  Administrative  Agent may specify to  Guarantor  in writing.  If
acceleration  of the time for payment of any amount payable by Borrower under or
with respect to any of the Guaranteed Obligations is stayed or otherwise delayed
upon the insolvency,  bankruptcy or reorganization of Borrower, all such amounts
otherwise subject to acceleration under the terms of the Guaranteed  Obligations
shall  nonetheless  be  payable by  Guarantor  hereunder  promptly  on demand by
Administrative Agent.

     7. Cumulative Remedies;  No Election.  If Guarantor is or becomes liable or
obligated for the Guaranteed  Obligations,  by  endorsement or otherwise,  other
than under this  Guaranty,  such  liability  or  obligation  shall not be in any
manner   impaired  or  affected   hereby,   and  the  rights  and   remedies  of
Administrative  Agent or any Lender hereunder shall be cumulative of any and all
other rights and remedies that Administrative Agent or such Lender may ever have
against  Guarantor.  The exercise by  Administrative  Agent or any Lender of any
right or remedy hereunder or under any other

<PAGE>

agreement,  document or instrument,  or at law or in equity,  shall not preclude
the concurrent or subsequent  exercise of any other right or remedy.  Without in
any way limiting the generality of the foregoing,  it is specifically understood
and agreed that this Guaranty is given by Guarantor as an additional guaranty or
security to any and all other  guaranties or security  heretofore,  concurrently
herewith or hereafter  executed and/or  delivered by Guarantor to or in favor of
Administrative Agent or any Lender relating to the Guaranteed  Obligations,  and
nothing  herein  shall ever be deemed to in any way  negate or replace  any such
other guaranties or security;  provided,  however, that Administrative Agent and
Lenders  shall  have  all of their  rights  and  remedies  under  this  Guaranty
irrespective of anything to the contrary  contained in any such other guaranties
or  security.  This  Guaranty  may be  enforced  from  time to time as  often as
occasion  therefor may arise,  and it is agreed and understood that it shall not
be necessary for  Administrative  Agent or any Lender,  in order to enforce this
Guaranty  against  Guarantor,  first to exercise any rights or remedies  against
Borrower or any other Person or institute  suit or exhaust any available  rights
or  remedies  against  security  in  Administrative   Agent's  or  any  Lender's
possession or under Administrative Agent's or any Lender's control, or to resort
to  any  other  sources  or  means  of  obtaining   payment  of  the  Guaranteed
Obligations.

     8. Joint and Several Obligation. Guarantor agrees that Administrative Agent
and Lenders, in their sole discretion, may (a) bring suit against all guarantors
or other Persons  liable or obligated to  Administrative  Agent or any Lender or
against  any one or more of  them,  for  interest,  penalties,  expenses,  fees,
indebtedness,  liabilities and obligations owed to  Administrative  Agent or any
Lender and apply any amounts obtained by  Administrative  Agent or any Lender in
such a manner as  Administrative  Agent or any Lender may elect,  (b) bring suit
against all  guarantors of the Guaranteed  Obligations  jointly and severally or
against  any one or more of them,  (c)  settle  fully or in part with any one or
more of such guarantors for such  consideration as  Administrative  Agent or any
Lender may deem proper,  and (d)  partially or fully release one or more of such
guarantors from liability under any guaranty agreement,  and that no such action
shall  impair the rights of  Administrative  Agent or any Lender to collect  the
Guaranteed  Obligations  (or the unpaid balance  thereof) from other  guarantors
(including, without limitation, Guarantor), or any of them, not so sued, settled
with or released.

     9.  Release  of  Collateral,  etc.  If all or any  part  of the  Guaranteed
Obligations is at any time secured,  Guarantor agrees that Administrative  Agent
or any Lender may, at any time and from time to time in its  discretion and with
or  without  valuable   consideration,   allow  substitution  or  withdrawal  of
collateral or other security and release  collateral or other  security  without
impairing or diminishing the liabilities or obligations of Guarantor  hereunder.
Guarantor further agrees that, if Borrower or any other Person executes in favor
of Administrative Agent or any Lender any collateral agreement,  mortgage,  deed
of  trust,   collateral   assignment,   security  agreement  or  other  security
instrument,  the exercise by Administrative  Agent or any Lender of any right or
remedy thereby conferred on  Administrative  Agent or any Lender shall be wholly
discretionary with Administrative Agent and such Lender, respectively,  and that
the  exercise  or failure to exercise  any such right or remedy  shall in no way
impair or diminish the  obligation  of Guarantor  hereunder.  Guarantor  further
agrees that (except to the extent  prohibited by applicable law  notwithstanding
an agreement of the parties to the contrary)  neither  Administrative  Agent nor
any Lender  shall be liable  for its  failure  to use  diligence  or care in the
collection of the Guaranteed Obligations, in the creation

<PAGE>

or perfection of any lien,  security interest or assignment intended as security
or in  preserving  the  liability  of any  Person  liable  or  obligated  on the
Guaranteed  Obligations,  and Guarantor  hereby waives  presentment for payment,
notice of nonpayment, protest and notice thereof, and diligence in bringing suit
against any Person liable on the Guaranteed Obligations or any part thereof.

     10.  Binding  Effect.  This  Guaranty is for the benefit of  Administrative
Agent and Lenders and their successors and permitted  assigns,  and in the event
of an  assignment  by  Administrative  Agent or any Lender or its  successors or
assigns  of the  Guaranteed  Obligations,  or any part  thereof,  the rights and
benefits  hereunder,  to the extent applicable to the indebtedness,  liabilities
and  obligations  so  assigned,  may  be  transferred  with  such  indebtedness,
liabilities and obligations.  This Guaranty is binding, not only upon Guarantor,
but upon its successors and assigns.

     11. WAIVER OF SUBROGATION,  CONTRIBUTION AND OTHER RIGHTS.  UPON PAYMENT BY
GUARANTOR  OF ANY  SUMS  IN  RESPECT  OF THE  GUARANTEED  OBLIGATIONS  HEREUNDER
(INCLUDING,  WITHOUT LIMITATION, ANY AMOUNTS ADVANCED TO BORROWER BY GUARANTOR),
ALL  RIGHTS  OF  GUARANTOR  AGAINST  BORROWER  OR  ANY  OTHER  GUARANTOR  OF THE
GUARANTEED  OBLIGATIONS  ARISING  AS A  RESULT  THEREFROM  BY  WAY OF  RIGHT  OF
SUBROGATION,  REIMBURSEMENT,  EXONERATION, CONTRIBUTION,  INDEMNIFICATION AND/OR
OTHERWISE  SHALL IN ALL RESPECTS BE  SUBORDINATE  AND JUNIOR IN RIGHT OF PAYMENT
AND ENFORCEMENT TO THE PRIOR INDEFEASIBLE PAYMENT AND ENFORCEMENT IN FULL OF THE
GUARANTEED OBLIGATIONS. GUARANTOR SHALL NOT HAVE, AND HEREBY IRREVOCABLY WAIVES,
ANY AND ALL RIGHTS AND  REMEDIES  OF  SUBROGATION,  REIMBURSEMENT,  EXONERATION,
CONTRIBUTION,  INDEMNIFICATION  AND/OR OTHERWISE AGAINST OR FROM BORROWER UNLESS
AND UNTIL ALL OF THE  GUARANTEED  OBLIGATIONS  HAVE BEEN PAID AND  PERFORMED  IN
FULL. IN ADDITION TO THE FOREGOING,  GUARANTOR HEREBY IRREVOCABLY WAIVES ANY AND
ALL CLAIMS OR OTHER  RIGHTS AND  REMEDIES IT MAY NOW HAVE OR  HEREAFTER  ACQUIRE
AGAINST  ADMINISTRATIVE  AGENT,  ANY LENDER,  BORROWER OR ANY OTHER PERSON UNDER
CHAPTER 34 OF THE TEXAS  BUSINESS AND COMMERCE  CODE,  UNDER RULES 31 AND 163 OF
THE TEXAS  RULES OF CIVIL  PROCEDURE,  UNDER  SECTION  17.001 OF THE TEXAS CIVIL
PRACTICE  AND  REMEDIES  CODE AND UNDER ANY OTHER  STATUTE OF ANY STATE OR OTHER
JURISDICTION  REQUIRING  RECOURSE  AGAINST THE PRIMARY OBLIGOR OR IMPOSING OTHER
REQUIREMENTS AS A CONDITION TO RECOURSE AGAINST A GUARANTOR IF AND TO THE EXTENT
THAT THE SAME MAY BE APPLICABLE TO THIS GUARANTY.  Except as expressly otherwise
provided in this Paragraph 11,  Guarantor  shall have all rights of subrogation,
reimbursement,  exoneration,  contribution  and  indemnification  that may exist
under currently applicable law.

<PAGE>

     12.  Subordination  of  Indebtedness  and Liens.  In  connection  with this
Guaranty, Guarantor hereby agrees that:

          (a) The  payment  of any  and all  principal  of and  interest  on the
     Subordinated  Indebtedness  (as  defined  below)  shall in all  respects be
     subordinate  and junior in right of payment  and  enforcement  to the prior
     payment and  enforcement in full of all Guaranteed  Obligations as provided
     in this Paragraph 12. The Subordinated  Indebtedness  shall not be payable,
     and no payment of principal,  interest or other amounts on account thereof,
     and no property or guaranty of any nature to secure,  guarantee  or pay the
     Subordinated Indebtedness shall be made or given, directly or indirectly by
     or on behalf of  Borrower  or  received,  accepted,  retained or applied by
     Guarantor unless and until the Guaranteed  Obligations shall have been paid
     and performed in full; except that, prior to the occurrence and continuance
     of an Event of Default, Guarantor shall have the right to receive regularly
     scheduled payments, but not prepayments,  on the Subordinated  Indebtedness
     made in the ordinary  course of business.  After the occurrence of an Event
     of  Default,  no payments of  principal  or interest  may be made or given,
     directly or indirectly, by or on behalf of Borrower or received,  accepted,
     retained  or  applied  by  Guarantor   unless  and  until  the   Guaranteed
     Obligations  shall have been paid and  performed in full. If any sums shall
     be paid to Guarantor or any Affiliate of Guarantor by Borrower or any other
     Person on account of the Subordinated Indebtedness when such payment is not
     permitted hereunder,  such sums shall be held in trust by Guarantor for the
     benefit  of  Administrative  Agent  and  Lenders  and  shall  forthwith  be
     delivered  to  Administrative  Agent  without  affecting  the  liability of
     Guarantor  under this Guaranty and may be applied by  Administrative  Agent
     against the Guaranteed Obligations in accordance with the Credit Agreement.
     Upon the request of Administrative Agent, Guarantor shall execute, deliver,
     and endorse to  Administrative  Agent such  documentation as Administrative
     Agent may request to perfect,  preserve  and enforce its rights  hereunder.
     For  purposes of this  Guaranty  and with  respect to  Guarantor,  the term
     "Subordinated   Indebtedness"  means  all  indebtedness,   liabilities  and
     obligations   of  Borrower  to   Guarantor,   whether  such   indebtedness,
     liabilities and  obligations now exist or are hereafter  incurred or arise,
     or are primary, absolute,  secondary,  direct, indirect, fixed, contingent,
     liquidated,  unliquidated,  secured or  unsecured,  matured  or  unmatured,
     joint,  several,  joint and several,  or  otherwise,  and  irrespective  of
     whether such  indebtedness,  liabilities or obligations  are evidenced by a
     note, contract,  open account or otherwise,  and irrespective of the Person
     or Persons in whose favor such  indebtedness,  obligations  or  liabilities
     may, at their  inception,  have been, or may  hereafter be created,  or the
     manner in which they have been or may hereafter be acquired by Guarantor;

          (b) Any and all Liens  (including any judgment  Liens) upon Borrower's
     property or assets securing payment of any Subordinated  Indebtedness  (the
     "Subordinated  Liens") shall be and remain  inferior and subordinate to any
     and all Liens upon  Borrower's  assets  securing  payment of the Guaranteed
     Obligations  or any part thereof,  regardless of whether such  Subordinated
     Liens  presently exist or are hereafter  created or when such  Subordinated
     Liens were  created,  perfected,  filed or  recorded.  Guarantor  shall not
     exercise or enforce  any  creditors'  rights or  remedies  that it may have
     against Borrower or foreclose,  repossess, sequester or otherwise institute
     any action or proceeding (whether judicial or otherwise,

<PAGE>

     including,  without  limitation,  the  commencement  of, or joinder in, any
     bankruptcy, insolvency, reorganization,  liquidation, receivership or other
     debtor  relief law) to enforce  any  Subordinated  Lien on any  property or
     assets of Borrower unless and until the Guaranteed  Obligations  shall have
     been irrevocably paid and performed in full.

          (c) In the  event  of any  receivership,  bankruptcy,  reorganization,
     rearrangement,  debtor's relief or other  insolvency  proceeding  involving
     Borrower as debtor,  Administrative Agent shall have the right to prove and
     vote any claim under the Subordinated  Indebtedness and to receive directly
     from  the  receiver,  trustee  or  other  court  custodian  all  dividends,
     distributions and payments made in respect of the Subordinated Indebtedness
     until the  Guaranteed  Obligations  have been paid in full.  Administrative
     Agent may apply any such dividends,  distributions and payments against the
     Guaranteed Obligations in accordance with the Credit Agreement;

          (d) All promissory notes, accounts receivable, ledgers, records or any
     other evidence of Subordinated  Indebtedness,  and all mortgages,  deeds of
     trust,  security  agreements,  assignments  and  other  security  documents
     evidencing the Subordinated  Liens, shall contain a specific written notice
     thereon that the indebtedness and Liens evidenced  thereby are subordinated
     under the terms of this Guaranty; and

          (e) The  terms  and  provisions  of this  Paragraph  12 are  given  by
     Guarantor as additional rights,  remedies and benefits to any and all other
     subordination  agreements  heretofore,  concurrently  herewith or hereafter
     executed by Guarantor to or in favor of Administrative Agent or any Lender,
     and nothing in this  Guaranty  shall ever be deemed to in any way negate or
     replace any other such  previous,  concurrent or  subsequent  subordination
     agreements.

     13. Right of Setoff.  Guarantor hereby grants to  Administrative  Agent and
each  Lender a right of  setoff  upon any and all  monies,  securities  or other
property of  Guarantor,  and the proceeds  therefrom,  now or hereafter  held or
received by or in transit to Administrative  Agent or any Lender from or for the
account of Guarantor,  whether for safekeeping,  custody, pledge,  transmission,
collection or otherwise, and also upon any and all deposits (general or special)
and  credits  of  Guarantor,  and  any  and  all  claims  of  Guarantor  against
Administrative  Agent or any  Lender at any time  existing.  The right of setoff
granted  pursuant to this Paragraph 13 shall be cumulative of and in addition to
Administrative Agent's and each Lender's common law right of setoff.

     14. Further  Assurances.  Upon the request of  Administrative  Agent or any
Lender,  Guarantor  will,  at any time and from time to time,  duly  execute and
deliver to Administrative  Agent any and all such further agreements,  documents
and instruments,  and supply such additional information, as may be necessary or
advisable,  in the reasonable opinion of Administrative  Agent or any Lender, to
obtain the full benefits of this Guaranty.

     15.  Invalid  Provisions.  If any  provision of this Guaranty is held to be
illegal,  invalid or unenforceable under present or future laws effective during
the term hereof, such provision shall be fully severable, this Guaranty shall be
construed and enforced as if such illegal, invalid or

<PAGE>

unenforceable  provision  had never  comprised a part hereof,  and the remaining
provisions  hereof  shall  remain  in full  force  and  effect  and shall not be
affected by the illegal,  invalid or unenforceable provision or by its severance
herefrom.  Furthermore,  in lieu  of  such  illegal,  invalid  or  unenforceable
provision  there  shall  be added  automatically  as a part of this  Guaranty  a
provision  as  similar  in  terms  to such  illegal,  invalid  or  unenforceable
provision as may be possible and be legal,  valid and enforceable.  No provision
herein or in any other Loan Document evidencing the Guaranteed Obligations shall
require  the  payment  or permit the  collection  of  interest  in excess of the
maximum permitted by applicable law.

     16. Modification in Writing. No modification,  consent, amendment or waiver
of any provision of this Guaranty,  and no consent to any departure by Guarantor
herefrom, shall be effective unless the same shall be in writing and signed by a
duly authorized officer of Administrative  Agent and Guarantor and then shall be
effective only in the specific  instance and for the specific  purpose for which
given.

     17. No Waiver,  Etc. No notice to or demand on Guarantor or  Administrative
Agent in any case shall entitle Guarantor or Administrative Agent, respectively,
to any other or further notice or demand in similar or other  circumstances.  No
delay or omission by Administrative Agent, any Lender or Guarantor in exercising
any  right or  remedy  hereunder  shall  impair  any such  right or remedy or be
construed  as a waiver  thereof or any  acquiescence  therein,  and no single or
partial  exercise of any such right or remedy  shall  preclude  other or further
exercise thereof or the exercise of any other right or remedy hereunder.

     18. Cumulative Rights. All rights and remedies of Administrative  Agent and
Lenders  hereunder  are  cumulative  of each other and of every  other  right or
remedy which  Administrative Agent or any Lender may otherwise have at law or in
equity or under any other contract or document,  and the exercise of one or more
rights or remedies  shall not  prejudice or impair the  concurrent or subsequent
exercise of other rights or remedies.

     19. Expenses. Guarantor agrees to pay on demand by Administrative Agent all
reasonable costs and expenses incurred by Administrative  Agent or any Lender in
connection  with the  enforcement  of the terms and  provisions of this Guaranty
and, if and to the extent that Borrower is obligated therefor in accordance with
the  Credit  Agreement,  any  and  all  amendments,   modifications,   renewals,
restatements  and/or  supplements hereto from time to time,  including,  without
limitation,  the reasonable fees and expenses of legal counsel to Administrative
Agent.  If  Guarantor  should  breach or fail to perform any  provision  of this
Guaranty, Guarantor agrees to pay to Administrative Agent all costs and expenses
incurred  by  Administrative  Agent or any  Lender  in the  enforcement  of this
Guaranty from time to time, including,  without limitation,  the reasonable fees
and expenses of all legal counsel to Administrative Agent and Lenders.

<PAGE>

     20.  APPLICABLE  LAW. THIS GUARANTY  SHALL BE GOVERNED BY, AND CONSTRUED IN
ACCORDANCE  WITH, THE LAWS OF THE STATE OF NEW YORK (WITHOUT REGARD TO CONFLICTS
OF LAWS PRINCIPLES).

     21. NO ORAL  AGREEMENTS.  THIS  GUARANTY  REPRESENTS  THE  FINAL  AGREEMENT
BETWEEN GUARANTOR AND  ADMINISTRATIVE  AGENT AND LENDERS RELATING TO THE SUBJECT
MATTER  OF THIS  GUARANTY  AND MAY NOT BE  CONTRADICTED  BY  EVIDENCE  OF PRIOR,
CONTEMPORANEOUS  OR SUBSEQUENT  ORAL  AGREEMENTS  OF SUCH PARTIES.  THERE ARE NO
UNWRITTEN ORAL AGREEMENTS BETWEEN OR AMONG GUARANTOR AND ADMINISTRATIVE AGENT OR
ANY LENDER.  THIS GUARANTY  SUPERSEDES ALL PRIOR (IF ANY) ORAL AGREEMENTS,  ORAL
ARRANGEMENTS  OR ORAL  UNDERSTANDINGS  RELATING  TO THE  SUBJECT  MATTER OF THIS
GUARANTY,  AND THIS GUARANTY  SUPERSEDES  ALL PRIOR (IF ANY) WRITTEN  AGREEMENTS
RELATING TO THE SUBJECT  MATTER OF THIS  GUARANTY IF AND TO THE EXTENT THAT SUCH
PRIOR AGREEMENTS ARE INCONSISTENT WITH THIS GUARANTY.

     22. Notices. All notices and other communications  required or permitted to
be given  under this  Guaranty  shall be given or made in  writing  and shall be
delivered in the manner and to the  addresses,  and shall be deemed to have been
duly given when, specified in the Credit Agreement.

     23. Survival. All representations,  warranties, covenants and agreements of
Guarantor in this Guaranty shall survive the execution of this Guaranty.

     24.  Counterparts.   This  Guaranty  may  be  executed  in  any  number  of
counterparts,  each of which shall constitute an original, but all of which when
taken together shall constitute one and the same Guaranty.

     25.  Limitation  on  Interest.  Notwithstanding  anything  to the  contrary
contained or referred to in this  Guaranty,  none of the terms and provisions of
this Guaranty, the Credit Agreement,  the Notes or any other Loan Document shall
ever be construed to create a contract or  obligation  to pay interest at a rate
in excess of the Maximum Rate, and neither  Administrative  Agent nor any Lender
shall ever charge, receive, take, collect,  reserve or apply, as interest on the
Obligations or the Guaranteed  Obligations,  any amount in excess of the Maximum
Rate. The parties hereto agree that any interest,  charge, fee, expense or other
indebtedness,  liability or obligation provided for in this Guaranty, the Credit
Agreement, the Notes or any other Loan Document which constitutes interest under
applicable law shall be, ipso facto and under any and all circumstances, limited
or reduced to an amount equal to the lesser of (a) the amount of such  interest,
charge, fee, expense or other  indebtedness,  liability or obligation that would
be payable  in the  absence of this  Paragraph  25 or (b) an amount,  which when
added to all other interest payable under this Guaranty,  the Credit  Agreement,
the  Notes  and  any  other  Loan   Document,   equals  the  Maximum  Rate.  If,
notwithstanding the foregoing, Administrative Agent or any Lender ever contracts
for, charges,  receives,  takes,  collects,  reserves or applies as interest any
amount  in  excess  of the  Maximum  Rate,  such  amount  which  would be deemed
excessive interest shall be deemed a partial payment or prepayment of

<PAGE>

principal  of  the  Obligations  and  the  Guaranteed  Obligations  and  treated
hereunder as such, and if the  Obligations  and the Guaranteed  Obligations,  or
applicable  portions  thereof,  are paid in full,  any  remaining  excess  shall
promptly be paid to Borrower,  Guarantor or such other Person (as  appropriate).
In  determining  whether  the  interest  paid or  payable,  under  any  specific
contingency, exceeds the Maximum Rate, Guarantor, Borrower, Administrative Agent
and Lenders  shall,  to the maximum  extent  permitted  by  applicable  law, (i)
characterize any nonprincipal  payment as an expense, fee or premium rather than
as interest,  (ii) exclude  voluntary  prepayments and the effects thereof,  and
(iii) amortize, prorate, allocate and spread in equal or unequal parts the total
amount of interest  throughout the entire  contemplated  term of the Obligations
and the Guaranteed  Obligations,  or applicable  portions  thereof,  so that the
interest  rate does not exceed the  Maximum  Rate at any time during the term of
the  Obligations  and the Guaranteed  Obligations;  provided that, if the unpaid
principal  balance  is paid and  performed  in full prior to the end of the full
contemplated term thereof, and if the interest received for the actual period of
existence  thereof  exceeds the Maximum Rate,  Administrative  Agent and Lenders
shall refund to Borrower,  Guarantor or such other Person (as  appropriate)  the
amount of such excess and, in such event,  neither  Administrative Agent nor any
Lender shall be subject to any  penalties  provided by any laws for  contracting
for, charging, receiving, taking, collecting,  receiving or applying interest in
excess of the Maximum Rate.

     26.  Irrevocable  Nature of Guaranty.  This  Guaranty may not be revoked by
Guarantor; provided, however, in the event it shall be determined that Guarantor
shall have the right, in accordance with applicable law and  notwithstanding its
express agreement herein to the contrary, to revoke this Guaranty, Guarantor may
deliver to  Administrative  Agent,  at its  address for notices set forth in the
Credit  Agreement,  written  notice of  Guarantor's  intention  not to be liable
hereunder for any  Guaranteed  Obligations  arising,  created or incurred  after
Administrative  Agent's  receipt of such notice,  whereupon such notice shall be
effective  to the extent (but only to the  extent)  provided  hereinbelow  as to
Guarantor  from and after (but not before) the time when such notice is actually
delivered  to and  received by and  receipted  for in writing by  Administrative
Agent (the "Effective Revocation Time"); provided,  further,  however, that such
notice shall not be effective as to, and shall not in any way  restrict,  limit,
impair,   release  or  otherwise  affect,   the  indebtedness,   liabilities  or
obligations of Guarantor  under this Guaranty with respect to (a) any Guaranteed
Obligations  consisting of  indebtedness,  liabilities or obligations  under the
Credit Agreement, the Notes or any other Loan Document,  whether incurred before
or after the Effective  Revocation  Time  (including,  without  limitation,  any
loans,  advances or  extensions  of credit at any time made or created under the
Credit Agreement, whether or not agreed, committed or contemplated to be made by
Administrative  Agent  or any  Lender  and  whether  or not  discretionary  with
Administrative  Agent or any Lender),  (b) any Guaranteed  Obligations  arising,
created or incurred prior to the Effective  Revocation Time, (c) any amendments,
modifications,  renewals,  extensions,  restatements and/or supplements to or of
the indebtedness,  liabilities or obligations referred to in clauses (a) and (b)
preceding,  whether occurring before or after the Effective  Revocation Time, or
(d) any interest or costs of collection with respect to any of the indebtedness,
liabilities or obligations referred to in clauses (a), (b) or (c) preceding. Any
revocation  or attempted  revocation  of this  Guaranty,  whether in whole or in
part, shall not be effective except under limited circumstances (if any), and to
the limited extent, expressly provided in this Paragraph 26.

<PAGE>

     27. Reinstatement of Guaranteed  Obligations.  Notwithstanding  anything to
the  contrary  contained  in this  Guaranty or any other Loan  Document,  if the
payment of any amount of principal of or interest with respect to the Guaranteed
Obligations,  or any portion thereof, is rescinded,  voided or must otherwise be
refunded by the  Administrative  Agent or any Lender or otherwise for any reason
whatsoever, then the Guaranteed Obligations will be automatically reinstated and
become  automatically  effective and in full force and effect, all to the extent
that and as though such payment so rescinded,  voided or otherwise  refunded had
never been made.

     28. Covenants and Agreements.  Guarantor covenants and agrees that, as long
as the Guaranteed  Obligations or any part thereof are outstanding or any Lender
has any  Commitment  under the Credit  Agreement,  it will  comply,  strictly in
accordance   with  the  terms   thereof,   with  all  covenants  and  agreements
specifically  applicable  to it as set  forth  in any one or more of the  Credit
Agreement and the other Loan Documents,  all of which are incorporated herein by
reference.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

<PAGE>

     IN WITNESS  WHEREOF,  the  undersigned has executed this Guaranty as of the
date first written above.

                                      GUARANTOR:
                                      ---------

                                      SAVVIS COMMUNICATIONS
                                      INTERNATIONAL, INC.

                                      By: /s/ Steven M. Gallant
                                         ---------------------------------------
                                      Name:   Steven M. Gallant
                                      Title:  President

     The  undersigned  has  executed  this  Guaranty  solely for the  purpose of
confirming   receipt  of  this   Guaranty  and  reliance  on  this  Guaranty  by
Administrative Agent and Lenders as of the date first written above.

                                      NORTEL NETWORKS INC.,
                                      as Administrative Agent

                                     By: /s/ Mitchell L. Stone
                                        ---------------------------------------
                                     Name:   Mitchell L. Stone
                                     Title:  Director, Customer Finance Americas

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