Contract for Services - MFS Telephone Inc. and Concentric Network Corp.


 
                             Contract for Services

     This Agreement (the 'Agreement') is entered into this 14th day of June,
1996, by and between MFS Telephone, Inc. ('MFS') and Concentric Network
Corporation ('Customer'). Pursuant to this Agreement, MFS agrees to arrange for
services specified herein to be delivered to Customer. In providing the services
identified herein, MFS will be acting as Customer's agent in procuring
telecommunications services from various affiliates of MFS, including (but not
limited to) MFS Intelenet, Inc. and MFS Telecom, Inc. The telecommunications
services provided to Customer hereunder are offered pursuant to the terms and
conditions contained in applicable state and federal tariffs of MFS and its
affiliates; except to the extent modified by this Agreement, Customer agrees to
be bound by the terms and conditions of the applicable tariffs.

     1.  TERM

     MFS Telecom and Customer agree that the term of this agreement shall be one
year, commencing on the date specified above. The term shall automatically renew
for successive one year periods unless either party notifies the other in
writing no less than 30 days prior to the expiration of the initial or renewal
term of its intention to terminate the Agreement at the expiration of the then-
current term.

     2.  RATES AND CHARGES

     In consideration of the special and unique services to be provided to
Customer hereunder, including but not limited to 'inward foreign exchange
service,' in which local telephone calls to Customer from outside Customer's
service area can be routed to Customer's location through use of different
telephone numbers in each different area, Customer agrees to pay MFS the
following rates for MFS on-net T-1 trunk service offered and available in the
following Local Exchange Carrier 'LEC') territories (rates stated are per month,
per T-1):


 
State                  T1 Trunk Charge
-----                  ---------------

                    
California             [*]
Maryland               [*]
New York               [*]
Georgia                [*]
Illinois & Michigan    [*]




-------------------------
     [*]Certain information on this page has been omitted and filed separately
with the Securities and Exchange Commission.  Confidential treatment has been
requested with respect to the omitted portions.

 
     The rates and services listed above are subject to availability; MFS's
obligation to provide the services in each state listed above is contingent on
MFS securing agreements with the applicable LEC allowing MFS to provision such
services on commercially reasonable terms.

     3.  DISCOUNTS

     In the event that Customer orders and MFS installs more than [*]
T-1 trunks in the United States, Customer shall receive a discount of [*] off of
the rates listed above for each T-1 in excess of [*]. In the event that Customer
orders and MFS installs more than [*] T-1 trunks in the United States, Customer
shall receive a discount of [*] off of the rates listed above for each T-1 in
excess of [*]. The discounts stated in this section shall apply only to the
extent that Customer has ordered T-l's in excess of the numbers listed in this
section. As an example, if Customer has ordered and MFS has installed [*] T-l's
then Customer's monthly charges for [*] T-l's shall be determined by the rates
in Section 2, and Customer's monthly charges for [*] T-l's shall be determined
by the rates in Section 2, less [*]. If Customer has ordered and installed [*]
T-I's, then the monthly charges shall be: (a) the prices listed in Section 2 for
[*] T-1's; (b) [*] off of those prices for [*] T-1's; and (c) [*] off those
prices for [*] T-1's.


     4.  INSTALLATION CHARGES

     Customer shall pay MFS [*] for each T-1 installed by MFS pursuant to
this Agreement, which installation fee shall be billed after installation.

     5.  MINIMUM MONTHLY USAGE COMMITMENT

     Customer agrees to maintain a minimum monthly usage commitment of [*]
of monthly billings for T-1 Trunk Charges listed in section 2 hereof. In any
month where Customer's actual billings fall below the minimum monthly usage
commitment, Customer agrees to pay a shortfall fee equal to the difference
between Customer's actual bill and the minimum monthly usage commitment. Only
the T-1 Trunk Charges contribute toward the minimum monthly usage commitment.
Charges that do not contribute to the minimum monthly usage commitment include
installation fees, access charges, late payment penalties, taxes and other
government-imposed surcharges.

     6.  TERMINATION LIABILITY

     If Customer terminates this Agreement prior to the end of the initial or
any renewal term, or MFS terminates this Agreement due to Customer's material
default, Customer shall pay to MFS, as liquidated damages and not as a penalty,
a termination charge equal to the minimum monthly usage commitment multiplied by
the number of months remaining on the initial or renewal term.  Customer


------------------------
     [*]Certain information on this page has been omitted and filed separately
with the Securities and Exchange Commission.  Confidential treatment has been
requested with respect to the omitted portions.


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may terminate this Agreement without liability if Customer provides written
notification of such cancellation to MFS, postmarked within 90 days of the date
of this Agreement.  Written notification must be sent to:

             MFS Telecom Companies, Inc.
             55 South Market Street, Suite 1250
             San Jose, CA 95113
             Attn: Contracts Department


     Notwithstanding cancellation of this Agreement, Customer shall be
responsible for all charges incurred under this Agreement through the date of
Customer's disconnection from MFS service.

     7.  ENTIRE AGREEMENT AND MODIFICATIONS

     The terms and conditions contained in this Agreement constitute the entire
agreement of the parties and supersede all previous written and oral
representations and/or agreements respecting the same subject matter between the
parties.  This Agreement may be amended only by a writing signed by Customer and
MFS's Customer Contracts Administrator.


Customer Acceptance                      MFS Acceptance


/s/ John Peters                            /s/ Douglas T. Hickey
-----------------------------            -------------------------------
Authorized Customer Signature            Authorized MFS Signature

6/17/96                                  6/17/96
-----------------------------            -------------------------------
Date                                     Date

John Peters                              Douglas T. Hickey
-----------------------------            -------------------------------
Typed or Printed Name                    Typed or Printed Name

Executive Vice President                 President
-----------------------------            -------------------------------
Title                                    Title





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