<Page>

                                                                    EXHIBIT:10.2

                                                                [EXECUTION COPY]

                                 AMENDMENT NO. 2

                 TO SECOND AMENDED AND RESTATED CREDIT AGREEMENT

          THIS AMENDMENT NO. 2 TO SECOND AMENDED AND RESTATED CREDIT AGREEMENT
(this "Amendment") dated as of April 17, 2002, is made among Cogent
Communications, Inc., a Delaware corporation ("Borrower"), Cogent Internet,
Inc., a Delaware corporation ("Additional Borrower"), Cogent Communications
Group, Inc., a Delaware corporation ("Holdings"), and Cisco Systems Capital
Corporation, a Nevada corporation ("Lender" or "Agent").

          WHEREAS, Borrower, Additional Borrower, Agent and the several
financial institutions from time to time party thereto ("Lenders") entered into
a Second Amended and Restated Credit Agreement dated as of October 24, 2001, as
amended by that certain Amendment No. 1 to Second Amended and Restated Credit
Agreement dated as of February 4, 2002 (as amended, the "Credit Agreement");

          WHEREAS, PN Acquisition Corp., a Delaware corporation ("PN
Acquisition"), a wholly owned subsidiary of Borrower, proposes to acquire
certain assets of PSINet, Inc. ("PSINet") pursuant to an asset sale under
Section 363 of the Bankruptcy Code (the "Asset Purchase Transaction"); and

          WHEREAS, in connection with the proposed Asset Purchase Transaction,
Borrower, Additional Borrower, Holdings and Agent desire, in accordance with
Section 8.1 of the Credit Agreement, to amend the Credit Agreement.

          NOW, THEREFORE, in consideration of the premises, the mutual covenants
herein contained, and other good and valuable consideration, the receipt of
which is hereby acknowledged, the parties hereto agree as follows

          SECTION 1  DEFINITIONS; INTERPRETATION.

          (a) TERMS DEFINED IN CREDIT AGREEMENT. All capitalized terms used in
this Amendment (including in the recitals hereof) and not otherwise defined
herein shall have the meanings assigned to them in the Credit Agreement.

          (b) INTERPRETATION. The rules of interpretation set forth in Section
1.2 of the Credit Agreement shall be applicable to this Amendment and are
incorporated herein by this reference.

          SECTION 2  AMENDMENTS TO THE CREDIT AGREEMENT.

          (a) AMENDMENTS. The Credit Agreement and the Schedule shall be amended
as follows, effective as of the date of satisfaction of the conditions set forth
in Section 4 (the "Effective Date"):

                                       1.
<Page>

          (i) Section 1.1 of the Credit Agreement is hereby amended as follows:

          (A) The definition of "Permitted Transactions" is hereby amended by
adding the following after the end of the last sentence:

          Notwithstanding anything to the contrary contained herein,
          the transactions (the "Asset Purchase Transaction")
          described in the PSINet Asset Purchase Documents shall
          constitute Permitted Transactions hereunder.

          (B) The following new definitions are added to this Section:

          "PN ACQUISITION" means PN Acquisition Corp., a Delaware
          corporation, and a wholly owned subsidiary of Holdings.

          "PSINET" means PSINet, Inc., a New York corporation.

          "PSINET ASSET PURCHASE AGREEMENT" means the Asset Purchase
          Agreement dated as of February 26, 2002, among PSINet, PN
          Acquisition, and the other parties named thereto.

          "PSINET ASSET PURCHASE DOCUMENTS" means the PSINet Purchase
          Agreement and all documents and agreements entered into in
          connection therewith.

          (ii)  Section 5.1(r) of the Credit Agreement is hereby deleted in its
entirety and replaced with the following:

          (r)   FINANCIAL COVENANTS.

          (i)   LEVERAGE RATIO. On a consolidated basis, Holdings and
          its Subsidiaries shall not, as of the last day of any fiscal
          quarter, permit its ratio of Consolidated Funded Debt to
          EBITDA (measured on a rolling four quarter basis for the
          four fiscal quarters ended as of each quarterly period set
          forth below) to be greater than the ratios indicated below:

<Table>
<Caption>
               QUARTERLY PERIOD ENDING                   REQUIRED RATIO
                                                           
               March 31, 2002                                  N/A
               June 30, 2002                                   N/A
               September 30, 2002                              N/A
               December 31, 2002                               N/A
               March 31, 2003                                  N/A
               June 30, 2003                                   N/A
               September 30, 2003                              N/A
               December 31, 2003                              11.6:1
</Table>

                                       2.
<Page>

<Table>
<Caption>
               QUARTERLY PERIOD ENDING                    REQUIRED RATIO
                                                           
               March 31, 2004                                 6.5:1
               June 30, 2004                                  4.3:1
               September 30, 2004                             3.2:1
               December 31, 2004                              2.6:1
               March 31, 2005                                 2.2:1
               June 30, 2005                                  2.0:1
               September 30, 2005                             2.2:1
               December 31, 2005                              2.4:1
               March 31, 2006                                 2.7:1
               June 30, 2006                                  2.7:1
               September 30, 2006                             2.5:1
               December 31, 2006                              2.2:1
               March 31, 2007                                 2.0:1
               June 30, 2007                                  1.8:1
               September 30, 2007                             0.9:1
               December 31, 2007                              0.8:1
               March 31, 2008                                 0.6:1
               Thereafter                                     0.6:1
</Table>

          (ii)   MINIMUM TOTAL REVENUES. On a consolidated basis,
          Holdings and its Subsidiaries shall not fail to maintain
          total monthly or total annualized quarterly revenues of
          Holdings and its Subsidiaries, for each monthly or quarterly
          period, as applicable, set forth below, of not less than the
          correlative amount indicated (it being understood that with
          respect to any quarterly period, annualized revenues shall
          be equal to revenues for such quarterly period, multiplied
          by four):

<Table>
<Caption>
               MONTHLY PERIOD ENDING
               (EXCLUDING REVENUE
               FROM PSINET RELATED ASSETS)               REQUIRED AMOUNT
                                                       
               March 31, 2002                             $   1,200,000
               April 30, 2002                             $   1,500,000
               May 31, 2002                               $   1,900,000
               June 30. 2002                              $   2,200,000
               July 31, 2002                              $   2,600,000
               August 31. 2002                            $   3,100,000
               September 30, 2002                         $   3,700,000
</Table>

                                       3.
<Page>

<Table>
<Caption>

               MONTHLY PERIOD ENDING
               (INCLUDING REVENUE FROM
               PSINET RELATED ASSETS)                    REQUIRED AMOUNT
                                                       
               March 31, 2002                             $   1,200,000
               April 30, 2002                             $   4,400,000
               May 31, 2002                               $   4,500,000
               June 30, 2002                              $   4,400,000
               July 31, 2002                              $   4,700,000
               August 31, 2002                            $   5,200,000
               September 30, 2002                         $   5,600,000

<Caption>
               QUARTERLY PERIOD ENDING             REQUIRED ANNUALIZED AMOUNT
                                                       
               December 31, 2002                          $  90,500,000
               March 31, 2003                             $ 109,300,000
               June 30, 2003                              $ 142,700,000
               September 30, 2003                         $ 182,000,000
               December 31, 2003                          $ 228,000,000
               March 31, 2004                             $ 280,300,000
               June 30, 2004                              $ 335,400,000
               September 30, 2004                         $ 393,200,000
               December 31, 2004                          $ 453,500,000
               March 31, 2005                             $ 443,300,000
               June 30, 2005                              $ 494,600,000
               September 30, 2005                         $ 549,000,000
               December 31, 2005                          $ 606,100,000
               March 31, 2006                             $ 564,900,000
               June 30, 2006                              $ 601,300,000
               September 30, 2006                         $ 641,000,000
               December 31, 2006                          $ 681,400,000
               March 31, 2007                             $ 620,100,000
               June 30, 2007                              $ 652,900,000
               September 30, 2007                         $ 689,100,000
               December 31, 2007                          $ 725,800,000
               March 31, 2008                             $ 654,900,000
               Thereafter                                 $ 654,900,000
</Table>

          (iii)  MINIMUM EBITDA. On a consolidated basis, Holdings and
          its Subsidiaries shall not fail to maintain EBITDA for each
          monthly or annualized quarterly period, as applicable, ended
          as of the last day of each monthly or quarterly period, as
          applicable, set forth below of not less than the correlative
          amount indicated (bracketed amounts (LESS THAN GREATER THAN)
          are negative), it being understood that with respect to any
          quarterly period, annualized revenues shall be equal to
          revenues for such quarterly period, multiplied by four:

                                       4.
<Page>

<Table>
<Caption>
               MONTHLY PERIOD ENDING                      REQUIRED AMOUNT
                                                       
               March 31, 2002                             $   (4,100,000)
               April 30, 2002                             $   (5,000,000)
               May 31, 2002                               $   (7,100,000)
               June 30, 2002                              $   (4,200,000)
               July 31, 2002                              $   (3,200,000)
               August 31, 2002                            $   (2,600,000)
               September 30, 2002                         $   (2,300,000)

<Caption>
               QUARTERLY PERIOD ENDING                    REQUIRED AMOUNT
                                                       
               December 31, 2002                          $  (40,800,000)
               March 31, 2003                             $  (26,300,000)
               June 30, 2003                              $   (3,700,000)
               September 30, 2003                         $   17,300,000
               December 31, 2003                          $   45,100,000
               March 31, 2004                             $   79,500,000
               June 30, 2004                              $  119,200,000
               September 30, 2004                         $  161,300,000
               December 31, 2004                          $  208,400,000
               March 31, 2005                             $  241,500,000
               June 30, 2005                              $  251,700,000
               September 30, 2005                         $  230,200,000
               December 31, 2005                          $  209,400,000
               March 31, 2006                             $  176,500,000
               June 30, 2006                              $  167,900,000
               September 30, 2006                         $  172,100,000
               December 31, 2006                          $  178,000,000
               March 31, 2007                             $  179,900,000
               June 30, 2007                              $  184,700,000
               September 30, 2007                         $  186,000,000
               December 31, 2007                          $  174,700,000
               March 31, 2008                             $  176,000,000
               Thereafter                                 $  176,000,000
</Table>

          (iv)   INTEREST COVERAGE RATIO. On a consolidated basis,
          Holdings and its Subsidiaries shall not permit the ratio of
          EBITDA to Interest Expense (measured on a rolling four
          quarter basis for the four fiscal quarters ended on the last
          day of each quarterly period set forth below) for each
          quarterly period set forth below to be less than the ratio
          set forth below (determined as of the end of the quarterly
          period set forth below):

                                       5.
<Page>

<Table>
<Caption>
               QUARTERLY PERIOD ENDING                     REQUIRED RATIO
                                                            
               March 31, 2002                                   N/A
               June 30, 2002                                    N/A
               September 30, 2002                               N/A
               December 31, 2002                                N/A
               March 31, 2003                                   N/A
               June 30, 2003                                    N/A
               September 30, 2003                              0.3:1
               December 31, 2003                               0.9:1
               March 31, 2004                                  1.6:1
               June 30, 2004                                   2.4:1
               September 30, 2004                              3.3:1
               December 31, 2004                               4.2:1
               March 31, 2005                                  3.9:1
               June 30, 2005                                   3.2:1
               September 30, 2005                              2.5:1
               December 31, 2005                               1.9:1
               March 31, 2006                                  1.4:1
               June 30, 2006                                   1.2:1
               September 30, 2006                              1.1:1
               December 31, 2006                               1.0:1
               March 31, 2007                                  1.0:1
               June 30, 2007                                   1.0:1
               September 30, 2007                              1.0:1
               December 31, 2007                               1.1:1
               March 31, 2008                                  1.2:1
               Thereafter                                      1.2:1
</Table>

          (v)    MAXIMUM FUNDED DEBT TO CAPITALIZATION. On a consolidated
          basis, Holdings and its Subsidiaries shall not permit the
          ratio of Consolidated Funded Debt to Capitalization to
          exceed the percentage amount set forth below (determined as
          of the end of the quarterly period set forth below):

<Table>
<Caption>
               QUARTERLY PERIOD ENDING                       PERCENTAGE
                                                             
               March 30, 2002                                   N/A
               June 30, 2002                                    N/A
               September 30, 2002                               71%
               December 31, 2002                                71%
               March 31, 2003                                   71%
</Table>

                                       6.
<Page>

<Table>
<Caption>
               QUARTERLY PERIOD ENDING                       PERCENTAGE
                                                             
               June 30, 2003                                    71%
               September 30, 2003                               71%
               December 31, 2003                                71%
               March 31, 2004                                   71%
               June 30, 2004                                    72%
               September 30, 2004                               73%
               December 31, 2004                                73%
               March 31, 2005                                   73%
               June 30, 2005                                    73%
               September 30, 2005                               73%
               December 31, 2005                                72%
               March 31, 2006                                   71%
               June 30, 2006                                    70%
               September 30, 2006                               68%
               December 31, 2006                                68%
               March 31, 2007                                   65%
               June 30, 2007                                    62%
               September 30, 2007                               50%
               December 31, 2007                                50%
               March 31, 2008                                   50%
               Thereafter                                       50%
</Table>

          (vi)   MINIMUM CUSTOMERS. The number of revenue generating
          customers of Holdings and its Subsidiaries (treating each
          office location of a Person purchasing services from
          Holdings or any Subsidiary to be a separate customer to the
          extent such office locations are in separate buildings) as
          of the end of the monthly or quarterly period set forth
          below shall not be less than the number listed opposite such
          period:

<Table>
<Caption>
               MONTHLY PERIOD                                  NUMBER
                                                            
               March 31, 2002                                    392
               April 30, 2002                                    498
               May 31, 2002                                      614
               June 30, 2002                                     745
               July 31, 2002                                     920
               August 31, 2002                                 1,107
               September 30, 2002                              1,311
</Table>

                                       7.
<Page>

<Table>
<Caption>
               QUARTERLY PERIOD                               NUMBER
                                                           
               December 31, 2002                               1,970
               March 31, 2003                                  2,809
               June 30, 2003                                   3,674
               September 30, 2003                              4,615
               December 31, 2003                               5,682
               March 31, 2004                                  7,054
               June 30, 2004                                   8,322
               September 30, 2004                              9,578
               December 31, 2004                              10,806
               March 31, 2005                                 11,977
               June 30, 2005                                  13,058
               September 30, 2005                             14,113
               December 31, 2005                              15,174
               March 31, 2006                                 16,245
               June 30, 2006                                  17,326
               September 30, 2006                             18,418
               December 31, 2006                              19,515
               March 31, 2007                                 20,635
               June 30, 2007                                  21,757
               September 30, 2007                             22,889
               December 31, 2007                              24,022
               March 31, 2008                                 25,168
               Thereafter                                     25,168
</Table>

          (vii)  MINIMUM CASH RESERVES. On a consolidated basis,
          Holdings and its Subsidiaries shall maintain as of the last
          day of each monthly or quarterly period, as applicable,
          Minimum Cash Reserves not less than the amount listed
          opposite such date below:

<Table>
<Caption>
               DATE                                           NUMBER
                                                       
               March 31, 2002                             $  68,200,000
               April 30, 2002                             $  55,800,000
               May 31, 2002                               $  42,000,000
               June 30, 2002                              $  35,800,000
               July 31, 2002                              $  30,700,000
               August 31, 2002                            $  26,400,000
               September 30, 2002                         $  22,400,000
               December 31, 2002                          $  37,200,000
               March 31, 2003                             $  26,700,000
</Table>

                                       8.
<Page>

<Table>
<Caption>
               DATE                                           NUMBER
                                                       
               June 30, 2003                              $  17,900,000
               September 30, 2003                         $  20,400,000
               December 31, 2003                          $  26,300,000
               March 31, 2004                             $  42,300,000
               June 30, 2004                              $  69,600,000
               September 30, 2004                         $ 112,000,000
               December 31, 2004                          $ 144,500,000
               March 31, 2005                             $ 164,600,000
               June 30, 2005                              $ 171,300,000
               September 30, 2005                         $ 192,400,000
               December 31, 2005                          $ 220,000,000
               March 31, 2006                             $ 233,500,000
               June 30, 2006                              $ 243,700,000
               September 30, 2006                         $ 257,400,000
               December 31, 2006                          $ 277,700,000
               March 31, 2007                             $ 299,400,000
               June 30, 2007                              $ 205,000,000
               September 30, 2007                         $ 222,900,000
               December 31, 2007                          $ 244,700,000
               Thereafter                                 $ 280,600,000
</Table>

          (viii) MINIMUM NODES ON NET. The number of nodes connected
          to the network maintained by Holdings and its Subsidiaries
          as of any date listed below shall not be less than the
          number listed opposite such monthly or quarterly period set
          forth below:

<Table>
<Caption>
               MONTHLY PERIOD                                 NUMBER
                                                             
               March 31, 2002                                   207
               April 30, 2002                                   230
               May 31, 2002                                     252
               June 30, 2002                                    275
               July 31, 2002                                    288
               August 31, 2002                                  302
               September 30, 2002                               316
<Caption>
               QUARTERLY PERIOD                               NUMBER
                                                             
               December 31, 2002                                388
               March 31, 2003                                   472
               June 30, 2003                                    556
               September 30, 2003                               640
</Table>

                                       9.
<Page>

<Table>
                                                           
               December 31, 2003                                724
               March 31, 2004                                   820
               June 30, 2004                                    916
               September 30, 2004                             1,012
               December 31, 2004                              1,108
               March 31, 2005                                 1,204
               June 30, 2005                                  1,300
               September 30, 2005                             1,396
               December 31, 2005                              1,492
               March 31, 2006                                 1,588
               June 30, 2006                                  1,684
               September 30, 2006                             1,780
               December 31, 2006                              1,876
               March 31, 2007                                 1,972
               June 30, 2007                                  2,068
               September 30, 2007                             2,164
               December 31, 2007                              2,260
               March 31, 2008                                 2,356
               Thereafter                                     2,356
</Table>

          (ix)   MAXIMUM CAPITAL EXPENDITURES. On a consolidated basis,
          Holdings and its Subsidiaries shall not make any
          expenditures for fixed or capital assets on an annual basis
          in excess of the amount listed below (determined as of the
          end of the annual period set forth below):

<Table>
<Caption>
               DATE                                       ANNUAL AMOUNT
                                                       
               December 31, 2002                          $  72,100,000
               December 31, 2003                          $  94,700,000
               December 31, 2004                          $ 108,300,000
               December 31, 2005                          $ 115,200,000
               December 31, 2006                          $  83,400,000
               December 31, 2007                          $  77,600,000
               Thereafter                                 $  77,600,000
</Table>

          As used in this subsection (r), the following terms shall
          have the following meanings: "Capitalization" means, on any
          date, the sum of (i) Consolidated Funded Debt, and (ii) the
          sum of common and preferred equity, including without
          duplication capital stock plus paid in capital of Holdings
          and its Subsidiaries on such date, on a

                                       10.
<Page>

          consolidated basis and as determined in accordance with,
          GAAP; "Consolidated Funded Debt" means, as of any date of
          determination, all Indebtedness of Holdings and its
          Subsidiaries on such date, on a consolidated basis and as
          determined in accordance with GAAP; "EBITDA" means, for any
          period with respect to Holdings and its Subsidiaries, net
          income (excluding extraordinary items), plus (except to the
          extent attributable to extraordinary items) the amount of
          any interest, taxes, depreciation, amortization and other
          non-cash charges deducted in determining such net income,
          all of the foregoing as determined on a consolidated basis
          for Holdings and its Subsidiaries, determined in conformity
          with GAAP; "Interest Expense" means, for any period with
          respect to Holdings and its Subsidiaries, the amount of
          interest expense, both expensed and capitalized (including
          the portion of any payments in respect of any capital leases
          allocable to interest expense), on a consolidated basis, as
          determined in accordance with GAAP, paid or payable during
          such period in respect of any Indebtedness of Holdings and
          its Subsidiaries; and "Minimum Cash Reserves" means
          unrestricted (i) cash, (ii) marketable, direct obligations
          of the United States of America, its agencies and
          instrumentalities maturing within three hundred sixty-five
          (365) days of the date of purchase, (iii) commercial paper
          issued by corporations, each of which shall have a combined
          net worth of at least $100,000,000 and each of which
          conducts a substantial part of its business in the United
          States of America, maturing within two hundred seventy (270)
          days from the date of the original issue thereof, and rated
          "P-1" or better by Moody's Investors Service, Inc., or "A-1"
          or better by Standard and Poor's Ratings Group, and (iv)
          repurchase agreements, bankers' acceptances, and
          certificates of deposit maturing within three hundred
          sixty-five (365) days of the date of purchase which are
          issued by, or time deposits maintained with, a United States
          national bank the deposits of which are insured by the
          Federal Deposit Insurance Corporation and having capital,
          surplus and undivided profits totaling more than
          $100,000,000 and rated "A" or better by Moody's Investors
          Service, Inc. or Standard and Poor's Ratings Group, of
          Borrower and its wholly-owned Subsidiaries. Notwithstanding
          anything in this Section 5.1(r) to the contrary, any
          Indebtedness or any Interest Expense thereon accruing or
          becoming due during the Permitted Period resulting from
          Permitted Purchases shall not be included by Holdings in
          determining compliance with the financial covenants set
          forth in this Section 5.1(r). Notwithstanding any provision
          to the contrary contained herein, if Holdings and its
          Subsidiaries fail to comply with any of the financial
          covenants set forth in this Section 5.1(r) prior to the
          period ending September 30, 2002, such non-compliance shall
          not constitute an Event of Default

                                       11.
<Page>

          hereunder, but neither Agent nor any other Lender shall have
          any obligation to make any Loans to Borrower (other than
          Tranche X Loans (as defined in the Schedule), which shall
          continue to be available to Borrower), until Holdings and
          its Subsidiaries shall have complied with all of the monthly
          financial covenants set forth in this Section 5.1(r) for a
          subsequent month during the period prior to and including
          the period ending September 30, 2002. On and after September
          30, 2002, any non-compliance with any of the financial
          covenants shall constitute an Event of Default hereunder.

          (iii) Subsections (i), (ii) and (iii) of Section 1(a) of the Schedule
to the Credit Agreement are hereby deleted in their entirety and replaced with
the following:

          (i) (A) Up to $145,000,000 ("Tranche Al") shall be available
          from the Original Closing Date to the Closing Date, (B) up
          to $40,000,000, ("Tranche A2"), shall be available from the
          Closing Date until September 30, 2002 (the "Tranche 2
          Availability Termination Date"), and (C) up to $85,000,000,
          PLUS any unused portion of Tranche A2 (the aggregate of such
          amounts, "Tranche A3"), shall be available from the first
          Banking Day following the Tranche 2 Availability Termination
          Date (the "Tranche A3 Commencement Date") until December 31,
          2004 (the "Tranche 3 Availability Termination Date"); and

          (ii) (A) Up to $29,000,000 ("Tranche B1") shall be available
          from the Original Closing Date to the Closing Date, and (B)
          up to $35,000,000, ("Tranche B3"), shall be available from
          the first Banking Day following the Tranche 2 Availability
          Termination Date to the Tranche 3 Availability Termination
          Date; and

          (iii) (A) Up to $20,000,000 ("Tranche X2") shall be
          available from the Closing Date until the Tranche 2
          Availability Termination Date, and (B) up to $55,000,000
          ("Tranche X3") shall be available from the Tranche A3
          Commencement Date until December 31, 2005 (the "Tranche X
          Availability Termination Date"); PROVIDED, however, that in
          the event that after the Closing Date one or more investors
          shall have made cash equity contributions to Borrower and
          Holdings in an aggregate amount together in excess of
          $300,000,000, the then unused portion of Tranche X shall be
          reduced by fifty percent (50%) of the amount by which the
          aggregate amount of such cash equity contributions exceeds
          $250,000,000.

          (iv) Subsection (iii) of Section 1(i) of the Schedule to the Credit
Agreement is hereby deleted in its entirety and replaced with the following:

                                       12.
<Page>


          (iii) CONDITIONS PRECEDENT TO TRANCHE 3: Loans under Tranche
          3 shall not be available unless Borrower has provided Agent
          with reasonably satisfactory evidence that the business plan
          of Borrower is "fully funded" (as described below). For
          purposes of this Agreement, Borrower's business plan shall
          be deemed "fully funded" if, on September 30, 2002, Borrower
          maintains (x) Minimum Cash Reserves equal to or greater than
          $22,400,000, and (y) minimum annualized EBITDA equal to or
          greater than ($44,700,000).

          (b) REFERENCES WITHIN CREDIT AGREEMENT. Each reference in the Credit
Agreement to "this Agreement" and the words "hereof," "herein," "hereunder," or
words of like import, shall mean and be a reference to the Credit Agreement as
amended by this Amendment.

          SECTION 3  CONDITIONS OF EFFECTIVENESS. The effectiveness of Section 2
of this Amendment shall be subject to the satisfaction of each of the following
conditions precedent:

          (a) FEES AND EXPENSES. Borrower shall have paid all invoiced costs and
expenses then due in accordance with Section 5(c) below.

          (b) LOAN DOCUMENTS. On or before the Effective Date (except as
otherwise provided below), Agent shall have received the following documents, in
form and substance satisfactory to it:

          (i)   the Guaranty by PN Acquisition in favor of Agent (on behalf of
each Lender) in substantially the form of EXHIBIT A attached hereto; -

          (ii)  the Security Agreement between PN Acquisition and Agent (on
behalf of each Lender) in substantially the form of EXHIBIT B attached hereto
(the "PN Acquisition Security Agreement");

          (iii) within ten (10) days after the Effective Date, the Copyright
Security Agreement between PN Acquisition and Agent (on behalf of each Lender)
in substantially the form of EXHIBIT C attached hereto;

          (iv)  within ten (10) days after the Effective Date, the Patent and
Trademark Security Agreement between PN Acquisition and Agent (on behalf of each
Lender) in substantially the form of EXHIBIT D attached hereto;

          (v)   the Amendment to Amended and Restated Stock Pledge Agreement
between Holdings and Agent (on behalf of each Lender) in substantially the form
of EXHIBIT E attached hereto (the "Amended Holdings Stock Pledge");

          (vi)  the consent of each Guarantor, in substantially the form of
EXHIBIT F (the "Guarantor Consent"), to the amendments contemplated by this
Amendment; and

                                       13.
<Page>

          (vii) within ten (10) days after the Effective Date, each of the
documents required under Section 5.1(o) of the Credit Agreement with respect to
the new Subsidiaries of Borrower, Cogent Fiber Services of Georgia and Cogent
Communications of California, Inc.

          (c) DOCUMENTS AND ACTION RELATING TO COLLATERAL. On or before the
Effective Date (except as otherwise provided below), Agent shall have received
the following, in form and substance satisfactory to it:

          (i)   UCC Financing Statements for PN Acquisition as required under
the PN Acquisition Security Agreement and the other Collateral Documents;

          (ii)  Original stock certificates of PN Acquisition pledged to Agent
(on behalf of Lenders) pursuant to the Amended Holdings Stock Pledge (together
with applicable Stock Power);

          (iii) Within thirty (30) days after the Effective Date, Collateral
Access Agreements as required under the PN Acquisition Security Agreement and
the other Collateral Documents;

          (iv)  Within thirty (30) days after the Effective Date, Account
Control Agreements as required under the PN Acquisition Security Agreement and
the other Collateral Documents;

          (v)   A Representations and Warranties Certificate with all requested
information completed by Borrower; and

          (vi)  Such other financing statements, searches, certificates,
filings, and other documents and instruments, in form reasonably satisfactory to
Agent, as Agent may reasonably require to effectuate the purposes of the Loan
Documents.

          (d) ADDITIONAL CLOSING DOCUMENTS AND ACTIONS. On or before the
Effective Date (except as expressly provided below), Agent shall have received
the following, in form and substance satisfactory to it:

          (i)   a fully executed copy (or copies) of the PSINet Asset Purchase
Documents with respect to the Asset Purchase Transaction, together with the
order of the applicable Bankruptcy Court approving such Asset Purchase
Transaction;

          (ii)  evidence that all (A) authorizations or approvals of any
Governmental Authority, and (B) approvals or consents of any other Person,
required in connection with the Asset Purchase Transaction and the execution,
delivery and performance of this Amendment shall have been obtained;

          (iii) a certificate of a senior officer of Borrower, stating that (A)
the representations and warranties contained in Section 4 and in the amendments
to the other Loan Documents are true and correct in all material respects on and
as of the date of such certificate as though made on and as of the Effective
Date and (B) on and as of the Effective Date, after

                                       14.
<Page>

and giving effect to the amendment of the Credit Agreement contemplated hereby,
no Default shall have occurred and be continuing;

          (iv)  a certificate of a senior officer of Borrower (i) attaching a
true and complete copy of the PSINet Asset Purchase Agreement, (ii) certifying
that none of the PSINet Asset Purchase Documents have been altered, amended or
otherwise changed or supplemented and that no condition therein or provision
thereof has been waived, (iii) certifying that there does not exist (A) any law,
order, decree, judgment, ruling or injunction which could restrain or prevent
the consummation of the Asset Purchase Transaction in the manner contemplated by
the PSINet Asset Purchase Agreement, and (B) any pending or, to the best
knowledge of such senior officers, threatened action, suit, investigation or
proceeding relating to the Asset Purchase Transaction which seeks or threatens
any of the foregoing and (iv) certifying that on the Effective Date the Asset
Purchase Transaction will be consummated in accordance with the terms of the
PSINet Asset Purchase Documents and in compliance with any applicable
Requirement of Law;

          (v)   all conditions precedent to the effectiveness of Amendment No. 1
to the Second Amended and Restated Credit Agreement shall have been satisfied in
full, as reasonably determined by Agent; and

          (vi)  such additional information with respect to the Asset Purchase
Transaction as Agent may reasonably request.

          (e) CORPORATE DOCUMENTS. Agent shall have received, in form and
substance satisfactory to it:

          (i)   a certificate of the Secretary or Assistant Secretary of
Borrower, dated the Effective Date, certifying (i) copies of the resolutions of
the Board of Directors of Borrower authorizing the execution, delivery and
performance of this Amendment and the amendments to the other Loan Documents and
(ii) the incumbency, authority and signatures of each officer of Borrower
authorized to execute and deliver this Amendment and the amendments to the other
Loan Documents; and

          (ii)  a certificate of the Secretary or Assistant Secretary of PN
Acquisition, dated the Effective Date, certifying (A) copies of the resolutions
of the Board of Directors of PN Acquisition authorizing the execution, delivery
and performance of the Guaranty and each of the other documents described herein
or related thereto to which it is a party, (B) the incumbency, authority and
signatures of each officer of PN Acquisition authorized to execute and deliver
such documents, and (C) copies of the certificate of incorporation and bylaws of
PN Acquisition.

          (f) LEGAL OPINIONS. Agent shall have received (i) the opinion of
Friedman, Kaplan, Seiler & Adelman, LLP, counsel to Borrower, Additional
Borrower, PN Acquisition and each Guarantor, dated the Effective Date, and (ii)
the opinion of Latham & Watkins, special counsel to Holdings, each in form and
substance satisfactory to Agent.

          (g) MATERIAL ADVERSE CHANGE. On and as of the Effective Date, there
shall have occurred no Material Adverse Change since the date of this Amendment.

                                       15.
<Page>

          (h) REPRESENTATIONS AND WARRANTIES; NO DEFAULT. On the Effective Date,
after giving effect to the amendment of the Credit Agreement contemplated
hereby:

          (i)   except as otherwise disclosed in writing to Agent and Lenders
under that certain disclosure schedule delivered to Lender prior to the
Effective Date, the representations and warranties contained in Section 4 and in
the other Loan Documents shall be true and correct on and as of the Effective
Date as though made on and as of such date; and

          (ii)  no Default shall have occurred and be continuing.

          (i) ADDITIONAL DOCUMENTS. Agent shall have received, in form and
substance satisfactory to it, such additional approvals, opinions, documents and
other information as Lender may reasonably request.

          SECTION 4  REPRESENTATIONS AND WARRANTIES.

          (a) To induce Agent to enter into this Amendment, Borrower hereby
confirms and restates, as of the date hereof, the representations and warranties
made by it in Section 4.1 of the Credit Agreement and in the other Loan
Documents (except as otherwise disclosed in writing to Agent and Lenders under
that certain disclosure schedule delivered to Lender prior to the Effective
Date). For the purposes of this Section 4, (i) each reference in Section 4.1 of
the Credit Agreement to "this Agreement," and the words "hereof," "herein,"
"hereunder," or words of like import in such Section, shall mean and be a
reference to the Credit Agreement as amended by this Amendment, and each
reference in such Section to "the Loan Documents" shall mean and be a reference
to the Loan Documents as amended as contemplated hereby, and (ii), clause (i)
shall take into account any amendments to any disclosures made in writing by
Borrower and any Guarantor to Agent and each Lender after the Effective Date and
approved by Agent (on behalf of each Lender).

          (b) Borrower further represents and warrants to Agent and Lenders that
as of the date hereof: (A) the PSINet Asset Purchase Documents have not been
altered, amended or otherwise changed or supplemented in any material respect
and no material condition therein or material provision thereof has been waived;
(B) the PSINet Asset Purchase Documents are in full force and effect and are
legal, valid and binding obligations of each party thereto enforceable against
each such party in accordance with their respective terms, except to the extent
that the enforceability thereof may be limited by applicable bankruptcy,
insolvency, reorganization, moratorium and other laws affecting creditor's
rights generally and by equitable principles (regardless of whether enforcement
is sought in equity or at law); (C) all representations and warranties of the
Borrower in the PSINet Asset Purchase Documents are true and correct in all
material respects as of each date made or deemed made; (D) to the Borrower's
knowledge, all representations and warranties of PSINet in the PSINet Asset
Purchase Documents are true and correct in all material respects as of each date
made or deemed made; and (E) the assets purchased under the PSINet Asset
Purchase Agreement are free and clear of any and all liens, security interests,
encumbrance and other interests.

                                       16.
<Page>

          SECTION 5 MISCELLANEOUS.

          (a) CREDIT AGREEMENT OTHERWISE NOT AFFECTED. Except as expressly
amended pursuant hereto, the Credit Agreement shall remain unchanged and in full
force and effect and is hereby ratified and confirmed in all respects. Agent's
execution and delivery of, or acceptance of, this Amendment and any other
documents and instruments in connection herewith (collectively, the "Amendment
Documents") shall not be deemed to create a course of dealing or otherwise
create any express or implied duty by it to provide any other or further
amendments, consents or waivers in the future.

          (b) NO RELIANCE. Borrower hereby acknowledges and confirms to Agent
that Borrower is executing this Amendment and the other Amendment Documents on
the basis of its own investigation and for its own reasons without reliance upon
any agreement, representation, understanding or communication by or on behalf of
any other Person.

          (c) COSTS AND EXPENSES. Borrower agrees to pay to Agent on demand the
reasonable out-of-pocket costs and expenses of Agent, and the reasonable fees
and disbursements of counsel to Lender, in connection with the negotiation,
preparation, execution and delivery of this Amendment and any other documents to
be delivered in connection herewith.

          (d) BINDING EFFECT. This Amendment shall be binding upon, inure to the
benefit of and be enforceable by Borrower, Agent, Additional Borrower, Holdings
and their respective successors and assigns.

          (e) GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED BY, AND CONSTRUED
IN ACCORDANCE WITH, THE LAW OF THE STATE OF NEW YORK.

          (f) COMPLETE AGREEMENT; AMENDMENTS. This Amendment, together with the
other Amendment Documents and the other Loan Documents, contains the entire and
exclusive agreement of the parties hereto and thereto with reference to the
matters discussed herein and therein. This Amendment supersedes all prior
commitments, drafts, communications, discussions and understandings, oral or
written, with respect thereto. This Amendment may not be modified, amended or
otherwise altered except in accordance with the terms of Section 8.1 of the
Credit Agreement.

          (g) SEVERABILITY. Whenever possible, each provision of this Amendment
shall be interpreted in such manner as to be effective and valid under all
applicable laws and regulations. If, however, any provision of this Amendment
shall be prohibited by or invalid under any such law or regulation in any
jurisdiction, it shall, as to such jurisdiction, be deemed modified to conform
to the minimum requirements of such law or regulation, or, if for any reason it
is not deemed so modified, it shall be ineffective and invalid only to the
extent of such prohibition or invalidity without affecting the remaining
provisions of this Amendment, or the validity or effectiveness of such provision
in any other jurisdiction.

          (h) COUNTERPARTS. This Amendment may be executed in any number of
counterparts and by different parties hereto in separate counterparts, each of
which when so

                                       17.
<Page>

executed shall be deemed to be an original and all of which taken together shall
constitute but one and the same agreement.

          (i) INTERPRETATION. This Amendment and the other Amendment Documents
are the result of negotiations between and have been reviewed by counsel to
Agent, Borrower and other parties, and are the product of all parties hereto.
Accordingly, this Amendment and the other Amendment Documents shall not be
construed against Agent or any Lender merely because of Agent's involvement in
the preparation thereof.

          (j) LOAN DOCUMENTS. This Amendment and the other Amendment Documents
shall constitute Loan Documents.

          [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK.]

                                       18.
<Page>

          IN WITNESS WHEREOF, the parties hereto have duly executed this
Amendment, as of the date first above written.

                                   Cogent Communications, Inc.

                                   By
                                       ----------------------------------
                                       Title:


                                   Cogent Communications Group, Inc.

                                   By
                                       ----------------------------------
                                       Title:


                                   Cogent Internet, Inc.

                                   By
                                       ----------------------------------
                                       Title:



                                   Cisco Systems Capital Corporation

                                   By
                                       ----------------------------------
                                       Title:

                                       19.
<Page>

                                    EXHIBIT A
       to Amendment No. 2 to Second Amended and Restated Credit Agreement

                             PN ACQUISITION GUARANTY

                                [TO BE PROVIDED]

                                       A-1

<Page>

                                    EXHIBIT B
       to Amendment No. 2 to Second Amended and Restated Credit Agreement

                        PN ACQUISITION SECURITY AGREEMENT

                                [TO BE PROVIDED]

                                      B-1
<Page>

                                    EXHIBIT C
       to Amendment No. 2 to Second Amended and Restated Credit Agreement

                   PN ACQUISITION COPYRIGHT SECURITY AGREEMENT

                                [TO BE PROVIDED]

                                      C-1
<Page>

                                    EXHIBIT D
       to Amendment No. 2 to Second Amended and Restated Credit Agreement

             PN ACQUISITION PATENT AND TRADEMARK SECURITY AGREEMENT

                                [TO BE PROVIDED]

                                      D-1
<Page>

                                    EXHIBIT E
       to Amendment No. 2 to Second Amended and Restated Credit Agreement

                 AMENDMENT TO AMENDED AND RESTATED STOCK PLEDGE

                                [TO BE PROVIDED]

                                      E-1
<Page>

                                    EXHIBIT F
       to Amendment No. 2 to Second Amended and Restated Credit Agreement

                       CONSENT AND AGREEMENT OF GUARANTORS

          Each of the undersigned, in its capacity as guarantor, acknowledges
that its consent to the foregoing Amendment is not required, but the undersigned
nevertheless does hereby consent to the foregoing Amendment and to any documents
and agreements referred to therein and to all future modifications and
amendments thereto (subject to the terms of the Guaranty ("Guaranty"), executed
by each of the undersigned in favor of Cisco Systems Capital Corporation
("CSCC") (as such Continuing Guaranty may be amended from time to time)), and
any termination thereof, and to any and all other present and future documents
and agreements by or between Cogent Communications, Inc. and CSCC. Nothing
herein shall in any way limit any of the terms or provisions of such Guaranty of
the undersigned or any other document or agreement executed by the undersigned
in CSCC's favor (as the same may be amended from time to time), all of which are
hereby ratified and affirmed in all respects. Each Guarantor further
acknowledges and agrees that all of the obligations guaranteed under its
Guaranty constitute "Designated Senior Debt" for purposes of the Indenture
between Allied Riser Communications Corporation and Wilmington Trust Company
dated June 28, 2000, as the same may be amended from time to time by any
amendment or supplemental indenture, and each Guaranty is hereby amended to
reflect such acknowledgment and agreement.

                                       GUARANTORS:

                                       Cogent Communications, Inc.

                                       By
                                             -----------------------------------
                                             Title:


                                       Cogent Communications Group, Inc.

                                       By
                                             -----------------------------------
                                             Title:


                                       Cogent Internet, Inc.

                                       By

                                             -----------------------------------
                                             Title:


                                       Allied Riser Communications Corporation

                                       By
                                             -----------------------------------
                                             Title:

                                      F-1