Exhibit 1.1

                         Metromedia Fiber Network, Inc.

                     $750,000,000 10% Senior Notes Due 2009

                   (euro)250,000,000 10% Senior Notes Due 2009

                             Underwriting Agreement

                                                              New York, New York

                                                               November 12, 1999

SALOMON SMITH BARNEY INC.
CHASE SECURITIES INC.
DEUTSCHE BANK SECURITIES INC.
DONALDSON, LUFKIN & JENRETTE SECURITIES CORPORATION
GOLDMAN, SACHS & CO.
MORGAN STANLEY & CO. INCORPORATED
As Representatives of the several Underwriters,
c/o   Salomon Smith Barney Inc.
      388 Greenwich Street
      New York, New York 10013

Ladies and Gentlemen:

            Metromedia Fiber Network, Inc., a Delaware corporation (the
"Company"), proposes to sell to the underwriters named in Schedule II hereto
(the "Underwriters"), for whom Salomon Smith Barney Inc., Chase Securities Inc.,
Deutsche Bank Securities Inc., Donaldson, Lufkin & Jenrette Securities
Corporation, Goldman, Sachs & Co. and Morgan Stanley & Co. Incorporated (the
"Representatives") are acting as representatives, an aggregate of $750,000,000
principal amount of its 10% Senior Notes due 2009 (the "U.S. Securities") and an
aggregate of (euro)250,000,000 principal amount of its 10% Senior Notes due 2009
(the "International Securities" and together with the U.S. Securities, the
"Securities"). The Securities are to be issued under an indenture (the
"Indenture") to be entered into between the Company and The Bank of New York, as
trustee (the "Trustee"). To the extent there are no additional Underwriters
listed on Schedule II other than you, the term Representatives as used herein
shall mean you, as Underwriters, and


the terms Representatives and Underwriters shall mean either the singular or
plural as the context requires. Any reference herein to the Registration
Statement, the Basic Prospectus, any Preliminary Final Prospectus or the Final
Prospectus shall be deemed to refer to and include the documents incorporated or
deemed to be incorporated by reference therein pursuant to Item 12 of Form S-3
which were filed under the Exchange Act on or before the Effective Date of the
Registration Statement or the issue date of the Basic Prospectus, any
Preliminary Final Prospectus or the Final Prospectus, as the case may be (the
"Incorporated Documents"); and any reference herein to the terms "amend",
"amendment" or "supplement" with respect to the Registration Statement, the
Basic Prospectus, any Preliminary Final Prospectus or the Final Prospectus shall
be deemed to refer to and include the filing of any document under the Exchange
Act after the Effective Date of the Registration Statement or the issue date of
the Basic Prospectus, any Preliminary Final Prospectus or the Final Prospectus,
as the case may be, deemed to be incorporated therein by reference. Certain
terms used herein are defined in Section 17 hereof.

      1. Representations and Warranties. The Company represents and warrants to,
and agrees with, each Underwriter as set forth below in this Section 1.

            (a) The Company meets the requirements for use of Form S-3 under the
      Act and has prepared and filed with the Commission a Registration
      Statement (file number 333-89087) on Form S-3, including a Basic
      Prospectus, for registration under the Act of the offering and sale of the
      Securities. The Company may have filed one or more amendments thereto,
      including a Preliminary Final Prospectus, each of which has previously
      been furnished to you. The Company will next file with the Commission one
      of the following: (1) after the Effective Date of such Registration
      Statement, a final prospectus supplement relating to the Securities in
      accordance with Rules 430A and 424(b), (2) prior to the Effective Date of
      such Registration Statement, an amendment to such Registration Statement
      (including the form of final prospectus supplement) or (3) a final
      prospectus in accordance with Rules 415 and 424(b). In the case of clause
      (1), the Company has included in such Registration Statement, as amended
      at the Effective Date, all information (other than Rule 430A Information)
      required by the Act and the rules thereunder to be included in such
      Registration Statement and the Final Prospectus. As filed, such final
      prospectus supplement or such amendment and form of final prospectus
      supplement shall contain all Rule 430A Information, together with all
      other such required information, and, except to the extent the
      Representatives shall agree in writing to a modification, shall be in all
      substantive respects in the form furnished to you prior to the Execution
      Time or, to the extent not completed at the Execution Time, shall contain
      only such specific additional information and other changes (beyond that
      contained in the Basic Prospectus and any Preliminary Final Prospectus) as
      the Company has advised you, prior to the Execution Time, will be


                                       2


      included or made therein. The Registration Statement, at the Execution
      Time, meets the requirements set forth in Rule 415(a)(1)(x).

            (b) On the Effective Date, the Registration Statement did or will,
      and when the Final Prospectus is first filed (if required) in accordance
      with Rule 424(b) and on the Closing Date (as defined herein), the Final
      Prospectus (and any supplement thereto) will, comply in all material
      respects with the applicable requirements of the Act, the Exchange Act and
      the Trust Indenture Act and the respective rules thereunder; on the
      Execution Time, the Registration Statement, as supplemented by any
      prospectus supplement filed pursuant to Rule 424(b), did not or will not
      contain any untrue statement of a material fact or omit to state any
      material fact necessary to make the statements therein, in light of the
      circumstances under which they were made, not misleading; on the Effective
      Date and on the Closing Date the Indenture did or will comply in all
      material respects with the applicable requirements of the Trust Indenture
      Act and the rules thereunder; and, on the Effective Date, the Final
      Prospectus, if not filed pursuant to Rule 424(b), will not, and on the
      date of any filing pursuant to Rule 424(b) and on the Closing Date, the
      Final Prospectus (together with any supplement thereto) will not, include
      any untrue statement of a material fact or omit to state a material fact
      necessary in order to make the statements therein, in the light of the
      circumstances under which they were made, not misleading; provided,
      however, that the Company makes no representations or warranties as to (i)
      that part of the Registration Statement which shall constitute the
      Statement of Eligibility and Qualification (Form T-1) under the Trust
      Indenture Act of the Trustee or (ii) the information contained in or
      omitted from the Registration Statement or the Final Prospectus (or any
      amendment or supplement thereto) in reliance upon and in conformity with
      information furnished in writing to the Company by or on behalf of any
      Underwriter through the Representatives specifically for inclusion
      therein, it being understood and agreed that the only such information is
      that described as such in Section 8(b) of this Agreement.

            (c) The Incorporated Documents heretofore filed, when they were
      filed (or, if any amendment with respect to any such document was filed,
      when such amendment was filed), conformed in all material respects with
      the requirements of the Exchange Act and the rules and regulations
      thereunder, any further Incorporated Documents so filed will, when they
      are filed, conform in all material respects with the requirements of the
      Exchange Act and the rules and regulations thereunder; no such document
      when it was filed (or, if an amendment with respect to any such document
      was filed, when such amendment was filed), contained an untrue statement
      of a material fact or omitted to state a material fact necessary to make
      the statements therein, in light of the circumstances under which they
      were made, not misleading; and no such further document, when it is filed,
      will contain an untrue statement of


                                       3


      a material fact or will omit to state a material fact required to be
      stated therein or necessary in order to make the statements therein not
      misleading.

            (d) Each of the Company and its subsidiaries has been duly
      incorporated and is validly existing as a corporation or limited liability
      company in good standing under the laws of the jurisdiction in which it is
      chartered or organized with full corporate power and authority to own or
      lease, as the case may be, and to operate its properties and conduct its
      business as described in the Final Prospectus (as then amended or
      supplemented), and is duly qualified to do business as a foreign
      corporation or limited liability company and is in good standing under the
      laws of each jurisdiction which requires such qualification, except where
      the failure to be so qualified would not have, singly or in the aggregate,
      a material adverse effect on the condition (financial or otherwise),
      prospects, earnings, business or properties of the Company and its
      subsidiaries, taken as a whole, whether or not arising from transactions
      in the ordinary course of business.

            (e) All the outstanding shares of capital stock of each subsidiary
      that is a corporation have been duly and validly authorized and issued and
      are fully paid and nonassessable, and, except as otherwise set forth in
      the Final Prospectus, all outstanding shares of capital stock of the
      subsidiaries are owned by the Company either directly or through wholly
      owned subsidiaries free and clear of any perfected security interest and,
      to the knowledge of the Company, any other security interests, claims,
      liens or encumbrances.

            (f) The Company's authorized capitalization is as set forth in the
      Final Prospectus under the heading "Capitalization".

            (g) There is no franchise, contract or other document of a character
      required to be described in the Registration Statement or Final
      Prospectus, or to be filed as an exhibit thereto, which is not described
      or filed as required. The statements in the Final Prospectus under the
      headings "Certain United States Federal Income Tax Considerations",
      "Business--Regulation," "Business-Franchise, License and Related
      Agreements," "Business-Regulation of International Operations,"
      "Description of the Notes" and "Business--Legal Proceedings" fairly
      summarize the matters therein described in all material respects.

            (h) This Agreement has been duly authorized, executed and delivered
      by the Company; the Indenture has been duly authorized by the Company and,
      assuming due authorization, execution and delivery thereof by the Trustee,
      when executed and delivered by the Company, will constitute a legal,
      valid, binding instrument enforceable against the Company in accordance
      with its terms (subject to applicable bankruptcy, reorganization,
      insolvency, moratorium, fraudulent conveyance or other laws affecting


                                       4


      creditors' rights generally from time to time in effect and to general
      principles of equity); the Securities have been duly and validly
      authorized by the Company, and, when executed, issued and authenticated in
      accordance with the provisions of the Indenture and delivered to and paid
      for in full by the Underwriters, will have been duly executed and
      delivered by the Company and will constitute the legal, valid and binding
      obligations of the Company entitled to the benefits of the Indenture
      (subject to applicable bankruptcy, insolvency, moratorium, fraudulent
      conveyance or other laws affecting creditors' rights generally from time
      to time in effect and to general principles of equity).

            (i) The Company is not, and after giving effect to the offering and
      sale of the Securities and the application of the proceeds thereof as
      described in the Final Prospectus, will not be, an "investment company"
      required to be registered under the Investment Company Act of 1940, as
      amended, without taking account of any exemption arising out of the number
      of holders of the Company's securities.

            (j) No consent, approval, authorization, filing with or order of any
      court or governmental agency or body is required in connection with the
      transactions contemplated herein or in the Indenture, except such as will
      be obtained under the Act and the Trust Indenture Act in connection with
      the registration of the Securities, and such as may be required under the
      blue sky laws of any jurisdiction in connection with the purchase and
      distribution of the Securities by the Underwriters in the manner
      contemplated herein or in the Final Prospectus.

            (k) None of the execution and delivery of the Indenture, this
      Agreement, the issue and sale of the Securities, the consummation of any
      of the transactions contemplated herein or therein or the fulfillment of
      the terms hereof or thereof, will conflict with, result in a breach or
      violation or imposition of any lien, charge or encumbrance upon any
      property or assets of the Company or any of its subsidiaries, pursuant to
      (i) the charter or by-laws of the Company or any of its subsidiaries; (ii)
      the terms of any indenture, contract, lease, mortgage, deed of trust, note
      agreement, loan agreement or other agreement, obligation, condition,
      covenant or instrument to which the Company or any of its subsidiaries is
      a party or bound or to which its or their property is subject; or (iii)
      any statute, law, rule, regulation, judgment, order or decree applicable
      to the Company or any of its subsidiaries of any court, regulatory body,
      administrative agency, governmental body, arbitrator or other authority
      having jurisdiction over the Company or any of its subsidiaries or any of
      its or their properties, except in the case of clauses (ii) and (iii), as
      could not be reasonably expected to have, singly or in the aggregate, a
      material adverse effect on the condition (financial or otherwise),
      prospects, earnings, business or properties of the Company and its


                                       5


      subsidiaries, taken as a whole, whether or not arising from transactions
      in the ordinary course of business.

            (l) The Securities conform as to legal matters to the description
      thereof contained in the Final Prospectus.

            (m) The consolidated historical financial statements of the Company
      and its consolidated subsidiaries included in the Final Prospectus present
      fairly in all material respects the financial condition, results of
      operations and cash flows of the Company as of the dates and for the
      periods indicated and have been prepared in conformity with generally
      accepted accounting principles applied on a consistent basis throughout
      the periods involved (except as otherwise noted therein). The selected
      financial data set forth under the caption "Selected Consolidated
      Financial Data" in the Final Prospectus fairly present, on the basis
      stated in the Final Prospectus, the information included therein.

            (n) The pro forma financial statements included in the Final
      Prospectus include assumptions that provide a reasonable basis for
      presenting the significant effects directly attributable to the
      transactions and events described therein, the related pro forma
      adjustments give appropriate effect to those assumptions, and the pro
      forma adjustments reflect the proper application of those adjustments to
      the historical financial statement amounts in the pro forma financial
      statements included in the Final Prospectus. The pro forma financial
      statements included in the Final Prospectus comply as to form in all
      material respects with the applicable accounting requirements of
      Regulation S-X under the Act and the pro forma adjustments have been
      properly applied to the historical amounts in the compilation of those
      statements.

            (o) No action, suit or proceeding by or before any court or
      governmental agency, authority or body or any arbitrator involving the
      Company or any of its subsidiaries or its or their property is pending or,
      to the best knowledge of the Company, threatened that (i) could reasonably
      be expected to have a material adverse effect on the performance of this
      Agreement, the Indenture, or the consummation of any of the transactions
      contemplated hereby or thereby; or (ii) could reasonably be expected to
      have a material adverse effect on the condition (financial or otherwise),
      prospects, earnings, business or properties of the Company and its
      subsidiaries, taken as a whole, whether or not arising from transactions
      in the ordinary course of business, except as set forth in or contemplated
      in the Final Prospectus (exclusive of any amendment or supplement
      thereto).

            (p) Except as described in the Final Prospectus, each of the Company
      and each of its subsidiaries owns, licenses, leases or has obtained


                                       6


      rights-of-way for all such properties as are necessary to the conduct of
      its operations as presently conducted. The Company and each of its
      subsidiaries has good and marketable title, free and clear of all liens or
      encumbrances, to all property and assets described in the Final Prospectus
      as being owned by it on the date hereof and such properties and assets are
      in good repair and suitable for use as so described except as set forth in
      the Final Prospectus. All leases to which the Company or its subsidiaries
      are a party are valid and binding (subject to applicable bankruptcy,
      reorganization, insolvency, moratorium, fraudulent conveyance or other
      laws affecting creditors' rights generally from time to time in effect and
      to general principles of equity) and no default has occurred or is
      continuing thereunder which could have, singly or in the aggregate, a
      material adverse effect on the condition (financial or otherwise),
      prospects, earnings, business or properties of the Company and its
      subsidiaries, taken as a whole, whether or not arising from transactions
      in the ordinary course of business, and the Company and each subsidiary
      enjoy peaceful and undisturbed possession under all such leases to which
      any of them is a party as lessee with such exceptions as do not interfere
      materially with the use made by the Company or such subsidiary.

            (q) Neither the Company nor any subsidiary is in violation or
      default of (i) any provision of its charter or bylaws; (ii) the terms of
      any indenture, contract, lease, mortgage, deed of trust, note agreement,
      loan agreement or other agreement, obligation, condition, covenant or
      instrument to which it is a party or bound or to which its property is
      subject; or (iii) any statute, law, rule, regulation, judgment, order or
      decree applicable to the Company or any of its subsidiaries of any court,
      regulatory body, administrative agency, governmental body, arbitrator or
      other authority having jurisdiction over the Company or such subsidiary or
      any of its properties, as applicable, except in the case of clauses (ii)
      and (iii) as could not be reasonably expected to have, singly or in the
      aggregate, a material adverse effect on the condition (financial or
      otherwise), prospects, earnings, business or properties of the Company and
      its subsidiaries, taken as a whole, whether or not arising from
      transactions in the ordinary course of business.

            (r) Each of (i) Deloitte & Touche LLP, (ii) Ernst & Young LLP, and
      (iii) PriceWaterhouseCoopers LLP, each of whom have audited certain
      financial statements of the Company and its consolidated subsidiaries or
      its acquired entities, as the case may be, and delivered their report with
      respect to the audited consolidated financial statements included and/or
      incorporated by reference in the Final Prospectus are independent public
      accountants with respect to the Company within the meaning of the Act and
      the applicable published rules and regulations thereunder.

            (s) The Company and each subsidiary has filed all foreign, federal,
      state and local tax returns that are required to be filed or has


                                       7


      requested extensions thereof except in any case in which the failure so to
      file would not have, singly or in the aggregate, a material adverse effect
      on the condition (financial or otherwise), prospects, earnings, business
      or properties of the Company and its subsidiaries, taken as a whole,
      whether or not arising from transactions in the ordinary course of
      business, and has paid all taxes required to be paid by it and any other
      assessment, fine or penalty levied against it, to the extent that any of
      the foregoing is due and payable, except for any such assessment, fine or
      penalty that is currently being contested in good faith or as would not
      have, singly or in the aggregate, a material adverse effect on the
      condition (financial or otherwise), prospects, earnings, business or
      properties of the Company and its subsidiaries, taken as a whole, whether
      or not arising from transactions in the ordinary course of business.

            (t) No labor problem or dispute with the employees of the Company or
      any of its subsidiaries exists or is threatened or imminent that could
      have, singly or in the aggregate, a material adverse effect on the
      condition (financial or otherwise), prospects, earnings, business or
      properties of the Company and its subsidiaries, taken as a whole, whether
      or not arising from transactions in the ordinary course of business.

            (u) There are no transfer taxes or other similar fees or charges
      under Federal law or the laws of any state, or any political subdivision
      thereof, required to be paid in connection with the execution and delivery
      of this Agreement or the issuance by the Company or sale by the Company of
      the Securities.

            (v) The Company and each of its subsidiaries are insured by insurers
      of recognized financial responsibility against such losses and risks and
      in such amounts as are prudent and customary in the businesses in which
      they are engaged; all policies of insurance and fidelity or surety bonds
      insuring the Company or any of its subsidiaries or their respective
      businesses, assets, employees, officers and directors are in full force
      and effect; the Company and its subsidiaries are in compliance with the
      terms of such policies and instruments in all material respects; and there
      are no claims by the Company or any of its subsidiaries under any such
      policy or instrument as to which any insurance company is denying
      liability or defending under a reservation of rights clause; neither the
      Company nor any such subsidiary has been refused any insurance coverage
      sought or applied for; and neither the Company nor any such subsidiary has
      any reason to believe that it will not be able to renew its existing
      insurance coverage as and when such coverage expires or to obtain similar
      coverage from similar insurers as may be necessary to continue its
      business at a cost that would not have, singly or in the aggregate, a
      material adverse effect on the condition (financial or otherwise),
      prospects, earnings, business or properties of the Company and


                                       8


      its subsidiaries, taken as a whole, whether or not arising from
      transactions in the ordinary course of business.

            (w) Except as described in the Final Prospectus, no subsidiary of
      the Company is currently prohibited, directly or indirectly, from paying
      any dividends to the Company, from making any other distribution on such
      subsidiary's capital stock, from repaying to the Company any loans or
      advances to such subsidiary from the Company or from transferring any of
      such subsidiary's property or assets to the Company or any other
      subsidiary of the Company.

            (x) Except as described in the Final Prospectus, the Company and its
      subsidiaries (i) possess the certificates, authorizations, approvals,
      franchises, licenses, rights-of-way and permits issued by the appropriate
      federal, state, local or foreign regulatory authorities necessary to
      conduct their respective businesses as presently conducted, (ii) are not
      in violation of any such certificates, authorizations, approvals,
      franchises, licenses, rights-of-way and permits, except where such
      violation would not have a material adverse effect on the condition
      (financial or otherwise), prospects, earnings, business or properties of
      the Company and its subsidiaries, taken as a whole, whether or not arising
      from transactions in the ordinary course of business and (iii) have not
      received any notice of proceedings relating to the revocation or
      modification of any such certificate, authorization, approval, franchise,
      license, right-of-way or permit which, singly or in the aggregate, if the
      subject of an unfavorable decision, ruling or finding, would have a
      material adverse effect on the condition (financial or otherwise),
      prospects, earnings, business or properties of the Company and its
      subsidiaries, taken as a whole, whether or not arising from transactions
      in the ordinary course of business.

            (y) The Company and its subsidiaries possess or have applied for the
      patents, patent rights, licenses, inventions, copyrights, know-how
      (including trade secrets and other unpatented and/or unpatentable
      proprietary or confidential information, systems or procedures),
      trademarks, service marks and trade names (collectively, "Intellectual
      Property") presently employed by them in connection with the businesses
      now operated by them, and neither the Company nor any of the Subsidiaries
      has received any notice of infringement of or conflict with asserted
      rights of others with respect to the foregoing except as could not have,
      singly or in the aggregate, a material adverse effect on the condition
      (financial or otherwise), prospects, earnings, business or properties of
      the Company and its subsidiaries, taken as a whole, whether or not arising
      from transactions in the ordinary course of business. To the Company's
      knowledge, the use of such Intellectual Property in connection with the
      business and operations of the Company and its subsidiaries does not
      infringe on the rights of any person.


                                       9


            (z) The Company and each of its subsidiaries maintain a system of
      internal accounting controls sufficient to provide reasonable assurance
      that (i) transactions are executed in accordance with management's general
      or specific authorizations; (ii) transactions are recorded as necessary to
      permit preparation of financial statements in conformity with generally
      accepted accounting principles and to maintain asset accountability; (iii)
      access to assets is permitted only in accordance with management's general
      or specific authorization; and (iv) the recorded accountability for assets
      is compared with the existing assets at reasonable intervals and
      appropriate action is taken with respect to any differences.

            (aa) The Company and its subsidiaries are (i) in compliance with any
      and all applicable foreign, federal, state and local laws and regulations
      relating to the protection of human health and safety, the environment or
      hazardous or toxic substances or wastes, pollutants or contaminants
      ("Environmental Laws"); (ii) have received and are in compliance with all
      permits, licenses or other approvals required of them under applicable
      Environmental Laws to conduct their respective businesses as described in
      the Final Prospectus; and (iii) have not received notice of any actual or
      potential liability for the investigation or remediation of any disposal
      or release of hazardous or toxic substances or wastes, pollutants or
      contaminants, except where such non-compliance with Environmental Laws,
      failure to receive required permits, licenses or other approvals, or
      liability would not, individually or in the aggregate, have a material
      adverse effect on the condition (financial or otherwise), prospects,
      earnings, business or properties of the Company and its subsidiaries,
      taken as a whole, whether or not arising from transactions in the ordinary
      course of business; neither the Company nor any of the subsidiaries has
      been notified that it has been named as a "potentially responsible party"
      under the Comprehensive Environmental Response, Compensation, and
      Liability Act of 1980, as amended.

            (bb) Except as described in the Final Prospectus, the Company and
      its subsidiaries are implementing a comprehensive, detailed program to
      analyze and address the risk that the computer hardware and software used
      by them may be unable to recognize and properly execute date-sensitive
      functions involving certain dates prior to and any dates after December
      31, 1999 (the "Year 2000 Problem"), and reasonably believe that such risk
      will be remedied on a timely basis without material expense and will not
      have a material adverse effect upon the financial condition and results of
      operations of the Company and its subsidiaries, taken as a whole.

            (cc) Each of the Company and its subsidiaries has fulfilled its
      obligations, if any, under the minimum funding standards of Section 302 of
      the United States Employee Retirement Income Security Act of 1974, as


                                       10


      amended ("ERISA"), and the regulations and published interpretations
      thereunder with respect to each "plan" (as defined in Section 3(3) of
      ERISA and such regulations and published interpretations) in which
      employees of the Company and its subsidiaries are eligible to participate
      and each such plan is in compliance in all material respects with the
      presently applicable provisions of ERISA and such regulations and
      published interpretations; the Company and its subsidiaries have not
      incurred any unpaid liability to the Pension Benefit Guaranty Corporation
      (other than for the payment of premiums in the ordinary course) or to any
      such plan under Title IV of ERISA.

            (dd) The subsidiaries listed on Schedule III attached hereto are the
      only significant subsidiaries of the Company as defined in Rule 1-02 of
      Regulation S-X (individually, a "Subsidiary" and collectively, the
      "Subsidiaries").

            (ee) None of the transactions contemplated by this Agreement
      (including, without limitation, the use of the proceeds from the sale of
      the Securities) will violate or result in a violation of Section 7 of the
      Exchange Act, or any regulation promulgated thereunder, including, without
      limitation, Regulations T, U and X of the Board of Governors of the
      Federal Reserve System.

            (ff) Neither the Company nor any of the subsidiaries is a "holding
      company" or a "subsidiary company" of a holding company, or an "affiliate"
      thereof required to be registered under the Public Utility Holding Company
      Act of 1935, as amended.

            (gg) Neither the Company nor any of its subsidiaries nor, to the
      Company's knowledge, any employee or agent of the Company or any
      subsidiary has made any payment of funds of the Company or any subsidiary
      or received or retained any funds in violation of any provision of the
      Foreign Corrupt Practices Act of 1977, as amended.

            (hh) No "nationally recognized statistical rating organization" as
      such term is defined for purposes of Rule 436(g)(2) under the Act has
      indicated to the Company that it is considering (i) the downgrading,
      suspension or withdrawal of, or any review for a possible change that does
      not indicate the direction of the possible change in, any rating assigned
      to the Company or any securities of the Company or (ii) any change in the
      outlook for any rating of the Company or any securities of the Company.

            (ii) No relationship, direct or indirect, exists between or among
      the Company or any of its subsidiaries on the one hand, and the directors,
      officers, stockholders, customers or suppliers of the Company or any of
      its


                                       11


      subsidiaries on the other hand, which is required by the Act to be
      described in the Final Prospectus which is not so described.

            (jj) The Company has not taken, directly or indirectly, any action
      designed to cause or which has constituted or which might reasonably be
      expected to cause or result, under the Exchange Act or otherwise, in the
      stabilization or manipulation of the price of any security of the Company
      to facilitate the sale or resale of the Securities.

            (kk) Except as may have been waived, no holders of securities of the
      Company have rights to the registration of such securities under the
      Registration Statement.

      Any certificate signed by any officer of the Company and delivered to the
Representatives or counsel for the Underwriters in connection with the offering
of the Securities shall be deemed a representation and warranty by the Company,
as to matters covered thereby, to each Underwriter.

      2. Purchase and Sale. Subject to the terms and conditions and in reliance
upon the representations and warranties herein set forth, the Company agrees to
sell to each Underwriter, and each Underwriter agrees, severally and not
jointly, to purchase from the Company, at a purchase price of (a) 96.576% of the
principal amount thereof in the case of the U.S. Securities and (b) 96.576% of
the principal amount thereof in the case of the International Securities, in
each case, plus accrued interest, if any, from the Closing Date, the principal
amount of the Securities set forth opposite such Underwriter's name in Schedule
II hereto.

      3. Delivery and Payment. Delivery of and payment for the Securities shall
be made on November 17, 1999 at 9:00 A.M., New York City time, at the offices of
Paul, Weiss, Rifkind, Wharton & Garrison, 1285 Avenue of the Americas, New York,
New York 10019 or at such time on such later date not more than three Business
Days after the foregoing date as the Representatives shall designate, which date
and time may be postponed by agreement between the Representatives and the
Company or as provided in Section 9 hereof (such date and time of delivery and
payment for the Securities being herein called the "Closing Date"). Delivery of
the Securities shall be made to the Representatives for the respective accounts
of the several Underwriters against payment by the several Underwriters through
the Representatives of the purchase price thereof to or upon the order of the
Company by wire transfer payable in same-day funds to the account specified by
the Company. The Company shall not be obligated to deliver any of the
Securities, except upon payment for all of the Securities to be purchased as
provided herein. Delivery of the U.S. Securities shall be made through the
facilities of The Depository Trust Company unless the Representatives shall
otherwise instruct, and delivery of the International Securities shall be made
through the facilities of a common depository for Morgan Guarantee Trust Company
of New York as operator of the Euroclear


                                       12


System ("Euroclear") and Cedelbank ("Cedel") unless the Representatives shall
otherwise instruct.

      4. Offering by Underwriters. It is understood that the several
Underwriters propose to offer the Securities for sale to the public as set forth
in the Final Prospectus. Each of the Underwriters represents and agrees that (i)
it has not offered or sold and will not offer or sell any Securities to persons
in the United Kingdom except to persons whose ordinary activities involve them
in acquiring, holding, managing or disposing of investments (as principal or
agent) for the purposes of their businesses or otherwise in circumstances which
have not resulted and will not result in an offer to the public in the United
Kingdom within the meaning of the Public Offers of Securities Regulations 1995,
(b) it has complied, and will comply, with all applicable provisions of the
Financial Services Act of 1986 of Great Britain with respect to anything done by
it in relation to the Securities in, from or otherwise involving the United
Kingdom, and (c) it has only issued or passed on and will only issue or pass on
in the United Kingdom any document received by it in connection with the
issuance of the Securities to a person who is of a kind described in Article
11(3) of the Financial Services Act 1986 (Investment Advertisements)
(Exemptions) Order 1996 of Great Britain or is a person to whom the document may
otherwise lawfully be issued or passed on.

      5. Agreements. The Company agrees with the several Underwriters that:

            (a) The Company will use its best efforts to cause the Registration
      Statement, if not effective at the Execution Time, and any amendment
      thereof, to become effective. Prior to the termination of the offering of
      the Securities, the Company will not file any amendment of the
      Registration Statement or supplement (including the Final Prospectus or
      any Preliminary Final Prospectus) to the Basic Prospectus or any Rule
      462(b) Registration Statement unless the Company has furnished you a copy
      for your review prior to filing and will not file any such proposed
      amendment or supplement without the prior consent of the Representatives,
      which consent shall not be unreasonably withheld, conditioned or delayed.
      Subject to the foregoing sentence, if the Registration Statement has
      become or becomes effective pursuant to Rule 430A, or filing of the Final
      Prospectus is otherwise required under Rule 424(b), the Company will cause
      the Final Prospectus, properly completed, and any supplement thereto to be
      filed with the Commission pursuant to the applicable paragraph of Rule
      424(b) within the time period prescribed and will provide evidence
      satisfactory to the Representatives of such timely filing. If necessary
      for the sale of the Securities, the Company will cause the Rule 462(b)
      Registration Statement, completed in compliance with the Act and the
      applicable rules and regulations thereunder, to be filed with the
      Commission pursuant to Rule 462(b) and will provide evidence satisfactory
      to the Representatives of such filing. The Company will


                                       13


      promptly advise the Representatives (1) when the Registration Statement,
      if not effective at the Execution Time, shall have become effective, (2)
      when the Final Prospectus, and any supplement thereto, shall have been
      filed (if required) with the Commission pursuant to Rule 424(b) or when
      any Rule 462(b) Registration Statement shall have been filed with the
      Commission, (3) when, prior to termination of the offering of the
      Securities, any amendment to the Registration Statement shall have been
      filed or become effective, (4) of any request by the Commission or its
      staff for any amendment of the Registration Statement, or any Rule 462(b)
      Registration Statement, or for any supplement to the Final Prospectus or
      for any additional information, (5) of the issuance by the Commission of
      any stop order suspending the effectiveness of the Registration Statement
      or the institution or threatening of any proceeding for that purpose and
      (6) of the receipt by the Company of any notification with respect to the
      suspension of the qualification of the Securities for sale in any
      jurisdiction or the institution or threatening of any proceeding for such
      purpose. The Company will use its best efforts to prevent the issuance of
      any such stop order or the suspension of any such qualification and, if
      issued, to obtain as soon as possible the withdrawal thereof. Prior to the
      completion of the sale of the Securities by the Underwriters, the Company
      will not file any document under the Exchange Act that is incorporated by
      reference in the Registration Statement unless, prior to such proposed
      filing, the Company has furnished the Representatives with a copy of such
      document for their review and the Representatives have not reasonably
      objected to the filing of such document within a reasonable period of
      time. The Company will promptly advise the Representatives when any
      document filed under the Exchange Act that is incorporated by reference in
      the Registration Statement shall have been filed with the Commission.

            (b) If, at any time when a prospectus relating to the Securities is
      required to be delivered under the Act, any event occurs as a result of
      which the Final Prospectus as then amended or supplemented would include
      any untrue statement of a material fact or omit to state any material fact
      necessary to make the statements therein, in the light of the
      circumstances under which they were made, not misleading, or if it should
      be necessary to amend the Registration Statement or supplement the Final
      Prospectus to comply with the Act or the Exchange Act or the respective
      rules thereunder, the Company promptly will (1) notify the Representatives
      of such event, (2) prepare and file with the Commission, subject to the
      second sentence of paragraph (a) of this Section 5, an amendment or
      supplement which will correct such statement or omission or effect such
      compliance and (3) supply any supplemented Final Prospectus to you in such
      quantities as you may reasonably request.


                                       14


            (c) In accordance with the requirements of the Exchange Act and the
      Act applicable to the Company, the Company will make generally available
      to its security holders and to the Representatives an earnings statement
      or statements of the Company and its subsidiaries which will satisfy the
      provisions of Section 11(a) of the Act and Rule 158 under the Act.

            (d) The Company will furnish to the Representatives and counsel for
      the Underwriters, without charge, signed copies of the Registration
      Statement (including exhibits thereto) which is filed in connection with
      the sale of the Securities, and to each other Underwriter a copy of the
      Registration Statement (without exhibits thereto) which is filed in
      connection with the sale of the Securities, and, so long as delivery of a
      prospectus by an Underwriter or dealer may be required by the Act, as many
      copies of each Preliminary Final Prospectus and the Final Prospectus and
      any supplement thereto as the Representatives may reasonably request. The
      Company will pay the expenses of printing or other production of all
      documents relating to the offering.

            (e) The Company will arrange, if necessary, for the qualification of
      the Securities for sale under the laws of such jurisdictions as the
      Representatives may designate, will maintain such qualifications in effect
      so long as required for the distribution of the Securities and will pay
      any fee of the National Association of Securities Dealers, Inc., in
      connection with its review of the offering; provided that in no event
      shall the Company be obligated to qualify to do business in any
      jurisdiction where it is not now so qualified or to take any action that
      would subject it to service of process in suits, other than those arising
      out of the offering or sale of the Securities, in any jurisdiction where
      it is not now so subject. The Company will promptly advise the
      Representatives of the receipt by the Company of any notification with
      respect to the suspension of the qualification of the Securities for sale
      in any jurisdiction or the initiation or threatening of any proceeding for
      such purpose. The Company shall use its best efforts to prevent the
      issuance of any order suspending the qualification or exemption of the
      Securities under any state securities or Blue Sky laws, and, if at any
      time any state securities commission or any other regulatory authority
      shall issue an order suspending the qualification or exemption of the
      Securities under any state securities or Blue Sky laws, the Company shall
      use every reasonable effort to obtain the withdrawal or lifting of such
      order at the earliest possible time.

            (f) The Company will not for a period of 180 days following the
      Execution Time, without the prior written consent of Salomon Smith Barney
      Inc., offer, sell or contract to sell, grant any other option to purchase
      or otherwise dispose of (or enter into any transaction which is designed
      to, or might reasonably be expected to, result in the disposition (whether
      by actual disposition or effective economic disposition due to cash
      settlement or


                                       15


      otherwise) by the Company or any Affiliate of the Company or any person in
      privity with the Company or any Affiliate of the Company), directly or
      indirectly, any debt securities issued or guaranteed by the Company (other
      than the Securities) except the Company may offer, sell, contract to sell,
      pledge, or otherwise dispose of convertible subordinated notes to Bell
      Atlantic Investments, Inc. ("Bell Atlantic") pursuant to a securities
      purchase agreement dated October 7, 1999 between the Company and Bell
      Atlantic.

            (g) The Company will cooperate with the Representatives and use its
      best efforts to permit the Securities to be eligible for clearance and
      settlement through The Depository Trust Company (in the case of the U.S.
      Securities) or Euroclear/Cedel (in the case of the International
      Securities), as the case may be.

            (h) The Company will not take, directly or indirectly, any action
      designed to or which has constituted or which might reasonably be expected
      to cause or result, under the Exchange Act or otherwise, in stabilization
      or manipulation of the price of any security of the Company to facilitate
      the sale or resale of the Securities.

            (i) The Company will not, for so long as the Securities are
      outstanding, be or become, or be or become owned by, an open-end
      investment company, unit investment trust or face-amount certificate
      company that is or is required to be registered under Section 8 of the
      Investment Company Act, and will not be or become, or be or become owned
      by, a closed-end investment company required to be registered, but not
      registered thereunder.

            (j) The Company will apply the net proceeds from the sale of the
      Securities as set forth in the Final Prospectus under the heading "Use of
      Proceeds."

            (k) The Company agrees to pay the costs and expenses relating to the
      following matters: (i) the preparation of the Indenture, the issuance of
      the Securities and the fees of the Trustee; (ii) the preparation, printing
      or reproduction of the Registration Statement, the Preliminary Final
      Prospectus and the Final Prospectus and each amendment or supplement to
      any of them; (iii) the printing (or reproduction) and delivery (including
      postage, air freight charges and charges for counting and packaging) of
      such copies of the Registration Statement, the Preliminary Final
      Prospectus and the Final Prospectus, and all amendments or supplements to
      any of them, as may, in each case, be reasonably requested for use in
      connection with the offering and sale of the Securities; (iv) the
      preparation, printing, authentication, issuance and delivery of
      certificates for the Securities, including any stamp or transfer taxes in
      connection with the original issuance and sale of the


                                       16


      Securities; (v) the printing (or reproduction) and delivery of this
      Agreement, any blue sky memorandum and all other agreements or documents
      printed (or reproduced) and delivered in connection with the offering of
      the Securities; (vi) any registration or qualification of the Securities
      for offer and sale under the securities or blue sky laws of the several
      states (including filing fees and the reasonable fees and expenses of one
      counsel for the Underwriters relating to such registration and
      qualification); (vii) listing the Securities on the Luxembourg Stock
      Exchange (the "Exchange"); (viii) the transportation and other expenses
      incurred by or on behalf of Company representatives in connection with
      presentations to prospective purchasers of the Securities; (ix) the fees
      and expenses of the Company's accountants and the fees and expenses of
      counsel (including local and special counsel) for the Company; and (x) all
      other costs and expenses incident to the performance by the Company of its
      obligations hereunder; provided, however, that, except as otherwise
      provided for herein, the Underwriters shall pay their own costs and
      expenses, including the fees of their counsel and any advertising expenses
      connected with any offers they may make.

            (l) The Company agrees to do and perform all things required to be
      done and performed by it under this Agreement that are within its control
      on or prior to or after the Closing Date, as applicable, and to use its
      best efforts to satisfy all conditions precedent on its part to the
      delivery of the Securities.

            (m) The Company confirms that it has caused to be made an
      application for the Securities to be listed on the Exchange. In connection
      with such application, the Company agrees to furnish from time to time any
      and all documents, instruments, information and undertakings and publish
      all advertisements or other material that may be necessary in order to
      effect and maintain such listing and to use its reasonable best efforts to
      maintain such listing so long as any of the Securities are outstanding (as
      defined in the Indenture); provided that if at any time the Company shall
      determine that it can no longer reasonably comply with the requirements
      for listing of the Securities on the Exchange and if maintenance of such
      listing becomes onerous, it will use its reasonable best efforts to obtain
      and thereafter to maintain a listing of Securities on such other stock
      exchange in a financial center as you may reasonably request and as the
      Trustee may approve.

      6. Conditions to the Obligations of the Underwriters. The obligations of
the Underwriters to purchase the Securities shall be subject to the accuracy of
the representations and warranties on the part of the Company contained herein
as of the Execution Time and the Closing Date, to the accuracy of the statements
of the Company made in any certificates pursuant to the provisions hereof, to
the performance by the Company of its obligations hereunder and to the following
additional conditions:


                                       17


            (a) If the Registration Statement has not become effective prior to
      the Execution Time, unless the Representatives agree in writing to a later
      time, the Registration Statement will become effective not later than (i)
      6:00 PM New York City time, on the date of determination of the public
      offering price, if such determination occurred at or prior to 3:00 PM New
      York City time on such date or (ii) 9:30 AM on the Business Day following
      the day on which the public offering price was determined, if such
      determination occurred after 3:00 PM New York City time on such date; if
      filing of the Final Prospectus, or any supplement thereto, is required
      pursuant to Rule 424(b), the Final Prospectus, and any such supplement,
      will be filed in the manner and within the time period required by Rule
      424(b); and no stop order suspending the effectiveness of the Registration
      Statement shall have been issued and no proceedings for that purpose shall
      have been instituted or threatened.

            (b) The Company shall have requested and caused Arnold L. Wadler,
      General Counsel of the Company, to furnish to the Representatives his
      opinion, dated the Closing Date and addressed to the Representatives, to
      the effect that:

                  i. each of the Company's Subsidiaries has been duly
      incorporated and is validly existing as a corporation in good standing
      under the laws of the jurisdiction in which it is chartered or organized,
      with full corporate power and authority to own or lease, as the case may
      be, and to operate, its properties and conduct its business as described
      in the Final Prospectus;

                  ii. all the outstanding shares of capital stock of the Company
      and each Subsidiary have been duly and validly authorized and issued and
      are fully paid and nonassessable, and, except as otherwise set forth in
      the Final Prospectus, all outstanding shares of capital stock of the
      Subsidiaries are owned by the Company either directly or through wholly
      owned subsidiaries free and clear of any security interest and, to the
      knowledge of such counsel, after due inquiry, any other security
      interests, claims, liens or encumbrances;

                  iii. the Company's authorized capitalization is as set forth
      in the Final Prospectus under the heading "Capitalization";

                  iv. to the knowledge of such counsel, without conducting a
      docket search, there is no pending or threatened action, suit or
      proceeding by or before any court or governmental agency, authority or
      body or any arbitrator involving the Company or any of its subsidiaries or
      its or their property that is not adequately disclosed in the Final
      Prospectus, except in


                                       18


      each case for such proceedings that, if the subject of an unfavorable
      decision, ruling or finding would not, singly or in the aggregate, result
      in a material adverse change in the condition (financial or otherwise),
      prospects, earnings, business or properties of the Company and its
      subsidiaries, taken as a whole; and the statements in the Final Prospectus
      under the heading "Business--Legal Proceedings" fairly summarize the
      matters therein described;

                  v. neither the execution and delivery of the Indenture, this
      Agreement, the issue and sale of the Securities, nor the consummation of
      any other of the transactions herein or therein contemplated, nor the
      fulfillment of the terms hereof or thereof, will conflict with, result in
      a breach or violation of, or imposition of any lien, charge or encumbrance
      upon, any property or asset of the Company or its subsidiaries pursuant to
      (i) the charter or by-laws of the Company's subsidiaries, or (ii) the
      terms of any indenture, contract, lease, mortgage, deed of trust, note
      agreement, loan agreement or other agreement, obligation, condition,
      covenant or instrument to which the Company or any of its subsidiaries is
      a party or bound or to which its respective property is subject which is
      known to such counsel;

                  vi. the statements in the Final Prospectus under the captions
      "Risk Factors - The Heavy Regulation of the Telecommunications Industry
      May Limit the Development of Our Networks and Affect Our Competitive
      Position" and "Business-Regulation" to the extent that they discuss U.S.
      federal, state, and local telecommunications statutes and regulations or
      legal or governmental proceedings of the FCC and state and local
      governments with respect to telecommunications regulatory matters, fairly
      summarize the matters referred to therein in all material respects;

                  vii. neither the execution and delivery of this Agreement by
      the Company nor the performance by the Company of its obligations under
      this Agreement will violate the Communications Act or the State
      Telecommunications Laws; and

                  viii. to the knowledge of such counsel and except such as
      would not have a material adverse effect on the Company's or any
      subsidiary's ability to conduct their respective businesses as they are
      presently conducted, (A) the Company and its subsidiaries have in effect
      all the U.S. federal and state telecommunications regulatory licenses,
      permits, authorizations, consents, and approvals (hereinafter, "Licenses")
      required to conduct their respective businesses as presently conducted;
      (B) all such Licenses have been validly issued and are in full force and
      effect; (C) no determination has been made by the FCC or any State
      Regulatory Agency that the Company or any subsidiaries is in violation of
      any such Licenses, and no proceeding is pending before any such agency in
      which any such violation


                                       19


      has been alleged; and (D) no proceedings by the FCC or any State
      Regulatory Agency to revoke or restrict any such Licenses are pending or
      threatened. "Validly issued" as used in this paragraph means that the
      Licenses have been issued through the means of regular agency procedures
      applied in conformity with the applicable governing statute and prior
      agency practice and there is no legal basis under the applicable governing
      statute to conclude that the Company or any subsidiary cannot hold one or
      more of the Licenses as a matter of law. "Full force and effect" as used
      in this paragraph means (i) the orders issuing the Licenses have become
      effective under the applicable governing statute, (ii) the Licenses
      contain no conditions, (iii) all conditions precedent set forth in the
      Licenses have been satisfied, and (iv) no stay of effectiveness has been
      issued.

            (c) The Company shall have requested and caused Paul, Weiss,
      Rifkind, Wharton & Garrison, counsel for the Company, to furnish to the
      Representatives its opinion, dated the Closing Date and addressed to the
      Representatives, to the effect that:

                  i. the Company and each of the Subsidiaries incorporated (in
      the case of a corporation) or organized (in the case of any other entity)
      under the laws of the States of Delaware or New York has been duly
      incorporated and is validly existing as a corporation in good standing
      under the laws of the State of Delaware or is a subsisting corporation in
      good standing under the laws of the State of New York, as applicable, with
      full corporate power and authority to own or lease, as the case may be,
      and to operate its properties and conduct its business as described in the
      Final Prospectus;

                  ii. such counsel has been advised orally by the staff of the
      Commission that the Registration Statement has become effective under the
      Act; any required filing of the Basic Prospectus, any Preliminary Final
      Prospectus and the Final Prospectus, and any supplements thereto, has been
      made pursuant to Rule 424(b); to the knowledge of such counsel, no stop
      order suspending the effectiveness of the Registration Statement has been
      issued, no proceedings for that purpose have been instituted or threatened
      by the Commission, and assuming that the statements made and/or
      incorporated in the Registration Statement and the Final Prospectus are
      complete and correct except those made under the caption "Description of
      the Notes" insofar as they relate to provisions of documents therein
      described, the Registration Statement and the Final Prospectus, as of
      their respective effective or issue dates, appear on their face to be
      appropriately responsive in all material respects to the applicable
      requirements of the Act and the rules and regulations of the Commission
      under the Act, except for the financial statements, and other financial
      and statistical information which are


                                       20


      contained or incorporated by reference therein or omitted therefrom and
      the Form T-1, as to which such counsel need express no opinion;

                  iii. this Agreement has been duly authorized, executed and
      delivered by the Company;

                  iv. the Indenture has been duly qualified under the Trust
      Indenture Act and has been duly authorized, executed and delivered by the
      Company, and, assuming due authorization, execution and delivery thereof
      by the Trustee, constitutes a legal, valid and binding instrument
      enforceable against the Company in accordance with its terms (subject to
      applicable bankruptcy, reorganization, insolvency, moratorium, fraudulent
      conveyance or other laws affecting creditors' rights generally from time
      to time in effect and to general principles of equity, regardless of
      whether enforceability is considered in a proceeding in equity or at law);
      the Securities have been duly and validly authorized by the Company, and,
      when duly executed, issued and authenticated in accordance with the
      provisions of the Indenture and delivered to and paid for in full by the
      Underwriters under this Agreement, will constitute legal, valid and
      binding obligations of the Company entitled to the benefits of the
      Indenture (subject to applicable bankruptcy, reorganization, insolvency,
      moratorium, fraudulent conveyance or other laws affecting creditors'
      rights generally from time to time in effect and to general principles of
      equity, regardless or whether enforceability is considered in a proceeding
      in equity or at law); and the statements set forth under the heading
      "Description of the Notes", insofar as such statements purport to
      summarize certain provisions of the Securities and the Indenture, provide
      a fair summary of such provisions;

                  v. to the extent that they constitute a summary of U.S.
      federal law and regulations, the statements in the Final Prospectus under
      the heading "Certain United States Federal Income Tax Considerations"
      fairly summarize the matters therein described in all material respects;

                  vi. the Company is not and, after giving effect to the
      offering and sale of the Securities and the application of the proceeds
      thereof as described in the Final Prospectus, will not be required to
      register as an "investment company" under the Investment Company Act;

                  vii. no consent, approval, authorization, filing with or order
      of any court or governmental agency or body under the Federal laws of the
      United States or the laws of the State of New York or under the General
      Corporation Law of the State of Delaware is required in connection with
      the due authorization, execution and delivery of this Agreement or the due
      execution, delivery or performance of the Indenture by the Company, or for
      the offering, issuance, sale or delivery of the Securities, except such as
      will


                                       21


      be obtained, taken or made or such, as may be required under the blue sky
      or securities laws of any state or foreign jurisdiction or the NASD (as to
      which such counsel need not express any opinion) or such other approvals
      (specified in such opinion) as have been obtained (provided that such
      counsel need not express any opinion with respect to any consent,
      approval, authorization under the Communications Act of 1934, as amended,
      or any published rules, regulations or policies of the Federal
      Communications Commission (the "FCC") thereunder); and

                  viii. neither the execution and delivery of the Indenture,
      this Agreement, the issue and sale of the Securities, nor the consummation
      of any other of the transactions herein or therein contemplated, nor the
      fulfillment of the terms hereof or thereof, will conflict with, result in
      a breach or violation of, or imposition of any lien, charge or encumbrance
      upon any property or asset of the Company or its subsidiaries pursuant to,
      (i) the charter or by-laws of the Company; or (ii) any statute, law, rule
      or regulation of the Federal government of the United States (excluding
      the FCC) or the State of New York or under the General Corporation Law of
      the State of Delaware, or to such counsel's knowledge, any judgment, order
      or decree applicable to the Company or any of its subsidiaries of any
      court, regulatory body, administrative agency, governmental body,
      arbitrator or other authority having jurisdiction over the Company, any of
      its subsidiaries or any of their respective properties which is known to
      such counsel except as described in the Final Prospectus or for such
      violations as could not be reasonably expected to have, singly or in the
      aggregate, a material adverse effect on the condition (financial or
      otherwise), prospects, earnings, business or properties of the Company and
      its subsidiaries, taken as a whole.

      In addition, such counsel shall state that it has participated in
conferences with officers and other representatives of the Company,
representatives of the independent accountants of the Company, the Underwriters
and counsel for the Underwriters at which the contents of the Registration
Statement and the Final Prospectus and related matters were discussed and,
although such counsel is not passing upon, and does not assume any
responsibility for, the accuracy, completeness or fairness of the statements
contained in the Registration Statement and the Final Prospectus (or any
amendments or supplements thereto) and has made no independent investigation or
verification thereof, and such counsel has not participated in the preparation
of the Incorporated Documents, on the basis of the foregoing, no facts have come
to the attention of such counsel that have led such counsel to believe that the
Registration Statement, at the Effective Time, and the Final Prospectus, at the
Execution Time and on the Closing Date, contained or contains any untrue
statement of a material fact or omitted or omits to state any material fact
necessary to make the statements therein, in the light of the circumstances
under which they were made, not misleading (in each case, other than the
financial statements, schedules and other financial and statistical information


                                       22


which are contained or incorporated by reference therein or omitted therefrom
and the Form T-1, as to which such counsel need express no opinion).

            In rendering such opinion, such counsel may rely (A) as to matters
involving the application of laws of any jurisdiction other than the State of
New York, the Federal laws of the United States or the General Corporation Law
of the State of Delaware, to the extent they deem proper and specified in such
opinion, upon the opinion of other counsel of good standing whom they believe to
be reliable and who are reasonably satisfactory to counsel for the Underwriters;
and (B) as to matters of fact, to the extent they deem proper, on certificates
of responsible officers of the Company and public officials. References to the
Registration Statement and the Prospectus in this Section 6(c) include any
amendment or supplement thereto at the Closing Date.

            (d) The Company shall have furnished to the Representatives the
      opinion of Baker & McKenzie, special regulatory counsel for the Company,
      dated the Closing Date, to the effect that:

                  i. to the extent they constitute a summary of the regulatory
      matters referred to therein, the statements in the Registration Statement
      and the Final Prospectus under the caption "Business--Regulation of
      International Operations" fairly summarize the matters referred to
      therein;

                  ii. no licenses under telecommunications legislation in
      England and Wales including the Telecommunications Act 1984, the Wireless
      Telegraphy Act 1949 or the Wireless Telegraphy Act 1998 other than the
      Licenses are required by the Company, ION LLC, ION or Racal to carry on
      the ION Business in the United Kingdom;

                  iii. no licenses under telecommunications legislation in
      England and Wales including the Telecommunications Act 1984, the Wireless
      Telegraphy Act 1949 or the Wireless Telegraphy Act 1998, other than the
      Licenses that are currently required by the Company in relation to the
      Company's telecommunications business as presently conducted in the United
      Kingdom; and

                  iv. no German telecommunications licenses, other than the
      class 3 license obtained by Metromedia Fiber Network GmbH, are currently
      required by the Company in relation to the European Network, the German
      Network, or the Company's telecommunications business as presently
      conducted in Germany.

            In rendering such opinion, such counsel may state that they express
no opinion as to the laws of any jurisdiction other than Germany or the United
Kingdom or the regulations of the European Union.


                                       23


            (e) The Representatives shall have received from Skadden, Arps,
      Slate, Meagher & Flom LLP, counsel for the Underwriters, such opinion or
      opinions, dated the Closing Date and addressed to the Representatives,
      with respect to the issuance and sale of the Securities, the Indenture,
      the Registration Statement, the Final Prospectus (together with any
      supplement thereto) and other related matters as the Representatives may
      reasonably require, and the Company shall have furnished to such counsel
      such documents as they reasonably request for the purpose of enabling them
      to pass upon such matters.

            (f) The Company shall have furnished to the Representatives a
      certificate of the Company, signed by the Chairman of the Board of
      Directors or the President and the principal financial or accounting
      officer of the Company, dated the Closing Date, to the effect that the
      signers of such certificate have carefully examined the Registration
      Statement, the Final Prospectus, any supplements to the Final Prospectus
      and this Agreement and that:

                  i. the representations and warranties of the Company in this
      Agreement are true and correct in all material respects on and as of the
      Closing Date with the same effect as if made on the Closing Date, and the
      Company has complied with all the agreements and satisfied all the
      conditions on its part to be performed or satisfied hereunder at or prior
      to the Closing Date;

                  ii. no stop order suspending the effectiveness of the
      Registration Statement has been issued and no proceedings for that purpose
      have been instituted or, to the Company's knowledge, threatened; and

                  iii. since the date of the most recent financial statements
      included or incorporated by reference in the Final Prospectus (exclusive
      of any amendment or supplement thereto), there has been no material
      adverse change in the condition (financial or otherwise), prospects,
      earnings, business or properties of the Company and its subsidiaries,
      taken as a whole, whether or not arising from transactions in the ordinary
      course of business, except as set forth in or contemplated in the Final
      Prospectus (exclusive of any amendment or supplement thereto).

            (g) At the Execution Time and at the Closing Date, the Company shall
      have requested and caused Ernst & Young LLP to furnish to the
      Representatives letters, dated respectively as of the Execution Time and
      as of the Closing Date, in form and substance satisfactory to the
      Representatives, confirming that they are independent accountants within
      the meaning of the Act and the Exchange Act and the applicable rules and
      regulations


                                       24


      thereunder, that they have performed a review of the unaudited interim
      financial information of the Company for the nine month period ended
      September 30, 1999 and as at September 30, 1999 and stating in effect
      that:

                  i. in their opinion the audited financial statements and
      financial statement schedules included or incorporated in the Registration
      Statement and the Final Prospectus and reported on by them comply as to
      form in all material respects with the applicable accounting requirements
      of the Exchange Act and the related published rules and regulations
      thereunder;

                  ii. on the basis of a reading of the latest unaudited
      financial statements made available by the Company and its subsidiaries;
      their limited review in accordance with standards established under
      Statement on Auditing Standards No. 71, of the unaudited interim financial
      information for the nine month period ended September 30, 1999, and as at
      September 30, 1999; carrying out certain specified procedures (but not an
      examination in accordance with generally accepted auditing standards)
      which would not necessarily reveal matters of significance with respect to
      the comments set forth in such letter; a reading of the minutes of the
      meetings of the stockholders, directors and committees of the Company and
      the Subsidiaries; and inquiries of certain officials of the Company who
      have responsibility for financial and accounting matters of the Company
      and its subsidiaries as to transactions and events subsequent to December
      31, 1998, nothing came to their attention which caused them to believe
      that:

                  (1) any unaudited financial statements included or
            incorporated in the Registration Statement and the Final Prospectus
            do not comply in form in all material respects with applicable
            accounting requirements and with the published rules and regulations
            of the Commission with respect to financial statements included or
            incorporated in quarterly reports on Form 10-Q under the Exchange
            Act; or that said unaudited financial statements are not in
            conformity with generally accepted accounting principles applied on
            a basis substantially consistent with that of the audited financial
            statements included or incorporated in the Registration Statement
            and the Final Prospectus;

                  (2) with respect to the period subsequent to September 30,
            1999, there were any changes, at a specified date not more than
            three days prior to the date of the letter, in the capital stock,
            increase in long-term debt of the Company and its subsidiaries or
            stockholders' equity of the Company as compared with the amounts
            shown on the September 30, 1999 consolidated balance sheet included
            in the Final Prospectus, or for the period from October 1, 1999 to
            such specified date there were any decreases, as compared with the
            corresponding


                                       25


            period in the preceding year in revenues of the Company and its
            subsidiaries, except in all instances for changes or decreases set
            forth in such letter, in which case the letter shall be accompanied
            by an explanation by the Company as to the significance thereof
            unless said explanation is not deemed necessary by the
            Representatives; or

                  (3) the information included under the headings "Selected
            Consolidated Financial Data" and "Management-Executive Compensation"
            is not in conformity with the disclosure requirements of Regulation
            S-K;

                  iii. they have performed certain other specified procedures as
      a result of which they determined that certain information of an
      accounting, financial or statistical nature (which is limited to
      accounting, financial or statistical information derived from the general
      accounting records of the Company and its subsidiaries) set forth in the
      Final Prospectus, including the information set forth under the captions
      "Risk Factors", "Use of Proceeds", "Capitalization", "Selected
      Consolidated Financial Data", "Management's Discussion and Analysis of
      Financial Condition and Results of Operations", "Business", "Management",
      and "Certain Relationships and Related Transactions" in the Final
      Prospectus, the information included or incorporated in Items 1, 2, 6, 7
      and 11 of the Company's Annual Report on Form 10-K incorporated in the
      Final Prospectus and the information included in the "Management's
      Discussion and Analysis of Financial Condition and Results of Operations"
      included or incorporated in the Company's Quarterly Reports on Form 10-Q,
      incorporated in the Final Prospectus agrees with the accounting records of
      the Company and its subsidiaries, excluding any questions of legal
      interpretation; and

                  iv. on the basis of a reading of the unaudited pro forma
      financial statements included or incorporated by reference in the
      Registration Statement and the Final Prospectus (the "pro forma financial
      statements"); carrying out certain specified procedures; inquiries of
      certain officials of the Company and AboveNet Communications, Inc. who
      have responsibility for financial and accounting matters; and proving the
      arithmetic accuracy of the application of the pro forma adjustments to the
      historical amounts in the pro forma financial statements, nothing came to
      their attention which caused them to believe that the pro forma financial
      statements do not comply as to form in all material respects with the
      applicable accounting requirements of Rule 11-02 of Regulation S-X or that
      the pro forma adjustments have not been properly applied to the historical
      amounts in the compilation of such statements.

            (h) [Intentionally Omitted]


                                       26


            (i) At the Execution Time and at the Closing Date, Deloitte & Touche
      LLP shall have furnished to the Representatives letters, dated
      respectively as of the Execution Time and as of the Closing Date, in form
      and substance satisfactory to the Representatives, confirming that they
      are independent accountants within the meaning of the Act and the
      applicable rules and regulations thereunder, and stating in effect that:

                  i. in their opinion the audited financial statements and
      financial statement schedules included in the Registration Statement and
      the Final Prospectus and reported on by them comply in form in all
      material respects with the applicable accounting requirements of the Act
      and the related published rules and regulations; and

                  ii. they have performed certain other specified procedures as
      a result of which they determined that certain information of an
      accounting, financial or statistical nature (which is limited to
      accounting, financial or statistical information derived from the general
      accounting records of the Company and its subsidiaries) set forth in the
      Registration Statement and the Final Prospectus agrees with the accounting
      records of the Company and its subsidiaries, excluding any questions of
      legal interpretation.

            References to the Final Prospectus in this paragraph (i) include any
supplement thereto at the date of the letter.

            (j) At the Execution Time and at the Closing Date,
      PricewaterhouseCoopers LLP shall have furnished to the Representatives a
      letter or letters, dated respectively as of the Execution Time and as of
      the Closing Date, in form and substance satisfactory to the
      Representatives, confirming that they are independent accountants within
      the meaning of the Act and the applicable rules and regulations
      thereunder, and stating in effect that:

                  i. in their opinion the audited financial statements and
      financial statement schedules included in the Registration Statement and
      the Final Prospectus and reported on by them comply in form in all
      material respects with the accounting requirements of the Act and the
      related published rules and regulations; and

                  ii. they have performed certain other specified procedures as
      a result of which they determined that certain information of an
      accounting, financial or statistical nature (which is limited to
      accounting, financial or statistical information derived from the general
      accounting records of the Company and its subsidiaries) set forth in the
      Registration Statement and the Final Prospectus agrees with the accounting
      records of the Company and its subsidiaries, excluding any questions of
      legal interpretation.


                                       27


            References to the Final Prospectus in this paragraph (j) include any
supplement thereto at the date of the letter.

            (k) Subsequent to the Execution Time or, if earlier, the dates as of
      which information is given in the Registration Statement (exclusive of any
      amendment thereof) and the Final Prospectus (exclusive of any amendment or
      supplement thereto), there shall not have been (i) any change or decrease
      specified in the letter or letters referred to in paragraph (g) of this
      Section 6 or (ii) any change, or any development involving a prospective
      change, in or affecting the condition (financial or otherwise), prospects,
      earnings, business or properties of the Company and its subsidiaries,
      taken as a whole, whether or not arising from transactions in the ordinary
      course of business, except as set forth in or contemplated in the Final
      Prospectus (exclusive of any amendment or supplement thereto) the effect
      of which, in any case referred to in clause (i) or (ii) above, is, in the
      sole judgment of the Representatives, so material and adverse as to make
      it impractical or inadvisable to market the Securities as contemplated by
      the Registration Statement (exclusive of any amendment thereof) and the
      Final Prospectus (exclusive of any amendment or supplement thereto).

            (l) Subsequent to the Execution Time, there shall not have been any
      decrease in the rating of any of the Company's debt securities, including
      the Securities, by any "nationally recognized statistical rating
      organization" (as defined for purposes of Rule 436(g) under the Act) or
      any notice given of any intended or potential decrease in any such rating
      or of a possible change in any such rating that does not indicate the
      direction of the possible change.

            (m) No stop order suspending the effectiveness of the Registration
      Statement shall have been issued and no proceedings for that purpose shall
      have been taken or, to the knowledge of the Company, shall be contemplated
      by the Commission at or prior to the Closing Date; (ii) there shall not
      have been any change in the capital stock of the Company nor any material
      increase in the short-term or long-term debt of the Company (other than in
      the ordinary course of business) from that set forth or contemplated in
      the Registration Statement or the Final Prospectus (or any amendment or
      supplement thereto); (iii) there shall not have been, since the respective
      dates as of which information is given in the Registration Statement and
      the Final Prospectus (or any amendment or supplement thereto), except as
      may otherwise be stated in the Registration Statement and Final Prospectus
      (or any amendment or supplement thereto), any material adverse change in
      the condition (financial or other), business, prospects, properties, net
      worth or results of operations of the Company and the Subsidiaries taken
      as a whole; (iv) the Company and the Subsidiaries shall not have any
      liabilities or obligations, direct or contingent (whether or not in the
      ordinary course of


                                       28


      business), that are material to the Company and the Subsidiaries, taken as
      a whole, other than those reflected in the Registration Statement or the
      Final Prospectus (or any amendment or supplement thereto); and (v) all the
      representations and warranties of the Company contained in this Agreement
      shall be true and correct on and as of the date hereof and on and as of
      the Closing Date as if made on and as of the Closing Date and you shall
      have received a certificate, dated the Closing Date and signed by the
      chief executive officer and the chief financial officer of the Company (or
      such other officers as are acceptable to you), to the effect set forth in
      this Section 6(f) hereof.

            (n) The Company shall not have failed at or prior to the Closing
      Date to have performed or complied with any of its agreements herein
      contained and required to be performed or complied with by it hereunder at
      or prior to the Closing Date.

            (o) Prior to the Closing Date, the Company shall have furnished to
      the Representatives such further information, certificates and documents
      as the Representatives may reasonably request.

            (p) If any of the conditions specified in this Section 6 shall not
      have been fulfilled in all material respects when and as provided in this
      Agreement, or if any of the opinions and certificates mentioned above or
      elsewhere in this Agreement shall not be in all material respects
      reasonably satisfactory in form and substance to the Representatives and
      counsel for the Underwriters, this Agreement and all obligations of the
      Underwriters hereunder may be cancelled at, or at any time prior to, the
      Closing Date by the Representatives. Notice of such cancellation shall be
      given to the Company in writing or by telephone or facsimile confirmed in
      writing.

            (q) The documents required to be delivered by this Section 6 will be
      delivered at the office of Paul, Weiss, Rifkind, Wharton & Garrison,
      counsel for the Company, at 1285 Avenue of the Americas, New York, New
      York 10019, on the Closing Date.

            (r) Prior to the Closing Date the Company shall have applied to list
      the Securities on the Luxembourg Stock Exchange.

      7. Reimbursement of Underwriters' Expenses. If the sale of the Securities
provided for herein is not consummated because any condition to the obligations
of the Underwriters set forth in Section 6 hereof is not satisfied, because of
any termination pursuant to Section 10 hereof or because of any refusal,
inability or failure on the part of the Company to perform any agreement herein
or comply with any provision hereof other than by reason of a default by any of
the Underwriters, the Company will reimburse the Underwriters severally through


                                       29


Salomon Smith Barney Inc. on demand for all out-of-pocket expenses (including
reasonable fees and disbursements of one counsel) that shall have been incurred
by them in connection with the proposed purchase and sale of the Securities.

      8. Indemnification and Contribution. (a) The Company agrees to indemnify
and hold harmless each Underwriter, the directors, officers, employees and
agents of each Underwriter and each person who controls any Underwriter within
the meaning of either the Act or the Exchange Act against any and all losses,
claims, damages or liabilities, joint or several, to which they or any of them
may become subject under the Act, the Exchange Act or other Federal or state
statutory law or regulation, at common law or otherwise, insofar as such losses,
claims, damages or liabilities (or actions in respect thereof) arise out of or
are based upon any untrue statement or alleged untrue statement of a material
fact contained in the registration statement for the registration of the
Securities as originally filed or in any amendment thereof, or in the Basic
Prospectus, any Preliminary Final Prospectus or the Final Prospectus, or in any
amendment thereof or supplement thereto, or arise out of or are based upon the
omission or alleged omission to state therein a material fact required to be
stated therein or necessary to make the statements therein, in the light of the
circumstances under which they were made, not misleading, and agrees to
reimburse each such indemnified party, as incurred, for any legal or other
expenses reasonably incurred by them in connection with investigating or
defending any such loss, claim, damage, liability or action; provided, however,
that (i) the Company will not be liable in any such case to the extent that any
such loss, claim, damage or liability arises out of or is based upon any such
untrue statement or alleged untrue statement or omission or alleged omission
made therein in reliance upon and in conformity with written information
furnished to the Company by or on behalf of any Underwriter through the
Representatives specifically for inclusion therein and (ii) with respect to any
untrue statement or alleged untrue statement of, or omission or alleged omission
to state, a material fact made in any Preliminary Final Prospectus, the
indemnity agreement contained in this Section 8(a) shall not inure to the
benefit of any Underwriter (or any of the directors, officers, employees and
agents of such Underwriter or any controlling person of such Underwriter) from
whom the person asserting any such loss, claim, damage or liability purchased
the Securities concerned, to the extent that any such loss, claim, damage or
liability of such Underwriter occurs under the circumstances where it shall have
been determined by a court of competent jurisdiction (or appropriate arbitral
proceeding) by final and nonappealable judgment that (w) the Company had
previously furnished copies of the Final Prospectus to the Underwriters, (x)
delivery of the Final Prospectus was required by the Act or under this Agreement
to be made to such person, (y) the untrue statement or omission of a material
fact contained in the Preliminary Final Prospectus was corrected in the Final
Prospectus and (z) there was not sent or given to such person, at or prior to
the written confirmation of the sale of such Securities to such person, a copy
of the Final Prospectus. This indemnity agreement will be in addition to any
liability which the Company may otherwise have.


                                       30


            (b) Each Underwriter severally and not jointly agrees to indemnify
      and hold harmless the Company, each of its directors, each of its officers
      who signs the Registration Statement, and each person who controls the
      Company within the meaning of either the Act or the Exchange Act, to the
      same extent as the foregoing indemnity from the Company to each
      Underwriter, but only with reference to written information relating to
      such Underwriter furnished to the Company by or on behalf of such
      Underwriter through the Representatives specifically for inclusion in the
      documents referred to in the foregoing indemnity. This indemnity agreement
      will be in addition to any liability which any Underwriter may otherwise
      have. The Company acknowledges that the statements set forth in the last
      paragraph of the cover page regarding delivery of the Securities, the
      first paragraph on page S-3 related to stabilization, syndicate covering
      transactions and penalty bids and, under the heading "Underwriting" or
      "Plan of Distribution", (i) the list of Underwriters and their respective
      participation in the sale of the Securities, (ii) the sentences related to
      concessions and reallowances and (iii) the paragraph related to
      stabilization, syndicate covering transactions and penalty bids in any
      Preliminary Final Prospectus and the Final Prospectus constitute the only
      information furnished in writing by or on behalf of the several
      Underwriters for inclusion in any Preliminary Final Prospectus or the
      Final Prospectus.

            (c) Promptly after receipt by an indemnified party under this
      Section 8 of notice of the commencement of any action, such indemnified
      party will, if a claim in respect thereof is to be made against the
      indemnifying party under this Section 8, notify the indemnifying party in
      writing of the commencement thereof; but the failure so to notify the
      indemnifying party (i) will not relieve it from liability under paragraph
      (a) or (b) above unless and to the extent it did not otherwise learn of
      such action and such failure results in the forfeiture by the indemnifying
      party of substantial rights and defenses as determined by a court of
      competent jurisdiction; and (ii) will not, in any event, relieve the
      indemnifying party from any obligations to any indemnified party other
      than the indemnification obligation provided in paragraph (a) or (b)
      above. The indemnifying party shall be entitled to assume the defense of
      such action and appoint counsel of the indemnifying party's choice at the
      indemnifying party's expense to represent the indemnified party in any
      action for which indemnification is sought (in which case the indemnifying
      party shall not thereafter be responsible for the fees and expenses of any
      separate counsel retained by the indemnified party or parties except as
      set forth below); provided, however, that such counsel shall be reasonably
      satisfactory to the indemnified party. Notwithstanding the indemnifying
      party's election to assume the defense of such action or appoint counsel
      to represent the indemnified party in an action, the indemnified party
      shall have the right to employ separate counsel (including local counsel),
      and


                                       31


      the indemnifying party shall bear the reasonable fees, costs and expenses
      of such separate counsel if (i) the use of counsel chosen by the
      indemnifying party to represent the indemnified party would present such
      counsel with a conflict of interest, which has not been waived; (ii) the
      actual or potential defendants in, or targets of, any such action include
      both the indemnified party and the indemnifying party and the indemnified
      party shall have been reasonably advised by such counsel that there are
      legal defenses available to it and/or other indemnified parties which are
      different from or additional to those available to the indemnifying party;
      (iii) the indemnifying party shall not have assumed the defense of the
      action or employed counsel reasonably satisfactory to the indemnified
      party to represent the indemnified party within a reasonable time after
      notice of the institution of such action; or (iv) the indemnifying party
      shall authorize the indemnified party to employ separate counsel at the
      expense of the indemnifying party. In any such case, the indemnifying
      party shall not, in connection with any one action or separate but
      substantially similar related actions in the same jurisdiction arising out
      of the same general allegations or circumstances, be liable for the fees
      and expenses of more than one separate firm of attorneys (in addition to
      any local counsel) for all indemnified parties. An indemnifying party will
      not, without the prior written consent of the indemnified parties, settle
      or compromise or consent to the entry of any judgment with respect to any
      pending or threatened claim, action, suit or proceeding in respect of
      which indemnification or contribution may be sought hereunder (whether or
      not the indemnified parties are actual or potential parties to such claim
      or action) unless such settlement, compromise or consent includes an
      unconditional release of each indemnified party from all liability arising
      out of such claim, action, suit or proceeding.

            (d) In the event that the indemnity provided in paragraph (a) or (b)
      of this Section 8 is unavailable to or insufficient to hold harmless an
      indemnified party for any reason, the Company and the Underwriters
      severally agree to contribute to the aggregate losses, claims, damages and
      liabilities (including legal or other expenses reasonably incurred in
      connection with investigating or defending same) (collectively "Losses")
      to which the Company and one or more of the Underwriters may be subject in
      such proportion as is appropriate to reflect the relative benefits
      received by the Company on the one hand and by the Underwriters on the
      other from the offering of the Securities; provided, however, that in no
      case shall any Underwriter (except as may be provided in any agreement
      among Underwriters relating to the offering of the Securities) be
      responsible for any amount in excess of the underwriting discount or
      commission applicable to the Securities purchased by such Underwriter
      hereunder. If the allocation provided by the immediately preceding
      sentence is unavailable for any reason, the Company and the Underwriters
      severally shall contribute in such proportion as is appropriate to reflect
      not only such relative benefits but also


                                       32


      the relative fault of the Company on the one hand and of the Underwriters
      on the other in connection with the statements or omissions or alleged
      statements or omissions which resulted in such Losses, as well as any
      other relevant equitable considerations. Benefits received by the Company
      shall be deemed to be equal to the total net proceeds from the offering
      (before deducting expenses) received by it, and benefits received by the
      Underwriters shall be deemed to be equal to the total underwriting
      discounts and commissions, in each case as set forth on the cover page of
      the Final Prospectus. Relative fault shall be determined by reference to,
      among other things, whether any untrue or any alleged untrue statement of
      a material fact or the omission or alleged omission to state a material
      fact relates to information provided by the Company on the one hand or the
      Underwriters on the other, the intent of the parties and their relative
      knowledge, access to information and opportunity to correct or prevent
      such untrue statement or omission or alleged untrue statement or omission.
      The Company and the Underwriters agree that it would not be just and
      equitable if contribution were determined by pro rata allocation or any
      other method of allocation which does not take account of the equitable
      considerations referred to above. Notwithstanding the provisions of this
      paragraph (d), no person guilty of fraudulent misrepresentation (within
      the meaning of Section 11(f) of the Act) shall be entitled to contribution
      from any person who was not guilty of such fraudulent misrepresentation.
      For purposes of this Section 8, each person who controls an Underwriter
      within the meaning of either the Act or the Exchange Act and each
      director, officer, employee and agent of an Underwriter shall have the
      same rights to contribution as such Underwriter, and each person who
      controls the Company within the meaning of either the Act or the Exchange
      Act and each officer of the Company who shall have signed the Registration
      Statement and each director of the Company shall have the same rights to
      contribution as the Company, subject in each case to the applicable terms
      and conditions of this paragraph (d).

      9. Default by an Underwriter. If any one or more Underwriters shall fail
to purchase and pay for any of the Securities agreed to be purchased by such
Underwriter or Underwriters hereunder and such failure to purchase shall
constitute a default in the performance of its or their obligations under this
Agreement, the remaining Underwriters shall be obligated severally to take up
and pay for (in the respective proportions which the principal amount of
Securities set forth opposite their names in Schedule II hereto bears to the
aggregate principal amount of Securities set forth opposite the names of all the
remaining Underwriters) the Securities which the defaulting Underwriter or
Underwriters agreed but failed to purchase; provided, however, that in the event
that the aggregate principal amount of Securities which the defaulting
Underwriter or Underwriters agreed but failed to purchase shall exceed 10% of
the aggregate principal amount of Securities set forth in Schedule II hereto,
the remaining Underwriters shall have the right to (i) make arrangements for the
purchase of the Securities which such defaulting Underwriter or


                                       33


Underwriters agreed but failed to purchase by other persons satisfactory to the
Company and the non-defaulting Underwriters, and/or (ii) purchase all, but shall
not be under any obligation to purchase any, of the Securities, and if such
nondefaulting Underwriters do not make such arrangements and/or purchase all the
Securities, this Agreement will terminate without liability to any nondefaulting
Underwriter or the Company. In the event of a default by any Underwriter as set
forth in this Section 9, the Closing Date shall be postponed for such period,
not exceeding five Business Days, as the Representatives shall determine in
order that the required changes in the Registration Statement and the Final
Prospectus or in any other documents or arrangements may be effected. Nothing
contained in this Agreement shall relieve any defaulting Underwriter of its
liability, if any, to the Company or any nondefaulting Underwriter for damages
occasioned by its default hereunder.

      10. Termination. This Agreement shall be subject to termination in the
absolute discretion of the Representatives, by notice given to the Company prior
to delivery of and payment for the Securities, if at any time prior to such time
(i) trading in the Company's Common Stock shall have been suspended by the
Commission or the NASDAQ National Market or trading in securities generally on
the New York Stock Exchange or the NASDAQ National Market shall have been
suspended or limited or minimum prices shall have been established on such
exchange or the NASDAQ National Market; (ii) a banking moratorium shall have
been declared either by Federal or New York State authorities; or (iii) there
shall have occurred any outbreak or escalation of hostilities, declaration by
the United States of a national emergency or war, or other calamity or crisis
the effect of which on financial markets is such as to make it, in the sole
judgment of the Representatives, impractical or inadvisable to proceed with the
offering or delivery of the Securities as contemplated by the Final Prospectus
(exclusive of any amendment or supplement thereto).

      11. Representations and Indemnities to Survive. The respective agreements,
representations, warranties, indemnities and other statements of the Company or
its officers and of the Underwriters set forth in or made pursuant to this
Agreement will remain in full force and effect, regardless of any investigation
made by or on behalf of any Underwriter or the Company or any of the officers,
directors, employees, agents or controlling persons referred to in Section 8
hereof, and will survive delivery of and payment for the Securities. The
provisions of Sections 7 and 8 hereof shall survive the termination or
cancellation of this Agreement.

      12. Notices. All communications hereunder will be in writing and effective
only on receipt, and, if sent to the Representatives, will be mailed, delivered
or telefaxed to Salomon Smith Barney Inc. General Counsel (fax no.: (212)
816-7912) and confirmed to the General Counsel, Salomon Smith Barney Inc., at
388 Greenwich Street, New York, New York, 10013, Attention: General Counsel; or,
if sent to the Company, will be mailed, delivered or telefaxed to Metromedia
Fiber Network Services, Inc. c/o Metromedia Fiber Network, Inc., One North


                                       34


Lexington Avenue, White Plains, New York 10601, Attention: Chief Financial
Officer (fax no.: (914) 421-6777) and confirmed to it at Metromedia Company, One
Meadowlands Plaza, East Rutherford, New Jersey 07073-2137, Attention: General
Counsel (fax no.: (201) 531-2803) and 215 East 67th Street, New York, New York
10021, Attention: Executive Vice President (fax no.: (212) 606-4337).

      13. Successors. This Agreement will inure to the benefit of and be binding
upon the parties hereto and their respective successors and the officers and
directors and controlling persons referred to in Section 8 hereof, and, except
as expressly set forth in Section 5(h) or Section 8 hereof, no other person will
have any right or obligation hereunder.

      14. Applicable Law. This Agreement will be governed by and construed in
accordance with the laws of the State of New York applicable to contracts made
and to be performed within the State of New York.

      15. Counterparts. This Agreement may be executed in one or more
counterparts, each of which shall constitute an original and all of which
together shall constitute one and the same instrument.

      16. Headings. The section headings used herein are for convenience only
and shall not affect the construction hereof.

      17. Definitions. The terms which follow, when used in this Agreement,
shall have the meanings indicated.

      "Act" shall mean the Securities Act of 1933, as amended and the rules and
regulations of the Commission promulgated thereunder.

      "Basic Prospectus" shall mean the prospectus referred to in paragraph 1(a)
above contained in the Registration Statement at the Effective Date including
any Preliminary Final Prospectus.

      "Business Day" shall mean any day other than a Saturday, a Sunday or a
legal holiday or a day on which banking institutions or trust companies are
authorized or obligated by law to close in New York City.

      "Commission" shall mean the Securities and Exchange Commission.

      "Communications Act" shall mean the Communications Act of 1934, as amended
(including amendments made by the Telecommunications Act of 1996), 47 U.S.C.
section 151 and the rules and regulations of the FCC.

      "Effective Date" shall mean each date and time that the Registration
Statement, any post-effective amendment or amendments thereto and any Rule
462(b) Registration Statement became or become effective.


                                       35


      "Exchange Act" shall mean the Securities Exchange Act of 1934, as amended,
and the rules and regulations of the Commission promulgated thereunder.

      "Execution Time" shall mean the date and time that this Agreement is
executed and delivered by the parties hereto.

      "Final Prospectus" shall mean the prospectus supplement relating to the
Securities that was first filed pursuant to Rule 424(b) after the Execution
Time, together with the Basic Prospectus.

      "Preliminary Final Prospectus" shall mean any preliminary prospectus
supplement to the Basic Prospectus which describes the Securities and the
offering thereof and is used prior to filing of the Final Prospectus, together
with the Basic Prospectus.

      "Registration Statement" shall mean the registration statement referred to
in paragraph 1(a) above, including exhibits and financial statements, as amended
at the Execution Time (or, if not effective at the Execution Time, in the form
in which it shall become effective) and, in the event any post-effective
amendment thereto or any Rule 462(b) Registration Statement becomes effective
prior to the Closing Date, shall also mean such registration statement as so
amended or such Rule 462(b) Registration Statement, as the case may be. Such
term shall include any Rule 430A Information deemed to be included therein at
the Effective Date as provided by Rule 430A.

      "Rule 415", "Rule 424", "Rule 430A" and "Rule 462" refer to such rules
under the Act.

      "Rule 430A Information" shall mean information with respect to the
Securities and the offering thereof permitted to be omitted from the
Registration Statement when it becomes effective pursuant to Rule 430A.

      "Rule 462(b) Registration Statement" shall mean a registration statement
and any amendments thereto filed pursuant to Rule 462(b) relating to the
offering covered by the registration statement referred to in Section 1(a)
hereof.

      "State Telecommunications Laws" shall mean the comparable state statutes
of all states in which the Company and/or its subsidiaries is certified to
provide services.

      "Trust Indenture Act" shall mean the Trust Indenture Act of 1939, as
amended and the rules and regulations of the Commission promulgated thereunder.


                                       36


      If the foregoing is in accordance with your understanding of our
agreement, please sign and return to us the enclosed duplicate hereof, whereupon
this Agreement and your acceptance shall represent a binding agreement among the
Company and the several Underwriters.

                                        Very truly yours,
                                        METROMEDIA FIBER NETWORK, INC.,


                                        By: /s/ Gerard Benedetto
                                            ------------------------------------
                                            Name: Gerard Benedetto
                                            Title: Chief Financial Officer
                                                   and Senior Vice President

      [Underwriting Agreement-Notes]


      The foregoing Agreement is
      hereby confirmed and accepted
      as of the date specified in
      Schedule I hereto.

      Salomon Smith Barney Inc.
      Chase Securities Inc.
      Deutsche Bank Securities Inc.
      Donaldson, Lufkin & Jenrette Securities Corporation
      Goldman, Sachs & Co.
      Morgan Stanley & Co. Incorporated

      By: SALOMON SMITH BARNEY INC.


      By: /s/ Robert Doherty
          -------------------------
          Name: Robert Doherty
          Title: Director

      For themselves and the other
      several Underwriters, if any,
      named in Schedule II to the
      foregoing Agreement.

      [Underwriting Agreement-Notes]


                                   SCHEDULE I

Underwriting Agreement dated: November 12, 1999


                                        1


                                   SCHEDULE II

                               Principal Amount      Principal Amount
                               of U. S. Securities   of International Securities
Underwriters                   to be Purchased       to be Purchased
- ------------                   -------------------   ---------------------------

Salomon Smith Barney Inc.      $375,000,000          (euro)125,000,000
Chase Securities Inc.            93,750,000                 31,250,000
Deutsche Bank Securities Inc.    75,000,000                 25,000,000
Donaldson, Lufkin & Jenrette
   Securities Corporation        93,750,000                 31,250,000
Goldman, Sachs & Co.             75,000,000                 25,000,000
Morgan Stanley & Co.
      Incorporated               37,500,000                 12,500,000

                               ------------          -----------------
         Total                 $750,000,000          (euro)250,000,000


                                        2


                                  SCHEDULE III

SUBSIDIARY

1. Metromedia Fiber Network NYC, Inc.

2. Metromedia Fiber Network Services, Inc.

3. AboveNet Communications Inc.

4. Metromedia Fiber Network International, Inc.


                                        3