AGREEMENT OF MERGER
                                 BY AND AMONG
                                  CAIS, INC.,
                              CGX 2 MERGER CORP.
                         AND CGX COMMUNICATIONS, INC.
                                        
     THIS AGREEMENT OF MERGER (this "Agreement"), dated as of October 2, 1998,
by and among CAIS, INC., a Virginia corporation ("CAIS" or the "Surviving
Corporation"), CGX 2 MERGER CORP., a Delaware corporation ("CGX 2 Merger") (CAIS
and CGX 2 Merger herein sometimes collectively the "Constituent Corporations"),
and CGX COMMUNICATIONS, INC., a Delaware corporation ("CGX").

                                  WITNESSETH:

     WHEREAS, CAIS is a corporation duly organized and validly existing under
the laws of the Commonwealth of Virginia, having been incorporated on April 3,
1996; and

     WHEREAS, CGX 2 Merger is a corporation duly organized and validly existing
under the laws of the State of Delaware, having been incorporated on July 14,
1998; and

     WHEREAS, CGX is a corporation duly organized and validly existing under the
laws of the State of Delaware, having been incorporated on December 4, 1997; and

     WHEREAS, CGX 2 Merger is a wholly-owned subsidiary of CGX; and

     WHEREAS, the parties hereto deem it desirable, upon the terms and subject
to the conditions herein stated, to effectuate a merger transaction (the
"Merger") whereby (i) CGX 2 Merger shall be merged with and into CAIS and CAIS
shall be the surviving corporation, (ii) the outstanding shares of  CAIS's
common stock, no par value (the "CAIS Common Stock"), shall be converted into
shares of CGX's common stock, par value $.01 per share (the "CGX Common Stock"),
and (iii) the outstanding shares of CGX 2 Merger's common stock, par value $.01
per share (the CGX 2 Merger Common Stock"), shall be converted into shares of
CAIS Common Stock, so that upon the effectiveness of the Merger all of the
outstanding CAIS Common Stock will be owned by CGX.

     NOW, THEREFORE, in consideration of the premises and the mutual covenants,
agreements and provisions hereinafter contained, and subject to the terms and
conditions herein, the parties to this Agreement hereby agree as follows.
<PAGE>
 
                                   Section I
                                   ---------

                                     Terms
                                     -----

     1.1  On the effective date of the Merger, CGX 2 Merger shall be merged with
and into CAIS, and CAIS shall be the surviving corporation.

     1.2  On the effective date of the Merger, each then outstanding share of
CAIS Common Stock shall, by virtue of the Merger and without any action on the
part of any holder thereof, be converted into 500 shares of CGX Common Stock.

     1.3  On the effective date of the Merger, all of the then outstanding
shares of CGX 2 Merger Common Stock shall, by virtue of the Merger and without
any action on the part of the holder thereof,  be converted into an aggregate
number of shares of CAIS Common Stock equal to the total number of shares of CGX
2 Merger Common Stock outstanding immediately prior to the effective date of the
Merger.

     1.4  Each holder of a stock certificate or certificates representing
outstanding shares of CAIS Common Stock immediately prior to effective date of
the Merger, upon surrender of such certificate or certificates to CGX after the
effective date of the Merger, shall be entitled to receive a stock certificate
or certificates representing the same number of shares of CGX Common Stock
specified in Section 1.2.  Until so surrendered, each such stock certificate
shall, by virtue of the Merger, be deemed for all purposes to evidence ownership
of the same number of shares of CGX Common Stock.

     1.5  CGX, as holder of the stock certificate or certificates representing
all of the outstanding shares of CGX 2 Merger Common Stock immediately prior to
effective date of the Merger, upon surrender of such certificate or certificates
to CAIS after the effective date of the Merger, shall be entitled to receive a
stock certificate representing the same number of shares of CAIS Common Stock
specified in Section 1.3.  Until so surrendered, each such stock certificate
shall, by virtue of the Merger, be deemed for all purposes to evidence ownership
of the same number of shares of CAIS Common Stock.

     1.6  If any certificate representing CGX Common Stock is to be issued in a
name other than that in which the certificate theretofore representing CAIS
Common Stock surrendered is registered, it shall be a condition of such issuance
that the certificate so surrendered shall be properly endorsed or otherwise in
proper form for transfer and that the person requesting such issuance shall
either pay to CGX or its transfer agents any transfer or other taxes required by
reason of the issuance of certificates representing CGX Common Stock in a name
other than that of the registered holder of the certificate surrendered, or
establish to the satisfaction of CGX or its transfer agents that such tax has
been paid or is not applicable.

                                       2
<PAGE>
 
                                   Section 2
                                   ---------

                                Effective Date
                                --------------

     2.1  This Agreement shall be submitted to the stockholders of CAIS and CGX
2 Merger entitled to vote thereon as provided by the applicable laws of the
Commonwealth of Virginia and the State of Delaware.  If this Agreement is duly
adopted by the requisite votes of such stockholders and is not terminated as
contemplated by Section 5, a certificate of merger, executed in accordance with
the laws of the State of Delaware, shall be filed with the Secretary of State of
the State of Delaware, and articles of merger, executed in accordance with the
laws of the Commonwealth of  Virginia,  shall be filed with the State
Corporation Commission of the Commonwealth of Virginia.

     2.1  The Merger shall become effective on the time and date specified in
the certificate of merger filed with the Secretary of State of the State of
Delaware and the articles of merger filed with the State Corporation Commission
of the Commonwealth of Virginia, herein sometimes referred to as the "effective
date of the Merger."

                                   Section 3
                                   ---------

                           Covenants and Agreements
                           ------------------------

     3.1  CAIS covenants and agrees that it will present this Agreement for
adoption or rejection by vote of the holders of CAIS Common Stock, will furnish
to such holders such documents and information in connection therewith as is
required by law, and will recommend approval of this Agreement by such holders.

     3.2  CGX 2 Merger covenants and agrees that it will present this Agreement
for adoption or rejection by vote of the holder of the CGX 2 Merger Common
Stock, will furnish to such holder such documents and information in connection
therewith as is required by law, and will recommend approval of this Agreement
by such holder.
 
     3.3  CGX covenants and agrees that (i) it will, as sole stockholder of CGX
2 Merger, vote all shares of CGX 2 Merger Common Stock owned by it to approve
this Agreement as provided by law, and (ii) prior to the effective date of the
Merger, it will not without obtaining the written consent of CAIS, permit any
change in CGX 2 Merger or its capital stock.

                                   Section 4
                                   ---------

               Certificate of Incorporation and By-Laws; Capital
               -------------------------------------------------

     4.1  The Articles of Incorporation of CAIS and all the terms and provisions
thereof are hereby incorporated in this Agreement and made a part hereof with
the same force and effect as if herein set forth in full; and from and after the
effective date of the Merger and, until further

                                       3
<PAGE>
 
amended as provided by law, said Articles of Incorporation shall be, and may be
separately certified as, the Articles of Incorporation of the Surviving
Corporation.

     4.2  The By-Laws of CAIS in effect on the effective date of the Merger
shall be the By-Laws of the Surviving Corporation, to remain unchanged until
amended in accordance with the provisions thereof and of applicable law.

     4.3  The Certificate of Incorporation and By-Laws of CGX shall not be
affected by the Merger.

                                   Section 5
                                   ---------

                           Amendment and Termination
                           -------------------------

     5.1  At any time prior to the filing of the articles of merger with the
State Corporation Commission of the Commonwealth of Virginia and of the
certificate of merger with the Secretary of State of the State of Delaware, this
Agreement may be amended by the Boards of Directors of CAIS and CGX to the
extent permitted by Virginia and Delaware law, respectively, notwithstanding
favorable action on the Merger by the stockholders of either or both of the
Constituent Corporations.

     5.2  At any time prior to the filing of the articles of merger with the
State Corporation Commission of the Commonwealth of Virginia and of the
certificate of merger with the Secretary of State of the State of Delaware, this
Agreement may be terminated and abandoned by the Board of Directors of either
CAIS or CGX, notwithstanding favorable action on the Merger by the stockholders
of either or both of the Constituent Corporations.

     5.3  To the extent permitted by law, this Agreement may be amended by an
agreement in writing, before or after the approval hereof by the stockholders of
CAIS and/or of CGX 2 Merger, at any time prior to the effective date of the
Merger, with respect to any of the terms contained herein except in the terms of
the conversion provided for in Sections 1.2 and 1.3.

     5.4  The Surviving Corporation may be served with process in the State of
Delaware in any proceeding for enforcement of any obligations of CGX 2 Merger,
as well as for enforcement of any obligations of the surviving corporation
arising from the merger, including any suit or other proceeding to enforce the
right of any stockholder as determined in an appraisal proceeding pursuant to
the provisions of section 262 of the General Corporation Law of the State of
Delaware, and it does hereby irrevocably appoint the secretary of State of
Delaware as its agent to accept service of process is any such suit or other
proceeding. The address to which a copy of such process shall be mailed by the
Secretary of State is 1232 22/nd/ Street, NW, Washington, D.C. 20037.

                                       4
<PAGE>
 
     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed by their respective duly authorized officers, all as of the date first
above written.


                                    CAIS, Inc.

                                    BY: /s/ Ulysses G. Auger, II
                                        ------------------------
                                        Ulysses G. Auger, II
                                        President

 
                                        CGX 2 Merger Corp.

                                    BY: /s/ Ulysses G. Auger, II
                                        ------------------------
                                        Ulysses G. Auger, II
                                        President

                                        CGX Communications, Inc.

                                    BY: /s/ Ulysses G. Auger, II
                                        ------------------------
                                        Ulysses G. Auger, II
                                        President

                                       5

Source: OneCLE Business Contracts.