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                                                                    Exhibit 4.5

               AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

         This Amended and Restated Registration Rights Agreement, dated August
10, 2001 (this "Agreement"), is entered into by and among Consolidated Edison
Communications, Inc. (the "Investor"), Exelon Enterprises Management, Inc.,
formerly known as Exelon Ventures Corp. ("Exelon") and NEON Communications, Inc.
(the "Company") (collectively, the "Original Parties").

         WHEREAS, the Company and Northeast Optic Network, Inc. entered into a
subscription agreement with each of the Investor and Exelon dated as of
September 14, 2000 and amended as of May 1, 2000 and September 6, 2000 (each, a
"Subscription Agreement"); and

         WHEREAS, the Original Parties entered into a Registration Rights
Agreement dated as of September 14, 2000 (the "Registration Rights Agreement")
pursuant to which the Original Parties agreed, among other things, to provide
for certain arrangements with respect to the registration of shares of capital
stock of the Company under the Securities Act of 1933 (the "Securities Act");
and

         WHEREAS, Exelon and the Company have entered into a separate
registration rights agreement dated the date hereof (the "Exelon Registration
Rights Agreement"), pursuant to which Exelon and the Company agreed, among other
things, to provide for certain arrangements with respect to the registration of
the shares of capital stock of the Company under the Securities Act which Exelon
has purchased pursuant to a subordinated convertible note purchase agreement
dated the date hereof, and the registration of the shares of capital stock which
Exelon purchased pursuant to the Subscription Agreement between Exelon and the
Company; and

         WHEREAS, the Original Parties mutually desire to amend and restate the
Registration Rights Agreement to terminate Exelon's rights and obligations
provided therein.

         NOW, THEREFORE, in consideration of the foregoing, the Original Parties
agree as follows:

         1. CERTAIN DEFINITIONS.

         As used in this Agreement, the following terms shall have the following
respective meanings:

         "BUSINESS DAY" means any day other than Saturday, Sunday and any day
which is a legal holiday or a day on which banking institutions in New York are
authorized or required by law or other action of a governmental authority to
close.

         "COMMISSION" means the Securities and Exchange Commission, or any other
federal agency at the time administering the Securities Act.

         "COMMON STOCK" means the common stock, $.01 par value per share, of the
Company.

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         "EXCHANGE ACT" means the Securities Exchange Act of 1934, as amended,
or any successor federal statute, and the rules and regulations of the
Commission issued under such Act, as they each may, from time to time, be in
effect.

         "INITIATING HOLDER" means the Investor initiating a request for
registration pursuant to Section 2.1(a).

         "OTHER HOLDERS" shall have the meaning set forth in Section 2.1(c).

         "PROSPECTUS" means the prospectus included in any Registration
Statement, as amended or supplemented by an amendment or prospectus supplement,
including post-effective amendments, and all material incorporated by reference
or deemed to be incorporated by reference in such Prospectus.

         "REGISTRATION STATEMENT" means a registration statement filed by the
Company with the Commission for a public offering and sale of securities of the
Company (other than a registration statement on Form S-8 or Form S-4, or their
successors, or any other form for a similar limited purpose, or any registration
statement covering only securities proposed to be issued in exchange for
securities or assets of another corporation).

         "REGISTRATION EXPENSES" means the expenses described in Section 2.4.

         "REGISTRABLE SHARES" means (i) the Shares and (ii) any other shares of
Common Stock issued in respect of the Shares (because of stock splits, stock
dividends, reclassifications, recapitalizations, or similar events); PROVIDED,
however, that shares of Common Stock which are Registrable Shares shall cease to
be Registrable Shares upon (i) any sale pursuant to a Registration Statement or
Rule 144 under the Securities Act (ii) their eligibility for sale pursuant to
Rule 144(k) under the Securities Act or (iii) any sale in any manner to a person
or entity which, by virtue of Section 3 of this Agreement, is not entitled to
the rights provided by this Agreement.

         "SECURITIES ACT" means the Securities Act of 1933, as amended, or any
successor federal statute, and the rules and regulations of the Commission
issued under such Act, as they each may, from time to time, be in effect.

         "SELLING STOCKHOLDER" means any Stockholder owning Registrable Shares
included in a Registration Statement.

         "SHARES" means the CEC NEON shares as defined in the Subscription
Agreements.

         "STOCKHOLDER" means the Investor and any persons or entities to whom
the rights granted under this Agreement are transferred by the Investor, its
successors or assigns pursuant to Section 3 hereof.

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         2. REGISTRATION RIGHTS

            2.1 REQUIRED REGISTRATIONS.

                (a) At any time after the first anniversary of the closing of
the Subscription Agreements, the Investor may request, in writing, that the
Company effect the registration on Form S-3 (or any successor form or any other
registration statement form which the Company is eligible to use) of Registrable
Shares owned by the Investor having an aggregate value of at least $5,000,000
(based on the then current market price or fair value).

                (b) Upon receipt of any request for registration pursuant to
this Section 2, the Company shall promptly give written notice of such proposed
registration to all other Stockholders. Such Stockholders shall have the right,
by giving written notice to the Company within 30 days after the Company
provides its notice, to elect to have included in such registration such of
their Registrable Shares as such Stockholders may request in such notice of
election, subject in the case of an underwritten offering to the approval of the
managing underwriter as provided in Section 2.1(c) below. Thereupon, the Company
shall, as expeditiously as possible, effect the registration of all Registrable
Shares which the Company has been requested to so register.

                (c) If the Initiating Holder intends to distribute the
Registrable Shares covered by its request by means of an underwriting, it shall
so advise the Company as a part of its request made pursuant to Section 2.1(a),
and the Company shall include such information in its written notice referred to
in Section 2.1(b). The right of any other Stockholder to include its Registrable
Shares in such registration pursuant to Section 2.1(a) shall be conditioned upon
such other Stockholders' participation in such underwriting on the terms set
forth herein. If the Company desires that any officers or directors of the
Company holding securities of the Company be included in any registration for an
underwritten offering requested pursuant to Section 2.1(c) or if other holders
of securities of the Company who are entitled, by contract with, or other
instrument executed by, the Company prior to the date hereof, to have securities
included in such a registration (the "Other Holders") request such inclusion,
the Company may include the securities of such officers, directors and Other
Holders in such registration and underwriting on the terms set forth herein. The
Company shall (together with all Stockholders, officers, directors and Other
Holders proposing to distribute their securities through such underwriting)
enter into an underwriting agreement in customary form (including, without
limitation, customary indemnification and contribution provisions on the part of
the Company) with the managing underwriter; PROVIDED that such underwriting
agreement shall not provide for indemnification or contribution obligations on
the part of Stockholders materially greater than the obligations of the
Stockholders pursuant to Section 2.5. Notwithstanding any other provision of
this Section 2.1(c), if the managing underwriter advises the Company that the
inclusion of all shares requested to be registered would adversely affect the
offering, the securities of the Company held by officers or directors of the
Company (other than Registrable Shares) shall be excluded from such registration
and underwriting to the extent deemed advisable by the managing underwriter, and
if a further limitation of the number of shares is required, the number of
shares that may be included in such registration and underwriting shall be
allocated among all

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Other Holders and holders of Registrable Shares pro rata in proportion to the
respective number shares they have requested to be registered. If any holder of
Registrable Shares, officer, director or Other Holder who has requested
inclusion in such registration as provided above disapproves of the terms of the
underwriting, such person may elect to withdraw therefrom by written notice to
the Company, and the securities so withdrawn shall also be withdrawn from
registration. If the managing underwriter has not limited the number of
Registrable Shares or other securities to be underwritten, the Company may
include securities for its own account in such registration if the managing
underwriter so agrees and if the number of Registrable Shares and other
securities which would otherwise have been included in such registration and
underwriting will not thereby be limited.

                (d) The Initiating Holder shall have the right to select the
managing underwriter(s) for any underwritten offering requested pursuant to
Section 2.1(a), subject to the approval of the Company, which approval will not
be unreasonably withheld.

                (e) The Company shall not be required to effect more than one
registration pursuant to Section 2.1(a). For purposes of this Section 2.1(e), a
Registration Statement shall not be counted until such time as such Registration
Statement has been declared effective by the Commission (unless the Initiating
Holder withdraws its request for such registration (other than as a result of
information concerning the business or financial condition of the Company which
is made known to the Stockholders after the date on which such registration was
requested) and elect not to pay the Registration Expenses therefor pursuant to
Section 2.4).

                (f) If at the time of any request to register Registrable Shares
by the Initiating Holder pursuant to this Section 2.1, the Company is engaged or
has plans to engage in a registered public offering or is engaged in any other
activity which, in the good faith determination of the Company's Board of
Directors, would be adversely affected by the requested registration, then the
Company may at its option direct that such request be delayed for a period not
in excess of 90 days from the date of such request, such right to delay a
request to be exercised by the Company not more than once in any 12-month
period.

         2.2 INCIDENTAL REGISTRATION.

             (a) Whenever the Company proposes to file a Registration
Statement (other than a Registration Statement filed pursuant to Section 2.1) at
any time and from time to time, it will, prior to such filing, give written
notice to all Stockholders of its intention to do so; PROVIDED, that no such
notice need be given if no Registrable Shares are to be included therein as a
result of a determination of the managing underwriter pursuant to Section
2.2(b). Upon the written request of a Stockholder or Stockholders given within
20 days after the Company provides such notice, the Company shall use its best
efforts to cause all Registrable Shares which the Company has been requested by
such Stockholder or Stockholders to register to be registered under the
Securities Act to the extent necessary to permit their sale or other disposition
in accordance with the intended methods of distribution specified in the request
of such Stockholder

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or Stockholders; provided that the Company shall have the right to postpone or
withdraw any registration effected pursuant to this Section 2.2 without
obligation to any Stockholder.

                (b) If the registration for which the Company gives notice
pursuant to Section 2.2(a) is a registered public offering involving an
underwriting, the Company shall so advise the Stockholders as a part of the
written notice given pursuant to Section 2.2(a). In such event, the right of any
Stockholder to include its Registrable Shares in such registration pursuant to
Section 2.2 shall be conditioned upon such Stockholder's participation in such
underwriting on the terms set forth herein. All Stockholders proposing to
distribute their securities through such underwriting shall enter into an
underwriting agreement in customary form with the underwriter or underwriters
selected for the underwriting by the Company. Notwithstanding any other
provision of this Section 2.2, if the managing underwriter determines that the
inclusion of all shares requested to be registered would adversely affect the
offering, the Company may limit the number of Registrable Shares to be included
in the registration and underwriting. The Company shall so advise all holders of
Registrable Shares requesting registration, and the number of shares that are
entitled to be included in the registration and underwriting shall be allocated
in the following manner. The securities of the Company held by holders other
than Stockholders and Other Holders shall be excluded from such registration and
underwriting to the extent deemed advisable by the managing underwriter, and, if
a further limitation on the number of shares is required, the number of shares
that may be included in such registration and underwriting shall be allocated
among all Stockholders and Other Holders requesting registration in proportion,
as nearly as practicable, to the respective number of shares of Common Stock
which they held at the time the Company gives the notice specified in Section
2.2(a). If any Stockholder or Other Holder would thus be entitled to include
more securities than such holder requested to be registered, the excess shall be
allocated among other requesting Stockholders and Other Holders pro rata in the
manner described in the preceding sentence. If any holder of Registrable Shares
or any officer, director or Other Holder disapproves of the terms of any such
underwriting, such person may elect to withdraw therefrom by written notice to
the Company, and any Registrable Shares or other securities excluded or
withdrawn from such underwriting shall be withdrawn from such registration.

                (c) Notwithstanding the foregoing, the Company shall not be
required, pursuant to this Section 2.2, to include any Registrable Shares in a
Registration Statement if such Registrable Shares can then be sold pursuant to
Rule 144(k) under the Securities Act.

         2.3 REGISTRATION PROCEDURES.

             (a) If and whenever the Company is required by the provisions of
this Agreement to use its best efforts to effect the registration of any
Registrable Shares under the Securities Act, the Company shall:

                 (i) file with the Commission a Registration Statement with
respect to such Registrable Shares and use its best efforts to cause that
Registration Statement to become effective as soon as possible;

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                 (ii) as expeditiously as possible prepare and file with the
Commission any amendments and supplements to the Registration Statement and the
prospectus included in the Registration Statement as may be necessary to comply
with the provisions of the Securities Act (including the anti-fraud provisions
thereof) and to keep the Registration Statement effective for 12 months from the
effective date or such lesser period until all such Registrable Shares are sold;

                 (iii) as expeditiously as possible furnish to each Selling
Stockholder such reasonable number of copies of the Prospectus, including any
preliminary Prospectus, in conformity with the requirements of the Securities
Act, and such other documents as such Selling Stockholder may reasonably request
in order to facilitate the public sale or other disposition of the Registrable
Shares owned by such Selling Stockholder;

                 (iv) as expeditiously as possible use its best efforts to
register or qualify the Registrable Shares covered by the Registration Statement
under the securities or Blue Sky laws of such states as the Selling Stockholders
shall reasonably request, and do any and all other acts and things that may be
necessary or desirable to enable the Selling Stockholders to consummate the
public sale or other disposition in such states of the Registrable Shares owned
by the Selling Stockholder; PROVIDED, however that the Company shall not be
required in connection with this paragraph (iv) to qualify as a foreign
corporation or execute a general consent to service of process in any
jurisdiction;

                 (v) as expeditiously as possible, cause all such Registrable
Shares to be listed on each securities exchange or automated quotation system on
which similar securities issued by the Company are then listed;

                 (vi) promptly provide a transfer agent and registrar for all
such Registrable Shares not later than the effective date of such registration
statement;

                 (vii) promptly make available for inspection by the Selling
Stockholders, any managing underwriter participating in any disposition pursuant
to such Registration Statement, and any attorney or accountant or other agent
retained by any such underwriter or selected by the Selling Stockholders, all
financial and other records, pertinent corporate documents and properties of the
Company and cause the Company's officers, directors, employees and independent
accountants to supply all information reasonably requested by any such seller,
underwriter, attorney, accountant or agent in connection with such Registration
Statement;

                 (viii) as expeditiously as possible, notify each Selling
Stockholder, promptly after it shall receive notice thereof, of the time when
such Registration Statement has become effective or a supplement to any
Prospectus forming a part of such Registration Statement has been filed; and

                 (ix) as expeditiously as possible following the effectiveness
of such Registration Statement, notify each seller of such Registrable Shares of
any request by the Commission for the amending or supplementing of such
Registration Statement or Prospectus.

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                 (b) If the Company has delivered a Prospectus to the Selling
Stockholders and after having done so the Prospectus is amended to comply with
the requirements of the Securities Act, the Company shall promptly notify the
Selling Stockholders and, if requested, the Selling Stockholders shall
immediately cease making offers of Registrable Shares and return all
Prospectuses to the Company. The Company shall promptly provide the Selling
Stockholders with revised Prospectuses and, following receipt of the revised
Prospectuses, the Selling Stockholders shall be free to resume making offers of
the Registrable Shares.

                 (c) In the event that, in the judgment of the Company, it is
advisable to suspend use of a Prospectus included in a Registration Statement
due to pending material developments or other events that have not yet been
publicly disclosed and as to which the Company believes public disclosure would
be detrimental to the Company, the Company shall notify all Selling Stockholders
to such effect, and, upon receipt of such notice, each such Selling Stockholder
shall immediately discontinue any sales of Registrable Shares pursuant to such
Registration Statement until such Selling Stockholder has received copies of a
supplemented or amended Prospectus or until such Selling Stockholder is advised
in writing by the Company that the then current Prospectus may be used and has
received copies of any additional or supplemental filings that are incorporated
or deemed incorporated by reference in such Prospectus. Notwithstanding anything
to the contrary herein, the Company shall not exercise its rights under this
Section 2.3(c) to suspend sales of Registrable Shares for a period in excess of
60 days in any 365-day period.

         2.4 ALLOCATION OF EXPENSES. The Company will pay all Registration
Expenses for all registrations under this Agreement; PROVIDED, however that if a
registration under Section 2.1 is withdrawn at the request of the Initiating
Holder (other than as a result of information concerning the business or
financial condition of the Company which is made known to the Stockholders after
the date on which such registration was requested) and if the Initiating Holder
elects not to have such registration counted as a registration requested under
Section 2.1, the requesting Stockholders shall pay the Registration Expenses of
such registration pro rata in accordance with the number of their Registrable
Shares included in such registration. For purposes of this Section, the term
"Registration Expenses" shall mean all expenses incurred by the Company in
complying with this Agreement, including, without limitation, all registration
and filing fees, exchange listing fees, printing expenses, fees and expenses of
counsel for the Company and the fees and expenses of one counsel selected by the
Selling Stockholders to represent the Selling Stockholders, state Blue Sky fees
and expenses, and the expense of any special audits incident to or required by
any such registration, but excluding underwriting discounts, selling commissions
and the fees and expenses of Selling Stockholders' own counsel (other than the
counsel selected to represent all Selling Stockholders).

         2.5 INDEMNIFICATION AND CONTRIBUTION.

             (a) In the event of any registration of any of the Registrable
Shares under the Securities Act pursuant to this Agreement, the Company will
indemnify and hold harmless the seller of such Registrable Shares, each
underwriter of such Registrable Shares, and

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each other person, if any, who controls such seller or underwriter within the
meaning of the Securities Act or the Exchange Act against any losses, claims,
damages or liabilities, joint or several, to which such seller, underwriter or
controlling person may become subject under the Securities Act, the Exchange
Act, state securities or Blue Sky laws 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 any material
fact contained in any Registration Statement under which such Registrable Shares
were registered under the Securities Act, any preliminary prospectus or final
prospectus contained in the Registration Statement, or any amendment or
supplement to such Registration Statement, or arise out of or are based upon the
omission or alleged omission to state a material fact required to be stated
therein or necessary to make the statements therein not misleading; and the
Company will reimburse such seller, underwriter and each such controlling person
for any legal or other expenses reasonably incurred by such seller, underwriter
or controlling person in connection with investigating or defending any such
loss, claim, damage, liability or action; PROVIDED, however that 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 untrue statement or
omission made in such Registration Statement, preliminary prospectus or
prospectus, or any such amendment or supplement, in reliance upon and in
conformity with information furnished to the Company, in writing, by or on
behalf of such seller, underwriter or controlling person specifically for use in
the preparation thereof.

                 (b) In the event of any registration of any of the Registrable
Shares under the Securities Act pursuant to this Agreement, each seller of
Registrable Shares, severally and not jointly, will indemnify and hold harmless
the Company, each of its directors and officers and each underwriter (if any)
and each person, if any, who controls the Company or any such underwriter within
the meaning of the Securities Act or the Exchange Act, against any losses,
claims, damages or liabilities, joint or several, to which the Company, such
directors and officers, underwriter or controlling person may become subject
under the Securities Act, Exchange Act, state securities or Blue Sky laws 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 any Registration Statement
under which such Registrable Shares were registered under the Securities Act,
any preliminary prospectus or final prospectus contained in the Registration
Statement, or any amendment or supplement to the Registration Statement, or
arise out of or are based upon any omission or alleged omission to state a
material fact required to be stated therein or necessary to make the statements
therein not misleading, if the statement or omission was made in reliance upon
and in conformity with information relating to such seller furnished in writing
to the Company by or on behalf of such seller specifically for use in connection
with the preparation of such Registration Statement, prospectus, amendment or
supplement; PROVIDED, however, that the obligations of a Stockholder hereunder
shall be limited to an amount equal to the net proceeds to such Stockholder of
Registrable Shares sold in connection with such registration.

                 (c) Each party entitled to indemnification under this Section
(the "Indemnified Party") shall give notice to the party required to provide
indemnification (the "Indemnifying Party") promptly after such Indemnified Party
has actual knowledge of any claim as to which indemnity may be sought, and shall
permit the Indemnifying Party to assume

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the defense of any such claim or any litigation resulting therefrom; PROVIDED,
however that counsel for the Indemnifying Party, who shall conduct the defense
of such claim or litigation, shall be approved by the Indemnified Party (whose
approval shall not be unreasonably withheld); and, PROVIDED, further, that the
failure of any Indemnified Party to give notice as provided herein shall not
relieve the Indemnifying Party of its obligations under this Section except to
the extent that the Indemnifying Party is adversely affected by such failure.
The Indemnified Party may participate in such defense at such party's expense;
PROVIDED, however, that the Indemnifying Party shall pay such expense if
representation of such Indemnified Party by the counsel retained by the
Indemnifying Party would be inappropriate due to actual or potential differing
interests between the Indemnified Party and any other party represented by such
counsel in such proceeding; PROVIDED, further, that in no event shall the
Indemnifying Party be required to pay the expenses of more than one law firm per
jurisdiction as counsel for the Indemnified Party. The Indemnifying Party also
shall be responsible for the expenses of such defense if the Indemnifying Party
does not elect to assume such defense. No Indemnifying Party, in the defense of
any such claim or litigation shall, except with the consent of each Indemnified
Party, consent to entry of any judgment or enter into any settlement which does
not include as an unconditional term thereof the giving by the claimant or
plaintiff to such Indemnified Party of a release from all liability in respect
of such claim or litigation, and no Indemnified Party shall consent to entry of
any judgment or settle such claim or litigation without the prior written
consent of the Indemnifying Party, which consent shall not be unreasonably
withheld.

                 (d) In order to provide for just and equitable contribution in
circumstances in which the indemnification provided for in this Section 2.5 is
due in accordance with its terms but for any reason is held to be unavailable to
an Indemnified Party in respect to any losses, claims, damages and liabilities
referred to herein, then the Indemnifying Party shall, in lieu of indemnifying
such Indemnified Party, contribute to the amount paid or payable by such
Indemnified Party as a result of such losses, claims, damages or liabilities to
which such party may be subject in such proportion as is appropriate to reflect
the relative fault of the Company on the one hand and the Stockholders on the
other in connection with the statements or omissions which resulted in such
losses, claims, damages or liabilities, as well as any other relevant equitable
considerations. The relative fault of the Company and the Stockholders shall be
determined by reference to, among other things, whether the untrue or alleged
untrue statement of material fact related to information supplied by the Company
or the Stockholders and the parties' relative intent, knowledge, access to
information and opportunity to correct or prevent such statement or omission.
The Company and the Stockholders agree that it would not be just and equitable
if contribution pursuant to this Section 2.5 were determined by pro rata
allocation or by any other method of allocation which does not take account of
the equitable considerations referred to above. Notwithstanding the provisions
of this paragraph of Section 2.5, (a) in no case shall any one Stockholder be
liable or responsible for any amount in excess of the net proceeds received by
such Stockholder from the offering of Registrable Shares and (b) the Company
shall be liable and responsible for any amount in excess of such proceeds;
PROVIDED, however, that no person guilty of fraudulent misrepresentation (within
the meaning of Section 11(f) of the Securities Act) shall be entitled to
contribution from any person who was not guilty of such fraudulent
misrepresentation. Any party entitled to contribution will, promptly after
receipt of notice of commencement of any action, suit or proceeding against such
party in respect of which

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a claim for contribution may be made against another party or parties under this
Section, notify such party or parties from whom contribution may be sought, but
the omission so to notify such party or parties from whom contribution may be
sought shall not relieve such party from any other obligation it or they may
have thereunder or otherwise under this Section. No party shall be liable for
contribution with respect to any action, suit, proceeding or claim settled
without its prior written consent, which consent shall not be unreasonably
withheld.

         2.6 OTHER MATTERS WITH RESPECT TO UNDERWRITTEN OFFERINGS. In the event
that Registrable Shares are sold pursuant to a Registration Statement in an
underwritten offering pursuant to Section 2.1, the Company agrees to (a) enter
into an underwriting agreement containing customary representations and
warranties with respect to the business and operations of the Company and
customary covenants and agreements to be performed by the Company, including
without limitation customary provisions with respect to indemnification by the
Company of the underwriters of such offering; (b) use its best efforts to cause
its legal counsel to render customary opinions to the underwriters with respect
to the Registration Statement; and (c) use its best efforts to cause its
independent public accounting firm to issue customary "cold comfort letters" to
the underwriters with respect to the Registration Statement.

         2.7 INFORMATION BY HOLDER. Each holder of Registrable Shares included
in any registration shall furnish to the Company such information regarding such
holder and the distribution proposed by such holder as the Company may
reasonably request in writing and as shall be required in connection with any
registration, qualification or compliance referred to in this Agreement.

         2.8 CONFIDENTIALITY OF NOTICES. Any Stockholder receiving any written
notice from the Company regarding the Company's plans to file a Registration
Statement shall treat such notice confidentially and shall not disclose such
information to any person other than as necessary to exercise its rights under
this Agreement.

         2.9 RULE 144 REQUIREMENTS. The Company hereby agrees to:

             (a) make and keep current public information about the Company
available, as those terms are understood and defined in Rule 144;

             (b) file with the Commission in a timely manner all reports and
other documents required of the Company under the Securities Act and the
Exchange Act; and

             (c) furnish to any holder of Registrable Shares upon request (i) a
written statement by the Company as to its compliance with the reporting
requirements of Rule 144 and of the Securities Act and the Exchange Act, (ii) a
copy of the most recent annual or quarterly report of the Company, and (iii)
such other reports and documents of the Company as such holder may reasonably
request to avail itself of any similar rule or regulation of the Commission
allowing it to sell any such securities without registration.

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         2.10 TERMINATION. All of the Company's obligations to register
Registrable Shares under Sections 2.1 and 2.2 of this Agreement shall terminate
five (5) years after the date hereof.

     3. TRANSFERS OF RIGHTS. This Agreement, and the rights and obligations
of the Investor hereunder, may be assigned by the Investor to any person or
entity to which at least 25% of the Shares held by the Investor are transferred
by the Investor, PROVIDED, however, that for purposes of Section 2.1(a), any
such transferees, together with the transferring Investor, if such Investor
continues to hold any Registrable Securities, shall be counted as one Investor,
and any decision to demand a registration pursuant to Section 2.1(a) shall be
made by the holders of a majority of the Registrable Securities held by the
transferring Investor and such transferees.

     4. TERMINATION OF OBLIGATIONS AND RIGHTS OF EXELON. In consideration of
Exelon entering into the Exelon Registration Rights Agreement, the Original
Parties hereby agree to terminate Exelon's rights and obligations under this
Agreement.

     5. GENERAL.

             (a) SEVERABILITY. The invalidity or unenforceability of any
provision of this Agreement shall not affect the validity or enforceability of
any other provision of this Agreement.

             (b) SPECIFIC PERFORMANCE. In addition to any and all other remedies
that may be available at law in the event of any breach of this Agreement, the
Investor shall be entitled to specific performance of the agreements and
obligations of the Company hereunder and to such other injunctive or other
equitable relief as may be granted by a court of competent jurisdiction.

             (c) GOVERNING LAW. This Agreement shall be governed by and
construed in accordance with the internal laws of the Commonwealth of
Massachusetts (without reference to the conflicts of law provisions thereof).

             (d) NOTICES. All notices, requests, consents, and other
communications under this Agreement shall be in writing and shall be deemed
delivered (i) two Business Days after being sent by registered or certified
mail, return receipt requested, postage prepaid or (ii) one Business Day after
being sent via a reputable nationwide overnight courier service guaranteeing
next Business Day delivery, in each case to the intended recipient as set forth
below:

                  If to the Company, to:

                  NEON Communications, Inc.
                  2200 West Park Drive
                  Westborough, MA 01581
                  Attention: Stephen A. Bogiages, General Counsel
                  Facsimile:  (508) 616-7895

                                       11
<PAGE>

                  or at such other address or addresses as may have been
furnished in writing by the Company to the Investor;

                  with a copy to:

                  Paul, Hastings, Janofsky & Walker LLP
                  1055 Washington Boulevard
                  Stamford, CT  06901
                  Attention: Esteban A. Ferrer
                  Facsimile: (203) 359-3031

                  If to the Investor:

                  Consolidated Edison Communications, Inc.
                  132 West 31st Street 13th Floor
                  New York, NY 10001
                  Attention: President
                  Facsimile Number: (212) 324-5050

                  with a copy to:

                  Consolidated Edison, Inc.
                  4 Irving Place, Room 1800
                  New York, NY 10003
                  Attention: Senior Vice President and General Counsel
                  Facsimile Number: (212) 324-5001

                  or at such other addresses as may have been furnished in
writing by the Investor to the Company.

         Any party may give any notice, request, consent or other communication
under this Agreement using any other means (including, without limitation,
personal delivery, messenger service, telecopy, first class mail or electronic
mail), but no such notice, request, consent or other communication shall be
deemed to have been duly given unless and until it is actually received by the
party for whom it is intended. Any party may change the address to which
notices, requests, consents or other communications hereunder are to be
delivered by giving the other parties notice in the manner set forth in this
Section.

             (e) COMPLETE AGREEMENT. This Agreement constitutes the entire
agreement and understanding of the parties hereto with respect to the subject
matter hereof and supersedes all prior agreements and understandings relating to
such subject matter.

             (f) AMENDMENTS AND WAIVERS. Any term of this Agreement may be
amended or terminated and the observance of any term of this Agreement may be
waived (either generally or in a particular instance and either retroactively or
prospectively), with the written consent of the Company and the holders of at
least 51% of the Registrable Shares held by

                                       12
<PAGE>

all of the Stockholders; PROVIDED, that this Agreement may be amended with the
consent of the holders of less than all Registrable Shares only in a manner
which applies to all such holders in the same fashion. Any such amendment,
termination or waiver effected in accordance with this Section 4(f) shall be
binding on all parties hereto, even if they do not execute such consent. No
waivers of or exceptions to any term, condition or provision of this Agreement,
in any one or more instances, shall be deemed to be, or construed as, a further
or continuing waiver of any such term, condition or provision.

             (g) PRONOUNS. Whenever the context may require, any pronouns used
in this Agreement shall include the corresponding masculine, feminine or neuter
forms, and the singular form of nouns and pronouns shall include the plural, and
vice versa.

             (h) COUNTERPARTS; FACSIMILE SIGNATURES. This Agreement may be
executed in any number of counterparts, each of which shall be deemed to be an
original, and all of which together shall constitute one and the same document.
This Agreement may be executed by facsimile signatures.

             (i) SECTION HEADINGS. The section headings are for the convenience
of the parties and in no way alter, modify, amend, limit or restrict the
contractual obligations of the parties.

              [the remainder of this page intentionally left blank]

                                       13
<PAGE>

                  IN WITNESS WHEREOF, the undersigned have executed, or have
caused to be executed, this Agreement on the date first written above.

                              CONSOLIDATED EDISON COMMUNICATIONS, INC.

                              By: /s/ Peter Rust
                                  ---------------------------------------------
                                  Name: Peter Rust
                                  Title: President and Chief Executive Officer

                                  EXELON ENTERPRISES MANAGEMENT, INC.

                                  By: /s/ Robert A. Shinn
                                      -----------------------------------------
                                      Name: Robert A. Shinn
                                      Title: President

                                      NEON COMMUNICATIONS, INC.

                                      By: /s/ Stephen E. Courter
                                          -------------------------------------
                                          Name: Stephen E. Courter
                                          Title: Chief Executive Officer