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                                                                     Exhibit 4.2

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                         REGISTRATION RIGHTS AGREEMENT


                           13% Senior Notes due 2010


                           Dated as of March 24, 2000

                                  by and among


                           MGC COMMUNICATIONS, INC.,

                          MPOWER HOLDING CORPORATION,

                           BEAR, STEARNS & CO. INC.,

                             SALOMON SMITH BARNEY,

                             GOLDMAN, SACHS & CO.,

                              MERRILL LYNCH & CO.

                                      and

                            WARBURG DILLON READ LLC






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          This Registration Rights Agreement (this "Agreement") is made and
entered into as of March 24, 2000 by and among MGC Communications, Inc., Nevada
corporation (the "Company"), and Mpower Holding Corporation, a Delaware
Corporation (the "Co-Obligor"), and Bear, Stearns & Co. Inc., Salomon Smith
Barney Inc., Goldman, Sachs & Co., Merrill Lynch, Pierce, Fenner & Smith
Incorporated and Warburg Dillon Read LLC (each an "Initial Purchaser" and
together, the "Initial Purchasers"), each o whom have agreed to purchase the
Company's 13% Senior Notes due 2010 (the "Notes") pursuant to the Purchase
Agreement (as defined below).

          This Agreement is made pursuant to Purchase Agreement, dated March 17,
2000 (the "Purchase Agreement"), by and among the Company, the Co-Obligor and
the Initial Purchasers. In order to induce the Initial Purchasers to purchase
the Notes, the Company and the Co-Obligor have agreed to provide the
registration rights set forth in this Agreement. The execution and delivery of
this Agreement is a condition to the obligations of the Initial Purchasers set
forth in Section 8 of the Purchase Agreement.

          The parties hereby agree as follows:

     SECTION 1. DEFINITIONS

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

          Act: The Securities Act of 1993, as amended from time to time, and
the rules and regulations of the Commission promulgated thereunder.

          Broker-Dealer: Any broker or dealer registered under the Exchange Act.

          Broker-Dealer Transfer Restricted Securities: Exchange Notes that are
acquired by a Broker-Dealer in the Exchange Offer in exchange for Notes that
such Broker-Dealer acquired for its own account as a result of market making
activities or other trading activities (other than Notes acquired directly from
the Company or any of its affiliates).

          Business Day: Any day except a Saturday, Sunday or other day in
the City of New York, or in the city of the corporate trust office of the
Trustee, on which banks are authorized to close.

          Closing Date: The date hereof.

          Commission: The Securities and Exchange Commission.

          Consummate: An Exchange Offer shall be deemed "Consummated" for
purposes of this Agreement upon the occurrence of (a) the filing and
effectiveness under the Act of the Exchange Offer Registration Statement
relating to the Exchange Notes to be issued in the Exchange Offer, (b) the
maintenance of such Registration Statement continuously effective and the
keeping of the Exchange Offer open for a period not less than the minimum period
required pursuant to Section 3(b) hereof and (c) the delivery by the Company to
the Registrar under the Indenture of Exchange Notes in the Same aggregate
principal amount as the aggregate principal amount of Notes tendered by Holders
thereof pursuant to the Exchange Offer.

          Exchange Act: The Securities Exchange Act of 1934, as amended from
time to time, and the rules and regulations of the Commission promulgated
thereunder.

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          Exchange Notes: The Company's 13% Series B Senior Notes due 2010 to be
issued pursuant to the Indenture (i) in the Exchange Offer or (ii) upon the
request of any holder of Notes covered by a Shelf Registration Statement, in
exchange for such Notes.

          Exchange Offer: The registration by the Company under the Act of the
Exchange Notes pursuant to the Exchange offer Registration Statement pursuant to
which the Company shall offer the Holders of all outstanding Transfer Restricted
Securities the opportunity to exchange all such outstanding Transfer Restricted
Securities for Exchange Notes in an aggregate principal amount equal to the
aggregate principal amount of the Transfer Restricted Securities tendered in
such exchanged offer by such Holders.

          Exchange Offer Registration Statement: The Registration Statement
relating to the Exchange Offer, including the related Prospectus.

          Exempt Resales: The transactions in which the Initial Purchasers
propose to sell the Notes to certain ("Qualified institutional buyers") as such
term is defined in Rule 144A under the Act, or pursuant to offers and sales that
occur outside the United States to persons other than U.S. persons within the
meaning of Regulation S under the Act.

          Holders: As defined in Section 2 hereof.

          Indenture: The Indenture, dated the Closing Date, between the Company,
the Co-Obligor and HSBC Bank USA, as Trustee (the 'Trustee"), pursuant to which
the Senior Notes are to be issued, as such Indenture is amended or supplemented
from time to time in accordance with the terms thereof.

          Interest Payment Due: As defined in the Indenture and the Senior
Notes.

          NASD: National Association of Securities Dealers, Inc.

          Offering Memorandum: The final offering memorandum, dated March 17,
2000, relating to the Company and the Notes.

          Permitted Suspension: As defined in Section 4(a) hereof.

          Person: An individual, partnership, corporation, trust, unincorporated
organization, limited liability entity, or a government or agency or political
subdivision thereof.

          Preliminary Offering Memorandum: The preliminary offering memorandum,
dated March 10, 2000, relating to the Company and the Notes.

          Prospectus: The prospectus included in a Registration Statement at the
time such Registration Statement is declared effective, as amended or
supplemented by any prospectus supplement and by all other amendments thereto,
including post-effective amendments, and all material incorporated by reference
into such Prospectus.

          Registration Default: As defined in Section 5 hereof.


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          Registration Statement: Any registration statement of the Company and
the Co-Obligor relating to (a) an offering of Exchange Notes pursuant to an
Exchange Offer or (b) the registration for resale of Transfer Restricted
Securities pursuant to the Shelf Registration Statement, in each case,
(i) which is filed pursuant to the provisions of this Agreement and
(ii) including the Prospectus included therein, all amendments and supplements
thereto (including post-effective amendments) and all exhibits and material
incorporated by reference therein.

          Restricted Broker-Dealer: Any Broker-Dealer which holds Broker-Dealer
Transfer Restricted Securities.

          Senior Notes: The Notes and the Exchange Notes.

          Shelf Registration Statement: As defined in Section 4 hereof.

          TIA: The Trust Indenture Act of 1939 (15 U.S.C. Section 77aaa-77bbbb)
as in effect on the date of the Indenture.

          Transfer Restricted Securities: Each Note until the earliest to occur
of (i) the date on which such Note is exchanged by a person other than a
broker-dealer for an Exchange Note in the Exchange Offer, (ii) following the
exchange by a broker-dealer in the Exchange Offer of a Note for an Exchange
Note, the date on which such Exchange Note is sold to a purchaser who receives
from such broker-dealer on or prior to the date of such sale a copy of the
prospectus contained in the Exchange Offer Registration Statement, (iii) the
date on which such Note is effectively registered under the Securities Act and
disposed of in accordance with the Shelf Registration Statement or (iv) the
date on which such Note may be distributed to the public pursuant to Rule 144
under the Act.

          Underwritten Registration or Underwritten Offering: A registration in
which securities of the Company are sold to an underwriter for reoffering to
the public.

     SECTION 2.  HOLDERS

          A Person is deemed to be a holder of Transfer Restricted Securities
(each, a "Holder") whenever such Transfer Restricted Securities are registered
in such Person's name.

     SECTION 3.  REGISTERED EXCHANGE OFFER

          a) Unless the Exchange Offer shall be permitted by applicable federal
law (after the procedures set forth in Section 6(a)(1) below have been complied
with), the Company and the Co-Obligor shall (i) cause to be filed with the
Commission as soon as practicable after the Closing Date, but in no event later
than 90 days after the Closing Date, the Exchange Offer Registration Statement,
(ii) use its best efforts to cause such Exchange Offer Registration Statement
to become effective at the earliest possible time, but in no event later than
180 days after the Closing Date, (iii) in connection with the foregoing (A)
file all pre-effective amendments to such Exchange Offer Registration Statement
as may be necessary in order to cause such Exchange Offer Registration
Statement to become effective, (B) file, if applicable a post-effective
amendment to such Exchange Offer Registration Statement pursuant to Rule 430A
under the Act and (C) cause all necessary filings, if any, in connection with
the registration and qualification of the Exchange Notes to be made under the
Blue Sky laws of such jurisdictions as are necessary to permit


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Consummation of the Exchange Offer and (iv) upon the effectiveness of such
Exchange Offer Registration Statement, commence and Consummate the Exchange
Offer. The Exchange Offer shall be on the appropriate form permitted
registration of the Exchange Notes to be offered in exchange for the Notes that
are Transfer Restricted Securities and to permit sales of Broker-Dealer
Transfer Restricted Securities by Restricted Broker-Dealers as contemplated by
Section 3(c) below.

          b) The Company and the Co-Obligor shall cause the Exchange Offer
Registration Statement to be effective continuously, and shall keep the
Exchange Offer open, for a period of not less that the minimum period required
under applicable federal and state securities laws to Consummate the Exchange
Offer; provided, however, that in no event shall such period be less the 20
Business Days. The Company and the Co-Obligor shall cause the Exchange Offer to
comply with all applicable federal and state securities laws. No securities
other than the Senior Notes and any additional Notes which may be issued after
the date hereof under the Indenture shall be included in the Exchange Offer
Registration Statement. The Company and the Co-Obligor shall use their
respective best efforts to cause the Exchange Offer to be Consummated on the
earliest practicable date after the Exchange Offer Registration Statement has
become effective, but in no event later than 30 Business Days thereafter unless
required by applicable law.

          c) The Company shall include a "Plan of Distribution" section in the
Prospectus contained in the Exchange Offer Registration Statement and indicate
therein that any Restricted Broker-Dealer who holds Notes that are Transfer
Restricted Securities and that were acquired for the account of such
Broker-Dealer as a result of market-making activities or other trading
activities, may exchange such Notes (other than Transfer Restricted Securities
acquired directly from the Company) pursuant to the Exchange Offer; however,
such Broker-Dealer may be deemed to be an "underwriter" within the meaning of
the Act and must, therefore, deliver a prospectus meeting the requirements of
the Act in connection with its initial sale of each Exchange Note received by
such Broker-Dealer in the Exchange Offer, which prospectus delivery requirement
may be satisfied by the delivery by such Broker-Dealer of the Prospectus
contained in the Exchange Offer Registration Statement. Such "Plan of
Distribution" section shall also contain all other information with respect to
such sales of Broker-Dealer Transfer Restricted Securities by Restricted
Borker-Dealers that the Commission may require in order to permit such sales
pursuant thereto, but such "Plan of Distribution" shall not name any such
Broker-Dealer or disclose the amount of Notes held by any such Broker-Dealer
except to the extent required by the Commission as a result of a change in
policy after the date of this Agreement.

          The Company and the Co-Obligor shall use their respective best
efforts to keep the Exchange Offer Registration Statement continuously
effective, supplemented and amended as required by the provisions of Section
6(c) below to the extent necessary to ensure that it is available for sales of
Broker-Dealer Transfer Restricted Securities by Restricted Broker-Dealers, and
to ensure that such Registration Statement conforms with the requirements of
this Agreement, the Act and the policies, rules and regulations of the
Commission as announced from time to time, for a period expiring on the
earlier of (i) the date that all Broker-Dealer Transfer Restricted Securities
cease to be Transfer Restricted Securities and (ii) 365 days from the date on
which the Exchange Offer Registration Statement is declared effective provided,
that the Company and the Co-Obligor will have the option of suspending the
effectiveness of the Exchange Offer Registration Statement at any time after
the consummation of the Exchange Offer for periods of up to an aggregate of 60
days in any calendar year if the Board of Directors of the Company and the
Co-Obligor determine that (x) the compliance with the disclosure obligations
necessary to maintain the effectiveness of the Exchange Offer Registration
Statement at such time could

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reasonably be expected to have a material adverse effect on the Company, the
Co-Obligor or a pending corporate transaction of the Company or the
Co-Obligor or (y) as a result of the occurrence of a corporate transaction it
is necessary to amend the Exchange Offer Registration Statement so that such
Registration Statement does not include any untrue statement of 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 (an
"Exchange Registration Permitted Suspension").

          The Company and the Co-Obligor shall promptly provide sufficient
copies of the latest version of such Prospectus to such Restricted
Broker-Dealers upon request at any time during such 365-day period in order to
facilitate such sales.

     SECTION 4. SHELF REGISTRATION

          a) Shelf Registration. If (i) the Company and the Co-Obligor are not
required to file the Exchange Offer Registration Statement with respect to the
Senior Notes or permitted to consummate the Exchange Offer because the Exchange
Offer is not permitted by applicable law or Commission policy (after the
procedures set forth in Section 6(a)(i) below have been complied with) or (ii)
any Holder of Transfer Restricted Securities notifies the Company within 20
Business Days following the Consummation of the Exchange Offer that (A) such
Holder is prohibited by law or Commission policy from participating in the
Exchange Offer or (B) such Holder may not resell the Exchange Notes acquired by
it in the Exchange Offer to the public without delivering a prospectus and the
Prospectus contained in the Exchange Offer Registration Statement is not
appropriate or available for such resales by such Holder or (C) such Holder is a
Broker-Dealer and holds Senior Notes acquired directly from the Company or an
affiliate of the Company, then the Company and the Co-Obligor shall:

               (x) cause to be filed on or prior to (1) in the case of
     Registration Statement filed pursuant to clause (i) above, 30 days after
     the date on which the Company and the Co-Obligor determine that they are
     not required to filed the Exchange Offer Registration Statement and in any
     event, within 150 days after the Closing Date and (2) in the case of a
     Registration Statement filed pursuant to clause (ii) above, 30 days after
     the date on which the Company receives the notice specified in clause (ii)
     above, a shelf registration statement pursuant to Rule 415 under the Act,
     (which may be an amendment to the Exchange Offer Registration Statement (in
     either event, the "Shelf Registration Statement")), relating to all
     Transfer Restricted Securities the Holders of which shall have provided the
     information required pursuant to Section 4(b) hereof, and

               (y) use their best efforts to cause such Shelf Registration
     Statement to become effective on or prior to (1) in the case of a
     Registration Statement filed pursuant to clause (i) above, 90 days after
     the date on which the Company and the Co-Obligor become obligated to file
     such Shelf Registration Statement (and in any event, within 240 days after
     the Closing Date), and (2) in the case of a Registration Statement filed
     pursuant to clause (ii) above, 90 days after the date on which the Company
     receives the notice specified in clause (ii) above. If, after the Company
     and the Co-Obligor have filed an Exchange Offer Registration Statement
     which satisfies the requirements of Section 3(a) above, the Company and the
     Co-Obligor are required to file and make effective a Shelf Registration
     Statement solely because the Exchange Offer is not permitted under
     applicable federal law, then the filing of the Exchange Offer Registration
     Statement shall be deemed to satisfy the requirements of clause (x) above.
     Such an event shall have no effect on the requirements of this clause (y),
     or on the Effectiveness Target Date as defined in Section 5 below.


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The Company and the Co-Obligor shall use their respective best efforts to keep
the Shelf Registration Statement referred to in this Section 4(a) continuously
effective, supplemented and amended as required by the provisions of Sections
6(b) and (c) hereof to the extent necessary to ensure that it is available for
sales of Transfer Restricted Securities by the Holders thereof entitled to the
benefit of this Section 4(a), and to ensure that it conforms with the
requirements of this Agreement, the Act and the policies, rules and regulations
of the Commission as announced from time to time, for a period expiring on the
earlier of (i) the date that all Holders of Transfer Restricted Securities have
sold such securities and (ii) 365 days from the date on which the Shelf
Registration Statement is declared effective provided, that the Company and the
Co-Obligor will have the option of suspending the effectiveness of the Shelf
Registration Statement for periods of up to an aggregate of 60 days in any
calendar year if the Board of Directors of the Company and the Co-Obligor
determine that (x) the compliance with the disclosure obligations necessary to
maintain the effectiveness of the Shelf Registration Statement at such time
could reasonably be expected to have a material adverse effect on the Company,
the Co-Obligor or a pending corporate transaction of the Company or the
Co-Obligor or (y) as a result of the occurrence of a corporate transaction it
is necessary to amend the Shelf Registration Statement so that such
Registration Statement does not include any untrue statement of 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 (an "Shelf
Registration Permitted Suspension" and, together with an Exchange Registration
Permitted Suspension, a "Permitted Suspension").

          (b) Provision by Holders of Certain Information in Connection with
the Shelf Registration Statement. No Holder of Transfer Restricted Securities
may include any of its Transfer Restricted Securities in any Shelf Registration
Statement pursuant to this Agreement unless and until such Holder furnishes to
the Company in writing, within 20 Business Days after receipt of a request
therefor, such information specified in item 507 of Regulation S-K under the
Act for use in connection with any Shelf Registration Statement or Prospectus
or preliminary Prospectus included therein. No Holder of Transfer Restricted
Securities shall be entitled to Liquidated Damages pursuant to Section 5 hereof
unless and until such Holder shall have provided all such information required
to be provided by such Holder for inclusion therein. Each Holder as to which
any Shelf Registration Statement is being effected agrees to furnish promptly
to the Company, for so long as the Registration Statement is effective, all
information required to be disclosed in order to make the information
previously furnished to the Company by such Holder not materially misleading.

     SECTION 5. LIQUIDATED DAMAGES

          If (i) the Company and the Co-Obligor fail to file any of the
Registration Statements required by this Agreement on or before the latest date
specified for such filing in this Agreement, (ii) any of such Registration
Statements is not declared effective by the Commission on or prior to the
latest date specified for such Effectiveness (the "Effectiveness Target Date").
(iii) the Company and the Co-Obligor fail to Consummate the Exchange Offer
within 30 Business Days of the effectiveness Target Date with respect to the
Exchange Offer Registration Statement or (iv) the Shelf Registration Statement
or the Exchange Offer Registration Statement is declared effective but
thereafter ceases to be effective or usable in connection with resales of
Transfer Restricted Securities during the periods specified in this Agreement
without being succeeded promptly by a post-effective amendment to such
Registration Statement that cures such failure and that is itself declared
effective within five Business Days of the date the Registration Statement
ceased to be effective or usable in connection with such resales provided that
such effectiveness

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was not suspended in connection with a Permitted Suspension (each such event
referred to in clauses (i) through (iv) above, a "Registration Default"), then
commencing on the day following the date on which such Registration Default
occurs, the Company and the Co-Obligor, jointly and severally, agree to pay to
each Holder of Transfer Restricted Securities, for the first 90-day period
immediately following the occurrence of such Registration Default, liquidated
damages in an amount equal to $.05 per week per $1,000 principal amount of Notes
constituting Transfer Restricted Securities held by such Holder for each week or
pro rata for a portion of each week thereof that the Registration Default
continues. The amount of liquidated damages payable to each Holder shall
increase by an additional $.05 per week per $1,000 principal amount of Notes
constituting Transfer Restricted Securities held by such Holder for each
subsequent 90-day period until all Registration Defaults have been cured, up to
a maximum of $.50 per week per $1,000 principal amount of Notes constituting
Transfer Restricted Securities held by such Holder provided, in no event shall
the Company and the Co-Obligor be required to pay liquidated damages on any
Transfer Restricted Security for more than one Registration Default at any given
time. Notwithstanding anything to the contrary set forth herein, (i) upon the
filing of the Exchange Offer Registration Statement (or, if applicable, the
Shelf Registration Statement), after a Registration Default of the type
specified in clause (i) above, (2) upon the effectiveness of the Exchange Offer
Registration Statement (or, if applicable, the Shelf Registration Statement),
after a Registration Default of the type specified in clause (ii) above, (3)
upon Consummation of the Exchange Offer, after a Registration Default of the
type specified in clause (iii) above, or (4) upon the filing of a post-effective
amendment to the Registration Statement or an additional Registration Statement
that causes the Exchange Offer Registration Statement (or, if applicable, the
Shelf Registration Statement) again to be declared effective or made usable
after a Registration Default of the type specified in clause (iv) above, the
liquidated damages payable with respect to the Transfer Restricted Securities as
a result of such clause (i), (ii), (iii) or (iv), as applicable, shall cease.

          All accrued liquidated damages shall be paid by the Company and the
Co-Obligor to Cede & Co., as nominee of the Depository Trust Company (the
"Global Security Holder") by wire transfer of immediately available funds or by
federal funds check and to Holders of Definitive Securities by mailing checks to
their registered addresses by the Company or the Co-Obligor on each Interest
Payment Date. All obligations of the Company and the Co-Obligor set forth in the
preceding paragraph that are outstanding with respect to any Transfer Restricted
Security at the time such security ceases to be a Transfer Restricted Security
shall survive until such time as all such obligations with respect to such
security shall have been satisfied in full.

     SECTION 6. REGISTRATION PROCEDURES

          a) Exchange Offer Registration Statement. In connection with the
Exchange Offer, the Company and the Co-Obligor shall comply with all applicable
provisions of Section 6(c) below, shall use their respective best efforts to
effect such exchange and to permit the sale of Broker-Dealer Transfer Restricted
Securities being sold in accordance with the intended method or methods of
distribution thereof, and shall comply with all of the following provisions:

               (i) If, following the date hereof there has been published a
     change in Commission policy with respect to exchange offers such as the
     Exchange Offer, such that in the reasonable opinion of counsel to the
     Company and the Co-Obligor there is a substantial question as to whether
     the Exchange Offer is permitted by applicable federal law, the Company and
     the Co-Obligor hereby agree to seek a no-action letter or other favorable
     decision from the Commission allowing the Company and the Co-Obligor to
     Consummate an Exchange Offer for such Notes. The


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     Company and the Co-Obligor hereby agree to pursue the issuance of such a
     decision to the Commission staff level. In connection with the foregoing,
     the Company and the Co-Obligor hereby agree to take such other actions as
     are requested by the Commission or otherwise required in connection with
     the issuance of such decision, including without limitation (A)
     participating in telephonic conferences with the Commission, (B) delivering
     to the Commission staff an analysis prepared by counsel to the Company and
     the Co-Obligor setting forth the legal bases, if any, upon which such
     counsel has concluded that such an Exchange Offer should be permitted and
     (C) diligently pursuing a resolution by the Commission staff of such
     submission.

          (ii) As a condition to its participation in the Exchange Offer
pursuant to the terms of this Agreement, each Holder of Transfer Restricted
Securities shall furnish, upon the request of the Company or the Co-Obligor,
prior to the Consummation of the Exchange Offer, a written representation to the
Company and the Co-Obligor (which may be contained in the letter of transmittal
contemplated by the Exchange Offer Registration Statement) to the effect that
(A) it is not an affiliate of the Company or the Co-Obligor, (B) it is not
engaged in, and does not intend to engage in, and has no arrangement or
understanding with any person to participate in, a distribution of the Exchange
Notes to be issued in the Exchange Offer and (C) it is acquiring the Exchange
Notes in its ordinary course of business. As a condition to its participation in
the Exchange Offer pursuant to the terms of this Agreement, each Holder shall
acknowledge and agree that any Broker-Dealer and any such Holder using the
Exchange Offer to participate in a distribution of the securities to be acquired
in the Exchange Offer (1) could not under Commission policy as in effect on the
date of this Agreement rely on the position of the Commission enunciated in
Morgan Stanley and Co., Inc. (available June 5, 1991) and Exxon Capital Holdings
Corporation (available May 13, 1988), as interpreted in the Commission's letter
to Shearman & Sterling dated July 2, 1993, and similar no-action letters
(including, if applicable, any no-action letter obtained pursuant to clause (i)
above), and (2) must comply with the registration and prospectus delivery
requirements of the Act in connection with a secondary resale transaction and
that such a secondary resale transaction must be converted by an effective
registration statement containing the selling security holder information
required by Item 507 or 508, as applicable, of Regulation S-K if the resales are
of Exchange Notes obtained by such Holder in exchange for Notes acquired by such
Holder directly from the Company and the Co-Obligor.

          (b) Shelf Registration Statement. In connection with the Shelf
Registration Statement each of the Company and the Co-Obligor shall comply with
all the provisions of Section 6(c) below and shall use its best efforts to
effect such registration to permit the sale of the Transfer Restricted
Securities being sold in accordance with the intended method or methods of
distribution thereof (as indicated in the information furnished to the Company
pursuant to Section 4(b) hereof), and pursuant thereto the Company and the
Co-Obligor will prepare and file with the Commission a Registration Statement
relating to the registration on any appropriate form under the Act, which form
shall be available for the sale of the Transfer Restricted Securities in
accordance with the intended method or methods of distribution thereof within
the time periods and otherwise in accordance with the provisions hereof.

          (c) General Provisions. In connection with any Registration Statement
and any related Prospectus required by this Agreement to permit the sale or
resale of Transfer Restricted Securities (including, without limitation, any
Exchange Offer Registration Statement and the related Prospectus, to the extent
that the same are required to be available to permit sale of Broker-Dealer
Transfer Restricted Securities by Restricted Broker-Dealers), the Company and
the Co-Obligor shall:





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          (i) subject to a Permitted Suspension, use their respective best
efforts to keep such Registration Statement continuously effective and provide
all requisite financial statements for the period specified in Section 3 or 4 of
this Agreement, as applicable. Upon the occurrence of any event that would cause
any such Registration Statement or the Prospectus contained therein (A) to
contain a material misstatement or omission or (B) not to be effective and
usable for resale of Transfer Restricted Securities during the period required
by this Agreement, the Company and the Co-Obligor shall file promptly an
appropriate amendment to such Registration Statement, (1) in the case of clause
(A), correcting any such misstatement or omission, and (2) in the case of either
clause (A) or (B), use their respective best efforts to cause such amendment to
be declared effective and such Registration Statement and the related Prospectus
to become usable for their intended purpose(s) as soon as practicable
thereafter;

          (ii) except in the event of a Permitted Suspension, prepare and file
with the Commission such amendments and post-effective amendments to the
Registration Statement as may be necessary to keep the Registration Statement
effective for the applicable period set forth in Section 3 or 4 hereof, or such
shorter period as will terminate when all Transfer Restricted Securities covered
by such Registration Statement have been sold; cause the Prospectus to be
supplemented by any required Prospectus supplement, and as so supplemented to be
filed pursuant to Rule 424 under the Act, and to comply fully with Rules 424 and
430A, as applicable, under the Act in a timely manner: and comply with the
provisions of the Act with respect to the disposition of all securities covered
by such Registration Statement during the applicable period in accordance with
the intended method or methods of distribution by the sellers thereof set forth
in such Registration Statement or supplement to the Prospectus;

          (iii) advise the underwriters, if any and selling Holders promptly
and, if requested by such Persons, confirm such advice in writing, (A) when the
Prospectus or any Prospectus supplement or post-effective amendment has been
filed, and, with respect to any Registration Statement or any post-effective
amendment thereto, when the same has become effective, (B) of any request by the
Commission for amendments to the Registration Statement or amendments or
supplements to the Prospectus or for additional information relating thereto,
(C) of the issuance by the Commission of any stop order suspending the
effectiveness of the Registration Statement under the Act or of the suspension
by any state securities commission of the qualification of the Transfer
Restricted Securities for offering or sale in any jurisdiction, or the
initiation of any proceeding for any of the preceding purposes, (D) of the
existence of any fact or the happening of any event that makes any statement of
a material fact made in the Registration Statement, the Prospectus, any
amendment or supplement thereto or any document incorporated by reference
therein untrue, or that requires the making of any additions to or changes in
the Registration Statement in order to make the statements therein not
misleading, or that requires the making of any additions to or changes in the
Prospectus in order to make the statements therein, in the light of the
circumstances under which they were made, not misleading. If at any time the
Commission shall issue any stop order suspending the effectiveness of the
Registration Statement, or any state securities commission or other regulatory
authority shall issue an order suspending the qualification or exemption form
qualification of the Transfer Restricted Securities under state securities or
Blue Sky laws, the Company and the Co-Obligor shall use their respective best
efforts to obtain the withdrawal or lifting of such order at the earliest
possible time;


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                 (iv) make available to each selling Holder named in any
         Registration Statement or Prospectus and each of the underwriters in
         connection with such sale, if any, before filing with the Commission,
         copies of any Registration Statement or any Prospectus included therein
         or any amendments or supplements to any such Registration Statement or
         Prospectus (including all documents incorporated by reference after the
         initial filing of such Registration Statement), substantially in the
         form proposed to be filed, which documents will be subject to the
         review and comment of such Holders and underwriters in connection with
         such sale, if any, for a period of at least five Business Days, and the
         Company and the Co-Obligor will not file any such Registration
         Statement or Prospectus or any amendment or supplement to any such
         Registration Statement or Prospectus (including all such documents
         incorporated by reference) to which the selling Holders of the Transfer
         Restricted Securities covered by such Registration Statement or the
         underwriters in connection with such sale, if any, shall reasonably
         object within five Business Days after the receipt thereof. A selling
         Holder or underwriter, if any, shall be deemed to have reasonably
         objected to such filing if such Registration Statement, amendment,
         Prospectus or supplement, as applicable, as proposed to be filed,
         contains a material misstatement or omission or fails to comply with
         the applicable requirements of the Act;

                 (v) promptly upon the filing of any document that is to be
         incorporated by reference into a Registration Statement or Prospectus,
         make available copies of such document to the selling Holders and to
         the underwriter(s) in connection with such sale, if any, make the
         Company's and the Co-Obligor's representatives available for discussion
         of such document and other customary due diligence matters, and include
         such information in such document prior to the filing thereof as such
         selling Holders or underwriter(s), if any, reasonably may request;

                 (vi) make available at reasonable times for inspection by the
         selling Holders, any underwriter participating in any disposition
         pursuant to such Registration Statement and any attorney or accountant
         retained by such selling Holders or any of such underwriters, all
         financial and other records, pertinent corporate documents and
         properties of the Company and the Co-Obligor and cause the Company's
         and the Co-Obligor's officers, directors and employees to supply all
         information reasonably requested by any such Holder, underwriter,
         attorney or accountant in connection with such Registration Statement
         or any post-effective amendment thereto subsequent to the filing
         thereof and prior to its effectiveness; provided that any person to
         whom information is provided under this clause (vi) agrees in writing
         to maintain the confidentiality of such information to the extent such
         information is not in the public domain;

                 (vii) if requested by any selling Holders or the underwriters
         in connection with such sale, if any, promptly include in any
         Registration Statement or Prospectus, pursuant to a supplement or
         post-effective amendment if necessary, such information as such selling
         Holders and underwriter(s), if any, may reasonably request to have
         included therein, including, without limitation, information relating
         to the "Plan of Distribution" of the Transfer Restricted Securities,
         information with respect to the principal amount of Transfer Restricted
         Securities being sold to such underwriters, the purchase price being
         paid therefor and any other terms of the offering of the Transfer
         Restricted Securities to be sold in such offering; and make all
         required filings of such Prospectus supplement or post-effective
         amendment as soon as practicable after the Company is notified of the
         matters to be included in such Prospectus supplement or post-effective
         amendment;

                                       10
<PAGE>   12
                 (viii) cause the Transfer Restricted Securities covered by the
         Registration Statement to be rated with the appropriate rating
         agencies, if so requested by the Holders of a majority in aggregate
         principal amount of Senior Notes covered thereby or the underwriters,
         if any;

                 (ix) furnish to each selling Holder and each of the
         underwriters in connection with such sale, if any, without charge, at
         least one copy of the Registration Statement, as first filed with the
         Commission, and of each amendment thereto, and make available all
         documents incorporated by reference therein and all exhibits (including
         exhibits incorporated therein by reference);

                 (x) deliver to each selling Holder and each of the
         underwriters, if any, without charge, as many copies of the Prospectus
         (and each preliminary prospectus) and any amendment or supplement
         thereto as such Persons reasonably may request; the Company and the
         Co-Obligor hereby consent to the use of the Prospectus and any
         amendment or supplement thereto by each of the selling Holders and each
         of the underwriters, if any, in connection with the offering and the
         sale of the Transfer Restricted Securities covered by the Prospectus or
         any amendment or supplement thereto;

                 (xi) enter into such agreements (including, unless not
         required pursuant to Section 10 hereof, an underwriting agreement) and
         make such representations and warranties and take all such other
         actions in connection therewith in order to expedite or facilitate the
         disposition of the Transfer Restricted Securities pursuant to any
         Registration Statement contemplated by this Agreement as may be
         reasonably requested by any Holder of Transfer Restricted Securities or
         underwriter in connection with any sale or resale pursuant to any
         Registration Statement contemplated by this Agreement, and in such
         connection, whether or not an underwriting agreement is entered into
         and whether or not the registration is an Underwritten Registration,
         the Company and the Co-Obligor shall upon request of any underwriter or
         any such Holder who is a Broker-Dealer or who may be deemed to be an
         underwriter:

                         (A) furnish to each such selling Holder and each
               underwriter, if any, upon the effectiveness of the Shelf
               Registration Statement and to each Restricted Broker-Dealer upon
               consummation of the Exchange Offer:

                 (1) (A) a certificate, signed by (x) the President or any Vice
                 President and (y) a principal financial or accounting officer
                 of the Company, and (B) a certificate signed by (x) the
                 President or any Vice President and a principal financial or
                 accounting officer of the Co-Obligor, each dated the date of
                 effectiveness of the Shelf Registration Statement or the date
                 of Consummation of the Exchange Offer, as the case may be,
                 confirming with respect to the Prospectus or any purchase or
                 underwriting agreement and the Transfer Restricted Securities,
                 as of the date thereof, the matters set forth in paragraphs
                 (a), (b), (c) and (d) of Section 8 of the Purchase Agreement
                 and such other matters as the Holders and/or underwriter(s) may
                 reasonably request;

                 (2) an opinion, dated the date of effectiveness of the Shelf
                 Registration Statement or the date of Consummation of the
                 Exchange Offer, as the case may be, of counsel for the Company
                 and the Co-Obligor, covering (i) due authorization and
                 enforceability of the Notes and the Exchange Notes, (ii) a
                 statement to the effect

                                       11
<PAGE>   13
                 that such counsel has participated in conferences with officers
                 and other representatives of the Company and the Co-Obligor and
                 representatives of the independent public accountants for the
                 Company and the Co-Obligor and have considered the matters
                 required to be stated therein and the statements contained
                 therein, although such counsel has not independently verified
                 the accuracy completeness or fairness of such statements; and
                 that such counsel advises that, on the basis of the foregoing
                 (relying as to materiality to a large extent upon facts
                 provided to such counsel by officers and other representatives
                 of the Company and the Co-Obligor and without independent check
                 or verification), no facts came to such counsel's attention
                 that caused such counsel to believe that the applicable
                 Registration Statement, at the time such Registration Statement
                 or any post-effective amendment thereto became effective, and,
                 in the case of the Exchange Offer Registration Statement, as of
                 the date of Consummation, contained an untrue statement of a
                 material fact or omitted to state a material fact required to
                 be stated therein or necessary to make the statements therein
                 not misleading, or that the Prospectus contained in such
                 Registration Statement as of its date and, in the case of the
                 opinion dated the date of Consummation of the Exchange Offer,
                 as of the date of Consummation, contained an untrue statement
                 of a material fact or omitted 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
                 and (iii) such other matters of the type customarily covered in
                 opinions of counsel for an issuer in connection with similar
                 securities offerings, as may reasonably be requested by such
                 parties. Without limiting the foregoing, such counsel may state
                 further that such counsel assumes no responsibility for, and
                 has not independently verified, the accuracy, completeness or
                 fairness of the financial statements, notes and schedules and
                 other financial, statistical and accounting data included in
                 any Registration Statement contemplated by this Agreement or
                 the related Prospectus; and

                 (3) if the registration is a registration in which securities
                 of the Company and the Co-Obligor are sold to an underwriter
                 for reoffering to the public, obtain a customary comfort
                 letter, dated as of the date of effectiveness of the Shelf
                 Registration Statement, addressed to the Board of Directors of
                 the Company and the Co-Obligor or any underwriter from the
                 Company's and the Co-Obligor's independent accountants, in the
                 customary form and covering manners of the type customarily
                 covered in comfort letters to boards of directors in
                 underwritten offerings;

                         (B) set forth in full in or incorporate by reference
          in the underwriting agreement, if any, in connection with any sale or
          resale pursuant to any Shelf Registration Statement the
          indemnification provisions and procedures of Section 8 hereof with
          respect to all parties to be indemnified pursuant to said Section; and

                         (C) deliver such other documents and certificates as
          may be reasonably requested by such parties to evidence compliance
          with clause (A) above and with any customary conditions contained in
          the underwriting agreement or other agreement entered into by the
          Company and the Co-Obligor pursuant to this clause (xi),if any.

                                       12





<PAGE>   14
         The above shall be done at each closing under such underwriting or
similar agreement, as and to the extent required thereunder, and if at any time
the representations and warranties of the Company and the Co-Obligor
contemplated in (A)(1) above cease to be true and correct, the Company and the
Co-Obligor shall so advise the underwriters, if any, and such selling Holders
promptly and if requested by such Persons, shall confirm such advice in writing;

                 (xii) prior to any public offering of Transfer Restricted
         Securities, cooperate with the selling Holders, the underwriters, if
         any, and their respective counsel in connection with the registration
         and qualification of the Transfer Restricted Securities under the
         securities or Blue Sky laws of such jurisdictions as the selling
         Holders or underwriters, if any, may request and do any and all other
         acts or things necessary or advisable to enable the disposition in such
         jurisdictions of the Transfer Restricted Securities covered by the
         applicable Registration Statement; provided, however, that neither the
         Company nor the Co-Obligor shall be required to register or qualify as
         a foreign corporation where it is not now so qualified or to take any
         action that would subject it to the service of process in suits or to
         taxation, other than as to matters and transactions relating to the
         Registration Statement, in any jurisdiction where it is not now so
         subject;

                 (xiii) issue, upon the request of any Holder of Notes covered
         by any Shelf Registration Statement contemplated by this Agreement.
         Exchange Notes having an aggregate principal amount equal to the
         aggregate principal amount of Notes surrendered to the Company or the
         Co-Obligor by such Holder in exchange therefor or being sold by such
         Holder; such Exchange Notes to be registered in the name of such Holder
         or in the name of the purchasers of such Exchange Notes; in return, the
         Notes held by such Holder shall be surrendered to the Company or the
         Co-Obligor for cancellation;

                 (xiv) in connection with any sale of Transfer Restricted
         Securities that will result in such securities no longer being Transfer
         Restricted Securities, cooperate with the selling Holders and the
         underwriters, if any, to facilitate the timely preparation and delivery
         of certificates representing Transfer Restricted Securities to be sold
         and not bearing any restrictive legends; and to register such Transfer
         Restricted Securities in such denominations and such names as the
         Holders or the underwriters, if any, may request at least two Business
         Days prior to such sale of Transfer Restricted Securities;

                 (xv) use their respective best efforts to cause the Transfer
         Restricted Securities covered by the Registration Statement to be
         registered with or approved by such other governmental agencies or
         authorities as may be necessary to enable the seller or sellers thereof
         or the underwriters, if any, to consummate the disposition of such
         Transfer Restricted Securities, subject to the proviso contained in
         clause (xii) above;

                 (xvi) if any fact or event contemplated by Section 6(c)(iii)(D)
         above shall exist or have occurred, except in the event of a Permitted
         Suspension, prepare a supplement or post-effective amendment to the
         Registration Statement or related Prospectus or any document
         incorporated therein by reference or file any other required document
         so that, as thereafter delivered to the purchasers of Transfer
         Restricted Securities, the Prospectus will not contain an 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;

                                       13
<PAGE>   15
                 (xvii) provide a CUSIP number for all Senior Notes not later
         than the effective date of a Registration Statement covering such
         Transfer Restricted Securities and provide the Trustee under the
         Indenture with printed certificates for the Senior Notes which are in a
         form eligible for deposit with the Depository Trust Company;

                 (xviii) cooperate and assist in any filings required to be
         made with the NASD and in the performance of any due diligence
         investigation by any underwriter (including any "qualified independent
         underwriter") that is required to be retained in accordance with the
         rules and regulations of the NASD, and use its best efforts to cause
         such Registration Statement to become effective and approved by such
         governmental agencies or authorities as may be necessary to enable the
         Holders selling Transfer Restricted Securities to consummate the
         disposition of such Transfer Restricted Securities;

                 (xix) otherwise use their respective best efforts to comply
         with all applicable rules and regulations of the Commission, and make
         generally available to its security holders with regard to any
         applicable Registration Statement, as soon as practicable, a
         consolidated earnings statement meeting the requirements of Rule 158
         (which need not be audited) covering a twelve-month period beginning
         after the effective date of the Registration Statement (as such term is
         defined in paragraph (c) of Rule 158 under the Act);

                 (xx) cause the Indenture to be qualified under the TIA not
         later than the effective date of the first Registration Statement
         required by this Agreement, and, in connection therewith, cooperate
         with the Trustee and the Holders of Senior Notes to effect such changes
         to the Indenture as may be required for such Indenture to be so
         qualified in accordance with the terms of the TIA; and execute and use
         their respective best efforts to cause the Trustee to execute, all
         documents that may be required to effect such changes and all other
         forms and documents required to be filed with the Commission to enable
         such Indenture to be so qualified in a timely manner;

                 (xxi) cause all Transfer Restricted Securities covered by the
         Registration Statement to be listed on each securities exchange on
         which similar securities issued by the Company are then listed if
         requested by the Holders of a majority in aggregate principal amount of
         Notes or the managing underwriters, if any; and

                 (xxii) provide promptly to each Holder upon written request
         each document filed with the Commission pursuant to the requirements of
         Section 13 or Section 15(d) of the Exchange Act.

         (d) Restrictions on Holders. Each Holder agrees by acquisition of a
Transfer Restricted Security that, upon receipt of any notice from the Company
or the Co-Obligor of the existence of any fact of the kind described in Section
6(c)(iii)(D) hereof, such Holder will forthwith discontinue disposition of
Transfer Restricted Securities pursuant to the applicable Registration Statement
until such Holder's receipt of the copies of the supplemented or amended
Prospectus contemplated by Section 6(c)(xvi) hereof, or until it is advised in
writing (the "Advice") by the Company or the Co-Obligor that the use of the
Prospectus may be resumed, and has received copies of any additional or
supplemental filings that are incorporated by reference in the Prospectus. If
so directed by the Company or the Co-Obligor, each Holder will deliver to the
Company or the Co-Obligor (at the Company's or the Co-Obligor's expense) all
copies, other than

                                       14
<PAGE>   16
permanent file copies then in such Holder's possession, of the Prospectus
covering such Transfer Restricted Securities that was current at the time of
receipt of such notice. In the event the Company or the Co-Obligor shall give
any such notice, the time period regarding the effectiveness of such
Registration Statement set forth in Section 3 or 4 hereof, as applicable, shall
be extended by the number of days during the period from and including the date
of the giving of such notice pursuant to Section 6(c)(iii)(D) hereof to and
including the date when each selling Holder covered by such Registration
Statement shall have received the copies of the supplemented or amended
Prospectus contemplated by Section 6(c)(xvi) hereof or shall have received the
Advice.

       Section 7.   Registration Expenses

         (a) All expenses incident to the Company's and the Co-Obligor's
performance of or compliance with this Agreement will be borne by the Company
and the Co-Obligor, jointly and severally, regardless of whether a Registration
Statement becomes effective, including without limitation: (i) all registration
and filing fees and expenses (including filings made with the NASD (including,
if applicable, the fees and expenses of any "qualified independent underwriter"
and its counsel, as may be required by the rules and regulations of the NASD));
(ii) all fees and expenses of compliance with federal securities and state Blue
Sky or securities laws; (iii) all expenses of printing (including printing
certificates for the Senior Notes and printing of Prospectuses), messenger and
delivery services and telephone; (iv) all fees and disbursements of counsel for
the Company and the Co-Obligor and, in accordance with Section 7(b) below, the
Holders of Transfer Restricted Securities; (v) all application and filing fees
in connection with listing the Senior Notes on a national exchange or automated
quotation system if required hereunder; and (vi) all fees and disbursements of
independent certified public accountants of the Company and the Co-Obligor
(including the expenses of any special audit and comfort letters required by or
incident to such performance).

         The Company and the Co-Obligor will, in any event, bear their
respective internal expenses (including, without limitation, all salaries and
expenses of its officers and employees performing legal or accounting duties),
the expenses of any annual audit and the fees and expenses of any Person,
including special experts, retained by the Company and the Co-Obligor.

         (b) In connection with any Registration Statement required by this
Agreement, the Company and the Co-Obligor will reimburse the Holders of Transfer
Restricted Securities being tendered in the Exchange Offer and/or resold
pursuant to the "Plan of Distribution" contained in the Exchange Offer
Registration Statement or registered pursuant to the Shelf Registration
Statement, as applicable, for the reasonable fees and disbursements of not more
than one counsel chosen by the Holders of a majority in principal amount of the
Transfer Restricted Securities for whose benefit such Registration Statement is
being prepared.

       Section 8.   Indemnification

         (a) The Company and the Co-Obligor agree, jointly and severally, to
indemnify and hold harmless (i) each Holder, (ii) each Person, if any, who
controls a Holder within the meaning of Section 15 of the Act or Section 20(a)
of the Exchange Act and (iii) the respective officers, directors, partners,
employees, representatives and agents of any Holder or any controlling person to
the fullest extent lawful, from and against any and all losses, liabilities,
claims, damages and expenses whatsoever (including but not limited to attorneys'
fees and any and all expenses whatsoever incurred in investigating, preparing or

                                       15
<PAGE>   17
defending against any investigation or litigation, commenced or threatened, or
any claim whatsoever, and any and all amounts paid in settlement of any claim or
litigation), joint or several, to which they or any of them may become subject
under the Act, the Exchange Act or otherwise, insofar as such losses,
liabilities, claims, damages or expenses (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 or the Prospectus, or in
any supplement thereto or amendment thereof, 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; provided, however,
that the Company and the Co-Obligor will not be liable in any such case to the
extent, but only to the extent, that (i) any such loss, liability, claim, damage
or expense arises out of or is based upon any such untrue statement or alleged
untrue statements 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 such Holder expressly for use therein and (ii) the foregoing indemnity
with respect to any untrue statement contained in or omitted from a Registration
Statement or the Prospectus shall not inure to the benefit of any Holder (or any
person controlling such Holder), from whom the person asserting any such loss,
liability, claim, damage or expense purchased any of the Senior Notes which are
the subject thereof if it is finally judicially determined that such loss,
liability, claim, damage or expense resulted solely from the fact that the
Holder sold Senior Notes to a person to whom there was not sent or given, at or
prior to the written confirmation of such sale, a copy of the Registration
Statement or the Prospectus, as amended or supplemented, and (x) the Company and
the Co-Obligor shall have previously and timely furnished sufficient copies of
the Registration Statement or Prospectus, as so amended or supplemented, to such
Holder in accordance with this Agreement and (y) the Registration Statement or
Prospectus, as so amended or supplemented, would have corrected such untrue
statement or omission of a material fact. This indemnity agreement will be in
addition to any liability which the Company or the Co-Obligor may otherwise
have, including, under this Agreement.

         (b) Each Holder, severally and not jointly, agrees to indemnify and
hold harmless the Company and the Co-Obligor, each Person, if any, who controls
the Company or the Co-Obligor within the meaning of Section 15 of the Act or
Section 20(a) of the Exchange Act and the respective officers, directors,
partners, employees, representatives and agents of the Company and the
Co-Obligor, against any losses, liabilities, claims, damages and expenses
whatsoever (including but not limited to attorneys' fees and any and all
expenses whatsoever incurred in investigating, preparing or defending against
any investigation or litigation, commenced or threatened, or any claim
whatsoever and any and all amounts paid in settlement of any claim or
litigation), joint or several, to which they or any of them may become subject
under the Act, the Exchange Act or otherwise, insofar as such losses,
liabilities, claims, damages or expenses (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 or the 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, in each case to the
extent, but only to the extent, that any such loss, liability, claim, damage or
expense arises out of or is based upon any 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
such Holder expressly for use therein. This indemnity will be in addition to any
liability which a Holder may otherwise have, including under this Agreement. In
no event, however, shall the liability of any selling Holder hereunder be
greater in amount than the dollar amount of the proceeds received by such Holder
upon its sale of the Senior Notes giving rise to such indemnification
obligation.

                                       16
<PAGE>   18
         (c) Promptly after receipt by an indemnified party under subsection (a)
or (b) above of notice of the commencement of any action, such indemnified party
shall, if a claim in respect thereof is to be made against the indemnifying
party under such subsection, notify each party against whom indemnification is
to be sought in writing of the commencement thereof (but the failure so to
notify an indemnifying party shall not relieve it from any liability which it
may have under this Section 8 except to the extent that it has been prejudiced
in any material respect by such failure or from any liability which it may
otherwise have). In case any such action is brought against any indemnified
party, and it notifies an indemnifying party of the commencement thereof, the
indemnifying party will be entitled to participate therein, and to the extent it
may elect by written notice delivered to the indemnified party promptly after
receiving the aforesaid notice from such indemnified party, to assume the
defense thereof with counsel reasonably satisfactory to such indemnified party.
Notwithstanding the foregoing, the indemnified party or parties shall have the
right to employ its or their own counsel in any such case, but the fees and
expenses of such counsel shall be at the expense of such indemnified party or
parties unless (i) the employment of such counsel shall have been authorized in
writing by the indemnifying parties in connection with the defense of such
action, (ii) the indemnifying parties shall not have employed counsel to take
charge of the defense of such action within a reasonable time after notice of
commencement of the action, or (iii) such indemnified party or parties shall
have reasonably concluded that there may be defenses available to it or them
which are different from or additional to those available to one or all of the
indemnifying parties (in which case the indemnifying party or parties shall not
have the right to direct the defense of such action on behalf of the indemnified
party or parties), in any of which events such fees and expenses of counsel
shall be borne by the indemnifying parties; provided, however, that the
indemnifying party under subsection (a) or (b) above, shall only be liable for
the legal expenses of one counsel (in addition to any local counsel) for all
indemnified parties in each jurisdiction in which any claim or action is
brought. Anything in this subsection to the contrary notwithstanding, an
indemnifying party shall not be liable for any settlement of any claim or action
effected without its prior written consent, provided, however, that such consent
was not unreasonably withheld.

         (d) In order to provide for contribution in circumstances in which the
indemnification provided for in this Section 8 is for any reason held to be
unavailable from the Company or the Co-Obligor or is insufficient to hold
harmless a party indemnified thereunder, the Company, the Co-Obligor and each
Holder shall contribute to the aggregate losses, claims, damages, liabilities
and expenses of the nature contemplated by such indemnification provision
(including any investigation, legal and other expenses incurred in connection
with, and any amount paid in settlement of, any action, suit or proceeding or
any claims asserted, but after deducting in the case of losses, claims, damages,
liabilities and expenses suffered by the Company or the Co-Obligor, any
contribution received by the Company or the Co-Obligor from persons, other than
the Holders, who may also be liable for contribution, including persons who
control the Company or the Co-Obligor within the meaning of Section 15 of the
Act or Section 20(a) of the Exchange Act) to which the Company, the Co-Obligor
and any Holder may be subject, in such proportion as is appropriate to reflect
the relative benefits received by the Company and the Co-Obligor from the
offering of Senior Notes on the one hand and any such Holder from its sale of
Senior Notes on the other hand or,if such allocation is not permitted by
applicable law or indemnification is not available as a result of the
indemnifying party not having received notice as provided in this Section 8, in
such proportion as is appropriate to reflect not only the relative benefits
referred to above but also the relative fault of the Company and the Co-Obligor
on the one hand and the Holders on the other hand in connection with the
statements or omissions which resulted in such losses, claims, damages,
liabilities or expenses, as well as any other relevant equitable considerations.
The relative benefits received by the Company and the Co-

                                       17



<PAGE>   19
Obligor on the one hand and any Holder on the other hand shall be deemed to be
in the same proportion as (x) the total proceeds from the offering of the Senior
Notes (net of discounts but before deducting expenses) received by the Company
and the Co-Obligor and (y) the total proceeds received by such Holder upon its
sale of Senior Notes which would otherwise give rise to the indemnification
obligation less any amount paid by such Holder to acquire the Senior Notes so
sold, respectively. The relative fault of the Company and the Co-Obligor on the
one hand and of the Holders on the other hand shall be determined by reference
to, among other things, whether the untrue or alleged untrue statement of a
material fact or the omission or alleged omission to state a material fact
relates to information supplied by the Company and the Co-Obligor or the Holders
and the parties' relative intent, knowledge, access to information and
opportunity to correct or prevent such statement or omission. The Company, the
Co-Obligor and each Holder agree that it would not be just and equitable if
contribution pursuant to this Section 8 were determined by pro rata allocation
or by any other method of allocation which does not take into account the
equitable considerations referred to above. Notwithstanding the provisions of
this Section 8, (i) no Holder shall be required to contribute, in the aggregate,
any amount in excess of the amount by which the total received by such Holder
with respect to the sale of its Senior Notes exceeds the sum of (A) the amount
paid by such Holder for such Senior Notes plus (B) the amount of any damages
which such Holder has otherwise been required to pay by reason of such untrue or
alleged untrue statement or omission or alleged omission and (ii) 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, (A) each
Person, if any, who controls a Holder within the meaning of Section 15 of the
Act or Section 20(a) of the Exchange Act and (B) the respective officers,
directors, partners, employees, representatives and agents of a Holder or any
controlling person shall have the same rights to contribution as such Holder,
and (X) each Person, if any, who controls the Company or the Co-Obligor within
the meaning of Section 15 of the Act or Section 20(a) of the Exchange Act and
(Y) the respective officers, directors, partners, employees, representatives and
agents of the Company and the Co-Obligor shall have the same rights to
contribution as the Company and the Co-Obligor, subject in each case to clauses
(i) and (ii) of this Section 8(d). 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 a claim for contribution may
be made against another party or parties under this Section 8, notify such party
or parties from whom contribution may be sought, but the failure to so notify
such party or parties shall not relieve the party or parties from whom
contribution may be sought from any obligation it or they may have under this
Section 8 or otherwise. No party shall be liable for contribution with respect
to any action or claim settled without its prior written consent; provided,
however, that such written consent was not unreasonably withheld.

       Section 9.   Rule 144A

         The Company and the Co-Obligor hereby agree with each Holder, for so
long as any Transfer Restricted Securities remain outstanding, to make
available, upon request of any Holder of Transfer Restricted Securities, to any
Holder or beneficial owner of Transfer Restricted Securities in connection with
any sale thereof and any prospective purchaser of such Transfer Restricted
Securities designated by such Holder or beneficial owner, the information
required by Rule 144A(d)(4) under the Act in order to permit resales of such
Transfer Restricted Securities pursuant to Rule 144A.

       Section 10.   Underwritten Registrations

                                       18
<PAGE>   20
         In the event a Shelf Registration Statement is required to be filed by
the Company and the Co-Obligor, the Holders of Transfer Restricted Securities
included or required to be included in such Shelf Registration Statement may
elect to sell their Transfer Restricted Securities pursuant to one or more
Underwritten Registrations; provided, however, that in no event shall any such
Underwritten Registration be commenced if a period of less than 180 days has
elapsed since the consummation of the most recent Underwritten Registration
hereunder; and provided further that in no event shall the Holders effect more
than three such Underwritten Registrations hereunder. No Holder may participate
in any Underwritten Registration hereunder unless such Holder (a) agrees to sell
such Holder's Transfer Restricted Securities on the basis provided in customary
underwriting arrangements entered into in connection therewith and (b) completes
and executes all reasonable questionnaires, powers of attorney, indemnities,
underwriting agreements, lock-up letters and other documents required under the
terms of such underwriting arrangements.

       Section 11.   Selection of Underwriters

         In any Underwritten Offering, the investment banker or investment
bankers and manager or managers that will administer the offering will be
selected by the Holders of a majority in aggregate principal amount of the
Transfer Restricted Securities included in such offering; provided, that such
investment bankers and managers must be reasonably satisfactory to the Company
and the Co-Obligor. Such investment bankers and managers are referred to herein
as the "underwriters."

       Section 12.   Miscellaneous

         (a) Remedies. Each Holder, in addition to being entitled to exercise
all rights provided herein, in the Indenture, the Purchase Agreement or granted
by law, including recovery of liquidated or other damages, will be entitled to
specific performance of its rights under this Agreement. The Company and the
Co-Obligor agree that monetary damages (including the liquidated damages
contemplated hereby) would not be adequate compensation for any loss incurred by
reason of a breach by it of the provisions of this Agreement and hereby agrees
to waive the defense in any action for specific performance that a remedy at law
would be adequate.

         (b) No Inconsistent Agreements. Each of the Company and the Co-Obligor
will not on or after the date of this Agreement enter into any agreement with
respect to its respective securities that conflicts with the rights granted to
the Holders in this Agreement or otherwise conflicts with the provisions hereof.
The rights granted to the Holders hereunder do not in any way conflict with and
are not inconsistent with the rights granted to the holders of the Company's or
the Co-Obligor's securities under any agreement in effect on the date hereof,
except where a waiver with respect thereto has been obtained prior to the date
of effectiveness of any registration statement required under this Agreement.

         (c) Adjustments Affecting the Senior Notes. Neither the Company nor the
Co-Obligor will take any action, or permit any change to occur, with respect to
the Senior Notes that would materially adversely affect the ability of the
Holders to Consummate any Exchange Offer.

         (d) Amendments and Waivers. The provisions of this Agreement may not be
amended, modified or supplemented, and waivers or consents to or departures from
the provisions hereof may not be given unless the Company and the Co-Obligor
have obtained the written consent of Holders of a majority of the outstanding
principal amount of Transfer Restricted Securities, and the consent of the

                                       19
<PAGE>   21
Holders of a majority of the outstanding principal amount of Registrable
Securities shall be binding on every Holder of Registrable Securities.
Notwithstanding the foregoing, a waiver or consent to departure from the
provisions hereof that relates exclusively to the rights of Holders whose
securities are being tendered pursuant to the Exchange Offer and that does not
affect directly or indirectly the rights of other Holders whose securities are
not being tendered pursuant to such Exchange Offer may be given by the Holders
of a majority of the outstanding principal amount of Transfer Restricted
Securities that are subject to such Exchange Offer.

         (e) Notices. All notices and other communications provided for or
permitted hereunder shall be made in writing by hand-delivery, first-class mail
(registered or certified, return receipt requested), telex, telecopier, or air
courier guaranteeing overnight delivery:

                 (i) if to a Holder, at the address set forth on the records of
         the Registrar under the Indenture, with a copy to the Registrar under
         the Indenture; and

                 (ii) if to the Company or the Co-Obligor:

                      MGC Communications, Inc.
                      171 Sully's Trail Suite 202
                      Pittsford, New York 14534
                      Telecopier No.: (716) 218-6550
                      Attention: General Counsel

                      With a copy to:

                      Shearman & Sterling
                      599 Lexington Avenue
                      New York, New York 10022
                      Telecopier No.: (212) 848-7179
                      Attention: Andrew Jansky, Esq.

       All such notices and communications shall be deemed to have been duly
given at the time delivered by hand, if personally delivered; five Business Days
after being deposited in the mail, postage prepaid, if mailed; when answered
back, if telexed; when receipt acknowledged, if telecopied; and on the next
business day, if timely delivered to an air courier guaranteeing overnight
delivery.

       Copies of all such notices, demands or other communications shall be
concurrently delivered by the Person giving the same to the Trustee at the
address specified in the Indenture.

         (f) Successors and Assigns. This Agreement shall inure to the benefit
of and be binding upon the successors and assigns of each of the parties,
including without limitation and without the need for an express assignment,
subsequent Holders of Transfer Restricted Securities; provided, however, that
this Agreement shall not inure to the benefit of or be binding upon a successor
or assign of a Holder unless and to the extent such successor or assign acquired
Transfer Restricted Securities directly from such Holder.

                                       20
<PAGE>   22
         (g) Counterparts. This Agreement may be executed in any number of
counterparts and by the parties hereto in separate counterparts, each of which
when so executed shall be deemed to be an original and all of which taken
together shall constitute one and the same agreement.

         (h) Headings. The headings in this Agreement are for convenience of
reference only and shall not limit or otherwise affect the meaning hereof.

         (i) Governing Law. THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK, WITHOUT REGARD TO THE
CONFLICT OF LAW RULES THEREOF.

         (j) Severability. In the event that any one or more of the provisions
contained herein, or the application thereof in any circumstance, is held
invalid, illegal or unenforceable, the validity, legality and enforceability of
any such provision in every other respect and of the remaining provisions
contained herein shall not be affected or impaired thereby.

         (k) Entire Agreement. This Agreement together with the other Operative
Documents (as defined in the Purchase Agreement) is intended by the parties as a
final expression of their agreement and intended to be a complete and exclusive
statement of the agreement and understanding of the parties hereto in respect of
the subject mater contained herein. There are no restrictions, promises,
warranties or undertakings, other than those set forth or referred to herein
with respect to the registration rights granted by the Company and the
Co-Obligor with respect to the Transfer Restricted Securities. This Agreement
supersedes all prior agreements and understandings between the parties with
respect to such subject matter.

         (l) Release. Notwithstanding anything to the contrary in this
agreement, provided that no Registration Default has occurred and is continuing,
upon the occurrence of a Release (as defined in the Indenture dated as of March
24, 2000 by and among the Company, the Co-Obligor and the Trustee named
therein), the Company shall be discharged from its obligations under this
agreement as of the date of the Release.

                            [Signature Page Follows]

                                       21
<PAGE>   23
IN WITNESS WHEREOF, the parties have executed this Registration Rights
Agreement as of the date first written above.



                                            MGC COMMUNICATIONS, INC.


                                            By:             [SIG]
                                               --------------------------------
                                            Name:
                                            Title:



                                            MPOWER HOLDING CORPORATION


                                            By:             [SIG]
                                               --------------------------------
                                            Name:
                                            Title:



BEAR, STEARNS & CO. INC.


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



SALOMON SMITH BARNEY INC.


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



GOLDMAN, SACHS & CO.


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



MERRILL LYNCH, PIERCE, FENNER
& SMITH INCORPORATED


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

<PAGE>   24
IN WITNESS WHEREOF, the parties have executed this Registration Rights
Agreement as of the date first written above.



                                            MGC COMMUNICATIONS, INC.


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



                                            MPOWER HOLDING CORPORATION


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



BEAR, STEARNS & CO. INC.


By:              [SIG]
   -------------------------------------
   Name:
   Title: Senior Managing Director



SALOMON SMITH BARNEY INC.


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



GOLDMAN, SACHS & CO.


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



MERRILL LYNCH, PIERCE, FENNER
& SMITH INCORPORATED


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

<PAGE>   25
IN WITNESS WHEREOF, the parties have executed this Registration Rights
Agreement as of the date first written above.



                                            MGC COMMUNICATIONS, INC.


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



                                            MPOWER HOLDING CORPORATION


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



BEAR, STEARNS & CO. INC.


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



SALOMON SMITH BARNEY INC.


By:                [SIG]
   -------------------------------------
   Name:  Lea V. Medow
   Title: Vice President



GOLDMAN, SACHS & CO.


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



MERRILL LYNCH, PIERCE, FENNER
& SMITH INCORPORATED


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

<PAGE>   26
IN WITNESS WHEREOF, the parties have executed this Registration Rights
Agreement as of the date first written above.



                                            MGC COMMUNICATIONS, INC.


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



                                            MPOWER HOLDING CORPORATION


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



BEAR, STEARNS & CO. INC.


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



SALOMON SMITH BARNEY INC.


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



GOLDMAN, SACHS & CO.


By:        [SIG]
   -------------------------------------
   Name:
   Title:



MERRILL LYNCH, PIERCE, FENNER
& SMITH INCORPORATED


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

<PAGE>   27
IN WITNESS WHEREOF, the parties have executed this Registration Rights
Agreement as of the date first written above.



                                            MGC COMMUNICATIONS, INC.


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



                                            MPOWER HOLDING CORPORATION


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



BEAR, STEARNS & CO. INC.


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



SALOMON SMITH BARNEY INC.


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



GOLDMAN, SACHS & CO.


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



MERRILL LYNCH, PIERCE, FENNER
& SMITH INCORPORATED


By:                [SIG]
   -------------------------------------
   Name:  [ILLEGIBLE]
   Title: Vice President

<PAGE>   28




   Name:
   Title



WARBURG DILLON READ LLC


By:             [SIG]
   -------------------------------------
   Name:  Vincent Lu
   Title: Executive Director


By:             [SIG]
   -------------------------------------
   Name:  P. Whitridge Williams
   Title: Associate Director