Exhibit 10.1


         FORM OF REGISTRATION RIGHTS AND TRANSFER RESTRICTION AGREEMENT

     This AGREEMENT (this  "Agreement"),  dated as of [         ],  2006,  among
Level 3  Communications,  Inc.,  a Delaware  corporation  ("Company"),  MCCC ICG
Holdings LLC, a Delaware limited liability Company ("Seller"),  Columbia Capital
Equity Partners III (QP), L.P., a Delaware limited partnership ("Columbia III"),
Columbia  Capital Equity Partners III (Cayman),  L.P., a Cayman Islands exempted
limited partnership  ("Columbia  Cayman"),  Columbia Capital Equity Partners III
(AI), L.P., a Delaware  limited  partnership  ("Columbia AI"),  Columbia Capital
Equity Investors III, L.L.C., a Delaware limited  liability  company  ("Columbia
LLC"),  Columbia  Capital  Employees  Investors III,  L.L.C., a Delaware limited
liability  company  ("Columbia  Employees"),  M/C Venture  Partners  V, L.P.,  a
Delaware  limited  partnership  ("M/C V"),  M/C  Venture  Investors,  L.L.C.,  a
Delaware limited liability company ("M/C LLC"), Chestnut Venture Partners, L.P.,
a Delaware  limited  partnership  ("Chestnut")  and Bear  Investments,  LLLP,  a
Colorado  limited  liability  limited  partnership  ("Bear"  and  together  with
Columbia III, Columbia Cayman,  Columbia AI, Columbia LLC,  Columbia  Employees,
M/C V, M/C LLC and Chestnut, the "Seller Owners")

                              W I T N E S S E T H:

     WHEREAS,  Company and Seller are parties to a Purchase Agreement,  dated as
of April 2006 (the "Purchase Agreement"), pursuant to which Company will acquire
from the Seller all of the issued and outstanding  shares of common stock of ICG
Communications, Inc., a Delaware corporation (the "Acquisition");

     WHEREAS,  in  connection  with the  Acquisition,  Seller  will  receive  an
aggregate of [ ] shares (such shares,  the "Shares") of common stock,  par value
$.01 per share of Company  ("Company Common Stock"),  including [ ] shares to be
held in escrow pursuant to the Escrow Agreement;

     WHEREAS,  the  Seller  Owners,  directly  or  indirectly,  own  all  of the
outstanding capital stock of the Seller;

     WHEREAS,  it is a condition to consummation of the Acquisition that Company
enter  into this  Agreement  providing  for the  registration  of the  shares of
Company Common Stock to be received by Seller in the Acquisition; and

     WHEREAS,  the  Company  is  willing  to  prepare  and  file a  registration
statement under the Securities Act of 1933, as amended (the  "Securities  Act"),
with the  Securities  and  Exchange  Commission  (the "SEC") with respect to the
Shares and to maintain the  effectiveness of such registration  statement,  upon
the terms and subject to the conditions set forth herein;

     NOW  THEREFORE,  in  consideration  of the  foregoing  and  the  respective
covenants and  agreements  hereinafter  contained,  the parties  hereby agree as
follows:

     SECTION 1. Definitions.  All terms used in this Agreement which are defined
in the  Purchase  Agreement  shall have the  meanings  specified in the Purchase
Agreement unless the context otherwise requires.




     SECTION 2. Registration of the Shares.

     2.1 Shelf Registration  Statement.  As soon as reasonably practicable after
the date hereof and in any event within five (5)  business  days  following  the
consummation of the Acquisition, the Company shall prepare and file with the SEC
a shelf  registration  statement,  relating  to the offer and sale by Seller and
Seller Owners at any time and from time to time on a delayed or continuous basis
in accordance with Rule 415 under the Securities Act and in accordance with this
Agreement, of all the Shares (the "Registration Statement").  If, at the time of
filing of the Registration Statement,  the Registration Statement is eligible to
become  effective  upon filing  pursuant to Rule 462(e) (or any successor  rule)
under the Securities Act, the Company shall file the  Registration  Statement as
an  automatic  shelf  registration  statement  pursuant  to  such  rule.  If the
Registration  Statement is not so eligible to become effective upon filing,  the
Company shall use its reasonable best efforts to have the Registration Statement
declared  effective  as  promptly  as  practicable  (with such date on which the
Registration  Statement becomes effective  referred to as the "Effective Date").
Promptly (i) upon the filing  thereof in the case of an automatic  shelf or (ii)
upon  receipt  of an  order  of the SEC  declaring  the  Registration  Statement
effective,  the  Company  shall  deliver to Seller and any of the Seller  Owners
included in the Registration Statement a copy of such Registration Statement and
any  amendments  thereto  together with an opinion of counsel  representing  the
Company for the purposes of such Registration,  in form and substance reasonably
acceptable to Seller and the Seller  Owners,  addressed to Seller and the Seller
Owners,  including,  confirming that the Registration Statement is effective and
that all of the Shares have been duly  registered  and,  subject to the transfer
restrictions  contained in this Agreement,  are freely transferable and that all
of the shares have been admitted for listing on the NASDAQ Stock Market.

     2.2  Adjustment.  If at any time the  Shares  as a class  shall  have  been
increased,  decreased, changed into or exchanged for a different number or class
of  shares or  securities  as a result  of a  reorganization,  recapitalization,
reclassification,  stock dividend, stock split, reverse stock split, combination
or  exchange  of  shares or other  similar  change  in  capitalization,  then an
appropriate and  proportionate  adjustment shall be made to the number of Shares
for all purposes under this Agreement.

     SECTION 3. Maintenance of Registration Statement and Prospectuses.

     3.1 The  Company  shall  use  its  reasonable  best  efforts  to  keep  the
Registration  Statement  and the  prospectus  contained  therein  (as amended or
supplemented  from time to time,  the  "Prospectuses"  and each a  "Prospectus")
continuously  effective  until the Termination  Date (as defined below).  In the
event the Registration  Statement cannot be kept effective for such period,  the
Company shall use its  reasonable  best efforts to prepare and file with the SEC
and have  declared  effective as promptly as  practicable  another  registration
statement on the same terms and conditions as the initial Registration Statement
and such registration  statement shall be considered the Registration  Statement
for purposes  hereof.  The Company shall furnish to Seller and the Seller Owners
such number of copies of a Prospectus in conformity with the requirements of the
Act, and an electronic  copy of the Prospectus to facilitate the  disposition of
the Shares owned by Seller and the Seller Owners.

                                      -2-


     3.2 The  Company  shall  advise  Seller and the Seller  Owners  promptly in
writing  when  the  Registration  Statement,  or  any  post-effective  amendment
thereto, has been declared effective by the SEC. The Company shall advise Seller
and the Seller Owners in writing of the receipt by the Company of any stop order
from the SEC suspending the effectiveness of the Registration Statement,  and if
at any time there  shall be a stop order  suspending  the  effectiveness  of the
Registration  Statement,  the Company shall use its  reasonable  best efforts to
obtain  promptly the  withdrawal of such order.  The Company shall advise Seller
and the Seller  Owners  promptly in writing of the existence of any fact and the
happening of any event that makes any  statement of a material  fact made in the
Registration  Statement or Prospectus untrue, or that requires the making of any
additions to or changes in the Registration  Statement or Prospectus in order to
make the  statements  therein not misleading and in such event the Company shall
prepare and file with the SEC, as soon as reasonably  practicable,  an amendment
to such Registration  Statement or an amendment or supplement to such Prospectus
so that, as so amended or  supplemented,  such  Registration  Statement and such
Prospectus  will not contain an untrue  statement of a material  fact or omit to
state a material  fact  required to be stated  therein or  necessary to make the
statements therein, in light of the circumstances then existing, not misleading.
Upon receipt of such written advice,  each of Seller and the Seller Owners shall
discontinue and refrain from making any sales of Shares,  until such time as the
Company advises Seller and the Seller Owners that such Registration Statement or
such Prospectus no longer contains an untrue statement or omission of a material
fact.

     3.3 Each of Seller and the Seller  Owners shall furnish to the Company such
information  regarding  such  party and the  distribution  of the  Shares as the
Company may from time to time  reasonably  request in writing in order to comply
with the  Securities  Act. Each of Seller and the Seller Owners shall notify the
Company as promptly as  practicable  of any  inaccuracy or change in information
previously  furnished  by such party to the Company or of the  happening  of any
event  in  either  case as a result  of which  any  Prospectus  relating  to the
Registration Statement contains an untrue statement of a material fact regarding
such party or the  distribution  of such Shares,  or omits to state any material
fact  regarding  such party or the  distribution  of such Shares  required to be
stated  therein or necessary to make the  statements  therein not  misleading in
light of the circumstances then existing, and to furnish promptly to the Company
any  additional  information  required  to  correct  or  update  any  previously
furnished  information  or required so that such  Prospectus  shall not contain,
with  respect  to such  party  or the  distribution  of such  Shares  an  untrue
statement  of a material  fact or omit to state a material  fact  required to be
stated  therein or necessary to make the  statements  therein not  misleading in
light of the circumstances then existing.

     3.4 Notwithstanding anything to the contrary contained herein, for a period
not to  exceed  forty-five  (45)  consecutive  calendar  days and not to  exceed
seventy (70) aggregate  calendar days in any twelve-month  period (each a "Black
Out  Period"),  the  Company  will  not be  required  to file  any  registration
statement pursuant to this Agreement,  file any amendment  thereto,  furnish any
supplement to a prospectus included in a registration statement pursuant to this
Agreement,  make  any  other  filing  with  the SEC  required  pursuant  to this
Agreement,  cause any  registration  statement  or other  filing with the SEC to
become effective, or take any similar action, and any and all sales of Shares by
Seller and the Seller  Owners  pursuant to an effective  registration  statement
shall be  suspended:  (i) if an event has occurred and is continuing as a result
of which any such  registration  statement or prospectus would, in the Company's
good faith

                                      -3-


judgment,  contain an untrue  statement  of a  material  fact or omit to state a
material fact required to be stated  therein or necessary to make the statements
therein  not  misleading,  (ii) if the  Company  notifies  Seller and the Seller
Owners that such actions would,  in the Company's good faith  judgment,  require
the disclosure of material  non-public  information which the Board of Directors
of the Company has determined  would be seriously  detrimental to the Company to
disclose  and which the Company  would not  otherwise be required to disclose or
(iii)  if the  Company  notifies  Seller  and the  Seller  Owners  that,  in the
Company's  good faith  judgment,  it is necessary to suspend  sales of Shares by
Seller and the Seller Owners, to facilitate a pending or proposed public or Rule
144A offering by the Company of Company Common Stock or Common Stock Equivalents
(as defined below),  provided,  however, that any such suspension of sales shall
be  not  longer  than  twenty-one  (21)  consecutive  calendar  days.  Upon  the
termination of the condition  described in clauses (i), (ii) or (iii) above, the
Company shall  promptly give written  notice to Seller and the Seller Owners and
shall promptly file any registration  statement or amendment thereto required to
be filed by it pursuant to this Agreement,  furnish any prospectus supplement or
amendment  required to be furnished  pursuant to this Agreement,  make any other
filing with the SEC required of it or terminate  any  suspension of sales it has
put into effect and shall take such other actions to permit  registered sales of
Shares as  contemplated  by this  Agreement.  For  purposes  of this  Agreement,
"Common Stock Equivalents" shall mean any rights, warrants, options, convertible
securities or indebtedness,  exchangeable  securities or indebtedness,  or other
rights,  exercisable  for or  convertible  or  exchangeable  into,  directly  or
indirectly, Company Common Stock and securities convertible or exchangeable into
Company  Common  Stock,  whether at the time of  issuance or upon the passage of
time or the occurrence of any future event.

     3.5 Company shall take all actions  necessary to execute such documents and
cause all of the Shares to be admitted for listing on the NASDAQ  Stock  Market,
which listing shall be effective on the Effective Date.

     SECTION 4. Restrictions on Transfer.

     4.1 On or prior to the Effective  Date, none of Seller or the Seller Owners
shall,  nor shall they permit any of their Affiliates or the Escrow Agent in its
capacity as such under the Escrow Agreement to sell,  contract to sell,  pledge,
grant any option to  purchase,  acquire any option to sell,  hypothecate,  loan,
make a short  sale or  otherwise  transfer  to any  Person or dispose of (each a
"Transfer")  any  shares  of  Company  Common  Stock.  For a period  of 180 days
following  the Effective  Date (the  "Transfer  Period"),  Seller and the Seller
Owners  shall not,  and shall not permit any of their  Affiliates  or the Escrow
Agent in its  capacity as such under the Escrow  Agreement  to,  Transfer in the
aggregate on any given day (a "Transfer  Date") such number of shares of Company
Common  Stock that  exceeds (i) the product of  (x)[Number  equal to 20% of the
Company's  average  daily  trading  volume  during  the  30-day  trading  period
immediately  preceding  the Closing] /1/ shares of Company  Common Stock and (y)
the number of trading days in the period from and including  the Effective  Date
to and including  the Transfer Date less (ii) the aggregate  number of shares of
Company Common Stock  Transferred by Seller,  the Seller Owners and any of their
Affiliates in accordance  with this section during the period from and including
the Effective Date to, but excluding, the Transfer Date; provided, however, that

/1/ This information will be determined and inserted at closing in the execution
version of this agreement.


                                      -4-



Seller  and the  Seller  Owners  shall  not,  and shall not  permit any of their
Affiliates  or the  Escrow  Agent  in its  capacity  as such  under  the  Escrow
Agreement to, Transfer, whether directly or indirectly,  more than [Number equal
to 60% of the Company's  average daily trading  volume during the 30-day trading
period  immediately  preceding the Closing]/2/ shares of Company Common Stock on
any such Transfer Date, and provided  further,  that in determining  the maximum
number of shares of Company  Common Stock that may be Transferred in any one day
as provided above, any Transfers  permitted by the succeeding sentence shall not
be  included  in  such  calculation.  Notwithstanding  anything  herein  to  the
contrary,  the transfer  restrictions  set forth in this section shall not apply
to: (1) any  Transfer of shares of Company  Common Stock by Seller to the Seller
Owners; (2) any Transfer to holders of membership units in Seller other than the
Seller Owners, provided, however, that such holders shall agree with the Company
in writing  prior to such  Transfer to be bound by the terms of this  Agreement;
and (3) any  Transfer  of all or part of the  Shares to one or more  persons  (a
"Negotiated Transaction"),  provided, however, that such person or persons shall
agree  with the  Company in writing  prior to such  Transfer  to be bound by the
terms of this  Agreement and provided  further that the maximum number of shares
of Company Common Stock that may be sold by all such persons,  together with the
Seller  Owners and  Affiliates,  shall not exceed in the  aggregate  the maximum
number of shares of Company Common Stock that may be sold as provided  above. In
addition to the foregoing, (i) at any time after the Effective Date and prior to
[            ], Seller and the Seller Owners shall not, and shall not permit any
of their  Affiliates  to  knowingly  make any direct  Transfer  in a  Negotiated
Transaction  that  would  result  in the  acquirer  holding  economic  or voting
ownership  in excess of five  percent  (5%) or more of Company  Common Stock and
(ii) at any time after the  Effective  Date,  Seller and the Seller Owners shall
not  knowingly  (after due inquiry of the  transferee)  and shall not  knowingly
permit  any  of  their  Affiliates  to  knowingly  (after  due  inquiry  of  the
transferee)  make any direct  Transfer in a  Negotiated  Transaction  that would
result in the  acquirer  holding  economic or voting  ownership in excess of ten
percent (10%) or more of Company  Common Stock.  For purposes of this Section 4,
neither  Seller  nor the Seller  Owners  shall be deemed to have made a transfer
that would result in the acquirer holding economic or voting ownership in excess
of five percent (5%) or ten percent (10%) of Company Common Stock as provided in
clauses (i) and (ii) above,  if such  transfer is made in an open market  broker
sale transaction  without  knowledge of the identity of the acquiror at the time
of the sale transaction by Seller or Seller Owners.

     4.2 Seller and Seller Owners (and any  subsequent  transferee who agrees to
be bound by the terms of this  Section 4) agree that  within  five (5)  business
days after the consummation of any Transfer  referred to in this Section 4, such
transferring party shall deliver  documentation to the Purchaser that identifies
the transferee, the number of shares of Company Common Stock transferred and the
date of such Transfer.

     SECTION 5. Blue Sky. In connection  with the  registration  under Section 2
hereof,  the Company  shall take all actions  necessary  to permit the resale by
Seller and the Seller Owners of any Company Common Stock under the blue sky laws
of the several states, except that the Company shall not for any such purpose be
required to qualify  generally  to do business as a foreign  corporation  in any
jurisdiction  wherein it would not but for the requirements of this


/2/ This information will be determined and inserted at closing in the execution
version of this agreement.

                                      -5-


Section 5 be obligated  to be so  qualified,  subject  itself to taxation in any
such  jurisdiction  or to  consent  to  general  service  of process in any such
jurisdiction.

     SECTION 6. Expenses.  All expenses incident to the Company's performance of
or  compliance  with this  Agreement  will be borne by the  Company,  including,
without  limitation,  all: (i) registration  and filing fees and expenses;  (ii)
expenses of printing;  (iii) fees and  expenses of counsel for the Company;  and
(iv)  fees and  expenses  of one  counsel  for  Seller  and the  Seller  Owners,
provided,  however,  such fees  pursuant  to this  clause  (iv) shall not exceed
$5,000.  Notwithstanding the foregoing,  the Company shall not be liable for and
shall not pay any  expenses  or fees of more than one  counsel for Seller or the
Seller Owners or any  commissions to be paid in connection  with any sale of the
Shares by Seller or the Seller Owners.

     SECTION 7.  Termination.  The  obligations of the Company  hereunder,  with
respect to the Shares, shall terminate upon the earlier of (i) the date on which
all Shares covered by the Registration Statement have been disposed of by Seller
and the Seller Owners and (ii) the second  anniversary of the  Acquisition.  The
date on which such  obligations  shall  terminate  shall be  referred  to as the
"Termination Date."

     SECTION 8. Indemnification.

     8.1 The Company will, and does hereby agree to, indemnify and hold harmless
each of Seller and the Seller  Owners,  and each of their  directors,  officers,
employees and agents and each person  controlling  Seller or a Seller Owner with
respect to any  registration  effected  pursuant to this  Agreement  against all
claims,  losses,  damages,  and  liabilities  (or  actions in  respect  thereto)
including  any  of the  foregoing  incurred  in  settlement  of any  litigation,
commenced  or  threatened,  to which  Seller  and the  Seller  Owners may become
subject  under the  Securities  Act,  the  Securities  Exchange Act of 1934 (the
"Exchange  Act"), or other federal or state law insofar as such claims,  losses,
damages or liabilities (or actions in respect thereto) arise out of or are based
on any untrue  statement  (or  alleged  untrue  statement)  of a  material  fact
contained in any registration statement or prospectus relating to the Shares, or
other  document,  or any  amendment or supplement  thereto,  or any omission (or
alleged omission) to state therein a material fact required to be stated therein
or necessary to make the statements  therein not misleading,  and will reimburse
each such  party for any legal and any other  expenses  reasonably  incurred  in
connection  with  investigating  or  defending  any such  claim,  loss,  damage,
liability,  or action;  provided that the Company will not be liable in any such
case to the extent  that any such  claim,  loss,  damage,  liability  or expense
arises out of or is based on any untrue statement or omission based upon written
information furnished to the Company by such party and stated to be specifically
for use therein and provided further, that the Company shall only reimburse such
parties  for the  fees  and  expenses  of a single  legal  counsel  for all such
parties.

     8.2 Each of Seller and the Sellers Owners will,  severally  based on Shares
sold pursuant to a registration  effected  pursuant to this  Agreement,  but not
jointly,  if  Shares  held  by or  issuable  to such  party  are  included  in a
registration effected pursuant to this Agreement, indemnify the Company, each of
its directors and officers, each person controlling the Company and the officers
and  directors  of each such  controlling  person  against all  claims,  losses,
damages,  and liabilities (or actions in respect  thereof)  including any of the
foregoing  incurred in settlement of any  litigation,  commenced or  threatened,
arising out of or based on any untrue statement (or alleged untrue statement) of
a material  fact  contained  in the  Registration  Statement  or the  Prospectus
included  therein,  or any  omission (or alleged  omission)  to state  therein a
material fact required to be stated  therein or necessary to make the statements
therein not misleading,  and will reimburse the Company, and each such director,
officer and controlling  person, for any legal or any other expenses  reasonably
incurred in connection  with  investigating  or defending any such claim,  loss,
damage, liability, or action, in each case to the extent, but only to the extent
that such untrue statement (or

                                      -6-


alleged  untrue  statement)  or omission (or alleged  omission) was made in such
Registration  Statement or Prospectus,  in reliance upon and in conformity  with
written  information  furnished  to the  Company  by such party and stated to be
specifically for use therein.  Notwithstanding  the foregoing,  the liability of
each  Seller and the Seller  Owners  under this  Section  shall be limited in an
amount equal to the per share sales price (less any  underwriting  discounts and
commissions)  multiplied by the number of Shares sold by such party  pursuant to
the Registration Statement.

     8.3 Each  party  entitled  to  indemnification  under  this  Section 8 (the
"Indemnified  Party") shall give written notice to the party required to provide
such  indemnification  (the  "Indemnifying  Party")  of any  claim  as to  which
indemnification  may be sought promptly after such Indemnified  Party has actual
knowledge thereof, and shall permit the Indemnifying Party to assume the defense
of any such claim or any litigation resulting  therefrom;  provided that counsel
for the  Indemnifying  Party,  who shall  conduct  the  defense of such claim or
litigation,  shall be  subject  to  approval  by the  Indemnified  Party  (whose
approval shall not be unreasonably  withheld) and after the  Indemnifying  Party
assumes the defense thereof,  the Indemnifying Party shall not be liable to such
Indemnified Party for any legal or other expenses  subsequently  incurred by the
latter in connection with the defense thereof, unless in the reasonable judgment
of the  Indemnified  Party,  representation  of such  Indemnified  Party by such
counsel would be inappropriate  due to actual or potential  differing  interests
between such Indemnified Party and the Indemnifying  Party in such proceeding in
which  case such  Indemnified  Party  shall  have the  right to employ  separate
counsel to participate in such defense at the expense of the Indemnifying Party;
it being  understood that the  Indemnifying  Party shall not, in connection with
any one such action or separate but substantially  similar or related actions in
the same jurisdiction arising out of the same general allegations, be liable for
the reasonable  fees and expenses of more than one separate firm of attorneys at
any  time  for  all  such  Indemnified  Parties  provided,   however,  that  the
Indemnifying  Party  shall bear the  expenses  of  independent  counsel  for the
Indemnified   Party  if  the  Indemnified   Party  reasonably   determines  that
representation of more than one party by the same counsel would be inappropriate
due to actual or potential  conflicts of interest between the Indemnified  Party
and the  Indemnifying  Party;  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 8, except to the extent
that  such  failure  to  give  notice  shall  materially  adversely  affect  the
Indemnifying  Party in the defense of any such claim or any such litigation.  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 that does not include as an  unconditional
term  thereof  the  giving  by  the  claimant  or  plaintiff  therein,  to  such
Indemnified  Party,  of a release from all liability in respect to such claim or
litigation.

     8.4 If the  indemnification  provided for in subsection  (a) or (b) of this
Section  8 is for any  reason  unavailable  to a party  to be  indemnified  with
respect to any claims, actions,

                                      -7-


demands,  losses, damages,  liabilities,  costs or expenses referred to therein,
then each Indemnifying Party under any such subsection,  in lieu of indemnifying
such  Indemnified  Party  thereunder,  hereby agrees to contribute to the amount
paid or payable by such Indemnified  Party as a result of such claims,  actions,
demands, losses, damages, liabilities, cost or expenses in such proportion as is
appropriate to reflect the relative fault of the  Indemnifying  Party on the one
hand and of the Indemnified Party on the other in connection with the statements
or omissions which resulted in such claims, actions,  demands,  losses, damages,
liabilities,  costs  or  expenses,  as  well  as any  other  relevant  equitable
considerations.  The  relative  fault  of  the  Indemnifying  Party  and  of the
Indemnified  Party 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 Indemnifying  Party or by the Indemnified Party and the parties'
relative intent, knowledge,  access to information and opportunity to correct or
prevent such statement or omission.  Notwithstanding  the foregoing,  the amount
Seller shall be obligated to contribute pursuant to this subsection (d) shall be
limited to an amount  equal to the per share sale price  (less any  underwriting
discount and commissions)  multiplied by the number of Shares sold by such party
pursuant to the  Registration  Statement  which gives rise to such obligation to
contribute  (less aggregate amount of any damages which such party has otherwise
been required to pay in respect of such claim,  action,  demand,  loss,  damage,
liability,  cost or expense or any substantially similar claim, action,  demand,
loss, damage,  liability, cost or expense arising from the sale of such Shares).
No person guilty of fraudulent  misrepresentation (within the meaning of Section
11(f) of the Securities  Act) shall be entitled to  contribution  hereunder from
any  person  who  was  not  guilty  of such  fraudulent  misrepresentation.  The
obligations of Seller and the Seller Owners under this paragraph will be several
(based on Shares  sold  pursuant  to a  registration  effected  pursuant to this
Agreement) and not joint.

     SECTION 9. Rule 144  Reporting.  With a view to making  available to Seller
and the Seller Owners the benefits of certain rules and  regulations  of the SEC
which may permit the sale of the Shares to the public without registration,  the
Company agrees to use its best efforts to:

     9.1 comply,  on a timely basis with all the reporting  requirements  of the
Exchange   Act,  and  comply  with  all  other  public   information   reporting
requirements of the SEC as a condition to the  availability of an exemption from
the Securities Act under Rule 144  thereunder,  as amended from time to time, or
successor rule thereto, for the sale of Shares by Seller or the Seller Owners;

     9.2 provide,  at the Company's  expense,  such opinion of counsel as may be
reasonably  requested by the transfer  agent for the Shares in  connection  with
each  sale  of  Registrable   Securities  pursuant  to  an  exemption  from  the
registration  requirements of the Securities Act (under Rule 144 thereunder,  as
amended from time to time, or successor rule thereto or otherwise) or otherwise,
so long as the Seller Owners have furnished to counsel documentation  reasonably
acceptable to such counsel related to the transfer and the Shares; and

     9.3 whenever  Seller or the Seller  Owners are able to  demonstrate  to the
Company that the  provisions  of Rule 144(k) (or any  successor  rule) under the
Securities  Act are  available  to them and have  furnished  to the Company such
documentation  in connection  therewith as the Company may  reasonably  request,
provide,  at  the  Company's  expense,  new  certificates  that  do  not  bear a
restrictive legend.

                                      -8-


     9.4 So long as any of Seller and the Seller Owners own any Shares,  furnish
to such  party  forthwith  upon  request,  a copy of the most  recent  annual or
quarterly  report of the Company,  and such other  reports and documents as such
party may reasonably request in availing itself of any rule or regulation of the
SEC allowing it to sell any such Shares without registration; provided that such
reports are not otherwise  available to Seller or the Seller Owners on the SEC's
Edgar web site.

     SECTION  10.  Amendments.  This  Agreement  may not be amended  without the
written consent of the Company and the holders of at least  two-thirds  (2/3rds)
of the aggregate of the Shares.

     SECTION 11. Miscellaneous.

     11.1 Benefits of Agreement. Except as otherwise provided herein, nothing in
this  Agreement,  expressed  or implied,  shall give or be construed to give any
person,  firm or  corporation,  other  than the  parties  hereto,  any  legal or
equitable  right,  remedy or claim under any  covenant,  condition  or provision
contained in this Agreement being for the sole benefit of the parties hereto.

     11.2  Successors  and  Assigns.  This  Agreement  shall be binding upon the
Company and its  successors and assigns and shall inure to the benefit of Seller
and the Seller  Owners  and to the  benefit of their  successors  and  permitted
assigns.

     11.3  Assignment  of  Registration  Rights.  The rights to have the Company
register Shares pursuant to this Agreement shall be assignable by Seller only in
connection with a transfer of Shares pursuant to Section 4.

     11.4 Notices.  Any notice,  request,  instruction  or other  document to be
given  hereunder  shall  be in  writing  and  delivered  personally  or  sent by
registered or certified mail,  postage  prepaid,  by reputable  national express
courier or shipping cost prepaid, according to the instructions set forth below.
Such notices shall be deemed given: at the time delivered by hand, if personally
delivered; three business days after having been sent by registered or certified
mail; and one business day after having been sent by express courier.

                  If to Seller or any Seller Owner:

                           MCCC ICG Holdings LLC
                           2010 8th Street
                           Boulder, CO 80302
                           Attn: Manager

                  Copy to:

                           Kendall, Koenig & Oelsner PC
                           1675 Broadway, Suite 750
                           Denver, CO 80202
                           Attn:  David J. Kendall

                                      -9-


                  If to the Company:

                           Level 3 Communications, Inc.
                           1025 Eldorado Blvd.
                           Building 2000
                           Broomfield, CO 80021
                           Attn: General Counsel

                  Copy to:

                           Willkie Farr & Gallagher LLP
                           787 Seventh Ave.
                           New York, New York 10019
                           Attn:  David K. Boston

     11.5 Governing  Law. THIS  AGREEMENT  SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK,  WITHOUT REGARD TO PRINCIPLES
OF CONFLICTS OF LAW.

     11.6  Counterparts.;  Facsimile.  This  Agreement may be executed in two or
more  counterparts,  each of which  will be  deemed  an  original,  but all such
counterparts  taken  together will  constitute one and the same  Agreement.  Any
facsimile copies hereof or signature  hereon shall, for all purposes,  be deemed
originals

     11.7  Severability.  In the event any provision in this Agreement  shall be
held  invalid,  illegal or  unenforceable  in any respect  for any  reason,  the
validity,  legality  and  enforceability  of any such  provision  in every other
respect  and  the  remaining  provisions  shall  not in any way be  affected  or
impaired thereby.



                                      -10-




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

                  LEVEL 3 COMMUNICATIONS, INC.


                  By:  ________________________________________________
                     Name:
                     Title:



                  MCCC ICG HOLDINGS, LLC

                  By:  ________________________________________________
                     Name:
                     Title:

                   COLUMBIA CAPITAL EQUITY PARTNERS III (QP), L.P.

                   By:      COLUMBIA CAPITAL EQUITY    PARTNERS III, L.P.,
                   as general partner


                   By:      _______________________________
                            Name:____
                            Title:

                   COLUMBIA CAPITAL EQUITY PARTNERS III (CAYMAN), L.P.

                   By:      COLUMBIA CAPITAL EQUITY    PARTNERS (CAYMAN)
                   III, LTD, as general partner


                   By:      _______________________________
                            Name:____
                            Title:


                 [Registration Rights Agreement Signature Page]

                                      -11-


                   COLUMBIA CAPITAL EQUITY PARTNERS III (AI), L.P.

                   By:      COLUMBIA CAPITAL EQUITY    PARTNERS III, L.P.,
                   as general partner


                   By:      _______________________________
                            Name:____
                            Title:

                        COLUMBIA CAPITAL INVESTORS III, L.L.C.

                        By:      COLUMBIA CAPITAL EQUITY    PARTNERS III, L.P.,
                        as managing member


                        By:      _______________________________
                                 Name:
                                 Title:

                        COLUMBIA CAPITAL EMPLOYEE INVESTORS III, L.L.C.

                        By:      COLUMBIA CAPITAL EQUITY    PARTNERS III, L.P.,
                        as managing member


                        By:      _______________________________
                                 Name:
                                 Title:

                        M/C VENTURE PARTNERS V, L.P.


                        By:      _______________________________
                                 Name:
                                 Title:

                        M/C VENTURE INVESTORS, L.L.C.


                        By:      _______________________________
                                 Name:
                                 Title:

                 [Registration Rights Agreement Signature Page]

                                      -12-


                        CHESTNUT VENTURE PARTNERS, L.P.


                        By:      _______________________________
                                 Name:
                                 Title:

                        BEAR INVESTMENTS, LLLP


                        By:      _______________________________
                                 Name:
                                 Title:





                 [Registration Rights Agreement Signature Page]


                                      -13-