Exhibit 10.1

THIS SECOND AMENDED AND RESTATED SHORT-TERM SUPPORT AGREEMENT (the “Agreement”)
dated as of April 24, 2009 is made

BETWEEN

NORTEL NETWORKS LIMITED

(hereinafter called the “Principal”)

AND

EXPORT DEVELOPMENT CANADA

(hereinafter called “EDC”)

WHEREAS, pursuant to a Second Amended and Restated Master Facility Agreement
dated as of December 14, 2007 between the Principal and EDC (the “Facility
Agreement”), EDC agreed to provide Support for the benefit of the Principal and
its affiliates, subject to the terms and conditions of the Facility Agreement;

WHEREAS the NNL Corporate Family Rating with respect to senior unsecured
long-term debt of the Principal has ceased to exist (the “Family Rating Event”),
thereby permitting EDC to terminate or suspend the Facilities pursuant to
Section 2.2 of the Facility Agreement;

WHEREAS the NNL Corporate Credit Rating with respect to senior unsecured
long-term debt of the Principal is rated at less than “B3” or “B minus” (the
“Credit Rating Event”) (the Family Rating Event and the Credit Rating Event are
hereby collectively referred to as the “Rating Events”), thereby permitting EDC
to terminate or suspend the Facilities pursuant to Section 2.2 of the Facility
Agreement;

WHEREAS the Principal commenced a voluntary proceeding seeking relief including
an initial order (as amended, the “Initial Order”) under the Companies’
Creditors Arrangement Act (Canada) (the “CCAA Proceeding”) and the Principal’s
subsidiaries have commenced administration proceedings in the United Kingdom and
restructuring proceedings under Chapter 11 of the United States Bankruptcy Code
(together, the “Filing Event”), and the Filing Event and certain consequences of
the Filing Event, including the inability to make certain representations
pertaining to certain tax obligations and tax compliance matters related to such
United Kingdom and United States proceedings (the “Filing Consequences”),
constitute or might constitute Defaults and Events of Default under the terms
and conditions of the Facility Agreement; and

WHEREAS the Principal and EDC entered into an Agreement dated as of January 14,
2009, as amended by the Amended and Restated Short-Term Support Agreement dated
as of February 10, 2009, by and between the Principal and EDC (the “Original
Agreement”), () pursuant to which EDC agreed, among other things, that, until
May 1, 2009, new Support would continue to be

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made available to the Principal under the Facilities, notwithstanding the
existence of the Rating Events and the Filing Event, to an aggregate maximum
amount of USD 30 million; and

WHEREAS the Principal and EDC wish to further amend and restate the terms and
conditions of the Original Agreement in accordance with the terms and conditions
herein.

THEREFORE, for good and valuable consideration, the sufficiency of which is
acknowledged, the parties agree as follows:

 

1. With effect as of the date hereof, the Original Agreement is hereby amended,
superseded and restated in its entirety, without novation and without derogation
from the rights and obligations of the Principal and EDC thereunder (save as
amended hereunder).

 

2. Unless otherwise defined herein, words and phrases herein shall have the
meanings ascribed to them in the Facility Agreement, the Original Agreement or
the Initial Order.

 

3. TEMPORARY FACILITY

 

  (a) EDC agrees that, for the period from January 14, 2009 to July 30, 2009
(the “Interim Period”), new Support will continue to be made available to the
Principal under the Facilities, notwithstanding the existence of the Rating
Events, the Filing Event and the Filing Consequences, to an aggregate maximum
amount of USD 30 million (taking into account any exclusions provided in
Schedule A). EDC acknowledges and agrees that only the Secured Support (as
defined in Schedule A) shall have the benefit of the EDC Charge (as defined in
Schedule A).

 

  (b) Except only with respect to the Rating Events and the Filing Event,
nothing in this Agreement shall prevent EDC from exercising, during the Interim
Period or thereafter, any other rights or recourses it may currently have or
acquire under the Facility Agreement.

 

  (c) Upon the termination of the Interim Period, EDC may enforce any and all
rights and recourses it may have under the Facility Agreement as provided for
therein, including those rights and recourses which may have arisen during the
Interim Period.

 

4. TERMS AND CONDITIONS

 

  (a) The obligation of EDC to make any Support available under the Facilities
during the Interim Period is, except as specifically stated above with respect
to the Ratings Events and the Filing Event, subject to the satisfaction of all
applicable conditions set forth in the Facility Agreement as well as the
conditions set out in this Agreement, including Schedule A.

 

  (b) The Principal shall pay to EDC the fees set out, and reimburse EDC for the
expenses described, in Schedule B to this Agreement.

 

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  (c) Nothing contained in this Agreement shall limit EDC’s discretionary or
other rights under the Facility Agreement with respect to the General Support
Facility.

 

  (d) The Principal hereby covenants that, if a request needs to be made to any
financial institution or surety company by a direct or indirect subsidiary of
the Principal (a “Subsidiary”) in order to extend or renew any Instrument that
could be drawn if not extended or renewed during the CCAA Proceeding, the
Principal shall use commercially reasonable efforts to have the Subsidiary make
such request. Where the Principal’s efforts have resulted in the Subsidiary
making the request, the Principal agrees that EDC may provide to any financial
institution or surety company to which EDC may, at the Principal’s request,
provide from time to time a guarantee, guarantee bond or surety bond
reinsurance, a copy of this Agreement and agrees that the such financial
institution or surety company, may rely on a copy of this Agreement, without
further inquiry, as its full and irrevocable authority to effect renewal or
extension of the relevant Instrument.

 

5. MISCELLANEOUS

 

  (a) Save only as expressly provided in this Agreement, the provisions of the
Facility Agreement continue in full force and effect, and the Facility
Agreement, the Original Agreement and this Agreement shall be read and construed
as one instrument.

 

  (b) This Agreement shall be governed and construed in accordance with the laws
of the Province of Ontario and the laws of Canada applicable therein.

 

  (c) This Agreement may be executed in counterparts, each of which shall be an
original, with the same effect as if the signatures thereto and hereto were upon
the same instrument.

 

  (d) This Agreement shall be binding upon and enure to the benefit of the
parties and their respective successors and assigns.

 

  (e) Any provision of this Agreement may be amended or waived if such amendment
or waiver is in writing and is signed by the Principal and EDC.

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IN WITNESS WHEREOF the parties have signed and delivered this Agreement as of
the date first written above.

 

NORTEL NETWORKS LIMITED, as Principal Per:   /s/ JOHN M. DOOLITTLE Name:   John
M. Doolittle Title:   Treasurer Per:   /s/ GORDON A. DAVIES Name:   Gordon A.
Davies Title:   Chief Legal Officer and Corporate Secretary Address:  

195 The West Mall

Toronto, Ontario M9C 5K1

Facsimile: 905-863-8563

 

EXPORT DEVELOPMENT CANADA Per:   /s/ DEREK AUSTIN Name:   Derek Austin Title:  
Manager, Contract Insurance and Bonding Per:   /s/ PAUL BURDZY Name:   Paul
Burdzy Title:   Senior Underwriter Address:  

151 O’Connor Street

Ottawa, Ontario K1A 1K3

Facsimile: 613-597-8504

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SCHEDULE A

CONDITIONS

 

(a) An order shall have been made in the CCAA Proceeding commenced by the
Principal amending paragraph 33 of the Initial Order to read as follows:

“33. THIS COURT ORDERS that EDC shall be entitled to the benefit of and is
hereby granted a charge on the Property (the “EDC Charge”) as security for the
Secured Support (as that term is used in the second amended and restated
short-term support agreement between NNL and EDC dated as of April 24, 2009 and
any amendments thereto made with the written approval of the Monitor
(collectively, the “Support Agreement”)), including agreed to fees and expenses,
but excluding any Unsecured Renewal Support (as that term is used in the Support
Agreement). The EDC Charge shall have the priority set out in paragraphs 42 and
44 hereof.”

 

(b) EDC is entitled to the benefit of the EDC Charge (as defined in the Initial
Order) for: (i) any new Support made after January 14, 2009 (which new Support
shall not include any Support made by EDC after April 14, 2009, other than any
Secured Renewal Support, which is a renewal, extension, substitution, or
replacement of Support outstanding on January 14, 2009) provided by EDC in
respect of an Instrument issued or executed during the CCAA Proceeding (the
“Secured New Support”), (ii) any future extension or renewal for such Secured
New Support during the CCAA Proceeding, and (iii) any extension or renewal of
Support made by EDC between January 14, 2009 and April 14, 2009 (the “Completed
Renewals”) and any further extension or renewal of the Completed Renewals during
the CCAA Proceeding (all extension or renewal Support described in
sub-paragraphs (ii) and (iii) being hereafter referred to as the “Secured
Renewal Support” and all Secured New Support and Secured Renewal Support being
hereafter referred to as the “Secured Support”)).

 

(c) Other than with respect to the Secured Renewal Support, EDC will not be
entitled to the benefit of the EDC Charge with respect to any Support made by
EDC after April 14, 2009, and during the CCAA Proceeding, which is a renewal,
extension, substitution, or replacement of Support outstanding on January 14,
2009 (the “Unsecured Renewal Support”) and the obligations of the Principal to
indemnify EDC in respect of the Unsecured Renewal Support shall be treated as
general unsecured claims in the CCAA Proceeding, as if they were incurred prior
to the date of commencement of the CCAA Proceeding.

 

(d) The Unsecured Renewal Support shall not be included for purposes of
calculating the aggregate maximum amount of Support available under Section 3(a)
of this Agreement or computing the remaining available portion of the “Aggregate
Allowed Limit” under any EDC Agreement issued and in effect under the Facility
Agreement.

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(e) No motion or other proceeding shall have been threatened or commenced
seeking to set aside the EDC Charge or to modify or vary the EDC Charge in any
way, except with the express consent of EDC.

 

(f) The Principal shall have paid to EDC any outstanding fees with respect to
the Support owing to EDC as of the date of this Agreement.

 

(g) EDC shall be satisfied on a case-by-case basis that any Support requested
under the Small Bonds Facility during the Interim Period is within the
parameters contemplated by the EDC Agreements in effect as of the date of this
Agreement.

 

(h) The Principal shall obtain EDC’s prior written consent, which shall not be
unreasonably withheld or delayed, to any amendments to letter of credit
agreements entered into between the Principal and certain financial
institutions.

 

(i) On dates to be mutually agreed to by the Principal and EDC, the Principal
shall deliver weekly reports to EDC, in form and substance satisfactory to EDC,
acting reasonably, which set out EDC’s outstanding exposure with respect to
Instruments issued or to be issued on behalf of the Principal and its
affiliates, including (i) the amounts of Instruments to be issued, increased,
extended or renewed or to expire, and (ii) corresponding dates of issuance,
increase, extension, renewal or expiry of such Instruments.

 

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SCHEDULE B

FEES AND EXPENSES

 

(a) For Support made available by EDC during the Interim Period (including,
without limitation, by way of any renewal or extension of Support made available
by EDC prior to the Interim Period that matures or expires during the Interim
Period), the Principal shall pay to EDC prior to the issuance of any Support by
EDC, a fee of 1.525% per annum calculated on the aggregate amount of such
Support for the stated term thereof.

 

(b) EDC acknowledges receipt from the Principal of a deposit of USD 450,000.00.
Such deposit shall be applied by EDC to the fees to be paid by the Principal to
EDC pursuant to paragraph (a) above. At the end of the Interim Period, the
balance of the deposit, if any, shall be returned by EDC to the Principal.

 

(c) The Principal shall reimburse EDC, on demand, for all reasonable fees and
expenses of external legal counsel and external financial advisors incurred by
EDC in connection with the negotiation and preparation of this Agreement and the
implementation of the arrangement between EDC and the Principal contemplated
hereby, including in connection with the CCAA proceedings, the EDC Charge and
the negotiation and preparation of EDC Agreements.