<Page>
                                                                    Exhibit 4.15

                              SERIES [C][D] WARRANT

THE WARRANT REPRESENTED BY THIS INSTRUMENT AND THE SECURITIES ISSUABLE UPON
EXERCISE HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED,
OR SECURITIES LAWS OF ANY STATE AND MAY NOT BE TRANSFERRED, SOLD OR OTHERWISE
DISPOSED OF EXCEPT WHILE A REGISTRATION STATEMENT RELATING THERETO IS IN EFFECT
UNDER SUCH ACT AND APPLICABLE STATE SECURITIES LAWS OR PURSUANT TO AN EXEMPTION
FROM REGISTRATION UNDER SUCH ACT OR SUCH LAWS.



                              SERIES [C][D] WARRANT

No. [C][D]-__                                [December][January] [__], 200[2][3]

               TO PURCHASE SHARES OF COMMON STOCK, PAR VALUE $0.01
                            PER SHARE, OF AVAYA INC.

1.     DEFINITIONS. Unless the context otherwise requires, when used herein the
       following terms shall have the meaning indicated.

       "AFFILIATE" means with respect to any Person, any other Person directly,
       or indirectly through one or more intermediaries, controlling, controlled
       by or under common control with such Person. For purposes of this
       definition, the term "control" (and correlative terms "controlling,"
       "controlled by" and "under common control with") means possession of the
       power, whether by contract, equity ownership or otherwise, to direct the
       policies or management of a Person.

       "BACKSTOP AGREEMENT" means the Backstop Agreement, dated as of December
       [__], 2002, by and among the Company and the Investors signatory thereto.

       "BOARD" means the Board of Directors of the Company.

       "BUSINESS COMBINATION" means (i) any reorganization, consolidation,
       merger, share exchange or similar business combination transaction
       involving the Company with any Person or (ii) the sale, assignment,
       conveyance, transfer, lease or other disposition by the Company of all or
       substantially all of its assets.

       "BUSINESS DAY" means any day except Saturday, Sunday and any day which
       shall be a legal holiday or a day on which banking institutions in New
       York City, New York generally are authorized or required by law or other
       governmental actions to close.

<Page>

       "CAPITAL STOCK" means (i) with respect to any Person that is a
       corporation or company, any and all shares, interests, participations or
       other equivalents (however designated) of capital or capital stock of
       such Person and (ii) with respect to any Person that is not a corporation
       or company, any and all partnership or other equity interests of such
       Person.

       "COMMON STOCK" means the Company's common stock, par value $0.01 per
       share.

       "COMPANY" means Avaya Inc., a Delaware corporation.

       "EXCHANGE ACT" means the Securities Exchange Act of 1934, as amended, or
       any successor statute, and the rules and regulations promulgated
       thereunder.

       "EXCLUDED STOCK" means (i) shares of Common Stock issued by the Company
       as a stock dividend payable in shares of Common Stock, or upon any
       subdivision or split-up of the outstanding shares of Capital Stock in
       each case which is subject o Section 13(B), or upon conversion of shares
       of Capital Stock (but not the issuance of such Capital Stock which will
       be subject to the provisions of Section 13(A)(iii)), (ii) the issuance of
       shares of Common Stock in any BONA FIDE underwritten public offering,
       (iii) the issuance of Common Stock in connection with any debt financing
       from or with one or more unaffiliated third parties approved by the Board
       (including upon the exercise of any warrants issued in connection with
       such financings), (iv) the issuance of shares of Common Stock (including
       upon exercise of options) to directors, advisors, employees or
       consultants of the Company pursuant to a stock option plan, employee
       stock purchase plan, restricted stock plan or other agreement approved by
       the Board, (v) the issuance of shares of Common Stock in connection with
       acquisitions of assets or securities of another Person (other than
       issuances to Affiliates of the Company), and (vi) shares of Common Stock
       issued pursuant to the terms of the Backstop Agreement or upon exercise
       of the Series A Warrants, the Series B Warrants, the Series [D][C]
       Warrants or the Warrants.

       "EXERCISE PRICE" has the meaning given to it in Section 2.

       "EXPIRATION TIME" has the meaning given to it in Section 3.

       "MARKET PRICE" means, with respect to a particular security, on any given
       day, the average of the highest and lowest reported sale prices regular
       way or, in case no such reported sales take place on such day, the
       average of the highest asked and lowest bid prices regular way, in either
       case on the principal national securities exchange on which the
       applicable security is listed or admitted to trading, or if not listed or
       admitted to trading on any national securities exchange, (i) the average
       of the highest and lowest sale prices for such day reported by the Nasdaq
       Stock Market if such security is traded over-the-counter and quoted in
       the Nasdaq Stock Market, or (ii) if such security is so traded, but not
       so quoted, the average of the


                                       2
<Page>

       highest reported asked and lowest reported bid prices of such security as
       reported by the Nasdaq Stock Market or any comparable system, or (iii) if
       such security is not listed on the Nasdaq Stock Market or any comparable
       system, the average of the highest asked and lowest bid prices as
       furnished by two members of the National Association of Securities
       Dealers, Inc. selected from time to time by the Company for that purpose.
       If such security is not listed and traded in a manner that the quotations
       referred to above are available for the period required hereunder, the
       Market Price per share of Common Stock shall be deemed to be the fair
       value per share of such security as determined in good faith by the
       Board.

       "ORDINARY CASH DIVIDENDS" means any cash dividend or cash distribution
       which, when combined on a per share of Common Stock basis with the per
       share amounts of all other cash dividends and cash distributions paid on
       the Common Stock during the 365-day period ending on the date of
       declaration of such dividend or distribution (as adjusted to
       appropriately reflect any of the events referred to in Section 13 and
       excluding cash dividends or cash distributions that resulted in an
       adjustment to the Exercise Price), does not exceed 7.5% of the Market
       Price of a share of Common Stock on the trading day immediately preceding
       the date of declaration of such dividend or distribution.

       "ORIGINAL ISSUE DATE" means the date on which the Warrants of this Series
       were first issued.

       "ORIGINAL PURCHASE AGREEMENT" means the Preferred Stock and Warrant
       Purchase Agreement, dated as of August 8, 2000, as amended by Amendment
       No. 1 thereto, dated as of September 29, 2000, by and among the Company
       and the Investors signatory thereto.

       "PERSON" means an individual, entity or group (within the meaning of
       Section 13(d)(3) or 14(d)(2) of the Exchange Act).

       "PRO RATA REPURCHASES" means any purchase of shares of Common Stock by
       the Company or any Affiliate thereof pursuant to any tender offer or
       exchange offer subject to Section 13(e) of the Exchange Act, or pursuant
       to any other offer available to substantially all holders of Common
       Stock, whether for cash, shares of capital stock of the Company, other
       securities of the Company, evidences of indebtedness of the Company or
       any other person or any other property (including, without limitation,
       shares of capital stock, other securities or evidences of indebtedness of
       a subsidiary of the Company), or any combination thereof, effected while
       this Warrant is outstanding; PROVIDED, HOWEVER, that "Pro Rata
       Repurchase" shall not include any purchase of shares by the Company or
       any Affiliate thereof made in accordance with the requirements of Rule
       l0b-18 as in effect under the Exchange Act. The "Effective Date" of a Pro
       Rata Repurchase shall mean the date of acceptance of shares for purchase
       or exchange under any tender or exchange offer which is a Pro Rata
       Repurchase or the date of purchase with respect to any Pro Rata
       Repurchase that is not a tender or exchange offer.


                                       3
<Page>

       "RIGHTS AGREEMENT" means the Rights Agreement, dated as of September 29,
       2000, between the Company and the Bank of New York, as Rights Agent, as
       amended February 28, 2002.

       "RIGHTS" is defined in Section 14.

       "SECURITIES ACT" means the Securities Act of 1933, as amended, or any
       successor statute, and the rules and regulations promulgated thereunder.

       "SERIES A WARRANTS" means the four-year warrants to purchase 6,883,933
       shares of Common Stock issued pursuant to the Original Purchase
       Agreement.

       "SERIES B WARRANTS" means the five-year warrants to purchase 5,507,146
       shares of Common Stock issued pursuant to the Original Purchase
       Agreement.

       "SERIES [C][D] WARRANTS" means the [__]-year warrants to purchase [__]
       shares of Common Stock issued pursuant to the Backstop Agreement.

       "SHARES" is defined in Section 2.

       "SUBSIDIARY" of a Person means (i) a corporation, a majority of whose
       stock with voting power, under ordinary circumstances, to elect directors
       is at the time of determination, directly or indirectly, owned by such
       Person or by one or more Subsidiaries of such Person, or (ii) any other
       entity (other than a corporation) in which such Person or one or more
       Subsidiaries of such Person, directly or indirectly, at the date of
       determination thereof has at least a majority ownership interest.

       "WARRANTHOLDER" has the meaning given to it in Section 2.

       "WARRANTS" means collectively the warrant represented hereby and the
       warrants of the same series hereof (and by any instrument replacing, in
       whole or in part, such instruments).

2.     NUMBER OF SHARES; EXERCISE PRICE. This certifies that, for value
       received, [__________] or its registered assigns (the "WARRANTHOLDER") is
       entitled, upon the terms and subject to the conditions hereinafter set
       forth, to acquire from the Company, in whole or in part, up to an
       aggregate of [__] fully paid and nonassessable shares of Common Stock
       (the "SHARES"), at a per Share purchase price of $[__] (the "EXERCISE
       PRICE"). The number and type of Shares and the Exercise Price are subject
       to adjustment as provided herein, and all references to "Shares", "Common
       Stock" and "Exercise Price" herein shall be deemed to include any such
       adjustment or series of adjustments.


                                       4
<Page>

3.     EXERCISE RIGHTS.

       (A)    EXERCISE OF WARRANT; TERM. The right to purchase the Shares
              represented by this Warrant is exercisable, in whole or in part,
              by the Warrantholder, at any time or from time to time but in no
              event later than 11:59 p.m. New York City Time, on [____], 200[_]
              (the "EXPIRATION TIME"), by (a) the surrender of this Warrant and
              Notice of Exercise annexed hereto, duly completed and executed on
              behalf of the Warrantholder, at the office of the Company in
              Basking Ridge, New Jersey (or such other office or agency of the
              Company in the United States as it may designate by notice in
              writing to the Warrantholder at the address of the Warrantholder
              appearing on the books of the Company), and (b) payment of the
              Exercise Price for the Shares thereby purchased at the election of
              the Warrantholder in one of the following manners:

       (i)    by tendering in cash, by certified or cashier's check or by wire
              transfer payable to the order of the Company; or

       (ii)   by having the Company withhold shares of Common Stock issuable
              upon exercise of this Warrant equal in value to the aggregate
              Exercise Price as to which this Warrant is so exercised based on
              the Market Price of the Common Stock on the trading day prior to
              the date on which this Warrant and the Notice of Exercise are
              delivered to the Company.

       (B)    REPLACEMENT OF WARRANT. If the exercising (or selling, as the case
              may be) Warrantholder does not exercise (or sell, as the case may
              be) this Warrant in its entirety, the Warrantholder will be
              entitled to receive from the Company within a reasonable time, not
              exceeding three (3) Business Days, a new warrant in substantially
              identical form for the purchase of that number of Shares equal to
              the difference between the number of Shares subject to this
              Warrant and the number of Shares as to which this Warrant is so
              exercised (or sold, as the case may be); PROVIDED, HOWEVER, that
              if the Warrantholder is required to deliver this Warrant to the
              Company pursuant to Section 3(B) and fails to do so, the
              Warrantholder shall not be entitled to receive a new warrant from
              the Company until the Warrantholder delivers this Warrant to the
              Company and then only in respect of the portion of the Warrant not
              exercised pursuant to Section 3(B).

4.     ISSUANCE OF SHARES; AUTHORIZATION; LISTING. Subject to the next sentence,
       certificates for Shares issued upon exercise of this Warrant will be
       issued in such name or names as the Warrantholder may designate and will
       be delivered to such named Person or Persons within a reasonable time,
       not to exceed three (3) Business Days after the date on which this
       Warrant has been duly exercised in accordance with the terms of this
       Warrant. In the event this Warrant is exercised prior to the final
       determination of the Exercise Price and the number of shares of Common
       Stock issuable upon exercise of this Warrant, such exercise shall be
       effective when made but payment of the exercise price shall be made and
       certificates for Shares shall be issued, three (3) Business Days after
       final


                                       5
<Page>

       determination of the Exercise Price. The Company hereby represents and
       warrants that any Shares issued upon the exercise of this Warrant in
       accordance with the provisions of Section 3 will, upon issuance and
       payment therefor, be duly and validly authorized and issued, fully paid
       and nonassessable, free from all preemptive rights and free from all
       taxes, liens, security interests and charges (other than liens or charges
       created by or imposed upon the Warrantholder or taxes in respect of any
       transfer occurring contemporaneously therewith). The Company agrees that
       the Shares so issued will be deemed to have been issued to the
       Warrantholder as of the close of business on the date on which this
       Warrant and payment of the Exercise Price are delivered to the Company in
       accordance with the terms of this Warrant, notwithstanding that the stock
       transfer books of the Company may then be closed or certificates
       representing such Shares may not be actually delivered on such date. The
       Company will at all times reserve and keep available, free from
       preemptive rights, out of its authorized but unissued Common Stock,
       solely for the purpose of providing for the exercise of this Warrant, the
       aggregate number of shares of Common Stock issuable upon exercise of this
       Warrant. The Company will procure, at its sole expense, the listing of
       the Shares, subject to issuance or notice of issuance, on the principal
       domestic stock exchange on which the Common Stock is then listed or
       traded. The Company will take all commercially reasonable action as may
       be necessary to ensure that the Shares may be issued without violation of
       any applicable law or regulation or of any requirement of any securities
       exchange on which the shares of Common Stock are listed or traded.

5.     NO FRACTIONAL SHARES OR SCRIP. No fractional Shares or scrip representing
       fractional Shares shall be issued upon any exercise of this Warrant. In
       lieu of any fractional Share to which the Warrantholder would otherwise
       be entitled, the Warrantholder shall be entitled to receive a cash
       payment equal to the Market Price per share of Common Stock computed as
       of the trading day immediately preceding the date the Warrant is
       presented for exercise, multiplied by such fraction of a Share.

6.     NO RIGHTS AS SHAREHOLDERS. This Warrant does not entitle the
       Warrantholder to any voting rights or other rights as a shareholder of
       the Company prior to the date of exercise hereof.

7.     CHARGES, TAXES AND EXPENSES. Issuance of certificates for shares of
       Common Stock upon the exercise of this Warrant shall be made without
       charge to the Warrantholder or such designated Persons for any issue or
       transfer tax (other than taxes in respect of any transfer occurring
       contemporaneously therewith or as a result of the holder being a non-U.S.
       person) or other incidental expense in respect of the issuance of such
       certificates, all of which taxes and expenses shall be paid by the
       Company; PROVIDED, HOWEVER, that the Company shall not be required to pay
       any tax which may be payable in respect of any transfer involved in the
       issuance or delivery of shares of Common Stock in a name other than that
       of the Warrantholder or such designated Persons, and no such issuance or
       delivery shall be made unless and until the person requesting such
       issuance or delivery


                                       6
<Page>

       has paid to the Company the amount of any such tax or has established, to
       the satisfaction of the Company, that such tax has been paid.

8.     TRANSFER/ASSIGNMENT. This Warrant and any rights hereunder are not
       transferable by the Warrantholder, in whole or in part, in the absence of
       any effective registration statement related to this Warrant or an
       opinion of counsel, satisfactory in form and substance to the Company,
       that such registration is not required under the Securities Act and any
       applicable state securities laws. Subject to compliance with the
       preceding sentence, this Warrant and all rights hereunder are
       transferable, in whole or in part, upon the books of the Company by the
       registered holder hereof in person or by duly authorized attorney, and a
       new warrant shall be made and delivered by the Company, of the same tenor
       as this Warrant but registered in the name of the transferee, upon
       surrender of this Warrant, duly endorsed, to the office or agency of the
       Company described in Section 3. All expenses, taxes (other than stock
       transfer taxes or taxes imposed because the transferee is a non-U.S.
       Person) and other charges payable in connection with the preparation,
       execution and delivery of the new warrants pursuant to this Section 8
       shall be paid by the Company. The restrictions imposed by the first
       sentence of this Section 8 shall terminate as to the Warrant (i) when
       such security has been effectively registered under the Securities Act
       and disposed of in accordance with the registration statement covering
       such security, except with respect to securities held following such
       disposition by Affiliates of the Company, or (ii) when, in the opinion of
       counsel for the Company, such restrictions are no longer required in
       order to achieve compliance with the Securities Act.

9.     EXCHANGE AND REGISTRY OF WARRANT. This Warrant is exchangeable, upon the
       surrender hereof by the Warrantholder at the office or agency of the
       Company described in Section 3, for a new warrant or warrants of like
       tenor representing the right to purchase in the aggregate a like number
       of shares. The Company shall maintain at the office or agency described
       in Section 3 a registry showing the name and address of the Warrantholder
       as the registered holder of this Warrant. This Warrant may be surrendered
       for exchange or exercise, in accordance with its terms, at the office of
       the Company, and the Company shall be entitled to rely in all respects,
       prior to written notice to the contrary, upon such registry.

10.    LOSS, THEFT, DESTRUCTION OR MUTILATION OF WARRANT. If this Warrant is
       mutilated, lost, stolen or destroyed, the Company will issue and deliver
       in substitution for and upon cancellation of the mutilated Warrant, or in
       substitution for the Warrant lost, stolen or destroyed, a new warrant or
       warrants of like tenor and representing an equivalent right or interest,
       but only upon, in the case of a lost, stolen or destroyed certificate,
       receipt of evidence satisfactory to the Company of such loss, theft or
       destruction. If required by the Company, the Warrantholder shall furnish
       an indemnity bond sufficient to protect the Company from any
       out-of-pocket loss which it may suffer if a Warrant is replaced. The
       Company may charge the Warrantholder for its reasonable expenses in
       replacing a Warrant.


                                       7
<Page>

11.    SATURDAYS, SUNDAYS, HOLIDAYS. ETC. If the last or appointed day for the
       taking of any action or the expiration of any right required or granted
       herein shall not be a Business Day, then such action may be taken or such
       right may be exercised on the next succeeding day that is a Business Day.

12.    RULE 144 INFORMATION. The Company covenants that it will file the reports
       required to be filed by it under the Securities Act and the Exchange Act
       and the rules and regulations promulgated thereunder (or, if the Company
       is not required to file such reports, it will, upon the request of any
       Warrantholder, make publicly available such information as is described
       in Ru1e l44(c)(2) under the Securities Act). Upon the request of any
       Warrantholder, the Company will deliver to such Warrantholder a written
       statement that it has complied with such requirements.

13.    ADJUSTMENTS AND OTHER RIGHTS. The Exercise Price and the number of Shares
       issuable upon exercise of this Warrant shall be subject to adjustment
       from time to time as follows:

       (A)    COMMON STOCK ISSUED AT LESS THAN MARKET VALUE. If the Company
              issues or sells any Common Stock other than Excluded Stock without
              consideration or for consideration per share less than the Market
              Price of the Common Stock, as of the day of such issuance or sale,
              the Exercise Price in effect immediately prior to each such
              issuance or sale will immediately (except as provided below) be
              reduced to the price determined by multiplying the Exercise Price,
              in effect immediately prior to such issuance or sale, by a
              fraction, (1) the numerator of which shall be (x) the number of
              shares of Common Stock outstanding immediately prior to such
              issuance or sale plus (y) the number of shares of Common Stock
              which the aggregate consideration received by the Company for the
              total number of such additional shares of Common Stock so issued
              or sold would purchase at the Market Price on the last trading day
              immediately preceding such issuance or sale and (2) the
              denominator of which shall be the number of shares of Common Stock
              outstanding immediately after such issue or sale. In such event,
              the number of shares of Common Stock issuable upon the exercise of
              this Warrant shall be increased to the number obtained by dividing
              (i) the product of (a) the number of Shares issuable upon the
              exercise of this Warrant before such adjustment, and (b) the
              Exercise Price in effect immediately prior to the issuance giving
              rise to this adjustment by (ii) the new Exercise Price determined
              in accordance with the immediately preceding sentence. For the
              purposes of any adjustment of the Exercise Price and the number of
              Shares issuable upon exercise of this Warrant pursuant to this
              Section 13(A), the following provisions shall be applicable:

       (i)    In the case of the issuance of Common Stock for cash, the amount
              of the consideration received by the Company shall be deemed to be
              the amount of the cash proceeds received by the Company for such
              Common Stock


                                       8
<Page>

              before deducting therefrom any discounts or commissions allowed,
              paid or incurred by the Company for any underwriting or otherwise
              in connection with the issuance and sale thereof.

       (ii)   In the case of the issuance of Common Stock (otherwise than upon
              the conversion of shares of Capital Stock or other securities of
              the Company) for a consideration in whole or in part other than
              cash, including securities acquired in exchange therefor (other
              than securities by their terms so exchangeable), the consideration
              other than cash shall be deemed to be the fair value thereof as
              determined by the Board, PROVIDED, HOWEVER, that such fair value
              as determined by the Board shall not exceed the aggregate Market
              Price of the shares of Common Stock being issued as of the date
              the Board authorizes the issuance of such shares.

       (iii)  In the case of the issuance of (a) options, warrants or other
              rights to purchase or acquire Common Stock (whether or not at the
              time exercisable) or (b) securities by their terms convertible
              into or exchangeable for Common Stock (whether or not at the time
              so convertible or exchangeable) or options, warrants or rights to
              purchase such convertible or exchangeable securities (whether or
              not at the time exercisable):

       (a)    the aggregate maximum number of shares of Common Stock deliverable
              upon exercise of such options, warrants or other rights to
              purchase or acquire Common Stock shall be deemed to have been
              issued at the time such options, warrants or rights are issued and
              for a consideration equal to the consideration (determined in the
              manner provided in Section 13(A)(i) and (ii)), if any, received by
              the Company upon the issuance of such options, warrants or rights
              plus the minimum purchase price provided in such options, warrants
              or rights for the Common Stock covered thereby;

       (b)    the aggregate maximum number of shares of Common Stock deliverable
              upon conversion of or in exchange for any such convertible or
              exchangeable securities, or upon the exercise of options, warrants
              or other rights to purchase or acquire such convertible or
              exchangeable securities and the subsequent conversion or exchange
              thereof, shall be deemed to have been issued at the time such
              securities were issued or such options, warrants or rights were
              issued and for a consideration equal to the consideration, if any,
              received by the Company for any such securities and related
              options, warrants or rights (excluding any cash received on
              account of accrued interest or accrued dividends), plus the
              additional consideration (determined in the manner provided in
              Section 13(A)(i) and (ii)), if any, to be received by the Company
              upon the conversion or exchange of such securities, or upon the
              exercise of any related options, warrants or rights to purchase or
              acquire such convertible or exchangeable securities and the
              subsequent conversion or exchange thereof;


                                       9
<Page>

       (c)    on any change in the number of shares of Common Stock deliverable
              upon exercise of any such options, warrants or rights or
              conversion or exchange of such convertible or exchangeable
              securities or any change in the consideration to be received by
              the Company upon such exercise, conversion or exchange, but
              excluding changes resulting from the anti-dilution provisions
              thereof (to the extent comparable to the anti-dilution provisions
              contained herein), the Exercise Price and the number of Shares
              issuable upon exercise of this Warrant as then in effect shall
              forthwith be readjusted to such Exercise Price and number of
              Shares as would have been obtained had an adjustment been made
              upon the issuance of such options, warrants or rights not
              exercised prior to such change, or of such convertible or
              exchangeable securities not converted or exchanged prior to such
              change, upon the basis of such change;

       (d)    on the expiration or cancellation of any such options, warrants or
              rights (without exercise), or the termination of the right to
              convert or exchange such convertible or exchangeable securities
              (without exercise), if the Exercise Price and the number of Shares
              issuable upon exercise of this Warrant shall have been adjusted
              upon the issuance thereof, the Exercise Price and the number of
              Shares issuable upon exercise of this Warrant shall forthwith be
              readjusted to such Exercise Price and number of Shares as would
              have been obtained had an adjustment been made upon the issuance
              of such options, warrants, rights or such convertible or
              exchangeable securities on the basis of the issuance of only the
              number of shares of Common Stock actually issued upon the exercise
              of such options, warrants or rights, or upon the conversion or
              exchange of such convertible or exchangeable securities; and

       (e)    if the Exercise Price and the number of Shares issuable upon
              exercise of this Warrant shall have been adjusted upon the
              issuance of any such options, warrants, rights or convertible or
              exchangeable securities, no further adjustment of the Exercise
              Price and the number of Shares issuable upon exercise of this
              Warrant shall be made for the actual issuance of Common Stock upon
              the exercise, conversion or exchange thereof.

       (B)    STOCK SPLITS, SUBDIVISIONS, RECLASSIFICATIONS OR COMBINATIONS. If
              the Company shall (1) declare a dividend or make a distribution on
              its Common Stock in shares of Common Stock, (2) subdivide or
              reclassify the outstanding shares of Common Stock into a greater
              number of shares, or (3) combine or reclassify the outstanding
              Common Stock into a smaller number of shares, the number of Shares
              issuable upon exercise of this Warrant at the time of the record
              date for such dividend or distribution or the effective date of
              such subdivision, combination or reclassification shall be
              proportionately adjusted so that the Warrantholder after such date
              shall be entitled to purchase the number of shares of Common Stock
              which such holder would have owned or been entitled to receive
              after such date had

                                       10
<Page>

              this Warrant been exercised immediately prior to such date. In
              such event, the Exercise Price in effect at the time of the record
              date for such dividend or distribution or the effective date of
              such subdivision, combination or reclassification shall be
              adjusted to the number obtained by dividing (i) the product of (a)
              the number of Shares issuable upon the exercise of this Warrant
              before such adjustment and (b) the Exercise Price in effect
              immediately prior to the issuance giving rise to this adjustment
              by (ii) the new number of Shares issuable upon exercise of the
              Warrant determined pursuant to the immediately preceding sentence.

       (C)    OTHER DISTRIBUTIONS. In case the Company shall fix a record date
              for the making of a distribution to all holders of shares of its
              Common Stock (i) of shares of any class or of any Person other
              than shares of the Common Stock or (ii) of evidence of
              indebtedness of the Company or any Subsidiary or (iii) of assets
              (excluding Ordinary Cash Dividends, and dividends or distributions
              referred to in Section 13(B)) or (iv) of rights or warrants, in
              each such case the number of Shares issuable upon exercise of this
              Warrant shall be multiplied by a fraction, the numerator of which
              is the Market Price per share of Common Stock on such record date
              and the denominator of which is the Market Price per share of
              Common Stock on such record date less the fair market value (as
              reasonably determined by the Board, which amount shall be the cash
              amount in the case of a distribution in cash) of said shares or
              evidences of indebtedness or assets or rights or warrants to be so
              distributed per share of Common Stock; such adjustment shall take
              effect on the record date for such distribution. In such event,
              the Exercise Price shall be multiplied by a fraction, the
              numerator of which is the number of Shares issuable upon the
              exercise of this Warrant before such adjustment, and the
              denominator of which is the new number of Shares issuable upon
              exercise of this Warrant determined in accordance with the
              immediately preceding sentence. Notwithstanding the foregoing, in
              the event that the fair market value (as determined above) of the
              shares or evidences of indebtedness or assets or rights or
              warrants to be so distributed with respect to one share of Common
              Stock is equal to or greater than the Market Price per share of
              Common Stock on such record date, then proper provision shall be
              made such that upon exercise of the Warrant, the holder shall
              receive the amount and kind of such shares, assets, evidences of
              indebtedness, rights or warrants such holders would have received
              had such holders exercised this Warrant immediately prior to such
              record date. In the event that such distribution is not so made,
              the Exercise Price and the number of Shares issuable upon exercise
              of this Warrant then in effect shall be readjusted, effective as
              of the date when the Board determines not to distribute such
              shares, evidences of indebtedness, assets, rights or warrants, as
              the case may be, to the Exercise Price that would then be in
              effect and the number of Shares that would then be


                                       11
<Page>

              issuable upon exercise of this Warrant if such record date had not
              been fixed.

       (D)    CERTAIN REPURCHASES OF COMMON STOCK. In case the Company effects a
              Pro Rata Repurchase of Common Stock, then the Exercise Price shall
              be reduced to the price determined by multiplying the Exercise
              Price in effect immediately prior to the effective date of such
              Pro Rata Repurchase by a fraction of which the numerator shall be
              (i) the product of (x) the number of shares of Common Stock
              outstanding immediately before such Pro Rata Repurchase and (y)
              the Market Price of a share of Common Stock on the trading day
              immediately preceding the first public announcement by the Company
              or any of its Affiliates of the intent to effect such Pro Rata
              Repurchase, minus (ii) the aggregate purchase price of the Pro
              Rata Repurchase, and of which the denominator shall be the product
              of (i) the number of shares of Common Stock outstanding
              immediately prior to such Pro Rata Repurchase minus the number of
              shares of Common Stock so repurchased and (ii) the Market Price
              per share of Common Stock on the trading day immediately preceding
              the first public announcement of such Pro Rata Repurchase. In such
              event, the number of shares of Common Stock issuable upon the
              exercise of this Warrant shall be increased to the number obtained
              by dividing (i) the product of (a) the number of Shares issuable
              upon the exercise of this Warrant before such adjustment, and (b)
              the Exercise Price in effect immediately prior to the Pro Rata
              Repurchase giving rise to this adjustment by (ii) the new Exercise
              Price determined in accordance with the immediately preceding
              sentence.

       (E)    BUSINESS COMBINATIONS. In case of any Business Combination or
              reclassification of Common Stock (other than a reclassification of
              Common Stock referred to in Section 13(B)), any Shares issued or
              issuable upon exercise of this Warrant after the date of such
              Business Combination or reclassification will be exchangeable for
              the number of shares of stock or other securities or property
              (including cash) to which the Common Stock issuable (at the time
              of such Business Combination or reclassification) upon exercise of
              this Warrant immediately prior to such Business Combination or
              reclassification would have been entitled upon such Business
              Combination or reclassification; and in any such case, if
              necessary, the provisions set forth herein with respect to the
              rights and interests thereafter of the Warrantholder shall be
              appropriately adjusted so as to be applicable, as nearly as may
              reasonably be, to any shares of stock or other securities or
              property thereafter deliverable on the exercise of this Warrant.
              In determining the kind and amount of stock, securities or the
              property receivable upon consummation of such Business Combination
              or reclassification, if the holders of Common Stock have the right
              to elect the kind or amount of consideration receivable upon
              consummation of such Business Combination, then the Warrantholder
              shall have the right to


                                       12
<Page>

              make a similar election upon exercise of this Warrant with respect
              to the number of shares of stock or other securities or property
              which the Warrantholder will receive upon exercise of this
              Warrant.

       (F)    SUCCESSIVE ADJUSTMENTS. Successive adjustments in the Exercise
              Price and the number of shares of Common Stock issuable upon
              exercise of this Warrant shall be made, without duplication,
              whenever any event specified in Sections 13(A), (B), (C), (D) or
              (E) shall occur.

       (G)    ROUNDING OF CALCULATIONS; MINIMUM ADJUSTMENTS. All calculations
              under this Section 13 shall be made to the nearest one-tenth
              (1/10th) of a cent or to the nearest one-hundredth (1/100th) of a
              share, as the case may be. No adjustment in the Exercise Price or
              the number of Shares into which this Warrant is exercisable is
              required if the amount of such adjustment would be less than $0.01
              or one-tenth (1/10th) of a share of Common Stock, as the case may
              be; PROVIDED, HOWEVER, that any adjustments which by reason of
              this Section 13(G) are not required to be made will be carried
              forward and given effect in any subsequent adjustment.

       (H)    TIMING OF ISSUANCE OF ADDITIONAL COMMON STOCK UPON CERTAIN
              ADJUSTMENTS. Notwithstanding the foregoing, in any case in which
              the provisions of this Section 13 shall require that an adjustment
              shall become effective immediately after a record date for an
              event, the Company may defer until the occurrence of such event
              (i) issuing to the Warrantholder of this Warrant exercised after
              such record date and before the occurrence of such event the
              additional shares of Common Stock issuable upon such exercise by
              reason of the adjustment required by such event over and above the
              shares of Common Stock issuable upon such exercise before giving
              effect to such adjustment and (ii) paying to such Warrantholder
              any amount of cash in lieu of a fractional share of Common Stock;
              PROVIDED, HOWEVER, that the Company upon request shall deliver to
              such Warrantholder a due bill or other appropriate instrument
              evidencing such Warrantholder's right to receive such additional
              shares, and such cash, upon the occurrence of the event requiring
              such adjustment.

       (I)    ADJUSTMENT FOR UNSPECIFIED ACTIONS. If the Company takes any
              action affecting the Common Stock, other than action described in
              this Section 13, which in the opinion of the Board would
              materially adversely affect the exercise rights of the
              Warrantholders, the Exercise Price for the Warrants and/or the
              number of Shares received upon exercise of the Warrant may be
              adjusted, to the extent permitted by law, in such manner, if any,
              and at such time, as such Board may determine in good faith to be
              equitable in the circumstances. Failure of the Board to provide
              for any such adjustment prior to the effective date of any such
              action by the Company affecting the Common Stock will be evidence
              that the Board has


                                       13
<Page>

              determined that it is equitable to make no adjustments in the
              circumstances.

       (J)    VOLUNTARY ADJUSTMENT BY THE COMPANY. The Company may at its
              option, at any time during the term of the Warrants, reduce the
              then current Exercise Price or increase the number of Shares for
              which the Warrant may be exercised to any amount deemed
              appropriate by the Board; PROVIDED, HOWEVER, that if the Company
              elects to make such adjustment, such adjustment will remain in
              effect for at least a 15-day period, after which time the Company
              may, at its option, reinstate the Exercise Price or number of
              Shares in effect prior to such adjustment, subject to any interim
              adjustments pursuant to this Section 13.

       (K)    STATEMENT REGARDING ADJUSTMENTS. Whenever the Exercise Price or
              the number of Shares into which this Warrant is exercisable shall
              be adjusted as provided in this Section 13, the Company shall
              forthwith file, at the principal office of the Company a statement
              showing in reasonable detail the facts requiring such adjustment
              and the Exercise Price that shall be in effect and the number of
              Shares into which this Warrant shall be exercisable after such
              adjustment and the Company shall also cause a copy of such
              statement to be sent by mail, first class postage prepaid, to each
              Warrantholder at the address appearing in the Company's records.

       (L)    NOTICES. In the event that the Company shall give notice or make a
              public announcement to the holders of Common Stock of any action
              of the type described in this Section 13 (but only if the action
              of the type described in this Section 13 would result in an
              adjustment in the Exercise Price or the number of Shares into
              which this Warrant is exercisable or a change in the type of
              securities or property to be delivered upon exercise of this
              Warrant), the Company shall, at the time of such notice or
              announcement, and in the case of any action which would require
              the fixing of a record date, at least 10 days prior to such record
              date, give notice to the Warrantholder, in the manner set forth in
              Section 13(K), which notice shall specify the record date, if any,
              with respect to any such action and the approximate date on which
              such action is to take place. Such notice shall also set forth the
              facts with respect thereto as shall be reasonably necessary to
              indicate the effect on the Exercise Price and the number, kind or
              class of shares or other securities or property which shall be
              deliverable upon exercise of this Warrant. Failure to give such
              notice, or any defect therein, shall not affect the legality or
              validity of any such action.

       (M)    MISCELLANEOUS. Except as provided in this Section 13, no
              adjustment in respect of any dividends or other payments or
              distributions made to Warrantholders of securities issuable upon
              exercise of Warrants will be made during the term of a Warrant or
              upon the exercise of a Warrant. In addition, notwithstanding any
              of the foregoing, no such adjustment will be


                                       14
<Page>

              made for the issuance or conversion of (a) the Series A Warrants,
              Series B Warrants, Series [C][D] Warrants or the Warrants or (b)
              any rights under the Rights Agreement or any successor agreement
              unless such rights become exercisable (in which case they will be
              deemed for purposes of this Warrant to have been issued at the
              time they become exercisable).

       (N)    NO IMPAIRMENT. The Company will not, by amendment of its
              certificate of incorporation or through any reorganization,
              transfer of assets, consolidation, merger, dissolution, issue or
              sale of securities or any other voluntary action, avoid or seek to
              avoid the observance or performance of any of the terms to be
              observed or performed hereunder by the Company, but will at all
              times in good faith assist in the carrying out of all the
              provisions of this Warrant and in taking of all such action as may
              be necessary or appropriate in order to protect the rights of the
              Warrantholder.

14.    RIGHTS. Whenever the Company shall issue shares of Common Stock upon
       exercise of this Warrant, the Company shall issue, together with each
       such share of Common Stock, one right to purchase Series A Junior
       Participating Preferred Stock, $1.00 par value per share, of the Company
       (or other securities in lieu thereof) pursuant to the Rights Agreement,
       or any similar rights issued to holders of Common Stock in addition
       thereto or in the replacement therefor (such rights, together with any
       additional or replacement rights, being collectively referred to as the
       "Rights"), whether or not such Rights shall be exercisable at such time,
       but only if such Rights are issued and outstanding and held by the other
       holders of Common Stock (or evidenced by outstanding share certificates
       representing Common Stock) at such time and have not expired or been
       redeemed.

15.    MERGER OR CONSOLIDATION OF THE COMPANY. The Company will not merge or
       consolidate into, or sell, transfer or lease all or substantially all of
       its property to, any other corporation unless the successor, transferee
       or lessee corporation, as the case may be (if not the Company), (a)
       expressly assumes the due and punctual performance and observance of each
       and every covenant and condition of this Warrant to be performed and
       observed by the Company and (b) expressly agrees to exchange, at the
       Warrantholder's option, this Warrant for a warrant or warrants on such
       surviving corporation's common stock on terms substantially similar to
       the terms under this Warrant.

16.    GOVERNING LAW. THIS WARRANT SHALL BE BINDING UPON ANY SUCCESSORS OR
       ASSIGNS OF THE COMPANY. THIS WARRANT SHALL CONSTITUTE A CONTRACT UNDER
       THE LAWS OF THE STATE OF DELAWARE AND FOR ALL PURPOSES SHALL BE CONSTRUED
       IN ACCORDANCE WITH AND GOVERNED BY THE LAWS OF THE STATE OF DELAWARE,
       WITHOUT GIVING EFFECT TO THE CONFLICT OF LAWS PRINCIPLES.

17.    ATTORNEYS' FEES. A party in breach of this Warrant shall, on demand,
       indemnify and hold harmless the other party for and against all
       reasonable out-of-pocket


                                       15
<Page>

       expenses, including legal fees, incurred by such other party by reason of
       the enforcement and protection of its rights under this Warrant. The
       payment of such expenses is in addition to any other relief to which such
       other party may be entitled.

18.    AMENDMENTS. This Warrant may be amended and the observance of any term of
       this Warrant may be waived only with the written consent of the Company
       and the Warrantholder.

19.    NOTICE. All notices hereunder shall be in writing and shall be effective
       (a) on the day on which delivered if delivered personally or transmitted
       by telex or telegram or telecopier with evidence of receipt, (b) one
       Business Day after the date on which the same is delivered to a
       nationally recognized overnight courier service with evidence of receipt,
       or (c) five Business Days after the date on which the same is deposited,
       postage prepaid, in the U.S. mail, sent by certified or registered mail,
       return receipt requested, and addressed to the party to be notified at
       the address indicated below for the Company, or at the address for the
       Warrantholder set forth in the registry maintained by the Company
       pursuant to Section 9, or at such other address and/or telecopy or telex
       number and/or to the attention of such other person as the Company or the
       Warrantholder may designate by ten-day advance written notice.

              To the Company:

                     Avaya Inc.
                     211 Mount Airy Road
                     Basking Ridge, NJ 07920
                     Attn:  Chief Financial Officer
                     Telephone:  (908) 953-6000
                     Fax:  (908) 953-9875

20.    ENTIRE AGREEMENT. This Warrant and the forms attached hereto contain the
       entire agreement between the parties with respect to the subject matter
       hereof and supersede all prior and contemporaneous arrangements or
       undertakings with respect thereto.


                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]


                                       16
<Page>

       IN WITNESS WHEREOF, the Company has caused this Warrant to be executed by
a duly authorized officer.

Dated: December __, 2002

                                       AVAYA INC.


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



















                                       17
<Page>

                          [FORM OF NOTICE OF EXERCISE]

                              Date: _______________

TO:    Avaya Inc.

RE:    Election to Subscribe for and Purchase
       Common Stock

              The undersigned, pursuant to the provisions set forth in the
attached Warrant, hereby agrees to subscribe for and purchase the number of
shares of the Common Stock set forth below covered by such Warrant. The
undersigned, in accordance with Section 3 of the Warrant, hereby agrees to pay
the aggregate Exercise Price for such shares of Common Stock in the manner set
forth below. A new warrant evidencing the remaining shares of Common Stock
covered by such Warrant, but not yet subscribed for and purchased, should be
issued in the name set forth below. If the new warrant is being transferred, an
opinion of counsel is attached hereto with respect to the transfer of such
warrant.

Number of Shares of Common Stock:
                                  ----------------------------

Method of Payment of Exercise Price:
                                     -------------------------

Name and Address of Person to be
Issued New Warrant:
                    ------------------------------------------

                    ------------------------------------------

                    ------------------------------------------

                    ------------------------------------------



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



                                       18