Exhibit 10.3

MASTER CONTINUING GUARANTY

FOR VALUE RECEIVED, the sufficiency of which is hereby acknowledged, and in consideration of credit and/or financial accommodation heretofore or hereafter from time to time made or granted SONUS NETWORKS, INC., a Delaware corporation (the “Borrower”) by the Lenders, which are party to that certain Credit Agreement (as amended, modified, supplemented or restated, from time to time, the “Credit Agreement”; capitalized terms not defined herein shall have the meaning given such term in the Credit Agreement) dated as of the date hereof among BANK OF AMERICA, N.A., as Administrative Agent, L/C Issuer and Swing Line Lender, any other Lenders from time to time party thereto, and the Borrower, each of the undersigned Guarantors (each a “Guarantor” and collectively, the “Guarantors”) furnishes its guaranty as follows:

1.              Guaranty.  Each Guarantor hereby unconditionally and irrevocably guarantees to Administrative Agent the full and prompt payment when due, whether at stated maturity, by required prepayment, upon acceleration, demand or otherwise, and at all times thereafter, of the Guaranteed Obligations (as hereafter defined) and the punctual performance of all of the terms contained in the documents executed by the Borrower in favor of Administrative Agent and the Lenders in connection with the Guaranteed Obligations. This Guaranty is a guaranty of payment and performance and is not merely a guaranty of collection. As used herein, the term “Guaranteed Obligations” means any and all existing and future indebtedness and liabilities under or with respect to the Loan Documents, including any Secured Cash Management Agreement or any Secured Hedge Agreement, of every kind, nature and character, direct or indirect, absolute or contingent, liquidated or unliquidated, voluntary or involuntary and whether for principal, interest, premiums, fees indemnities, damages, costs, expenses or otherwise, of the Borrower to the Administrative Agent and the Lenders, whether associated with any credit or other financial accommodation made to or for the benefit of the Borrower by the Administrative Agent or the Lenders or otherwise and whenever created, arising, evidenced or acquired  (including all renewals, extensions, amendments, refinancings and other modifications thereof and all costs, attorneys’ fees and expenses incurred by the Administrative Agent  in connection with the collection or enforcement thereof), Without limiting the generality of the foregoing, the Guaranteed Obligations shall include such indebtedness, obligations, and liabilities which may be or hereafter become unenforceable or shall be an allowed or disallowed claim under any proceeding or case commenced by or against the Guarantors or the Borrower under the Bankruptcy Code (Title 11, United States Code), any successor statute or any other liquidation, conservatorship, bankruptcy, assignment for the benefit of creditors, moratorium, rearrangement, receivership, insolvency, reorganization, or similar debtor relief laws of the United States or other applicable jurisdictions from time to time in effect and affecting the rights of creditors generally (collectively, “Debtor Relief Laws”), and shall include interest that accrues after the commencement by or against the Borrower of any proceeding under any Debtor Relief Laws (collectively, the “Guaranteed Obligations”).    Notwithstanding the foregoing, with respect to any Guarantor that is not a Qualified ECP Guarantor, Guaranteed Obligations shall not include any “Excluded Swap Obligations”.  “Excluded Swap Obligations” means, with respect to any Guarantor, any Swap Obligations if, and to the extent that, all or a portion of the Guaranty of such Guarantor of, or the grant by such Guarantor of a security interest to secure, such Swap Obligations (or any Guaranty thereof) is or becomes illegal under the Commodity Exchange Act or any rule, regulation or order of the Commodity Futures Trading Commission (or the application or official interpretation of any thereof) by virtue of such Guarantor’s failure for any reason to constitute an “eligible contract participant” as defined in the Commodity Exchange Act (determined after giving effect to any “keepwell, support or other agreement” for the benefit of such Guarantor and any and all guarantees of such Guarantor’s Swap Obligations by other Loan Parties) at the time the Guaranty of such Guarantor, or a grant by such Guarantor of a security interest, becomes effective with respect to such Swap Obligations. If a Swap Obligation arises under a master agreement governing more than one swap, such exclusion shall apply only to the portion of

such Swap Obligation that is attributable to swaps for which such Guaranty or security interest becomes illegal. “Swap Obligations” means with respect to any Guarantor any obligation to pay or perform under any agreement, contract or transaction that constitutes a “swap” within the meaning of Section 1a (47) of the Commodity Exchange Act. Commodity Exchange Act” means the Commodity Exchange Act (7 U.S.C. § 1 et seq.), as amended from time to time, and any successor statute.  Notwithstanding any provision to the contrary contained herein or in any of the other Loan Documents, Secured Cash Management Agreements or Secured Hedge Agreements, the obligations of each Guarantor under this Guaranty and the other Loan Documents shall be limited to an aggregate amount equal to the largest amount that would not render such obligations subject to avoidance under the Debtor Relief Laws or any comparable provisions of any applicable state law.

2.              No Setoff or Deductions; Taxes; Payments.   Each Guarantor shall make all payments hereunder without setoff or counterclaim and free and clear of and without deduction for any taxes, levies, imposts, duties, charges, fees, deductions, withholdings, compulsory loans, restrictions or conditions of any nature now or hereafter imposed or levied by any jurisdiction or any political subdivision thereof or taxing or other authority therein unless such Guarantor is compelled by law to make such deduction or withholding.  If any such obligation (other than one arising with respect to taxes based on or measured by the income or profits of the Administrative Agent or any Lender) is imposed upon any Guarantor with respect to any amount payable by it hereunder, such Guarantor will pay to the Administrative Agent, on the date on which such amount is due and payable hereunder, such additional amount in U.S. dollars as shall be necessary to enable the Administrative Agent to receive the same net amount which the Administrative Agent would have received on such due date had no such obligation been imposed upon such Guarantor.  Each Guarantor will deliver promptly to the Administrative Agent certificates or other valid vouchers for all taxes or other charges deducted from or paid with respect to payments made by such Guarantor hereunder.  The obligations of each Guarantor under this paragraph shall survive the payment in full of the Guaranteed Obligations and termination of this Guaranty.  At the Administrative Agent’s option, all payments under this Guaranty shall be made in the United States.  The obligations hereunder shall not be affected by any acts of any legislative body or governmental authority affecting the Borrower, including but not limited to, any restrictions on the conversion of currency or repatriation or control of funds or any total or partial expropriation of the Borrower’s property, or by economic, political, regulatory or other events in the countries where the Borrower is located.

3.              Rights of Administrative Agent.  Each Guarantor consents and agrees that the Administrative Agent may, at any time and from time to time, without notice or demand, and without affecting the enforceability or continuing effectiveness hereof:  (a) amend, extend, renew, compromise, discharge, accelerate or otherwise change the time for payment or the terms of the Guaranteed Obligations or any part thereof; (b) take, hold, exchange, enforce, waive, release, fail to perfect, sell, or otherwise dispose of any security for the payment of this Guaranty or any Guaranteed Obligations; (c) apply such security and direct the order or manner of sale thereof as the Administrative Agent in its sole discretion may determine; and (d) release or substitute one or more of any endorsers or other guarantors of any of the Guaranteed Obligations.  Without limiting the generality of the foregoing, each Guarantor consents to the taking of, or failure to take, any action which might in any manner or to any extent vary the risks of such Guarantor under this Guaranty or which, but for this provision, might operate as a discharge of such Guarantor.

4.              Certain Waivers.  Each Guarantor waives to the fullest extent permitted by law(a) any defense arising by reason of any disability or other defense of the Borrower or any other guarantor, or the cessation from any cause whatsoever (including any act or omission of the Administrative Agent) of the liability of the Borrower; (b) any defense based on any claim that such Guarantor’s obligations exceed or are more burdensome than those of the Borrower; (c) the benefit of any statute of limitations affecting such Guarantor’s liability hereunder; (d) any right to require the Administrative Agent to

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proceed against the Borrower, proceed against or exhaust any security for the Guaranteed Obligations, or pursue any other remedy in the Administrative Agent’s power whatsoever and any defense based upon the doctrine of marshalling of assets or of election of remedies; (e) any benefit of and any right to participate in any security now or hereafter held by the Administrative Agent; (f) any fact or circumstance related to the Guaranteed Obligations which might otherwise constitute a defense to the obligations of such Guarantor under this Guaranty and (g) to the fullest extent permitted by law, any and all other defenses or benefits that may be derived from or afforded by applicable law limiting the liability of or exonerating guarantors or sureties other than the defense that the Guaranteed Obligations have been fully performed and indefeasibly paid in full in cash.

Each Guarantor expressly waives all presentments, demands for payment or performance, notices of nonpayment or nonperformance, protests, notices of protest, notices of dishonor and all other notices or demands of any kind or nature whatsoever with respect to the Guaranteed Obligations, and all notices of acceptance of this Guaranty or of the existence, creation or incurrence of new or additional Guaranteed Obligations. This Guaranty shall not be affected by the genuineness, validity, regularity or enforceability of the Guaranteed Obligations or any instrument or agreement evidencing any Guaranteed Obligations, or by the existence, validity, enforceability, perfection, non-perfection or extent of any collateral therefor, or by any fact or circumstance relating to the Guaranteed Obligations which might otherwise constitute a defense to the obligations of the Guarantors under this Guaranty, and each Guarantor hereby irrevocably waives any defenses it may now have or hereafter acquire in any way relating to any or all of the foregoing.

5.              Obligations Independent.  The obligations of each Guarantor hereunder are those of primary obligor, and not merely as surety, and are independent of the Guaranteed Obligations and the obligations of any other guarantor, and a separate action may be brought against any Guarantor to enforce this Guaranty whether or not the Borrower or any other person or entity is joined as a party.

6.              Subrogation.  No Guarantor shall exercise any right of subrogation, contribution, indemnity, reimbursement or similar rights with respect to any payments it makes under this Guaranty until all of the Guaranteed Obligations and any amounts payable under this Guaranty have been indefeasibly paid and performed in full and any commitments of the Administrative Agent or facilities provided by the Administrative Agent with respect to the Guaranteed Obligations are terminated.  If any amounts are paid to any Guarantor in violation of the foregoing limitation, then such amounts shall be held in trust for the benefit of the Administrative Agent and shall forthwith be paid to the Administrative Agent to reduce the amount of the Guaranteed Obligations, whether matured or unmatured.

7.              Termination; Reinstatement.  This Guaranty is a continuing and irrevocable guaranty of all Guaranteed Obligations now or hereafter existing and shall remain in full force and effect until all Guaranteed Obligations and any other amounts payable under this Guaranty are indefeasibly paid in full in cash and any commitments of the Administrative Agent or facilities provided by the Administrative Agent with respect to the Guaranteed Obligations are terminated.  Notwithstanding the foregoing, this Guaranty shall continue in full force and effect or be revived, as the case may be, if any payment by or on behalf of the Borrower or any Guarantor is made, or the Administrative Agent exercises its right of setoff, in respect of the Guaranteed Obligations and such payment or the proceeds of such setoff or any part thereof is subsequently invalidated, declared to be fraudulent or preferential, set aside or required (including pursuant to any settlement entered into by the Administrative Agent in its discretion) to be repaid to a trustee, receiver or any other party, in connection with any proceeding under any Debtor Relief Laws or otherwise, all as if such payment had not been made or such setoff had not occurred and whether or not the Administrative Agent is in possession of or has released this Guaranty and regardless of any prior revocation, rescission, termination or reduction.  The obligations of each Guarantor under this paragraph shall survive termination of this Guaranty.

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8.              Subordination.  Each Guarantor hereby subordinates the payment of all obligations and indebtedness of the Borrower owing to such Guarantor, whether now existing or hereafter arising, including but not limited to any obligation of the Borrower to such Guarantor as subrogee of the Administrative Agent or resulting from such Guarantor’s performance under this Guaranty, to the indefeasible payment in full in cash of all Guaranteed Obligations, provided, however, that nothing in this Guaranty shall limit the incurrence or repayment of such obligations or indebtedness until after the occurrence and during the continuance of an Event of Default.  If the Administrative Agent so requests, any such obligation or indebtedness of the Borrower to such Guarantor shall be enforced and performance received by such Guarantor as trustee for the Administrative Agent and the proceeds thereof shall be paid over to the Administrative Agent on account of the Guaranteed Obligations, but without reducing or affecting in any manner the liability of such Guarantor under this Guaranty.

9.              Stay of Acceleration.  In the event that acceleration of the time for payment of any of the Guaranteed Obligations is stayed, in connection with any case commenced by or against any Guarantor or the Borrower under any Debtor Relief Laws, or otherwise, all such amounts shall nonetheless be payable by such Guarantor immediately upon demand by the Administrative Agent.

10.       Expenses.  Each Guarantor shall pay on demand all out-of-pocket expenses (including reasonable attorneys’ fees and expenses) in any way relating to the enforcement or protection of the Administrative Agent’s rights under this Guaranty or in respect of the Guaranteed Obligations, including any incurred during any “workout” or restructuring in respect of the Guaranteed Obligations and any incurred in the preservation, protection or enforcement of any rights of the Administrative Agent in any proceeding under any Debtor Relief Laws.  The obligations of each Guarantor under this paragraph shall survive the payment in full of the Guaranteed Obligations and termination of this Guaranty.

11.       Miscellaneous.  The Administrative Agent’s books and records showing the amount of the Guaranteed Obligations shall be admissible in evidence in any action or proceeding, and shall be binding upon each Guarantor and conclusive, absent manifest error, for the purpose of establishing the amount of the Guaranteed Obligations.  No provision of this Guaranty may be waived, amended, supplemented or modified, except by a written instrument executed by the Administrative Agent and the Guarantors.  No failure by the Administrative Agent to exercise, and no delay in exercising, any right, remedy or power hereunder shall operate as a waiver thereof; nor shall any single or partial exercise of any right, remedy or power hereunder preclude any other or further exercise thereof or the exercise of any other right, power or remedy.  The remedies herein provided are cumulative and not exclusive of any remedies provided by law or in equity.  The unenforceability or invalidity of any provision of this Guaranty shall not affect the enforceability or validity of any other provision herein.  Unless otherwise agreed by the Administrative Agent and the Guarantors in writing, this Guaranty is not intended to supersede or otherwise affect any other guaranty now or hereafter given by the Guarantors for the benefit of the Administrative Agent or any term or provision thereof.

12.       Condition of Borrowers.  Each Guarantor acknowledges and agrees that it has the sole responsibility for, and has adequate means of, obtaining from the Borrower and any other guarantor such information concerning the financial condition, business and operations of such Borrower and any such other guarantor as such Guarantor requires, and that the Administrative Agent has no duty, and such Guarantor is not relying on the Administrative Agent at any time, to disclose to such Guarantor any information relating to the business, operations or financial condition of the Borrower or any other guarantor (the guarantor waiving any duty on the part of the Administrative Agent to disclose such information and any defense relating to the failure to provide the same).

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13.       Setoff.  If and to the extent any payment is not made when due hereunder, the Administrative Agent may setoff and charge from time to time any amount so due against any or all of the Guarantors’ accounts or deposits with the Administrative Agent.

14.       Representations and Warranties.  Each Guarantor represents and warrants that (a) it is organized under the laws of the United States of America, (b) it is duly organized and in good standing under the laws of the jurisdiction of its organization and has full capacity and right to make and perform this Guaranty, and all necessary authority has been obtained; (c) this Guaranty constitutes its legal, valid and binding obligation enforceable in accordance with its terms; (d) the making, existence, and performance of this Guaranty does not and will not violate the provisions of any applicable law, regulation or order, and does not and will not result in the breach of, or constitute a default or require any consent under, any material agreement, instrument, or document to which it is a party or by which it or any of its property may be bound or affected; and (e) all consents, approvals, licenses and authorizations of, and filings and registrations with, any governmental authority required under applicable law and regulations for the making and performance of this Guaranty have been obtained or made and are in full force and effect.

15.       GOVERNING LAW; Assignment; Jurisdiction; Notices.  THIS GUARANTY SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE INTERNAL LAWS OF THE STATE OF NEW YORK.  This Guaranty shall (a) bind each Guarantor and its successors and assigns, provided that such Guarantor may not assign its rights or obligations under this Guaranty without the prior written consent of the Administrative Agent (and any attempted assignment without such consent shall be void), and (b) inure to the benefit of the Administrative Agent and its successors and assigns and the Administrative Agent may, without notice to the Guarantors and without affecting the Guarantors’ obligations hereunder, assign, sell or grant participations in the Guaranteed Obligations and this Guaranty, in whole or in part.  Each Guarantor hereby irrevocably (i) submits to the non-exclusive jurisdiction of any United States Federal or State court sitting in the State of New York, City of New York in any action or proceeding arising out of or relating to this Guaranty, and (ii) waives to the fullest extent permitted by law any defense asserting an inconvenient forum in connection therewith.  Service of process by the Administrative Agent in connection with such action or proceeding shall be binding on the Guarantors if sent to the Guarantors by registered or certified mail at the address specified below or such other address as from time to time notified by the Guarantors.  Each Guarantor agrees that the Administrative Agent may disclose to any assignee of or participant in, or any prospective assignee of or participant in, any of its rights or obligations of all or part of the Guaranteed Obligations any and all information in the Administrative Agent’s possession concerning such Guarantor, this Guaranty and any security for this Guaranty.  All notices and other communications to the Guarantors under this Guaranty shall be in writing and shall be delivered by hand or overnight courier service, mailed by certified or registered mail or sent by telecopier to the Guarantors at their addresses set forth below or at such other address in the United States as may be specified by the Guarantors in a written notice delivered to the Administrative Agent at such office as the Administrative Agent may designate for such purpose from time to time in a written notice to the Guarantors.

16.       WAIVER OF JURY TRIAL; FINAL AGREEMENT.  TO THE EXTENT ALLOWED BY APPLICABLE LAW, EACH GUARANTOR AND THE ADMINISTRATIVE AGENT EACH IRREVOCABLY WAIVES TRIAL BY JURY WITH RESPECT TO ANY ACTION, CLAIM, SUIT OR PROCEEDING ON, ARISING OUT OF OR RELATING TO THIS GUARANTY OR THE GUARANTEED OBLIGATIONS.  THIS GUARANTY REPRESENTS THE FINAL AGREEMENT BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS BETWEEN THE PARTIES.  THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.

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18.       Foreign Currency.  If the Administrative Agent so notifies the Guarantors in writing, at the Administrative Agent’s sole and absolute discretion, payments under this Guaranty shall be the U.S. Dollar equivalent of the Guaranteed Obligations or any portion thereof, determined as of the date payment is made.  If any claim arising under or related to this Guaranty is reduced to judgment denominated in a currency (the “Judgment Currency”) other than the currencies in which the Guaranteed Obligations are denominated or the currencies payable hereunder (collectively the “Obligations Currency”), the judgment shall be for the equivalent in the Judgment Currency of the amount of the claim denominated in the Obligations Currency included in the judgment, determined as of the date of judgment.  The equivalent of any Obligations Currency amount in any Judgment Currency shall be calculated at the spot rate for the purchase of the Obligations Currency with the Judgment Currency quoted by the Administrative Agent in the place of the Administrative Agent’s choice at or about 8:00 a.m. on the date for determination specified above.  Each Guarantor shall indemnify the Administrative Agent and hold the Administrative Agent harmless from and against all loss or damage resulting from any change in exchange rates between the date any claim is reduced to judgment and the date of payment thereof by such Guarantor or any failure of the amount of any such judgment to be calculated as provided in this paragraph.

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Executed this        day of                                 , 2014.

[Signature Page to Guaranty]