EMPLOYMENT AGREEMENT

Exhibit 10.1

EMPLOYMENT AGREEMENT

THIS EMPLOYMENT AGREEMENT (the “Agreement”) is made and entered into as of May 11, 2009, between Ixia, a California corporation (“Employer”), and Richard A. Karp (“Executive”).

RECITALS

A. Prior to the execution of this Agreement, Executive has been an employee of Catapult Communications Corporation (“Chariot”).

B. Employer has executed or plans to execute an Agreement and Plan of Merger (the “Merger Agreement”) providing for the merger of a newly-formed subsidiary with and into Chariot, resulting in Chariot becoming a wholly-owned subsidiary of Employer (the “Transaction”).

C. If the Closing (as defined in the Merger Agreement) of the Transaction occurs, Employer desires to obtain the benefit of Executive’s service to Employer, and Executive is willing to perform such services for Employer on the terms and conditions hereinafter set forth.

D. Employer has expended and will continue to expend a great deal of time, money and effort to develop and maintain its proprietary, trade secret and other confidential business information which, if misused or disclosed, could be very harmful to its business, including the Business (as defined in the Merger Agreement) to be conducted by Employer after the Closing (the “Buyer Business”).

E. Executive is the owner of approximately 25% of the issued and outstanding shares of capital stock of Chariot. Upon the Closing, Employer will acquire all of Employee’s ownership interest in Chariot, and Executive will receive from Employer in the Transaction substantial consideration in exchanges for such shares.

F. Employer is unwilling to consummate the Transaction unless Executive agrees herein (i) to commence employment with Executive as of the Effective Date pursuant to this Agreement, and (ii) not to compete with Employer and the Buyer Business, as specified herein.

G. Executive acknowledges that (i) the services previously provided by him for Chariot and the Business and the services to be performed by him for Employer and the Buyer Business (as defined herein) are and will be of a special and unique character, and (ii) in order to assure Employer that the Buyer Business will retain its value as a going concern and to preserve the goodwill associated with the Buyer Business, it is necessary that Executive undertake not to utilize his special knowledge of Chariot, the Business, Employer and the Buyer Business, to compete with Employer and the Buyer Business as set forth herein.

NOW, THEREFORE, in consideration of the provisions and the mutual covenants of the parties hereinafter set forth, it is hereby agreed as follows:

AGREEMENT

     1. Effective Date. Executive’s employment under this Agreement will commence on the date on which the Effective Time occurs, as described in Section 3 of the Merger Agreement (the “Effective Date”).

     2. Employment and Duties

          2.1 Full-Time Employment Period. During the six-month period commencing on the Effective Date (the “Full-Time Employment Period”), Executive will perform services for Employer in the position of Chief Evangelist, Wireless, or in such other capacity or capacities as may be approved from time to time by Employer’s Board of Directors (the “Board”), and shall report directly to Atul Bhatnagar or such other officer of Employer as may be designated by the Board. In such capacity or capacities, Executive shall have such responsibilities, duties and authority as may from time to time be assigned to Executive by Executive’s supervisor. Executive will perform his duties at the offices of Employer to be located from time to time in or near Santa Clara, California, provided that Executive may be required to do reasonable traveling in connection with the performance of his duties hereunder. Employer agrees to continue the employment of Executive’s assistant at Chariot for a period of six months following the Effective Date, on the same terms and conditions of employment as are in effect as of May 10, 2009 and provided that the assistant shall also provide support to other Chariot and Employer personnel assigned to her.

          2.2 Part-Time Employment Period.. During the eighteen-month period commencing immediately upon expiration of the Full-Time Employment Period (the “Part-Time Employment Period” and, together with the Full-Time Employment Period, the “Employment Period”), Employer shall continue to engage Executive on a part-time basis. Executive shall be required to perform up to 40 hours of services (in eight-hour, one -day increments) for Employer in each consecutive 90-day period during the Part-Time Employment Period, during such weeks that are mutually agreeable to Executive and Employer, and shall continue to have such responsibilities, duties and authority as may from time to time be assigned to Executive by Executive’s supervisor. Executive will continue to perform his duties at the offices of Employer to be located from time to time in or near Santa Clara, California, provided that Executive may be required to do reasonable traveling in connection with the performance of his duties hereunder.

     3. Exclusive Service; Compliance with Agreement, Law and Policies. During the Full-Time Employment Period, Executive will loyally devote his exclusive and full-time efforts to his employment with Employer hereunder. During the Employment Period, Executive will comply with the terms of this Agreement, with all applicable laws and with the policies and procedures of Employer applicable to officers of Employer. Executive may perform work for other entities (whether as an employee or consultant) during the Part-Time Employment Period, so long as he is not in violation of any other provision of this Agreement.

     4. Term of Agreement. The term of this Agreement will commence on the Effective Date and will continue until (i) the close of business on the second-year anniversary of the Effective Date (or the most recent business day prior thereto if such date is not a business day); or (ii) the earlier termination of this Agreement pursuant to Section 6 hereof. Notwithstanding anything hereinto the contrary, Executive’s employment with Employer during the Employment Period shall at all times be “at-will,” meaning that Executive may resign at any time and that Employer reserves

the right at any time to terminate Executive’s employment and this Agreement, for any or no particular reason or cause, subject to the provisions set forth in Sections 6 and 7. The “at-will” nature of Executive’s employment cannot be changed except by an express written agreement which must be signed by an executive officer of Employer. Termination of this Agreement shall result in the contemporaneous termination of the Employment Period.

     5. Compensation and Benefits.

          5.1 Base Salary. As compensation for services rendered under this Agreement during the Full-Time Employment Period, provided Executive is not in default of any obligation hereunder, Executive shall be paid an aggregate base salary of $160,000, payable in accordance with Employer’s standard payroll schedules in effect from time to time and subject to usual and required employee payroll deductions, withholding and reductions. During the Part-Time Employment Period, provided Executive is not in default of any obligation hereunder, Executive shall be paid $500 for each day on which services are rendered under this Agreement. During the Part-Time Employment, Executive shall also be entitled to compensation in the form of the continued vesting of the Options (as described in Section 5.4) and any COBRA (as defined herein) benefits provided in Section 5.3(b).

          5.2 Bonus Plans. Executive acknowledges that Employer has not adopted an officer bonus plan applicable to the Employment Period and, therefore, Executive shall not be entitled to participate in any bonus plan during the Employment Period.

          5.3 Additional Benefits.

               (a) During the Full-Time Employment Period, Executive will be eligible to participate in Employer’s employee benefit plans that are applicable to executive officers, including, without limitation, any plans covering medical, dental, vision, life and disability, 401(k) plans and educational assistance programs. Any such participation in such employee benefit plans will be subject to the terms, conditions and limitations contained in the applicable plan documents and/or policies, as well as applicable law; provided, however, that, to the extent permitted under such plans, for purposes of his participation in, and vesting in the benefits under, such plans, he shall be credited with his service to Chariot prior to the Effective Date. In general, Executive will receive such benefits during the Full-Time Employment Period as Employer provides to its executive officers, it being understood that Employer retains the right to establish, change or terminate any such plans, programs and benefits from time to time at its sole discretion. Additionally, Executive shall be entitled to paid vacation from July 20, 2009 through August 6, 2009, and one additional week of paid vacation in October 2009, during a week that is mutually agreeable to Employer and Executive.

               (b) During the Part-Time Employment Period, Employer shall pay Executive’s premiums for coverage of Executive and his eligible dependents under the Consolidated Omnibus Budget Reconciliation Act “(“COBRA”).

          5.4 Equity Incentive. Within 30 days following the Effective Date, Employer shall grant to Executive nonstatutory stock options to acquire up to 150,000 shares of Employer’s common stock (the “Options”) under Employer’s 2008 Equity Incentive Plan. Such Options will vest in eight equal quarterly installments commencing on September 30, 2009 and continuing

through the term of this Agreement. The Options will in all respect be subject to the terms and provisions of Employer’s 2008 Equity Incentive Plan and the agreement evidencing the Options; provided , however , that, notwithstanding anything to the contrary that may be contained in the applicable equity incentive plan and/or the agreement evidencing the Options, Executive will have twenty-four (24) months following the date the Employment Period is terminated in which to exercise any outstanding Options. Furthermore, all outstanding Options will vest in full as to 100% of the unvested portion of the Option upon termination of the Employment Period if, and only if, such termination is by Employer without Cause (as defined below) or by Executive with Good Reason (as defined below).

          5.5 Expenses. Executive will be reimbursed for all reasonable and necessary expenses incurred by Executive in performing his duties hereunder, provided that such expenses are in accordance with the Employer’s applicable policies and are properly documented and accounted for in accordance with such policies. Notwithstanding the foregoing, Executive shall be entitled to business class air travel (or, if traveling on a flight with only two classes of service, the class above economy/coach), and hotel accommodations of Executive’s choice.

     6. Termination.

          6.1 General. Further to Section 4 of this Agreement, this Agreement and Executive’s employment with Employer hereunder may be terminated at any time as follows:

               (a) Mutual Written Agreement. Employer and Executive may agree in writing to terminate this Agreement and the Employment Period.

               (b) Termination by Employer. Employer may terminate this Agreement and the Employment Period hereunder at any time at Employer’s sole discretion, with or without “Cause” (as defined under Section 6.2 below), effective immediately or as of such other time as may be agreed by the parties, by giving written notice to Executive (except that no notice is required to be given in the event of Executive’s death, in which case this Agreement and Executive’s employment hereunder will automatically terminate). If Employer is effecting any such termination for Cause, Employer shall state in the notice that the termination is for Cause and the basis for such termination under Section 6.2.

               (c) Resignation by Executive. Executive may terminate this Agreement and the Employment Period at any time, with or without “Good Reason” (as defined under Section 6.3 below), effectively immediately or as of such other time as may be agreed by the parties, by giving written notice to Employer. If Executive is effecting any such resignation for Good Reason, Executive shall state in the notice that the termination is for Good Reason and the basis for such termination under Section 6.3; provided , however , that Executive’s resignation shall only be deemed to have been for Good Reason if he provides the written notice to Employer of his resignation and of the existence of Good Reason within 90 days after the initial existence of the condition and Employer then fails to remedy the condition within 30 days after receipt of such notice.

               (d) Death or Disability of Executive. This Agreement shall automatically terminate upon the death of Executive or a determination that Executive has a long-term disability. For purposes of this Agreement, “long-term disability” shall mean a condition which substantially

impairs Executive’s ability to perform his obligations hereunder for at least 90 consecutive work days or for any 90 work days during any 180-day period.

Executive acknowledges and agrees that the transfer of Executive to another Employer Entity (as defined below) or to different division of Employer shall not be deemed to be a termination of the Employment Period and shall not constitute Good Reason in the absence of any other specific event set forth in the definition of Good Reason under Section 6.2 below.

          6.2 Cause Defined. For purposes of this Agreement, “Cause” for Executive’s termination by Employer will exist at any time after the happening of one or more of the following events following the Effective Date:

               (a) willful refusal or failure to follow one or more important Employer policies, including without limitation those set forth in the Code;

               (b) any conduct amounting to gross incompetence;

               (c) refusal or failure to perform material, appropriate duties;

               (d) embezzlement, misappropriation of any property or other asset of Employer or misappropriation of a corporate opportunity of Employer;

               (e) conviction of Executive for or the entering of a plea of nolo contendere with respect to any felony whatsoever or for any misdemeanor involving moral turpitude;

               (f) unlawful use (including being under the influence) or possession of illegal drugs on Employer’s premises;

               (g) any material breach of Executive’s obligations under this Agreement other than his obligations under Sections 8 (Executive Non-Compete and Non-Solicitation) and 9 (Confidentiality and Assignment of Inventions) of this Agreement; or

               (h) any breach by Executive of his obligations under Sections 8 (Executive Non-Compete and Non-Solicitation) and 9 (Confidentiality and Assignment of Inventions) of this Agreement or any other nondisclosure or proprietary agreement with or on behalf of Employer;

provided, however, that for any acts described under sections (a), (b), (c) and (g), Employer must provide written notice to Executive of the actions constituting Cause, with such notice to state that Employer believes such actions constitute Cause, and allow Executive ten days to cure such events, which period can be extended by up to five days in the event that Executive is outside the United States on Company business during the ten-day period, in which case the ten-day period shall be extended for such number of days (up to five days) as Executive is outside the United States.

          6.3 “Good Reason” Defined. For purposes of this Agreement, “Good Reason” means, without the express written consent of Executive, the occurrence of one or more of the following events after the Effective Date:

               (a) a reduction by Employer in Executive’s base salary;

               (b) Employer’s requiring Executive to be based for two consecutive months or more at an office more than 30 miles from Santa Clara, California;

               (c) the assignment to Executive of duties materially inconsistent with the duties associated with Executive’s position upon commencement of his employment with Employer on the Effective Date; or

               (d) the material breach of Employer’s obligations to Executive under this Agreement if such breach has not been cured within ten days after written notice from Executive to Employer (and provided that any such written notice from Executive shall be required to state that Executive believes the breach constitutes a basis for Good Cause termination under this Agreement).

     7. Effect of Termination or Resignation.

          7.1 Termination by Employer for Cause, Death or Disability or Resignation by Executive without Good Reason. In the event of any termination of this Agreement and Employer’s employment of Executive by Employer hereunder either as a result of termination by Employer for Cause, as a result of Executive’s death or long-term disability or resignation by Executive other than for Good Reason:

               (a) Employer shall pay Executive (or Executive’s executor or personal representative in the case of death) the compensation and benefits accrued and payable to Executive under Section 5 through the date of such termination; and

               (b) Executive’s (or Executive’s executor’s or personal representative’s in the case of death) rights following any such termination under Employer’s equity incentive plans and under Employer’s benefit plans of applicable to executive officers, including without limitation any medical, dental, vision, life, disability and 401(k) plans then in effect, shall be determined under the provisions of those plans for terminated employees.

          7.2 Termination by Employer without Cause or Resignation by Executive with Good Reason. In the event of any termination of this Agreement and the Employment Period hereunder either as a result of termination by Employer without Cause or resignation by Executive for Good Reason:

               (a) Employer shall pay to Executive the compensation and benefits payable to Executive under Section 5 through the date of such termination; provided , that, if such termination occurs prior to the expiration of the Full-Time Employment Period, Employer shall pay to Executive the base salary payable to Executive under Section 5 through the end of the Full-Time Employment Period;

               (b) Employer shall continue to pay Executive’s COBRA through the Part-Time Employment Period to the extent required by Section 5.3(b); and

               (c) Executive’s rights following any such termination under Employer’s equity incentive plans and under Employer’s benefit plans applicable to executive officers, including

without limitation any medical, dental, vision, life, disability and 401(k) plans then in effect but excluding any general severance policies of Employer, shall be determined under the provisions of those plans for terminated employees.

          7.3 Termination Covered by Chariot Change in Control Agreement. Executive shall remain eligible for severance benefits under his existing change in control severance benefits agreement with Chariot, subject to the terms and conditions of that agreement, upon the termination of his employment with Employer.

     8. Non-Compete and Non-Solicitation.

          8.1 So long as Executive is an employee of or a consultant to Employer or any affiliated entity (each, an “Employer Entity”) and in any event until the five-year anniversary of the Effective Date (the “Non-Compete Period”) and in addition to and not in limitation of all other applicable obligations of Executive hereunder, Executive shall not, directly or indirectly, either for himself or for any other person or entity, directly or indirectly:

               (a) engage in any business or venture that competes, directly or indirectly, with the Buyer Business as conducted by any Employer Entity on or after the Effective Date (a “Competing Business Activity”) or enter into an employment, consulting or agency relationship with any entity or person engaging in such a Competing Business Activity (a “Competitive Business”);

               (b) call upon or cause to be called upon, or solicit or assist in the solicitation of, in connection with any Competing Business Entity or Competing Business Activity, any entity, agency, person, firm, association, partnership or corporation that was a customer of Chariot prior to the Effective Date or that is a customer of any Employer Entity during the Non-Compete Period for the purpose of selling, licensing or supplying any products or services that are the same as, similar to or competitive with the products or services sold or developed by the Business as conducted by Chariot prior to the Effective Date and/or the Buyer Business as conducted by any Employer Entity on or after the Effective Date; and/or

               (c) solicit, induce or attempt to solicit or induce any person to leave his or her employment, agency, directorship or office with any Employer Entity.

          8.2 Employer and Executive specifically acknowledge and agree that the covenants set forth in Section 8.1 are commercially reasonable and reasonably necessary, including without limitation with respect to time period, geographic area and scope of business, to protect the interest in Chariot that Employer will acquire in the Transaction.