NETSCOUT SYSTEMS, INC.
1999 STOCK OPTION AND INCENTIVE PLAN, AS AMENDED
1. PURPOSE AND ELIGIBILITY
The purpose of this 1999 Stock Option and Incentive Plan, as amended (the "PLAN") of NetScout Systems,
Inc. (the "COMPANY") is to provide stock options and other equity interests in the Company (each an
"AWARD") to employees, officers, directors, consultants and advisors of the Company and its Subsidiaries, all
of whom are eligible to receive Awards under the Plan. Any person to whom an Award has been granted under
the Plan is called a "PARTICIPANT". Additional definitions are contained in Section 8.
a. ADMINISTRATION BY BOARD OF DIRECTORS. The Plan will be administered by the Board of
Directors of the Company (the "BOARD"). The Board, in its sole discretion, shall have the authority to grant and
amend Awards, to adopt, amend and repeal rules relating to the Plan and to interpret and correct the provisions
of the Plan and any Award. All decisions by the Board shall be final and binding on all interested persons. Neither
the Company nor any member of the Board shall be liable for any action or determination relating to the Plan.
b. APPOINTMENT OF COMMITTEES. To the extent permitted by applicable law, the Board may delegate
any or all of its powers under the Plan to one or more committees or subcommittees of the Board (a
"COMMITTEE"). All references in the Plan to the "BOARD" shall mean such Committee or the Board.
c. DELEGATION TO EXECUTIVE OFFICERS. To the extent permitted by applicable law, the Board may
delegate to one or more executive officers of the Company the power to grant Awards and exercise such other
powers under the Plan as the Board may determine, PROVIDED THAT the Board shall fix the maximum
number of Awards to be granted and the maximum number of shares issuable to any one Participant pursuant to
Awards granted by such executive officers.
3. STOCK AVAILABLE FOR AWARDS
a. TYPE OF SECURITY; NUMBER OF SHARES. For purposes of this Plan, the