Sec Form 4 Filing - GAYNOR MITCHELL L @ JUNIPER NETWORKS INC - 2012-02-17

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person GAYNOR MITCHELL L 2. Issuer Name and Ticker or Trading Symbol JUNIPER NETWORKS INC [ JNPR] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) EVP General Counsel (Last) (First) (Middle) 1194 NORTH MATHILDA AVENUE 3. Date of Earliest Transaction (MM/DD/YY) 02/17/2012 (Street) SUNNYVALE, CA94089 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 02/20/2012 M 19,481 ( 1 ) A $ 0 ( 2 ) 31,894 D Common Stock 02/20/2012 F( 3 ) 7,236 D $ 24.2 24,658 D Common Stock 02/21/2012 S 12,245 D $ 24.1102 12,413 D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Non-Qualified Stock Option (right to buy) $ 24.2 02/17/2012 A 90,000 02/17/2013( 4 ) 02/17/2019 Common Stock 90,000 $ 0 ( 5 ) 90,000 D Performance Shares $ 0 ( 2 ) 02/20/2012 M 19,481 ( 6 ) 02/20/2012 03/01/2012 Common Stock 19,481 $ 0 ( 5 ) 0 D Performance Shares $ 0 02/17/2012 A 75,000 ( 7 ) 02/20/2015( 8 ) 02/20/2015 Common Stock 75,000 $ 0 ( 5 ) 75,000 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other GAYNOR MITCHELL L 1194 NORTH MATHILDA AVENUE SUNNYVALE, CA94089 EVP General Counsel Signatures Mitchell L Gaynor 02/21/2012 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents the issuance of common stock pursuant to the vest of performance share award. ( 2 )Represents the per share price for the award. ( 3 )Represents shares withheld from the released share award for the payment of applicable income and payroll withholding taxes due on release. ( 4 )Vests as to 25% of the shares subject to the option one year from the grant date and the balance shall vest 1/48th of the total shares granted each month thereafter. ( 5 )Column 8 is not an applicable reportable field. ( 6 )Represents acquistion of shares vested under the performance share award granted 2/20/2009. The shares vest on the third year anniversary of the grant date and upon determination of the achievement of certain Company performance targets over the three year period. ( 7 )Represents the maximum quantity of shares issuable. The exact number of shares issuable with respect to each year will be determined based on achievement of certain Company performance targets for each year, as determined by the Compensation Committee of the Board. The executive can earn between 0% and 250% of the target shares with respect to each year. ( 8 )All of the shares earned over the three year period will vest, provided that the reporting person is still providing service to the Company, after the final calculation is approved by the Compensation Committee.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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