Cosine Communications (COSN) 10-Q 2005 Q1 Quarterly report

EXHIBIT 32.1

CERTIFICATION PURSUANT TO
18 U.S.C. SECTION 1350
AS ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

     In connection with the Quarterly Report of Cosine Communications, Inc. (the “Company”) on Form 10-Q for the quarterly period ended March 31, 2005 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Terry Gibson, Director, Chief Executive Officer and Chief Financial Officer of the Company, certify, pursuant to 18 U.S.C. section 1350, as adopted pursuant to section 906 of the Sarbanes-Oxley Act of 2002, that, to my knowledge:

(1)	The Report fully complies with the requirements of section 13(a) of the Securities Exchange Act of 1934; and
(2)	The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ Terry Gibson
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Terry Gibson
Director, Chief Executive Officer and Chief Financial Officer
May 13, 2005