Exhibit 32.1

CERTIFICATION OF PRINCIPAL EXECUTIVE OFFICER AND PRINCIPAL FINANCIAL OFFICER

PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO SECTION 906

OF THE SARBANES-OXLEY ACT OF 2002

I, Jayshree Ullal, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that the Annual Report of Arista Networks, Inc. on Form 10-K for the fiscal year ended December 31, 2015 fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 and that the information contained in such Annual Report on Form 10-K fairly presents in all material respects the financial condition and results of operations of Arista Networks, Inc.

Date: February 25, 2016

By:	/s/ JAYSHREE ULLAL
Name:	Jayshree Ullal
Title:	President, Chief Executive Officer and Director
	(Principal Executive Officer)

I, Ita Brennan, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that the Annual Report of Arista Networks, Inc. on Form 10-K fiscal year ended December 31, 2015 fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 and that the information contained in such Annual Report on Form 10-K fairly presents in all material respects the financial condition and results of operations of Arista Networks, Inc.

Date: February 25, 2016

By:	/s/ ITA BRENNAN
Name:	Ita Brennan
Title:	Chief Financial Officer
	(Principal Financial Officer and Principal Accounting Officer)