Guarantor And Non-Guarantor Subsidiaries (Schedule Of Consolidated Statement Of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Apr. 28, 2012	Apr. 30, 2011
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	$ 267,319	$ 231,941
Purchases of short-term investments	0	(38)
Proceeds from maturities and sale of short-term investments	0	20
Proceeds from sale of subsidiary	35
Purchases of property and equipment	(38,269)	(50,575)
Net cash used in investing activities	(38,234)	(50,593)
Payment of principal related to the term loan	(120,000)	(98,640)
Payment of principal related to capital leases	(920)	(868)
Common stock repurchases	(25,066)	0
Proceeds from issuance of common stock	47,261	47,388
Excess tax benefits (detriments) from stock-based compensation	1,332	(877)
Net cash used in financing activities	(97,393)	(52,997)
Effect of exchange rate fluctuations on cash and cash equivalents	(1,555)	1,227
Net increase in cash and cash equivalents	130,137	129,578
Cash and cash equivalents, beginning of period	414,202	333,984
Cash and cash equivalents, end of period	544,339	463,562
Brocade Communications Systems, Inc. [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	215,395	147,352
Purchases of short-term investments		0
Proceeds from maturities and sale of short-term investments		0
Proceeds from sale of subsidiary	35
Purchases of property and equipment	(32,841)	(44,897)
Net cash used in investing activities	(32,806)	(44,897)
Payment of principal related to the term loan	(120,000)	(98,640)
Payment of principal related to capital leases	(920)	(868)
Common stock repurchases	(25,066)
Proceeds from issuance of common stock	47,261	47,388
Excess tax benefits (detriments) from stock-based compensation	1,332	(1,044)
Net cash used in financing activities	(97,393)	(53,164)
Effect of exchange rate fluctuations on cash and cash equivalents	0	0
Net increase in cash and cash equivalents	85,196	49,291
Cash and cash equivalents, beginning of period	101,366	23,455
Cash and cash equivalents, end of period	186,562	72,746
Subsidiary Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	1,260	3,067
Purchases of short-term investments		(38)
Proceeds from maturities and sale of short-term investments		20
Proceeds from sale of subsidiary	0
Purchases of property and equipment	0	(18)
Net cash used in investing activities	0	(36)
Payment of principal related to the term loan	0	0
Payment of principal related to capital leases	0	0
Common stock repurchases	0
Proceeds from issuance of common stock	0	0
Excess tax benefits (detriments) from stock-based compensation	0	0
Net cash used in financing activities	0	0
Effect of exchange rate fluctuations on cash and cash equivalents	0	0
Net increase in cash and cash equivalents	1,260	3,031
Cash and cash equivalents, beginning of period	1,528	6,907
Cash and cash equivalents, end of period	2,788	9,938
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	50,664	81,522
Purchases of short-term investments		0
Proceeds from maturities and sale of short-term investments		0
Proceeds from sale of subsidiary	0
Purchases of property and equipment	(5,428)	(5,660)
Net cash used in investing activities	(5,428)	(5,660)
Payment of principal related to the term loan	0	0
Payment of principal related to capital leases	0	0
Common stock repurchases	0
Proceeds from issuance of common stock	0	0
Excess tax benefits (detriments) from stock-based compensation	0	167
Net cash used in financing activities	0	167
Effect of exchange rate fluctuations on cash and cash equivalents	(1,555)	1,227
Net increase in cash and cash equivalents	43,681	77,256
Cash and cash equivalents, beginning of period	311,308	303,622
Cash and cash equivalents, end of period	354,989	380,878
Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	0	0
Purchases of short-term investments		0
Proceeds from maturities and sale of short-term investments		0
Proceeds from sale of subsidiary	0
Purchases of property and equipment	0	0
Net cash used in investing activities	0	0
Payment of principal related to the term loan	0	0
Payment of principal related to capital leases	0	0
Common stock repurchases	0
Proceeds from issuance of common stock	0	0
Excess tax benefits (detriments) from stock-based compensation	0	0
Net cash used in financing activities	0	0
Effect of exchange rate fluctuations on cash and cash equivalents	0	0
Net increase in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	$ 0	$ 0