Document And Entity Information (USD $)	12 Months Ended
	Oct. 29, 2011	Dec. 09, 2011	Apr. 29, 2011
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Oct. 29, 2011
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
Entity Registrant Name	BROCADE COMMUNICATIONS SYSTEMS INC
Entity Central Index Key	0001009626
Current Fiscal Year End Date	--10-29
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 2,970,054,519
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes
Entity Common Stock, Shares Outstanding		455,071,968