Zsombor explained it pretty well but if you want more detail: http://www.cisco.com/en/US/customer/tech/tk827/tk831/technologies_white_paper09186a00800a62d9.shtml#express
Dave Jans van Deventer wrote: > Does the CEF cache and Fast Switching cache reside in router memory? And > if so what makes CEF faster > than Fast Switching? > > Regards, > Jans > > >>Fast switching builds a forwarding cache on the fly, based on the packets >>that reach the router and need to be switched. CEF builds the "cache" (CEF >>table) based on the routing table, independently from the traffic. >> >>The fast switching cache does not (necessarily) contain all the information >>that's in the routing table; it starts out empty and entries are aged out >>of it later on. Consequently the first packet of every new "session" going >>through the router must be process switched, ie. a routing table lookup and >>cache population need to take place before the packet can be forwarded. >> >>The CEF table always contains all the information that the router has >>access to, it changes (almost) immediately after the router receives a >>routing update. >> >>Thanks, >> >>Zsombor >> >>At 03:17 AM 7/3/2003 +0000, wj chou wrote: >> >> >> >>>Can anyone tell me what's the difference between fast switching and cef >>>switching? >>> >>>thanks first! >>> >>>Ellie >> -- David Madland CCIE# 2016 Sr. Network Engineer Qwest Communications 612-664-3367 "Government can do something for the people only in proportion as it can do something to the people." -- Thomas Jefferson Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71844&t=71815 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
