Couple of other minor points to add. The fast switching cache is on the RSP and uses it's memory as does CEF. You can distribute the CEF tables to VIP (versatile interface processors) cards. This enables the VIP cards to store and process the packets based on the CEF tables on the VIP cards. Uses memory and CPU on the VIP and hence frees up the RSP for other tasks.
We use distributed CEF quite a bit along with Turbo ACL's for better performance. Ian www.ccie4u.com Rack Rentals -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Zsombor Papp Sent: Thursday, July 03, 2003 2:43 PM To: [EMAIL PROTECTED] Subject: Re: fast switching v.s. cef switching [7:71815] At 04:37 PM 7/3/2003 +0000, Jans van Deventer wrote: >Does the CEF cache and Fast Switching cache reside in router memory? Yes. > And >if so what makes CEF faster >than Fast Switching? The cache structure is more efficient. Thanks, Zsombor >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 >-- >================================ >Jans van Deventer >Phone: (55-61) 361-1466 >Fax: (55-61) 234-8722 >www.rhox.com.br >================================ Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71862&t=71862 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
