ip route-cache cef

vinodbharwani · ‎06-06-2007

hi

Can anybody tell me ip route-cache cef commnd do ...

Please share good documents

Jon Marshall · ‎06-06-2007

Hi

It turns on CEF switch (CEF = Cisco Express Forwarding).

Attached is an introductory paper on different switching types you can use with Cisco. There is a section on CEF.

http://www.cisco.com/en/US/tech/tk827/tk831/technologies_white_paper09186a00800a62d9.shtml

HTH

Jon

bvsnarayana03 · ‎06-06-2007

Hi,

Switching methods that routers use, define the way how pkts are handled by router. There are 3 methods:

Process Switching: legacy switching type. Each & evry pkt does a routing lookup to find reachability to destination, next-hop, & the interface from where next-hop is available.

Fast Switching: 1st pkt is process switched. Stores the info in a cache, thus reduce the router lookup time for following pkt to same destination. The cache info is timed out at regular intervals.

CEF: no process switching for 1st pkt. Router builds 2 tables, cef table that defines reachability of network, & adjacenccy table to define the next-hop & interface via which nxt-hop is reachable. Cache is not aged out.