ip cef

[carl_townshend]

is this enabled by using the ip route-cache function ?

[Martin Parry]

Hi Carl

To enable Cisco Express Forwarding (CEF) on the route processor card, use the ip cef command in global configuration mode.

Regards

Martin

[carl_townshend]

Is this not the same as enabling ip route-cache on the interface ?

[glen.grant]

No it is not , for info on how to configure all the different flavors of fast switching go to

http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_configuration_guide_chapter09186a00800ca7ca.html

[carl_townshend]

what is the difference, which one is better ?

[amit-singh]

Carl,

There is a lot of difference between CEF and fast switching i.e ip route-caching enabled on an interface.

With the Fast switch enabled on the interface it only caches the source and destination IP's and does a destination based packet forwarding while CEF caches the source and destination IP along with the next hop IP addess and also does the destination based load-balancing.

With CEF you have both FIB table and Adjancncy table created which results in faster look up and processing of the packets.

HTH,

-amit singh