CEF should be called Customer Enrangement Feature. It is a very very very bad idea to have linecards be anything else than forwarders. They should not make any intelligent routing decisions. There should not be a tons of copies of routing table on line cards. That is what creates problems.
Alex
CEF allows linecards to be forwarders. They don't make any routing decisions, they just forward packets according to a routing table. (Routing = deciding where packets should go, ie building a routing table. Forwarding = sending packets to their destination, ie using a routing table.) The reality is that having only one copy of the routing table creates an inevitable bottleneck. For the same reasons this won't work on a regional network, it won't work on a single router if the router is sufficiently complex. The same techniques that work to scale the Internet as a whole work inside a box. Why do you think central fowarding is superior to distributed forwarding? DS