gigabit router (was Re: Getting a "portable" /19 or /20)

Wed Apr 11 00:56:05 UTC 2001

> > 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.

> 	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.)

Excellent idea. Why, pray tell, then there is such things as "show cef
drop" and "show cef not-cef-switched"?

> 	The reality is that having only one copy of the routing table
> creates an inevitable bottleneck.

Wrong answer. Routing table != forwarding table

> 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.

Wrong answer again. Routing view != forwarding table

> The same techniques that work to scale the Internet as a whole work inside
> a box.

Wrong answer again. 

> 	Why do you think central fowarding is superior to distributed forwarding?

Because you will have consistency problem. You are nearly 100% guaranteed to
have them.

> 	DS

Alex