nanog mailing list archives
RE: gigabit router (was Re: Getting a "portable" /19 or /20)
From: <alex () yuriev com>
Date: Tue, 10 Apr 2001 20:56:05 -0400 (EDT)
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
Current thread:
- Re: Getting a "portable" /19 or /20, (continued)
- Re: Getting a "portable" /19 or /20 Adrian Chadd (Apr 10)
- Re: Getting a "portable" /19 or /20 Henry Yen (Apr 10)
- Re: Getting a "portable" /19 or /20 Valdis . Kletnieks (Apr 10)
- Re: Getting a "portable" /19 or /20 Adrian Chadd (Apr 10)
- Re: Getting a "portable" /19 or /20 Richard A. Steenbergen (Apr 10)
- Re: Getting a "portable" /19 or /20 Greg Maxwell (Apr 10)
- Re: Getting a "portable" /19 or /20 Richard A. Steenbergen (Apr 10)
- gigabit router (was Re: Getting a "portable" /19 or /20) Craig Partridge (Apr 10)
- Re: gigabit router (was Re: Getting a "portable" /19 or /20) Richard A. Steenbergen (Apr 10)
- Re: gigabit router (was Re: Getting a "portable" /19 or /20) alex (Apr 10)
- RE: gigabit router (was Re: Getting a "portable" /19 or /20) David Schwartz (Apr 10)
- RE: gigabit router (was Re: Getting a "portable" /19 or /20) alex (Apr 10)
- RE: gigabit router (was Re: Getting a "portable" /19 or /20) David Schwartz (Apr 11)
- Re: gigabit router (was Re: Getting a "portable" /19 or /20) Matt Zimmerman (Apr 11)
- Re: gigabit router (was Re: Getting a "portable" /19 or /20) Craig Partridge (Apr 11)
- Re: gigabit router (was Re: Getting a "portable" /19 or /20) Brett Frankenberger (Apr 11)
- Re: Getting a "portable" /19 or /20 Greg Maxwell (Apr 10)
- Re: gigabit router (was Re: Getting a "portable" /19 or /20) Richard A. Steenbergen (Apr 10)
- Re: gigabit router (was Re: Getting a "portable" /19 or /20) Rafi Sadowsky (Apr 11)
- Re: gigabit router (was Re: Getting a "portable" /19 or /20) Craig Partridge (Apr 10)
- Re: gigabit router (was Re: Getting a "portable" /19 or /20) Greg Maxwell (Apr 10)
- Re: gigabit router (was Re: Getting a "portable" /19 or /20) Richard A. Steenbergen (Apr 10)
- Re: gigabit router (was Re: Getting a "portable" /19 or /20) Peter Galbavy (Apr 11)