nanog mailing list archives

Re: Load balancing in routers


From: "Stephen Sprunk" <ssprunk () cisco com>
Date: Mon, 8 Apr 2002 11:49:16 -0500


Thus spake "joe mcguckin" <joe () via net>
I don't think flow-caching is necessarily due to CEF.

Even on dinky 2500 & 2600 series where you don't run CEF,
load balancing over multiple links uses a flow-hashed method.

For the 312534906703247th time:

Switching  Balancing per-
Process    packet
Fast       dest (net)
Flow       flow
CEF*       src-dest pair
CEF**      packet

* by default
** with "ip load-sharing per-packet" on incoming interface

If you want per-packet load distribution you have to specifically
enable it by saying "no ip route-cache" on each interface.

If you want to crater your router, sure.  Otherwise, I'd consider one of the
other options.

S


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