From: Price, Jamie (jprice@xxxxxxxxxxx)
Date: Wed Sep 13 2000 - 23:42:31 GMT-3
Title: RE: ip route-cache
Great!!!
Thanks to both yourself and Kevin - both the access-list and load
balancing scenarios put it truly into perspective for me.
As for the VLAN int's though - I've noticed that you have the option
on the lower catalysts, say a 2900, to configure ip route-cache on the
VLAN interfaces. How would you explain that? A thought I had(after
being informed by you guys of the previous) is that its possibly there
for trunking to ensure load balancing over the
trunk??.......maybe.......I'm not sure.
Any thoughts?
-----Original Message-----
From: David Ankers [mailto:d.ankers@cable.a2000.nl]
Sent: Wednesday, September 13, 2000 9:34 PM
To: Price, Jamie
Cc: ccielab@groupstudy.com
Subject: Re: ip route-cache
ip route-cacheJamie,
You're question is not as basic as you might think. Different
switching
methods are also highly platform and ISO specific, it also a cause of
great
confusion.
There is one very good reason for turning off fast switching i.e. no
ip
route-cache, this is load balancing. If a router has 2 (or more) equal
cost
routes to a destination and is configured for load balancing it will
load
balance per destination when fast switching is enabled i.e. first ftp
from
host a to b take path one, second ftp to b takes path two. If fast
switching
is disabled load balencing is done per packet.
As for autonomous switching (ip route-cache cbus) it allows the
ciscoBus to
switch packets independently without interrupting the system
processor.
Basically an early CEF but there are a few cases where it can't be
used for
example when extended access-list or accounting is turned on.
As for the vlan ints, I'm *guessing* that you are using an RSM, in
which
case this is just a 7500 router anyway and runs basically the same
software.
Dave.
----- Original Message -----
From: Price, Jamie
To: ccielab@groupstudy.com
Sent: Thursday, September 14, 2000 3:05 AM
Subject: ip route-cache
Hi,
Can anyone help me out here?
I've been wondering about the aforementioned command. I realize,
after
looking at the docs that "ip route-cache" enables fast switch
processing but
I'm curious about the parameters and the ability to disable it.
Can anyone provide me with some solid, factual, reasons as to why you
would
want to turn fast switching off or turn autonomous switching on, etc?
Also
why can you use it on a Vlan interface in a switch - this one sort of
has me
at the moment?
If this is something basic that I'm overlooking.......well....I was
going to
apologize but we all have to take a trip back to the basics sometime
dont
we.....so I wont :)
Thanks
Jamie
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