From: Jason T. Rohm (jtrohm@xxxxxxxxxxx)
Date: Sat Jul 22 2000 - 06:57:02 GMT-3
I can't speed for the others specifically, but the 5xxx series (and
presumably the others) use a hybrid switching type.
Explain:
A pure cut through switch switches all packets w/o error checking (other
than runt).
Pure Store-and-forward, copies the entire frame to the switch processor,
checks it out, then copies the frame to the outbound port(s).
A catalyst 5xxx, will immediately copy the frame to ALL active ports and the
switch processor. The switch processor will check the frame for errors and
destination, then inform all the non-destination ports to drop the frame
from their send queues.
The result is a hybrid switching type that gives you all the benefits of a
pure store and forward, but incurs less switching delay because the second
frame copy is eliminated.
The disadvantage of this method is that it requires a lot of back-plane
bandwidth and large buffers on the individual ports.
-Jason T. Rohm
jtrohm@athenet.net
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
alfred zhang
Sent: Saturday, July 22, 2000 3:25 AM
To: ccielab@groupstudy.com
Subject: cut-through or store-and-forward
Hi
Can anybody help me?Does a Catalyst switch(for example
6509,4003,2948G) use cut-through switching by default and
store-and-forward based on errors?
Thank you and best regards
alfred
This archive was generated by hypermail 2.1.4 : Thu Jun 13 2002 - 08:23:57 GMT-3