From: Church, Chuck (cchurch@wamnetgov.com)
Date: Tue Jun 01 2004 - 14:54:37 GMT-3
QOS is better when deployed at the edge of the network, where the
devices tend to have deeper interface queues and slower links. QOS will
help a saturated gigE link only so much, as the packets being dropped
(the non-time critical ones) will probably be re-sent, making a bad
situation worse. Etherchannel'ing in more links when you start to see
output queue drops on the core links will probably fix any BW issues.
LAN BW is cheap compared to WAN, so keep the core fast and simple!
Chuck Church
Lead Design Engineer
CCIE #8776, MCNE, MCSE
Wam!Net Government Services - Design & Implementation Team
13665 Dulles Technology Dr. Ste 250
Herndon, VA 20171
Office: 703-480-2569
Cell: 703-819-3495
cchurch@wamnetgov.com
PGP key:
http://pgp.mit.edu:11371/pks/lookup?op=index&search=cchurch%40wamnetgov.
com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Kenneth Wygand
Sent: Tuesday, June 01, 2004 11:48 AM
To: Group Study
Subject: Connecting two core switches / Design
Hello all,
I was thinking about large providers that need to connect core switches
at very fast speeds. For example, say I have two 6506 core switches I
wanted to connect in the backbone. Say each one is terminating 20 - 30
fiber gigabit speed links. I would think it would be a poor idea to
oversubscribe the link between these switches to a 1GBit or even 10GBit
link. If the link was oversubscribed, logic would think that QoS should
be employed here to make sure critical traffic (voice, video) gets
through first, but all design guides point towards keeping all QoS out
of the core to simply switch packets as fast as possible...
What is recommended and is there any documentation / experience anyone
can contribute?
Thanks!
Kenneth E. Wygand
Systems Engineer, Project Services
CISSP #37102, CCNP, CCDP, ACSP, Cisco IPT Design Specialist, MCP, CNA,
Network+, A+
Custom Computer Specialists, Inc.
"I am not really smart. I just stick with problems longer."
-Albert Einstein
Custom Computer Specialists, Inc.
"Celebrating 25 Years of Excellence"
[GroupStudy removed an attachment of type image/gif which had a name of
image001.gif]
This archive was generated by hypermail 2.1.4 : Sat Jul 03 2004 - 19:40:30 GMT-3