From: Pierre-Alex (paguanel@hotmail.com)
Date: Sun Jun 04 2006 - 07:35:56 ART
I have labed point number 2 and I my statement is actually wrong!
With the configuration as is, the router will refuse the commands because the
available bandwidth is actually 75% of the interface bandwidth .
( I think I got confused because when I did the test with shapping, I was
abled to use 100% of the shapped rate. )
----- Original Message -----
From: Pierre-Alex
To: ccielab@groupstudy.com
Sent: Sunday, June 04, 2006 11:38 AM
Subject: QoS default-class - oversubscription
I need a quick "yes" or "no" + quick optional comments on the following
points .
Theses are deductions I have made from several readings on CCO and research
in the group-study archives.
I just want to make sure I am not inventing wrong rules here ...
1. QoS bandwidth usage is calculated based on L3 packet size.
2. On non-7500 + platforms: 25% of the interface bandwidth SHOULD be left
aside for overhead traffic, including Layer 2 (frame? overhead), control
traffic (routing,cdp,snmp etc ...), and best-effort traffic. This traffic, and
in particular NON IP traffic, will be allocated to the DEFAULT-CLASS .
Because the 25% is a recommendation and is NOT enforced by the routers when
using absolute bandwidth values. Nothing prevents me from doing the following
and starve my overhead traffic.
interface s 0/0
bandwidth 100
policy a
class 1
bandwidh 90
class 2
banwith 10
clas-class default
3. The command "maximum bandwith-percent xx" is only releavant when using
configurations with "bandwidth percent" .
When left to the default maximum bandwith-percent 75 of interface bandwidth
and when using "bandwidth percent " type configurations, then the overhead is
taken care off.
When changed to maximum bandwith-percent 100 then care must be taken to
leave enough in the default class for overhead traffic.
This archive was generated by hypermail 2.1.4 : Sat Jul 01 2006 - 07:57:31 ART