From: Church, Chuck (cchurch@netcogov.com)
Date: Mon Dec 27 2004 - 10:49:45 GMT-3
I think I'd go with solution 1. Like Bob said, I don't think assigning
a bandwidth to the class-default makes any sense. You don't want random
detect being applied to the email traffic either, which makes a better
case for solution 1 as well. Of course with any complicated QOS
configuration, it's going to take some fine tuning to get the settings
you want. Other things you can consider is policing or shaping your
less-than-normal-importance traffic, such as file-sharing apps, etc.
That'll lessen your WRED drops for your class-default traffic.
Chuck Church
Lead Design Engineer
CCIE #8776, MCNE, MCSE
Netco Government Services - Design & Implementation Team
1210 N. Parker Rd.
Greenville, SC 29609
Home office: 864-335-9473
Cell: 703-819-3495
cchurch@netcogov.com
PGP key: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x4371A48D
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
David Duncon
Sent: Monday, December 27, 2004 2:54 AM
To: ccielab@groupstudy.com
Subject: Class class-default
Hi Group,
I got a Q on MQC 'c class class-default behavior. And appreciate your
guidance on this.
On production network, let us consider that we have end to end L3 MQC
policy
which primarily aimed to protect Business critical apps such as Voice
and
Citrix and bundled every other traffic type such as File transfers ,
HTTP
and Emails ..etc in to a common default class with random detect feature
enabled. Since there is a bit of concern on the email (MS Exchange &
Lotus
Notes Domino) traffic with in a default class as we are seeing some
drops
there. So If we were to segregate & prioritize email traffic from the
rest
of default class traffic , then which of the following options is the
better
way to go. Either to leave the email traffic with in class class-default
and
assign a guaranteed bandwidth or to segregate email traffic in to
separate
class-map with in policy-map. The reason I am asking this Q is to
understand
any negative impacts the NON time sensitive email traffic can bring in
to
policy maps processing where already time sensitive traffic types (Voice
&
citrix) are being serviced.
Option 1:
=================
Policy-map data
Class voice
Match access-group xxx
Priority xxx
Class citrix
Match access-group xxx
Bandwidth xxx
Class email
Match access-group xxx
Bandwidth xxx
Class class-default
Random detect
Option 2:
==================
Policy-map data
Class voice
Match access-group xxx
Priority xxx
Class citrix
Match access-group xxx
Bandwidth xxx
Class class-default
Random detect
Bandwidth xxx ---------------------------------------> emails are
bundled
together along with file transfers & HTTP traffic with in class default.
And my Qs are :
1) is there any way where we can create 2 class-maps with in class
class-default , one for email and the rest for all default traffic ? If
yes
is there any benefit in doing that ?
2) or is it safe for me to create another class-map for email and slot
that
in with policy-map itself along with voice & citrix and dedicate certain
amount of bandwidth to it.
3) Thirdly , what is the between a class class-default with a bandwidth
command and one with out a bandwidth command. And also what is the
difference between a class class-default with a random detect command
and
one with out it. Though I do aware the functionality of congestion
avoidance
techniques such as WRED and RED , I was in the impression that besides
configuring random detect , you need to map it to a relevant DSCP code
which
underlines a certain level of drop probability. In other words, you are
telling the policy engine on what type of traffic you want her to drop
should she pick up any early congestion warnings.
Any feed back is much appreciated.
- David.
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