RE: LLQ Question - Multiple Traffic Classes in the Priority

From: Vincent Mashburn (vmashburn@fedex.com)
Date: Tue Oct 03 2006 - 11:50:05 ART

It is my understanding from your configuration that Class 1 has a
priority bandwidth of 100 and class 2 has a priority bandwidth of 200.
While it is true that both will be serviced in a FIFO manner since they
are both in the priority queue, it is important to realize that the
priority bandwidth is a policer. For instance, if class 1 attempts to
prioritize more than 100k then the excess will be dropped. Class 2 is
allowed to put up to 200k on the link before its excess is dropped. But
they are both FIFO since there is only 1 priority queue. I hope that
this helps.

Vince Mashburn
Voice / Data Engineer
901-263-5072
CCVP, CCNP, CCDA,Network +
Cisco IP Telephony Support Specialist
Cisco IP Telephony Operations Specialist
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Mohamed Saeed
Sent: Tuesday, October 03, 2006 5:55 AM
To: ccielab@groupstudy.com
Subject: RE: LLQ Question - Multiple Traffic Classes in the Priority
Queue

Why will CLASS1 be serviced first?

Anyway, if this is the case then CLASS2 traffic would NOT have expedite
forwarding processing, right?

Regards
Mohamed Saeed, CCNP - CCIP

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Gavin Lawson
Sent: Tuesday, October 03, 2006 12:33 PM
To: ccielab@groupstudy.com
Subject: RE: LLQ Question - Multiple Traffic Classes in the Priority
Queue

Hi Mohamed

With your example there are 2 software based Priority Queue's
The CLASS1 priority Queue will be serviced first and then CLASS2

GL

________________________________

From: nobody@groupstudy.com on behalf of Mohamed Saeed
Sent: Tue 3/10/2006 5:39 PM
To: ccielab@groupstudy.com
Subject: RE: LLQ Question - Multiple Traffic Classes in the Priority
Queue

Hi GL,

Let me state an example to clarify my point:

policy-map TEST
  class CLASS1
    priority 100
  class CLASS2
    priority 200

With this setup, traffic of both CLASS1 and CLASS2 will be assigned to
the priority queue. So, how will the router assign max BW of 100 to
traffic of CLASS1 and assign max BW of 200 to traffic of CLASS2 although
they are both in the same single queue and should be treated as FIFO.

Regards
Mohamed Saeed, CCNP - CCIP

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Gavin Lawson
Sent: Tuesday, October 03, 2006 11:23 AM
To: ccielab@groupstudy.com
Subject: RE: LLQ Question - Multiple Traffic Classes in the Priority
Queue

HI Mohamed

The priority queue will be serviced in a FIFO manner, no matter what the
markings are of the packets in the queue.

GL

________________________________

From: nobody@groupstudy.com on behalf of Mohamed Saeed
Sent: Tue 3/10/2006 4:57 PM
To: ccielab@groupstudy.com
Subject: LLQ Question - Multiple Traffic Classes in the Priority Queue

Hi All,

It is a fact that you can assign multiple traffic classes to the
priority queue in the same policy map. All traffic from these classes is
queued to the same, single, priority queue.

I am a little bit confused, how will the system police different traffic
classes to different rates although they are in the same priority queue.

Does anyone has an idea?

Regards

Mohamed Saeed, CCNP - CCIP

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