Cisco 6500 QoS Priority Queuing (DSCP & EXP based)

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1

I would to translate following 7200 QoS configuration to Catalyst 6500:

class-map match-any PQ
  match dscp ef
  match mpls experimental topmost 5

policy-map QOS-PE-OUT
class PQ
   priority percent 33
class class-default

AFAIK we need extra command on 6500 to enable Priority Queuing at the
interface level but my problem is that interface priority command are only
COS based not DSCP nor EXP. I may be wrong.

I would appreciate any 6500 QoS help.

Thanks in advance

2

This depends on which line cards you have in your chassis. This configuration below won't work on 6700 series line cards. You have to use the wrr commands. I didn't test it, but MQC configuration below should work on ES series line cards.

Jim

3

Thanks Jim,

The line cards are 6700 series only.

It seems (i will test it) that wrr commands can only be associated with COS
marking not DSCP nor EXP.

May be Priority Queuing is not supported for MPLS traffic on 6700 modules ?

4

These are lan modules. They have fixed queues that you map traffic into.
Research lan qos methods and it should make sense.

Thanks Jim,

The line cards are 6700 series only.

It seems (i will test it) that wrr commands can only be associated with

COS

marking not DSCP nor EXP.

May be Priority Queuing is not supported for MPLS traffic on 6700 modules

?

This depends on which line cards you have in your chassis. This
configuration below won't work on 6700 series line cards. You have to use
the wrr commands. I didn't test it, but MQC configuration below should

work

on ES series line cards.

Jim

From: Manu Chao [mailto:linux.yahoo@gmail.com]
Sent: Wednesday, November 17, 2010 9:11 AM
To: NANOG list
Subject: Cisco 6500 QoS Priority Queuing (DSCP & EXP based)

I would to translate following 7200 QoS configuration to Catalyst 6500:

class-map match-any PQ
match dscp ef
match mpls experimental topmost 5

policy-map QOS-PE-OUT
class PQ
priority percent 33
class class-default

AFAIK we need extra command on 6500 to enable Priority Queuing at the
interface level but my problem is that interface priority command are

only

5

Well, I'm not 100% sure I have this right but; if you are trusting
traffic on ingress then doesn't EXP get copied into internal DSCP,
which in turn is then copied into egress values based on mapping. So
you might like to:

mls qos map exp-dscp 0 8 16 24 32 46 48 56

...and then match cos for the priority queue on the LAN module.

6

As it relates directly to QoS on 6700 series cards, yes those blades do COS based QoS. So if you want to put voice traffic in a priority queue you would do something like this:

! map COS 5 to the priority queue, assuming you want COS 5 in the priority queue
priority-queue cos-map 1 5
! Set the queue limit to the size you want
priority-queue queue-limit 10

Jim