6500 QoS not enabling rcv-queue defaults

[Robert Juric]

One one of our Cisco 6509s I've globally enabled QoS and set a port to "trust cos". However when I look at the queueing for that interface, I notice that the receive queue thresholds have not changed to the default.

I'm kind of new to QoS so I'm not sure if I'm missing something.

We are using a Cisco 6509 running 12.2(33)SXI3 using the WS-X6724-SFP card. I thought I'd be seeing the default tail-drop thresholds, but instead I still see the defaults as if QoS were not enabled:

Queueing Mode In Rx direction: mode-cos

    Receive queues [type = 1q8t]:

    Queue Id    Scheduling  Num of thresholds

    -----------------------------------------

       01         WRR                 08

    WRR bandwidth ratios:  100[queue 1]

    queue-limit ratios:    100[queue 1]

    queue tail-drop-thresholds

    --------------------------

    1     100[1] 100[2] 100[3] 100[4] 100[5] 100[6] 100[7] 100[8]

    queue thresh cos-map

    ---------------------------------------

    1     1      0 1 2 3 4 5 6 7

    1     2     

    1     3     

    1     4     

    1     5     

    1     6     

    1     7     

    1     8     

[acampbell]

Robert,

QOS - A huge subject

Yes you enable qos mls globally

and you can "trust cos" on interfaces

BUT

You need to carry out some more config

Your 6724 uses a 1P3Q8T queing mechanism

Please see this link

http://www.cisco.com/en/US/docs/solutions/Enterprise/WAN_and_MAN/QoS_SRND_40/QoSCampus_40.html#wp1120476

Hope this helps

Regards,
Alex.
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[Robert Juric]

I get a 403 Forbidden File or Application error when I follow the link.

Yes the 6724 has a 1P3Q8T *transmit* queue, but doesn't it also have a 1Q8T receive queue with tail-drop thresholds?

I know I don't have all the pieces implement yet, but I was just looking at the rx queue at this point.

Unless I'm misunderstanding something, after enabling QoS globally, the standard COS to Threshold mappings should be enabled on the interface, at least the interfaces that are setup to trust COS or DSCP?

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide/qos.html#wp1478881

Robert

[Robert Juric]

I think I may have found an issue...

I had configured trust dscp and trust cos on different interfaces on the same ASIC. When I went back and removed the trust dscp from interfaces on that ASIC, my default rcv-queue thresholds were there.

[acampbell]

Robert,

Sorry you can see the link.

I have tried to attach the pdf in this reply.

I thinkj you will be interested in this information.

Regards,
Alex.
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