ā06-17-2011 01:54 AM - edited ā03-07-2019 12:51 AM
I have seen that when configuring AutoQoS on a Cat 2960 / 3560 / 3750 the default for queue-set 1 is changed but not for queue-set 2, and when applying an Auto QoS command to an interface, queue-set 1 is configured for a Fastethernet interface but queue-set 2 for a Gigabit interface.
I canĀ“t figure out why is it. It is supossed that Gigabit interfaces suports all accumulative traffic (link to the backbone) and that a more accurate QoS configuration is needed for that kind of links.
Does anyone know te reason for this? I donĀ“t think itĀ“s an IOS programmer mistake.
I'm using IOS 12.2(55)SE3 and auto qos srnd4.
Regards.
ā06-17-2011 02:48 PM
It depends on the interface capabilities, if they have 4Q3T, it would use queue-set 1
If they have 1P3Q3T, they would use queue-set 2
You can find out the queue type with the command:
show interface x/x capabilities
ā06-18-2011 01:51 AM
Hi Edison:
Thanks for the answer but I canĀ“t agree:
On a Cat 2960 model WS-C2960-48PST-L all the interfaces appears as 4Q3T, Gigabit or Fast ethernet, but the config generated by auto qos trust cos is different (output from debug auto qos):
Gigabit:
Jun 18 10:49:26: mls qos trust cos
Jun 18 10:49:26: no queue-set 1
Jun 18 10:49:26: queue-set 2
Jun 18 10:49:26: priority-queue out
Jun 18 10:49:26: srr-queue bandwidth share 1 30 35 5
FastEthernet:
Jun 18 10:47:03: mls qos trust cos
Jun 18 10:47:04: no queue-set 1
Jun 18 10:47:04: priority-queue out
Jun 18 10:47:04: srr-queue bandwidth share 1 30 35 5
Regards.
ā06-19-2011 04:07 AM
Disclaimer
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
Liability Disclaimer
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
I think you may already answered your own question. Using different queue sets for FastE vs. GigE allows different resource allocation for the two different bandwidths. Everything else being equal, BDP (bandwidth delay product) is larger for GigE hence to support it correctly requires larger buffers.
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide