Solved: qos input-queue

Aqdas Muneer · ‎03-17-2010

hello,

had a question regarding the configuration of the ingree-queue on a 3560. Here is the configuration from my switch

mls qos srr-queue input threshold 1 8 16

mls qos srr-queue input threshold 2 34 66

mls qos srr-queue input dscp-map queue 1 threshold 3 0 1 2 3 4 5 6 7

mls qos srr-queue input dscp-map queue 1 threshold 3 32

mls qos srr-queue input dscp-map queue 2 threshold 1 16 17 18 19 20 21 22 23

mls qos srr-queue input dscp-map queue 2 threshold 2 33 34 35 36 37 38 39 48

mls qos srr-queue input dscp-map queue 2 threshold 2 49 50 51 52 53 54 55 56

mls qos srr-queue input dscp-map queue 2 threshold 2 57 58 59 60 61 62 63

mls qos srr-queue input dscp-map queue 2 threshold 3 24 25 26 27 28 29 30 31

mls qos srr-queue input dscp-map queue 2 threshold 3 40 41 42 43 44 45 46 47

i believe this is the default configuration generated by auto-qos. here is the output from a show mls qos input-queue command

Queue : 1 2

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

buffers : 67 33

bandwidth : 90 10

priority : 0 10

threshold1: 8 34

threshold2: 16 66

so my question is if i have only two threshold configured for each queue, how come the switch put certain dscp values in queue 2 threshold 3. check the highlighted lines. its really confusing me.

thanks.

Aaron Harrison · ‎03-17-2010

Hi

You have 3 thresholds :-)

Two configurable; and one implicit one - the end of the queue.

So for queue 1 in your output -

Thresh 1 - 8

Thresh 2 - 16

Thresh 3 - 100% of available buffer space.

Regards

Aaron

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View solution in original post

Aaron Harrison · ‎03-17-2010

Hi

You have 3 thresholds :-)

Two configurable; and one implicit one - the end of the queue.

So for queue 1 in your output -

Thresh 1 - 8

Thresh 2 - 16

Thresh 3 - 100% of available buffer space.

Regards

Aaron

Please rate helpful posts...

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!

Aqdas Muneer · ‎03-17-2010

that clears all the confusion.

thanks.

Aaron Harrison · ‎03-17-2010

Well - probably clears some of it.

There'll be more

I like to think I know a thing or two but they don't make it simple!

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!

vasanth77 · ‎01-28-2016

Hi,

Is there any difference in Qos configuration of 37xx series switches and 45XX ,65xx?

can anyone clarify ?

For Qos what parameters are the most important?

Joseph W. Doherty · ‎01-28-2016

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Posting

Yes, QoS configurations differ, as often do the supported QoS features. Additionally, with the chassis devices, QoS features may vary based on installed line card(s) and/or supervisor (and sometimes QoS version too).

As to which QoS parameters are most important, that would be an "it depends" answer.

francisco_1 · ‎03-17-2010

aqdas,

it is very easy to get confused with Qos.

The ingress queue has a total of 4 queues. The first 2 are used internally by the system for inter-stack communication and priority packets originated from the CPU. Out of the 4 queues, only 2 may be configured. One queue is priority by default, which has bigger priority weight. The other qeueue is the normal queue used of rtraffic that is considered to be best effort. within each of the queues are 3 weighted tail drop threasholds with that allow for 2 threasholds to be configured and the third fixed at 100%.

Francisco