Question on if our policy-map is working.

Answered Question
Oct 30th, 2009
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Attached is an output from show policy-map interface for our WAN router. I see that traffic desired is being matched in each of the classes, but it looks like there is no queueing at all.I say this as under queueing section for each class the below appears

(pkts matched/bytes matched) 0/0


I expected to see some statistics that packets were actually queued.


Please review attached. What would be another way that I can verify that the policy is working and traffic will be queued when needed.


the output was taken right after a clear counters, then i ran again after a minute (both outputs in attached).


Thanks in advance,



Correct Answer by Joseph W. Doherty about 7 years 9 months ago

You'll only see queuing matched when packets are queued. It looks to me this might be attached to a DS3 with only about 5 Mbps average traffic in the last 5 minutes. If this is correct, it's not surprising that no packets have been actually queued.


BTW, router interfaces also have their own FIFO hardware queues. Only when these overflow does software queuing happen. So it's also possible, even if there are occasional 100% utilization bursts, they don't engage the software queues. (NB: For effective QoS, you sometimes need to manually decrease the hardware FIFO queue to get the traffic proiritized by the software queues.)

Correct Answer by thotsaphon about 7 years 9 months ago

Daniel,

What's the type of your wan interface? Did your wan interface get congestion while doing a show policy-map command?


Toshi


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Correct Answer
thotsaphon Fri, 10/30/2009 - 11:18
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Daniel,

What's the type of your wan interface? Did your wan interface get congestion while doing a show policy-map command?


Toshi


Correct Answer
Joseph W. Doherty Fri, 10/30/2009 - 11:30
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You'll only see queuing matched when packets are queued. It looks to me this might be attached to a DS3 with only about 5 Mbps average traffic in the last 5 minutes. If this is correct, it's not surprising that no packets have been actually queued.


BTW, router interfaces also have their own FIFO hardware queues. Only when these overflow does software queuing happen. So it's also possible, even if there are occasional 100% utilization bursts, they don't engage the software queues. (NB: For effective QoS, you sometimes need to manually decrease the hardware FIFO queue to get the traffic proiritized by the software queues.)

UCcomp2007 Fri, 10/30/2009 - 11:45
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Thanks to both. The type of interface is an ATM (DS3).


Regards,

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