QoS

Shane Tominey · ‎11-23-2015

Hi All,

Reviewing a client QoS configuration...this policy-map is bound to a 1Gbit interface which neg to 100Mbits, the WAN service is 20Mbits..

policy-map PM-SHAPE-QUEUE-OUT
class CM-SHAPE-QUEUE-OUT
shape average 20000000 10000000 100000

Forgive me Im still very new to QoS and all the workings :)

Getting alot of dropped traffic with the above policy.

This above configuration dosn't look correct to me, I understand CIR being the 20Mbit, 10Mbit being the bc and 100k be.

Is this telling me for each time interval a 10Mbit token bucket is available? Seems a bit large? Is there a way to I find out the Time Interval which is being used by the policy? What would be recommended in the above case?

Thoughts/Recommendations?

Thanks for your help in advance.

Joseph W. Doherty · ‎11-24-2015

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Posting

Bc and Be parameters should be bits, not bps.

Is there a way to I find out the Time Interval which is being used by the policy?

Sometimes it's shown, but given CIR and Bc, Tc = Bc / CIR

What would be recommended in the above case?

Insufficient information about the cause of the drops and/or your service requirements.

Shapers, like interfaces, if overdriven will drop packets. And/or, one or more of your queues are insufficient sized for the BDP of a 20 Mbps WAN link.