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New Member



I have a configuration like this:

policy-map child

class VoiceData


police cir 1000000 bc 31250 be 31250 conform-action transmit exceed-action drop

class Business

bandwidth remaining percent 60

class VoiceSig

bandwidth remaining percent 15

class IProuting

bandwidth remaining percent 10

class class-default

bandwidth remaining percent 5

policy-map parent

class class-default

shape average 100000000

service-policy child

And I constantly have output drops on interface.

when I issue command :show policy-map interface ge-WAN 9/1, the output on terminal is like this :

Service-policy output: parent

Class-map: class-default (match-any)

5890788 packets, 1351633668 bytes

30 second offered rate 162000 bps, drop rate 0 bps

Match: any


queue limit 128 (packets)

(queue depth/total drops/no-buffer drops) 0/3808/0

(pkts queued/bytes queued) 5886980/1350757828

shape (average) cir 100000000, bc 400000, be 400000

target shape rate 100000000

(shape parameter is rounded to 99968000 bps due to granularity)

Service-policy : child

Class-map: VoiceData (match-all)

5469193 packets, 1214132622 bytes

30 second offered rate 132000 bps, drop rate 0 bps

Match: mpls experimental topmost 5

Priority: b/w exceed drops: 3808


cir 1000000 bps, bc 31250 bytes

(Police cir is rounded to 983040 bps due to granularity)

Are these drops happening because of policing? I thought that It would police VoiceData traffic only if the whole link is congested? Can anyone help me with this?


Re: QoS

Since you are using elements of percentage based rate-limiting, make sure you have "max-reserved-bandwidth 100" configured on your physical interface. I think the default is on 75% as opposed to 100% which throws off some of the percentage calculations. Also, make sure that you have a proper bandwidth statement for the interface as well. For example, a ten meg limit would be "bandwidth 10240".

Hope this helps.


Re: QoS

A few questions and theory here.

Why are you shaping a gig interface down to 100meg?

If you are indeed wanting to do this down to 100meg then max-reserved-bandwidth command is not needed - by default your queues will have 750meg to play with.

What IOS/platform are you using as it took me 7 attempts to find a suitable IOS which actually worked with child policies properly.

New Member

Re: QoS

I am shapping it down do 100 Mbps because that is interconnecting link that I've got from ISP and the available bandwith is 100Mbps.

I'm using 12.2(18)SXF version of IOS

But is my statement correct regarding the configuration: VoiceData traffic will be dropped if it exceeds 1Mbps? Rest od of the classes will have the minimum bandwith according with the configured percentage (i.e. Bussiness will have minimum 60%, and that is little less than 60Mbps (complete capacity of the link is 100Mbps, 1Mbps is for VoiceData, and for business is 60% of 99Mbps )?

Do I have on disposal only 75 Mbps for gueues or that 75% is percentage of phisyscal capacity of the link which is than 750Mbps.?


Re: QoS

your statement is 100% correct the voice traffic will be dropped if it exceeds ~1meg. You have 750 meg available as the max-reserved-bandwidth statement is based on physical interface. Now to the bad news - SXF ah the joys i had with this code. I had to upgrade to SXF4 before i could actually get the traffic to pass within contract without being dropped. So if you stay with SXF at about 80meg (may be lower cant remember) you will start to see output drops - upgrade to SXF4 and with the same traffic profile you shall see no drops.


New Member

Re: QoS

Thank you very much

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