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New Member

QoS: CBWFQ: unfair between two sources?

I cannot figure out why router(7204 & 12.4) drop packets from one source1 packet and not source2. I am sending 20 Mbps from source1 & 10 Mbps from Source2. Both sources send with AF41 & UDP, 1399 frame size.

Following is the QoS policy:

policy-map shape

class test

match dscp af41

bandwidth 20000 kbps

queue limit 4096

shape average 20000000

int g0/2

ipv6 address

service-policy output shape

I tried sending single stream of 20 Mbps & 10 Mbps & multiple streams of 2 Mbps from both sources & for some reason router drop only packets from source1.

I am using IPv6. I have not tried IPv4.

Any suggestion?

  • Other Network Infrastructure Subjects

Re: QoS: CBWFQ: unfair between two sources?

I think the packet drop may be because of the class-map command.In a CBWFQ, class-maps defines a named class,that is used to select specific traffics and put them into a specific flow or queue. You can use either match-all or match-any option for this class-map cmd.match-any is like Logical AND and all match statements specified in class-map should be satisfied to apply the policy. match-any is like OR.If any one match statement is true, then it will be fine to apply the specific policy.So, I think u should have used 'match-all ' option and any one match statement is not satisfied.So, the packet is dropped from one source(1) according to the mentioned policy. Use the show class-map cmd to see match-all/match-any option.Also, use sh policy-map cmd and sh queue cmd.Then debug.

New Member

Re: QoS: CBWFQ: unfair between two sources?

can you confirm you have generated the two traffics with same packet size, becasue the queueing mechanism of cbwfq is wfq, only guarantee the small size packets and high priority traffic when the queue is congested. so, please check first, are the two traffic in same packet size?