Solved: CBWFQ and LLQ

voiper_99 · ‎06-05-2007

Hi, I understand that LLQ is an extension of CBWFQ and is a strict priority class but I am unable to find information as to how to assign traffic flows/types to the LLQ queue. Is this done by a command of some sort e.g setting a DSCP value? Or does the router automatically assign traffic flows to the priority class itself? I think it may have something to do with the EF DSCP value, but I am not certain.

Thank you in advance.

royalblues · ‎06-05-2007

Yes you are correct.

LLQ is an option applied to CBWFQ under one or more classes. CBWFQ treats these classes as strict priority queues and always services packets in these classes.

HTH, rate if it does

Narayan

View solution in original post

royalblues · ‎06-05-2007

Friend,

The traffic flows are assigned to the LLQ using the "priority" command under the policy map.

When you do QoS for giving priority to a certain traffic, you need to classify that traffic. DSCP is just one way of doing it. Additionally you can also set/mark the DSCP values

eg..

class-map match-all voice

match ip dscp ef

policy-map LLQ

class voice

priority 512

class class-default

fair-queue

HTH, rate if it does

Narayan

voiper_99 · ‎06-05-2007

Ahh I see what you mean. So what you are saying is that the bandwidth assigned to the policy map (with the priority command) gives that policy map a slice of the "strict LLQ priority queue". Is that correct?

By the way thank you for the quick reply.

royalblues · ‎06-05-2007

Yes you are correct.

LLQ is an option applied to CBWFQ under one or more classes. CBWFQ treats these classes as strict priority queues and always services packets in these classes.

HTH, rate if it does

Narayan

voiper_99 · ‎06-05-2007

Thanks a lot for your help.

Have a great day.