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Contributor
Posts: 23
Registered: ‎03-19-2013

QoS WRED Queuing

Hello,

I am trying to understand more from this part of QoS, I read that Brocade uses WRED for queuing, and when implemented it helps not to throw packets going into the TM....because it does not care if the have priority 5 or 0....it will drop the packet there in case of congestion...right?

The question is, when I enable for example

Brocade(config)#qos queue-type 3 wred enable

I am  enabling for the Virtual Output Queue (Internal priority 3) WRED in a global basis....Im I right?

This means virtual queue 3 in every Inbound TM will have WRED enabled? What will this do against the other queues (0,1,2,4,5,6,7)?

This means that packets marked with internal priority 3 will be queued and not dropped in case of congestion and will be forwarded to the Outband TM for scheduling? 

What if I enable WRED for all queues? What will be the result?

This phase is not really clear for me....this is how I understood.

Regards,

Ernesto

Frequent Contributor
Posts: 160
Registered: ‎08-07-2009

Re: QoS WRED Queuing

Hi Ernesto,

Let me look into this and try to gather some detail for you.

Stay tuned.

-Bill

Contributor
Posts: 23
Registered: ‎03-19-2013

Re: QoS WRED Queuing

Thanks Bill!

Frequent Contributor
Posts: 160
Registered: ‎08-07-2009

Re: QoS WRED Queuing

Ernesto,

Below is some feedback on your questions:

I am  enabling for the Virtual Output Queue (Internal priority 3) WRED in a global basis....Im I right?

Correct, this enables WRED globally

This means virtual queue 3 in every Inbound TM will have WRED enabled?

This is correct.

What will this do against the other queues (0,1,2,4,5,6,7)?

Nothing will happen to these queues and based on congestion packets will be tail dropped in ingress TM

This means that packets marked with internal priority 3 will be queued and not dropped in case of congestion and will be forwarded to the Outband TM for scheduling?

The packet will be dropped based on the drop probability – for example if drop probability is 10 then 1 out of 10 packets will be dropped

What if I enable WRED for all queues? What will be the result?

Packets will be randomly dropped based on drop probability as explain above to avoid congestion


-Bill

Contributor
Posts: 23
Registered: ‎03-19-2013

Re: QoS WRED Queuing

Thank you very much!!!!

Ernesto

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