priority-queue out

[tedauction]

Hello I have been told to use the following config in normal workstation interfaces:

interface XXXXXX
srr-queue bandwidth share 1 20 20 60
srr-queue bandwidth shape 3 0 0 0
service-policy input Markin

I understand this will give queue 1 30% bandwidth with the remainder shared between queues 2,3, & 4 according to the ratios.

My question is, what difference would it make if I also entered the command 'priority-queue out' on this interface ?

and is there any advantage of using 'priority-queue out' on a normal workstation interface ?

Thank you kindly.

[Mark Malone]

It will make sure everything in the priority queue is serviced first before anything else until its empty , sometimes this can cause starvation of other queues so you need to be careful implementing it but generally works well

 Priority queue is serviced until empty before the other queues are serviced. You enable the priority queue by using the priority-queue out interface configuration command.

[paul driver]

Hello
Just like to add, Shape weights take precedence of Shared when both are enabled ,and both are ignored when the priority queue is enabled hence this relates to mark answer.

res
Paul

[Joseph W. Doherty]

Also to add to Mark's an Paul's posts . .

and is there any advantage of using 'priority-queue out' on a normal workstation interface ?

Sure, as described by Mark, it guarantees traffic in PQ will be transmitted first.  Useful for traffic like VoIP bearer, if you had a VoIP phone and PC hung off the port.  Downloading data to the PC would have minimal adverse impact to a concurrent VoIP call.