Cisco 2960 QoS for VoIP DSCP 40

[daffymd]

I am trying to put together a config for a 2960 switch (running 12.2(25)SEE3 C2960-LANBASE-M) that will give priority to voice packets which are already marked with DSCP 40 by the VoIP phone systems. I have successfully used Cisco 2950 switches to do this in the past so I want to ensure that my 2960 will do the same job.

There is a 3662 router connected to Fast0/1 that connects off to a number of other sites that run the same model VoIP PBX. The local VoIP PBX connects to Fast0/2. Gig0/2 links down to a Cisco 2950 that has a VoIP analogue phone module.

I have posted the relevant parts of my config file below:-


hostname switch16
!
!
!
mls qos
!
!
!
interface FastEthernet0/1
description To Cisco 3662
switchport mode trunk
srr-queue bandwidth share 30 20 25 25
priority-queue out
mls qos trust dscp
!
interface FastEthernet0/2
description To VoIP phone system
switchport mode trunk
srr-queue bandwidth share 30 20 25 25
priority-queue out
mls qos trust dscp
!
interface FastEthernet0/3
spanning-tree portfast
!
interface FastEthernet0/24
spanning-tree portfast
!
!
interface GigabitEthernet0/2
description To Parts Cisco 2950
switchport mode trunk
srr-queue bandwidth share 30 20 25 25
priority-queue out
mls qos trust dscp

end

Am I doing the right thing by using the priority queue command?

Should I be doing anything to the ingress queues as well?

Any thought / suggestions are gratefully received.

 

[uzumaki]

What brand of PBX are u trying to use? Are you using avaya? Nortel?

 

[iptuser]

You may wish to remap the DSCP 40 to 46 as this is cisco voice setting and call control 24

 

[daffymd]

Hello guys. Thanks for your responses.

The PBX is from a UK company called Splicecom.

I was wanting to ensure that anything marked with DSCP was put into a priority queue rather than remapping the DSCP to 46.

My problem is that I have studied the output from the command

sh mls qos maps

and although some of it makes sense my poor old brain just doesn't make complete sense of it. See output attached.