Qos configuration for 3945 Router for Voice Priority

[Jim Matuska]

What is the current recommended configuration on a 3945 Router to prioritize voice for Cisco IP Phones over data?  We used to just use auto qos on our older routers which worked quite well but it looks like this is no longer available on these routers and the 15.2T IOS.  

What is the best/recommended way to make sure that my voice traffic takes priority over other traffic such as normal web browsing and such?  

Jim

[Dennis Mink]

https://www.cisco.com/c/en/us/td/docs/routers/access/800M/software/800MSCG/QoS.html   is probably the best starting point,

if you trust the phones settings from the access ports they are connected to, you can just do a match on ef, af41 and 42.

on top of that use an accesslist to define RTP, port 5060/61 to set the dscp values to ef and af41 respectively.

cheers

[Francesco Molino]

Hi

If you have Cisco IP phones with video capabilities you'll probably have ef and af41 traffic.

A quick example below, but make sure you'll consider everything before applying this basic qos configuration.

class-map match-any CMAP_VOICE

match dscp ef

!

class-map match-any CMAP_VIDEO

 match dscp af41

!

policy-map QOS_EXAMPLE

class CMAP_VOICE

  priority level 1

  police cir percent 10

class CMAP_VIDEO

  priority level 2

  police cir percent 20

class class-default

  fair-queue

  random-detect

!

This will imply that traffic is trusted on the LAN. If there's no making, you can replace the match dscp by match access-grouo using acl for example.