Below is an example of a  quick start quality of service configuration.  We will walk through this configuration over the phone.

 

Apply the below under global configuration mode:

 

Config t

 

class-map match-any Voice
 match ip dscp ef

class-map match-any Routing

  match ip dscp cs6

class-map match-any Call-Signaling

  match ip dscp cs3

policy-map QOS
 class Voice
  priority percent 5
 class Routing
  bandwidth percent 5

class Call-Signaling

   bandwidth percent 5
 class class-default
  bandwidth percent 60

  queue-limit 256

 

Then apply the qos policy, in the outbound direction, to the interface:

 

interface "interface-name"

service-policy output QOS

 

We set DSCP CS3 for call-signaling. Some older devices use AF31 instead.  If this is the case then add AF31 to your call-signaling class-map.

 

class-map match-any Call-Signaling

  match ip dscp cs3

  match ip dscp af31

 

 

Also please reference the Cisco Solutions Reference Network Design (SRND) Guide for specific questions to best practice deployments within the enterprise.  Please click on the link below to access our SRND for QOS.

 

 

http://www.cisco.com/univercd/cc/td/doc/solution/esm/qossrnd.pdf