Using the CLI to Configure DiffServ VoIP Support

1. Enter Global Config mode. Set queue 5 on all ports to use strict priority mode. This queue shall be used for all VoIP packets. Activate DiffServ for the switch.

   (Extreme 220) (Routing) #config
   cos-queue strict 5
   diffserv

2. Create a DiffServ classifier named 'class_voip' and define a single match criterion to detect UDP packets. The class type match-all indicates that all match criteria defined for the class must be satisfied in order for a packet to be considered a match.

   class-map match-all class_voip
   match protocol udp
   exit

3. Create a second DiffServ classifier named 'class_ef' and define a single match criterion to detect a DiffServ code point (DSCP) of 'EF' (expedited forwarding). This handles incoming traffic that was previously marked as expedited elsewhere in the network.

   class-map match-all class_ef
   match ip dscp ef
   exit

4. Create a DiffServ policy for inbound traffic named 'pol_voip', then add the previously created classes 'class_ef' and 'class_voip' as instances within this policy.

   This policy handles incoming packets already marked with a DSCP value of 'EF' (per 'class_ef' definition), or marks UDP packets per the 'class_voip' definition) with a DSCP value of 'EF'. In each case, the matching packets are assigned internally to use queue 5 of the egress port to which they are forwarded.

   policy-map pol_voip in
   class class_ef
   assign-queue 5
   exit
   class class_voip
   mark ip-dscp ef
   assign-queue 5
   exit
   exit

5. Attach the defined policy to an inbound service interface.

   interface1/0/2
   service-policy in pol_voip
   exit
   exit