Filter and Force DSCP Values (IPv4 ACLs)

In IPv4 extended ACL rules, re-marking (forcing) DSCP values can change the priority on egress traffic, by which you can prioritize ingress traffic.

1. Access global configuration mode.
   

   device# configure
   

2. Create or access the ACL.
   

   device(config)# ip access-list extended extd_ACL5
   

3. To filter incoming or outgoing packets by DSCP value, define permit or deny rules specifying the dscp parameters.
   

   device(config-ipacl-ext)# seq 5 deny tcp host 10.24.26.145 any dscp 25
   device(config-ipacl-ext)# seq 15 permit tcp 10.24.26.146 any dscp 20
   

4. To re-mark the DSCP value of incoming packets, define permit rules specifying the dscp-force parameters.
   

   device(config-ipacl-ext)# seq 25 permit tcp 10.24.26.147 any dscp-force 10
   

   

   Note

   (SLX 9740/Extreme 8820 only) If traffic is bridged, then the egressing PCP (802.1p) is re-marked to the equivalent value of the forced DSCP.
5. Apply the ACL to the appropriate interface.
   

   device(config)# interface ethernet 2/2
   device(conf-if-eth-2/2)# ip access-group extd_ACL5 in