Concept Guide
Applying DSCP and VLAN Match Criteria on a Service Queue
You can congure Layer 3 class maps which contain both a Layer 3 Dierentiated Services Code Point (DSCP) and IP VLAN IDs as match
criteria to lter incoming packets on a service queue on the switch.
To congure a Layer 3 class map to classify trac according to both an IP VLAN ID and DSCP value, use the match ip vlan vlan-id
command in class-map input conguration mode. You can include the class map in a policy map, and apply the class and policy map to a
service queue using the service-queue command. In this way, the system applies the match criteria in a class map according to queue
priority (queue numbers closer to 0 have a lower priority).
To congure IP VLAN and DSCP match criteria in a Layer 3 class map, and apply the class and policy maps to a service queue:
1 Create a match-any or a match-all Layer 3 class map, depending on whether you want the packets to meet all or any of the match
criteria. By default, a Layer 3 class map is created if you do not enter the layer2 option with the class-map command. When you
create a class map, you enter the class-map conguration mode.
CONFIGURATION mode
Dell(conf)#class-map match-all pp_classmap
2 Congure a DSCP value as a match criterion.
CLASS-MAP mode
Dell(conf-class-map)#match ipdscp 5
3 Congure an IP VLAN ID as a match criterion.
CLASS-MAP mode
Dell(conf-class-map)#match ip vlan 5
4 Create a QoS input policy.
CONFIGURATION mode
Dell(conf)#qos-policy-input pp_qospolicy
5 Congure the DSCP value to be set on matched packets.
QOS-POLICY-IN mode
Dell(conf-qos-policy-in)#set ip-dscp 5
6 Create an input policy map.
CONFIGURATION mode
Dell(conf)#policy-map-input pp_policmap
7 Create a service queue to associate the class map and QoS policy map.
POLICY-MAP mode
Dell(conf-policy-map-in)#service-queue 0 class-map pp_classmap qos-policy pp_qospolicy
Ordering ACL Rules
When you link class-maps to queues using the service-queue command, the system matches the class-maps according to queue
priority (queue numbers closer to 0 have lower priorities).
For example, as described in the previous example, class-map cmap2 is matched against ingress packets before cmap1.
ACLs acl1 and acl2 have overlapping rules because the address range 20.1.1.0/24 is within 20.0.0.0/8. Therefore (without the keyword
order), packets within the range 20.1.1.0/24 match positive against cmap1 and are buered in queue 7, although you intended for these
packets to match positive against
cmap2 and be buered in queue 4.
850
Quality of Service (QoS)