Users Guide

Examples of Traffic Classifications
The following example shows incorrect traffic classifications.
Dell#show running-config policy-map-input
!
policy-map-input PolicyMapIn
service-queue 1 class-map ClassAF1 qos-policy QosPolicyIn-1
service-queue 2 class-map ClassAF2 qos-policy QosPolicyIn-2
Dell#show running-config class-map
!
class-map match-any ClassAF1
match ip access-group AF1-FB1 set-ip-dscp 10
match ip access-group AF1-FB2 set-ip-dscp 12
match ip dscp 10 set-ip-dscp 14
match ipv6 dscp 20 set-ip-dscp 14
!
class-map match-all ClassAF2
match ip access-group AF2
match ip dscp 18
Dell#show running-config ACL
!
ip access-list extended AF1-FB1
seq 5 permit ip host 23.64.0.2 any
seq 10 deny ip any any
!
ip access-list extended AF1-FB2
seq 5 permit ip host 23.64.0.3 any
seq 10 deny ip any any
!
ip access-list extended AF2
seq 5 permit ip host 23.64.0.5 any
seq 10 deny ip any any
In the previous example, the ClassAF1 does not classify traffic as intended. Traffic matching the first match criteria is classified
to Queue 1, but all other traffic is classified to Queue 0 as a result of CAM entry 20419.
When you remove the explicit “deny any” rule from all three ACLs, the CAM reflects exactly the desired classification.
Create a QoS Policy
There are two types of QoS policies — input and output.
Input QoS policies regulate Layer 3 and Layer 2 ingress traffic. The regulation mechanisms for input QoS policies are rate
policing and setting priority values.
• Layer 3 — QoS input policies allow you to rate police and set a DSCP or dot1p value. In addition, you can configure a drop
precedence for incoming packets based on their DSCP value by using a DSCP color map. For more information, see DSCP
Color Maps.
• Layer 2 — QoS input policies allow you to rate police and set a dot1p value.
Output QoS policies regulate egress traffic. The regulation mechanisms for output QoS policies are bandwidth percentage,
scheduler strict, rate shaping and WRED.
NOTE: When changing a "service-queue" configuration in a QoS policy map, all QoS rules are deleted and re-added
automatically to ensure that the order of the rules is maintained. As a result, the Matched Packets value shown in the show
qos statistics command is reset.
Quality of Service (QoS) 627