Cisco Systems A9014CFD manual Classification Based on Vlan IDs, 24-12

Chapter 24 Configuring QoS

Understanding QoS

You can independently assign QoS-group numbers at the ingress to any combination of interfaces, VLANs, traffic flows, and aggregated traffic. To assign QoS-group numbers, configure a QoS group marking in an input policy map, along with any other marking or policing actions required in the input policy map for the same service class. This allows the input marking and policing functions to be decoupled from the egress classification function if necessary because only the QoS group must be used for egress classification.

This example identifies specific packets as part of QoS group 1 for later processing in an output policy:

Router(config)# policy-map in-gold-policy

Router(config-pmap)# class in-class1

Router(config-pmap-c)# set qos-group 1

Router(config-cmap-c)# exit

Router(config-cmap)# exit

Use the set qos-groupcommand only in an input policy. The assigned QoS group identification is subsequently used in an output policy with no mark or change to the packet. Use the match qos-groupin the output policy.

Note You cannot configure match qos-groupfor an input policy map.

This example creates an output policy to match the QoS group created in the input policy map in-gold-policy. Traffic internally tagged as qos-group 1 is identified and processed by the output policy.

Router(config)# class-map out-class1

Router(config-cmap)# match qos-group 1

Router(config-cmap)# exit

Classification Based on VLAN IDs

With classification based on VLAN IDs, you can apply QoS policies to frames carried on a user-specified VLAN for a given interface. Per-VLAN classification is not required on access ports because access ports carry traffic for a single VLAN.

The router supports two policy levels: a parent level and a child level. With the QoS parent-child structure, you can reference a child policy in a parent policy to provide additional control of a specific traffic type. For per-port, per-VLAN QoS, the parent-level class-default matches the VLAN; match criteria is defined by the service instance encapsulation. You cannot configure multiple service classes at the parent level to match different combinations of VLANs.

Note A per-port, per-VLAN parent-level class map supports only class class-default; it should be configured with single rate policer. A flat policy can have multiple classes with match vlan and any action.

Note You can configure only class-default in the parent level of a per-port, per-VLAN hierarchical policy map.

In this example, the class maps in the child-level policy map specify matching criteria for voice, data, and video traffic, and the child policy map sets the action for input policing each type of traffic. The parent-level policy map specifies the VLANs to which the child policy maps are applied on the specified port.

Router(config)# class-map match-any dscp-1 data

Router(config-cmap)# match ip dscp 1

Router(config-cmap)# exit

Router(config)# class-map match-any dscp-23 video

	Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide
24-12	OL-23826-09