Cisco Systems A9014CFD manual Class Maps, Match Command, 24-8

Chapter 24 Configuring QoS

Understanding QoS

These sections contain additional information about classification:

•“Class Maps” section on page 24-8

•“The match Command” section on page 24-8

•“Classification Based on Layer 2 CoS” section on page 24-9

•“Classification Based on IP Precedence” section on page 24-9

•“Classification Based on IP DSCP” section on page 24-9

•“Classification Comparisons” section on page 24-10

•“Classification Based on QoS Groups” section on page 24-11

•“Classification Based on VLAN IDs” section on page 24-12

Class Maps

Use an MQC class map to name a specific traffic flow (or class) and to isolate it from all other traffic. A class map defines the criteria used to match against a specific traffic flow to further classify it. If you wish to classify more than one type of traffic, you can create another class map and use a different name. When you use the class-mapcommand with a class-map name, the router enters the class-map configuration mode. In this mode, you define the match criterion for the traffic by using the match class-mapconfiguration command. After a packet is matched against the class-map criteria, it is acted on by the associated action specified in a policy map.

You can match more than one criterion for classification. You can also create a class map that requires that all matching criteria in the class map be in the packet header by using the class map match-allclass-map name global configuration command to enter class map configuration mode.

Note You can configure only one match entry in a match-allclass map.

You can use the class map match-anyclass-map name global configuration command to define a classification with any of the listed criteria.

Note If you do not enter match-allor match-any, the default is to match all. A match-all class map cannot have more than one classification criterion (match statement). A class map with no match condition has a default of match all.

The match Command

To configure the type of content used to classify packets, use the match class-map configuration command to specify the classification criteria. If a packet matches the configured criteria, it belongs to a specific class and is forwarded according to the specified policy. For example, you can use the match class-map command with CoS, IP DSCP, and IP precedence values. These values are referred to as markings on a packet.

•For an input policy map, you cannot configure an IP classification (match ip dscp, match ip precedence, match ip acl) and a non-IP classification (match cos or match mac acl) in the same policy map or class map.

•In an output policy map, no two class maps can have the same classification criteria, that is, the same match qualifiers and values.

	Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide
24-8	OL-23826-09