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Command Reference Guide
Default Values
No default values are necessary for this command.
Command History
Release 11.1
Release R10.1.0
Usage Examples
The following example instructs the QoS map named MYMAP to match the IPv4 header with a DSCP AF
Class 1, Subclass 2 (af12):
(config)#qos map MYMAP 20
(config-qos-map)#match ip dscp af12
The following example instructs the QoS map named MYMAP to match either an IPv4 header or IPv6
header with a DSCP AF Class 1, Subclass 2 (af12):
(config)#qos map MYMAP 20
(config-qos-map)#match dscp af12
Technology Review
The DSCP model was created in RFC 2474 and 2475 to build on the original IPv4 header type of service
(ToS) field by creating a 6-bit sequence (combining the precedence value with the delay, throughput, and
reliability bits). (IPv6 headers have an 8-bit traffic class field serving the same purpose.) This 6-bit
sequence increased the number of available values from 8 to 64. The DiffServ model introduced a new
concept to QoS in the IP network environment: per-hop behaviors (PHBs). The PHB premise is that
equipment using the DiffServ model have an agreed upon set of rules (PHB types) for handling certain
network traffic. Though the RFC explicitly defines what each PHB should be capable of, it does not restrict
vendor-specific implementation of the PHBs. Each vendor is free to decide how their network product
implements the various defined PHBs.
According to RFC 2474, the differentiated services (DS) field contains the following bits:
*The previously unused bits in the DS field are now used for congestion control and are not discussed in this document.
60000CRG0-35E
Command was introduced.
Command was expanded to include ip and ipv6 parameters to
accommodate IPv4 and IPv6 traffic.
0
1
2
3
Differentiated Services Code Point
Copyright © 2012 ADTRAN, Inc.
Quality of Service Map Command Set
4
5
6
7
Unused*
3279
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