Cisco 4500M User Manual

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Software Configuration Guide—Release 12.2(25)EW
OL-6696-01
Chapter 29 Configuring QoS
Configuring QoS
Configuring the CoS-to-DSCP Map
You use the CoS-to-DSCP map to map CoS values in incoming packets to a DSCP value that QoS uses
internally to represent the priority of the traffic.
Table 29-4 shows the default CoS-to-DSCP map.
If these values are not appropriate for your network, you need to modify them.
To modify the CoS-to-DSCP map, perform this task:
To return to the default map, use the no qos cos to dscp global configuration command.
This example shows how to modify and display the CoS-to-DSCP map:
Switch# configure terminal
Switch(config)# qos map cos 0 to dscp 20
Switch(config)# end
Switch# show qos maps cos dscp
CoS-DSCP Mapping Table:
CoS: 0 1 2 3 4 5 6 7
--------------------------------
DSCP: 20 8 16 24 32 40 48 56
Switch(config)#
Configuring the Policed-DSCP Map
You use the policed-DSCP map to mark down a DSCP value to a new value as the result of a policing
and marking action.
The default policed-DSCP map is a null map, which maps an incoming DSCP value to the same DSCP
value.
Table 29-4 Default CoS-to-DSCP Map
CoS value 01 2 345 6 7
DSCP value 0 8 16 24 32 40 48 56
Command Purpose
Step 1
Switch# configure terminal
Enters global configuration mode.
Step 2
Switch(config)# qos map cos cos1 ... cos8
to dscp
dscp
Modifies the CoS-to-DSCP map.
For cos1...cos8, you can enter up to 8 CoS; valid values range
from 0 to 7. Separate each CoS value with a space.
The dscp range is 0 to 63.
Step 3
Switch(config)# end
Returns to privileged EXEC mode.
Step 4
Switch# show qos maps cos-dscp
Verifies your entries.
Step 5
Switch# copy running-config startup-config
(Optional) Saves your entries in the configuration file.

Cisco 4500M Specifications

General

Brand	Cisco
Model	4500M
Category	Network Router
Language	English