Cisco Systems 2950 Configuring the DSCP-to-CoS Map

30-36
Catalyst2950 and Catalyst2955 Switch Software Configuration Guide
78-11380-10
Chapter30 Co nf iguring QoS
Configuring Standard QoS
Configuring the DSCP-to-CoS Map
You use the DSCP-to-CoS map to map DSCP values in incoming packets to a CoS value, which is used
to select one of the four egress queues.
The switch supports these DSCP values: 0, 8, 10, 16, 18, 24, 26, 32, 34, 40, 46, 48, and 56.
Table30-8 shows the default DSCP-to-CoS map.
If these values are not appropriate for your network, you need to modify them.
Beginning in privileged EXEC mode, follow these steps to modify the DSCP-to-CoS map:
To return to the default map, use the no mls qos map dscp-cos global configuration command.
This example shows how the DSCP values 26 and 48 are mapped to CoS value 7. For the remaining
DSCP values, the DSCP-to-CoS mapping is the default.
Switch(config)# mls qos map dscp-cos 26 48 to 7
Switch(config)# exit
Switch# show mls qos maps dscp-cos
Dscp-cos map:
dscp: 0 8 10 16 18 24 26 32 34 40 46 48 56
-----------------------------------------------
cos: 0 1 1 2 2 3 7 4 4 5 5 7 7
Table30-8 Default DSCP-to-CoS Map
DSCP values 0 8, 10 16, 18 24, 26 32, 34 40, 46 48 56
CoS values01234567
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 mls qos map dscp-cos dscp-list to cos Modify the DSCP-to-CoS map.
For dscp-list, enter up to 13 DSCP values separated by s paces . Then e nter
the to keyword.
For cos, enter the CoS value to which the DSCP values correspond.
The supported DSCP values are 0, 8, 10, 16, 18, 24, 26, 32, 34, 40, 46 , 48,
and 56. The CoS range is 0 to 7.
Step3 end Return to privileged EXEC mode.
Step4 show mls qos maps dscp-cos Verify your entries.
Step5 copy running-config startup-config (Optional ) Save your entries in the co nfiguration file.