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Catalyst 2950 Desktop Switch Software Configuration Guide
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Chapter 26 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 26-3 shows the default CoS-to-DSCP 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 th e CoS-to-DSCP map:
To return to the default map, use the no mls qos map cos-dscp global configur ation c omman d.
This example shows how to modify and display the CoS-to-DSCP map:
Switch# configure terminal
Switch(config)# mls qos map cos-dscp 8 8 8 8 24 32 56 56
Switch(config)# end
Switch# show mls qos maps cos-dscp
Cos-dscp map:
cos: 0 1 2 3 4 5 6 7
--------------------------------
dscp: 8 8 8 8 24 32 56 56
Table 2 6-3 Default CoS-to-DSCP Map
CoS value012345 6 7
DSCP value 0 8 16 24 32 40 48 56
Command Purpose
Step 1 configure terminal Enter globa l configurati on mode.
Step 2 mls qos map cos-dscp dscp1...dscp8 Modify the CoS-to-DSCP map.
For dscp1...dscp8, ente r 8 DSCP values t hat corr es pond to CoS values 0
to 7. Separate each DSCP value with a space.
The support ed DSCP values are 0, 8, 10 , 16, 18, 24, 2 6, 32, 34, 40, 46,
48, and 56.
Step 3 end Return to p rivileged EXEC mode.
Step 4 show mls qos maps cos-dscp Verify yo ur ent rie s.
Step 5 copy running-config startup-config (Optiona l) Save your entries in the co nfigurati on file.