26-26
Catalyst 2950 Desktop Switch Software Configuration Guide
78-14982-01
Chapt er 26 Conf i gurin g QoS
Configuring QoS

Configuring the DSCP-to-CoS Map

You use the DSCP-to-CoS ma p t o map DSCP values in incoming packets to a CoS value, which is use d
to sele ct one of the fou r egress queues .
The switc h supports these D SCP values: 0, 8, 10, 16, 18, 24, 26, 32 , 34, 40, 46, 48, and 56.
Table 26-4 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 mo de, follow these steps t o modify th e DSCP-to- CoS map:
To return to the default map, use the no mls qos map dscp-cos global co nfigurati on comm and.
This example shows how the DSCP values 26 and 48 are mapped to CoS value 7. For the rema ining
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
Table 26-4 Default DSCP-to-CoS Map
DSCP values 0 8, 10 16, 18 24, 26 32, 34 40, 46 48 56
CoS values01234567
Command Purpose
Step 1 configure terminal Enter globa l configurati on mode.
Step 2 mls qos map dscp-cos dscp-list to cos Modify the D SCP- to-CoS ma p.
For dscp-list, en ter up to 13 DSCP v alu es sepa rated b y s paces. Then e nter
the to keyword.
For cos, enter the CoS value to which the DSCP values correspond.
The support ed DSCP values are 0, 8, 10 , 16, 18, 24, 2 6, 32, 34, 40, 46,
48, and 56. T he CoS r a nge i s 0 to 7.
Step 3 end Return to privileged EXEC mode.
Step 4 show mls qos maps dscp-cos Verify yo ur e ntri es.
Step 5 copy running-config startup-config (Optiona l) Save your entries in the co nfigurati on file.