Configuring The Dscp-To-Cos Map - Cisco Catalyst 3550 series Software Configuration Manual

Configuring Standard QoS
This example shows how to map DSCP values 50 to 57 to a marked-down DSCP value of 0:
Switch# configure terminal
Switch(config)# mls qos map policed-dscp 50 51 52 53 54 55 56 57 to 0
Switch(config)# end
Switch# show mls qos maps policed-dscp
Policed-dscp map:
Note In this policed-DSCP map, the marked-down DSCP values are shown in the body of the matrix. The d1
column specifies the most-significant digit of the original DSCP; the d2 row specifies the
least-significant digit of the original DSCP. The intersection of the d1 and d2 values gives the
marked-down value. For example, an original DSCP value of 53 corresponds to a marked-down DSCP
value of 0.

Configuring the DSCP-to-CoS Map

You use the DSCP-to-CoS map to generate a CoS value, which is used to select one of the four egress
queues.
Table 29-8
Table 29-8 Default DSCP-to-CoS Map
DSCP value
CoS value
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:
Command
Step 1 configure terminal
Step 2 mls qos map dscp-cos dscp-list to cos
Step 3
end
Step 4
show mls qos maps dscp-to-cos
Step 5 copy running-config startup-config
To return to the default map, use the no mls qos map dscp-cos global configuration command.
Catalyst 3550 Multilayer Switch Software Configuration Guide
29-54
d1 : d2 0 1 2 3 4
---------------------------------------
0 : 00 01 02 03 04 05 06 07 08 09
1 : 10 11 12 13 14 15 16 17 18 19
2 : 20 21 22 23 24 25 26 27 28 29
3 : 30 31 32 33 34 35 36 37 38 39
4 : 40 41 42 43 44 45 46 47 48 49
5 : 00 00 00 00 00 00 00 00 58 59
6 : 60 61 62 63
shows the default DSCP-to-CoS map.
0–7 8–15
0 1
Purpose
Enter global configuration mode.
Modify the DSCP-to-CoS map.
•
•
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
5 6 7 8 9
16–23 24–31 32–39
2 3 4
For dscp-list, enter up to eight DSCP values, with each value
separated by a space. Then enter the to keyword. The range is 0 to 63.
For cos, enter the CoS value to which the DSCP values correspond.
The range is 0 to 7.
Chapter 29
40–47 48–55 56–63
5 6 7
Configuring QoS
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