Chapter 32
Configuring QoS
Beginning in privileged EXEC mode, follow these steps to map DSCP or CoS values to an egress queue
and to a threshold ID. This procedure is optional.
Command
Step 1
configure terminal
Step 2
mls qos srr-queue output dscp-map
queue queue-id threshold threshold-id
dscp1...dscp8
or
mls qos srr-queue output cos-map
queue queue-id threshold threshold-id
cos1...cos8
Step 3
end
Step 4
show mls qos maps
Step 5
copy running-config startup-config
To return to the default DSCP output queue threshold map or the default CoS output queue threshold
map, use the no mls qos srr-queue output dscp-map or the no mls qos srr-queue output cos-map
global configuration command.
This example shows how to map DSCP values 10 and 11 to egress queue 1 and to threshold 2:
Switch(config)# mls qos srr-queue output dscp-map queue 1 threshold 2 10 11
78-16180-02
Purpose
Enter global configuration mode.
Map DSCP or CoS values to an egress queue and to a threshold ID.
By default, DSCP values 0–15 are mapped to queue 2 and threshold 1.
DSCP values 16–31 are mapped to queue 3 and threshold 1. DSCP values
32–39 and 48–63 are mapped to queue 4 and threshold 1. DSCP values
40–47 are mapped to queue 1 and threshold 1.
By default, CoS values 0 and 1 are mapped to queue 2 and threshold 1.
CoS values 2 and 3 are mapped to queue 3 and threshold 1. CoS values 4,
6, and 7 are mapped to queue 4 and threshold 1. CoS value 5 is mapped to
queue 1 and threshold 1.
For queue-id, the range is 1 to 4.
•
For threshold-id, the range is 1 to 3. The drop-threshold percentage
•
for threshold 3 is predefined. It is set to the queue-full state.
For dscp1...dscp8, enter up to eight values, and separate each value
•
with a space. The range is 0 to 63.
For cos1...cos8, enter up to eight values, and separate each value with
•
a space. The range is 0 to 7.
Return to privileged EXEC mode.
Verify your entries.
The DSCP output queue threshold map appears as a matrix. The d1
column specifies the most-significant digit of the DSCP number; the d2
row specifies the least-significant digit in the DSCP number. The
intersection of the d1 and the d2 values provides the queue ID and
threshold ID; for example, queue 2 and threshold 1 (02-01).
The CoS output queue threshold map shows the CoS value in the top row
and the corresponding queue ID and threshold ID in the second row; for
example, queue 2 and threshold 2 (2-2).
(Optional) Save your entries in the configuration file.
Catalyst 3750 Switch Software Configuration Guide
Configuring Standard QoS
32-63