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Catalyst 3560 Switch Software Configuration Guide
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Chapter 28 Configuring QoS
Configuring Standard QoS
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
Configuring SRR Shaped Weights on Egress Queues
You can specify how much of the available bandwidth is allocated to each queue. The ratio of the weights
is the ratio of frequency in which the SRR scheduler sends packets from each queue.
You can configure the egress queues for shaped or shared weights, or both. Use shaping to smooth bursty
traffic or to provide a smoother output over time. For information about, see the
“SRR Shaping and
Sharing” section on page 28-12
. For information about shared weights, see the
“Configuring SRR
Shared Weights on Egress Queues” section on page 28-62
.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
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
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.
Step 3
end
Return to privileged EXEC mode.
Step 4
show mls qos maps
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).
Step 5
copy running-config startup-config
(Optional) Save your entries in the configuration file.
