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Cisco IE 3000 Switch Software Configuration Guide
OL-13018-03
Chapter 36 Configuring QoS
Configuring Standard QoS
To return to the default CoS input queue threshold map or the default DSCP input queue threshold map,
use the
no mls qos srr-queue input cos-map
or the
no mls qos srr-queue input dscp-map
global
configuration command. To return to the default WTD threshold percentages, use the
no mls qos
srr-queue input threshold
queue-id
global configuration command.
This example shows how to map DSCP values 0 to 6 to ingress queue 1 and to threshold 1 with a drop
threshold of 50 percent. It maps DSCP values 20 to 26 to ingress queue 1 and to threshold 2 with a drop
threshold of 70 percent:
Switch(config)#
mls qos srr-queue input dscp-map queue 1 threshold 1 0 1 2 3 4 5 6
Switch(config)#
mls qos srr-queue input dscp-map queue 1 threshold 2 20 21 22 23 24 25 26
Switch(config)#
mls qos srr-queue input threshold 1 50 70
In this example, the DSCP values (0 to 6) are assigned the WTD threshold of 50 percent and will be
dropped sooner than the DSCP values (20 to 26) assigned to the WTD threshold of 70 percent.
Allocating Buffer Space Between the Ingress Queues
You define the ratio (allocate the amount of space) with which to divide the ingress buffers between the
two queues. The buffer and the bandwidth allocation control how much data can be buffered before
packets are dropped.
Beginning in privileged EXEC mode, follow these steps to allocate the buffers between the ingress
queues. This procedure is optional.
Step 5
show mls qos maps
Verify your entries.
The DSCP input 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 input 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 6
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Command
Purpose
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
mls qos srr-queue input buffers
percentage1 percentage2
Allocate the buffers between the ingress queues
By default 90 percent of the buffers are allocated to queue 1, and 10
percent of the buffers are allocated to queue 2.
For
percentage1 percentage2,
the range is 0 to 100. Separate each value
with a space.
You should allocate the buffers so that the queues can handle any
incoming bursty traffic.
Step 3
end
Return to privileged EXEC mode.
