Configuring The Ingress Priority Queue - Cisco Catalyst 2928 Software Configuration Manual

Chapter 31 Configuring QoS
Beginning in privileged EXEC mode, follow these steps to map CoS values to an ingress queue and to
set WTD thresholds. This procedure is optional.
Command
Step 1 configure terminal
Step 2
mls qos srr-queue input 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 CoS input queue threshold map, use the no mls qos srr-queue input cos-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.

Configuring the Ingress Priority Queue

You should use the priority queue only for traffic that needs to be expedited (for example, voice traffic,
which needs minimum delay and jitter).
The priority queue is guaranteed part of the bandwidth to reduce the delay and jitter under heavy network
traffic on an oversubscribed ring (when there is more traffic than the backplane can carry, and the queues
are full and dropping frames).
SRR services the priority queue for its configured weight as specified by the bandwidth keyword in the
mls qos srr-queue input priority-queue queue-id bandwidth weight global configuration command.
Then, SRR shares the remaining bandwidth with both ingress queues and services them as specified by
the weights configured with the mls qos srr-queue input bandwidth weight1 weight2 global
configuration command.
OL-23389-01
Purpose
Enter global configuration mode.
Map CoS values to an ingress queue and to a threshold ID.
By default, CoS values 0 to 4, 6, and 7 are mapped to queue 1 and
threshold 1. CoS value 5 is mapped to queue 2 and threshold 1.
• For queue-id, the range is 1 to 2.
• 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 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 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).
(Optional) Save your entries in the configuration file.
Catalyst 2928 Switch Software Configuration Guide
Configuring Standard QoS
31-13