26-71
Catalyst 3750 Metro Switch Software Configuration Guide
78-15870-01
Chapter 26 Configuring QoS
Configuring Standard QoS
To return to the default setting, use the no mls qos queue-set output qset-id buffers global configuration
command. To return to the default WTD threshold percentages, use the no mls qos queue-set output
qset-id threshold [queue-id] global configuration command.
This example shows how to map a port to queue-set 2. It allocates 40 percent of the buffer space to egress
queue 1 and 20 percent each to egress queues 2, 3, and 4. It configures the drop thresholds for queue 2
to 40 and 60 percent of the allocated memory, guarantees (reserves) 100 percent of the allocated memory,
and configures 200 percent as the maximum memory that this queue can have before packets are
dropped.
Switch(config)# mls qos queue-set output 2 buffers 40 20 20 20
Switch(config)# mls qos queue-set output 2 threshold 2 40 60 100 200
Switch(config)# interface fastethernet1/0/1
Switch(config-if)# queue-set 2
Mapping DSCP or CoS Values to an Egress Queue-Set and to a Threshold ID
You can prioritize traffic by placing packets with particular DSCP or CoS values into certain queues and
by adjusting the queue thresholds so that packets with lower priorities are dropped.
Note The egress queue-set default settings are suitable for most situations. You should change them only when
you have a thorough understanding of the queues and only if these settings do not meet your QoS
solution.
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 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 for a
port.
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.
To Next Page
Loading...
Need help?
General
