Cisco WS-C3550-12G Software Configuration Manual page 512

QoS Configuration Examples
Command
Step 5 switchport mode trunk
Step 6
exit
Step 7 interface gigabitethernet0/2
Step 8 mls qos trust dscp
Step 9
wrr-queue dscp-map threshold-id
dscp1 ... dscp8
Step 10
switchport mode trunk
Step 11
exit
Step 12
mls qos map dscp-cos dscp-list to cos
Step 13
interface gigabitethernet0/5
Step 14
priority-queue out
Step 15
wrr-queue bandwidth weight1 weight2
weight3 weight4
Step 16
wrr-queue random-detect
max-threshold queue-id
threshold-percentage1
threshold-percentage2
Catalyst 3550 Multilayer Switch Software Configuration Guide
20-60
Purpose
Configure this port as a trunk port.
Return to global configuration mode.
Enter interface configuration mode, and specify the ingress interface
connected to the intelligent wiring closet.
Classify incoming packets on this port by using the packet DSCP value.
Map the ingress DSCP values to the WRED thresholds of the egress
queues.
In the default DSCP-to-threshold map, all DSCP values are mapped to
threshold 1.
• For threshold-id, specify the threshold ID of the queue. The range is
1 to 2.
For dscp1 ... dscp8, specify the DSCP values that are mapped to a
•
threshold ID. Enter up to eight DSCP values per command. Separate
each value with a space. The DSCP range is 0 to 63.
Configure this port as a trunk port.
Return to global configuration mode.
Modify the DSCP-to-CoS map. You can enter up to eight DSCP values
separated by spaces in the DSCP-to-CoS map.
For example, to map DSCP values 57 to 63 to CoS 5, enter:
mls qos map dscp-cos 57 58 59 60 61 62 63 to 5
Enter interface configuration mode, and specify the egress interface to
configure.
Enable the expedite queue.
Configure WRR weights to the egress queues to determine the ratio of the
frequency at which packets are dropped. Separate each value with a space.
The weight range is 0 to 65536.
In this example, to configure the weights so that queue 4 is serviced more
frequently than the other queues, enter:
wrr-queue bandwidth 1 2 3 4
Because the expedite queue is enabled, only the first three weights are
used in the ratio calculation.
Enable WRED and assign two WRED threshold values to an egress queue
of a Gigabit-capable Ethernet port.
• For queue-id, the range is 1 to 4.
For threshold-percentage1 threshold-percentage2, the range is 1 to
•
100 percent.
In this example, to configure the thresholds, enter:
wrr-queue random-detect max-threshold 1 20 100
wrr-queue random-detect max-threshold 2 40 100
wrr-queue random-detect max-threshold 3 60 100
wrr-queue random-detect max-threshold 4 80 100
Chapter 20 Configuring QoS
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