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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter20 Configuring QoS Configuring QoS
To return to the default bandwidth setting, use the no wrr-queue bandwidth interface configuration
command.
This example shows how to configure the weight ratio of the WR R sche du ler runni ng on t he eg re ss
queues. In this example, four queues are used (no expedit e que ue) , and t he r atio of the b andw idt h
allocated for each queue is 1/(1+2+3+4), 2/(1+2+3+4), 3/(1+2+3+4), and 4/(1+2+3+4), which is 1/10,
1/5, 3/10, and 2/5 for queues 1, 2, 3, and 4.
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# wrr-queue bandwidth 1 2 3 4
Configuring Egress Queues on 10/100 Ethernet Ports
This section describes how to configure the egress queues on 10/100 Ethernet ports. For information on
configuring Gigabit-capable Ethernet ports, see the “Configurin g Egr ess Que ues o n Gi gabi t-Capa ble
Ethernet Ports” section on page 20-44.
Depending on the complexity of your network and your QoS solution, you might need to perform all of
the tasks in the next sections. You will need to make decisions about these characteristics:
•Which packets are assigned (by CoS value) to each queue?
•How much of the available buffer space is allotted to each queue?
•Is one of the queues the expedite (high-priority) egress queue?
•How much of the available bandwidth is allotted to each queue?
Step4 wrr-queue bandwidth weight1 weight2
weight3 weight4 Assign WRR weights to the egress queues.
By default, all the weight s ar e s et t o 2 5 (1/4 of the bandwidth is allocated
to each queue).
For weight1 weight2 weight3 weight4, enter the ratio, which determines
the ratio of the frequency in which the WRR scheduler drops packets.
Separate each value with a space. The range is 0 to 65536.
All four queues participate in the WRR unless the expedite queue
(queue 4) is enabled, in which case weight4 is ignored (not used in the
ratio calculation). The expedite queue is a strict-priority queue, an d it
is serviced until empty before the other queues are serviced.
A weight of 0 means no bandwidth is allocated for that queue, and the
available bandwidth is shared among the remaining queues.
Step5 end Return to privileged EXEC mode.
Step6 show mls qos interface queueing Verify your entries.
Step7 copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose