Cisco Catalyst 3550 Series User Manual

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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter 29 Configuring QoS
Configuring Standard QoS
Beginning in privileged EXEC mode, follow these steps to allocate bandwidth to each queue:
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 WRR scheduler running on the egress
queues. In this example, four queues are used (no expedite queue), and the ratio of the bandwidth
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,
2/10, 3/10, and 4/10 for queues 1, 2, 3, and 4.
Switch(config)# interface fastethernet0/1
Switch(config-if)# wrr-queue bandwidth 1 2 3 4
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
mls qos Enable QoS on the switch.
Step 3
interface interface-id Enter interface configuration mode, and specify the egress 10/100
Ethernet interface.
Step 4
wrr-queue bandwidth weight1 weight2
weight3 weight4
Assign WRR weights to the egress queues.
By default, all the weights are set to 25 (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 dequeues
packets. Separate each value with a space. The range is 1 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 priority queue, and it is
serviced until empty before the other queues are serviced.
A weight of 1 means that the minimum bandwidth is allocated for that
queue.
To allocate no bandwidth for a queue, use the wrr-queue cos-map
interface configuration command so that the available bandwidth is
shared among the remaining queues.
Step 5
end Return to privileged EXEC mode.
Step 6
show mls qos interface queueing Verify your entries.
Step 7
copy running-config startup-config (Optional) Save your entries in the configuration file.

Cisco Catalyst 3550 Series Specifications

General

Form Factor	Rack-mountable
Manageable	Yes
RAM	64 MB
Device Type	Switch
MAC Address Table Size	12000 entries
Routing Protocol	RIP
Features	VLAN support
Power Supply	AC 120/230 V (50/60 Hz)
Ports	24 or 48 x 10/100Base-TX, 1 x GBIC, 2 x 10/100/1000Base-T
Operating Temperature	32 to 113°F (0 to 45°C)