Cisco Systems 3750E Configuring SRR Shaped Weights on Egress Queues, Weight2 weight3 weight4

Chapter 36 Configuring QoS

Configuring Standard QoS

Configuring SRR Shaped Weights on Egress Queues

You can specify how much of the available bandwidth is allocated to each queue. The ratio of the weights is the ratio of frequency in which the SRR scheduler sends packets from each queue.

You can configure the egress queues for shaped or shared weights, or both. Use shaping to smooth bursty traffic or to provide a smoother output over time. For information about shaped weights, see the “SRR Shaping and Sharing” section on page 36-14. For information about shared weights, see the “Configuring SRR Shared Weights on Egress Queues” section on page 36-79.

Beginning in privileged EXEC mode, follow these steps to assign the shaped weights and to enable bandwidth shaping on the four egress queues mapped to a port. This procedure is optional.

	Command	Purpose
Step 1
	configure terminal	Enter global configuration mode.
Step 2
	interface interface-id	Specify the port of the outbound traffic, and enter interface configuration
		mode.
Step 3
	srr-queue bandwidth shape weight1	Assign SRR weights to the egress queues.
	weight2 weight3 weight4	By default, weight1 is set to 25; weight2, weight3, and weight4 are set to 0,
		and these queues are in shared mode.
		For weight1 weight2 weight3 weight4, enter the weights to control the
		percentage of the port that is shaped. The inverse ratio (1/weight) controls
		the shaping bandwidth for this queue. Separate each value with a space.
		The range is 0 to 65535.
		If you configure a weight of 0, the corresponding queue operates in shared
		mode. The weight specified with the srr-queue bandwidth shape
		command is ignored, and the weights specified with the srr-queue
		bandwidth share interface configuration command for a queue come into
		effect. When configuring queues in the same queue-set for both shaping
		and sharing, make sure that you configure the lowest number queue for
		shaping.
		The shaped mode overrides the shared mode.
Step 4
	end	Return to privileged EXEC mode.
Step 5
	show mls qos interface interface-id	Verify your entries.
	queueing
Step 6
	copy running-config startup-config	(Optional) Save your entries in the configuration file.

To return to the default setting, use the no srr-queue bandwidth shape interface configuration command.

This example shows how to configure bandwidth shaping on queue 1. Because the weight ratios for queues 2, 3, and 4 are set to 0, these queues operate in shared mode. The bandwidth weight for queue 1 is 1/8, which is 12.5 percent:

Switch(config)# interface gigabitethernet2/0/1

Switch(config-if)#srr-queue bandwidth shape 8 0 0 0

	Catalyst 3750-E and 3560-E Switch Software Configuration Guide
36-78	OL-9775-02