Cisco Systems 3750E Mls qos srr-queue input dscp-map, Mls qos srr-queue input cos-map, 36-70

Chapter 36 Configuring QoS

Configuring Standard QoS

Mapping DSCP or CoS Values to an Ingress Queue and Setting WTD Thresholds

You can prioritize traffic by placing packets with particular DSCPs or CoSs into certain queues and adjusting the queue thresholds so that packets with lower priorities are dropped.

Beginning in privileged EXEC mode, follow these steps to map DSCP or CoS values to an ingress queue and to set WTD thresholds. This procedure is optional.

	Command	Purpose
Step 1
	configure terminal	Enter global configuration mode.
Step 2
	mls qos srr-queue input dscp-map	Map DSCP or CoS values to an ingress queue and to a threshold ID.
	queue queue-id threshold threshold-id	By default, DSCP values 0–39 and 48–63 are mapped to queue 1 and
	dscp1...dscp8
		threshold 1. DSCP values 40–47 are mapped to queue 2 and threshold 1.
	or	By default, CoS values 0–4, 6, and 7 are mapped to queue 1 and threshold
	mls qos srr-queue input cos-map	1. CoS value 5 is mapped to queue 2 and threshold 1.
	queue queue-id threshold threshold-id	• For queue-id, the range is 1 to 2.
	cos1...cos8
		• 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
	mls qos srr-queue input threshold	Assign the two WTD threshold percentages for (threshold 1 and 2) to an
	queue-id threshold-percentage1	ingress queue. The default, both thresholds are set to 100 percent.
	threshold-percentage2	• For queue-id, the range is 1 to 2.
		• For threshold-percentage1 threshold-percentage2, the range is 1 to
		100. Separate each value with a space.
		Each threshold value is a percentage of the total number of queue
		descriptors allocated for the queue.
Step 4
	end	Return to privileged EXEC mode.
Step 5
	show mls qos maps	Verify your entries.
		The DSCP input queue threshold map appears as a matrix. The d1 column
		specifies the most-significant digit of the DSCP number; the d2 row
		specifies the least-significant digit in the DSCP number. The intersection
		of the d1 and the d2 values provides the queue ID and threshold ID; for
		example, queue 2 and threshold 1 (02-01).
		The CoS input queue threshold map shows the CoS value in the top row
		and the corresponding queue ID and threshold ID in the second row; for
		example, queue 2 and threshold 2 (2-2).
Step 6
	copy running-config startup-config	(Optional) Save your entries in the configuration file.

To return to the default CoS input queue threshold map or the default DSCP input queue threshold map, use the no mls qos srr-queue input cos-mapor the no mls qos srr-queue input dscp-mapglobal configuration command. To return to the default WTD threshold percentages, use the no mls qos srr-queue input threshold queue-idglobal configuration command.

	Catalyst 3750-E and 3560-E Switch Software Configuration Guide
36-70	OL-9775-02