Cisco Systems 3750E manual Generated Auto-QoS Configuration, 36-23

Chapter 36 Configuring QoS

Configuring Auto-QoS

Generated Auto-QoS Configuration

By default, auto-QoS is disabled on all ports.

When auto-QoS is enabled, it uses the ingress packet label to categorize traffic, to assign packet labels, and to configure the ingress and egress queues as shown in Table 36-2.

Table 36-2	Traffic Types, Packet Labels, and Queues
		VoIP1 Data	VoIP Control	Routing Protocol	STP BPDU	Real-Time
		Traffic	Traffic	Traffic	Traffic	Video Traffic	All Other Traffic
DSCP		46	24, 26	48	56	34	–
CoS		5	3	6	7	4	–
CoS-to-Ingress		2, 3, 4, 5, 6, 7 (queue 2)					0,	1 (queue 1)
Queue Map
CoS-to-Egress		5 (queue 1)	3, 6, 7 (queue 2)			4 (queue 3)	2	(queue 3)	0, 1
Queue Map									(queue 4)

1. VoIP = voice over IP

Table 36-3shows the generated auto-QoS configuration for the ingress queues.

Table 36-3	Auto-QoS Configuration for the Ingress Queues
					Queue Weight	Queue (Buffer)
Ingress Queue		Queue Number	CoS-to-Queue Map		(Bandwidth)	Size
SRR shared		1	0,	1	81 percent	67 percent
Priority		2	2,	3, 4, 5, 6, 7	19 percent	33 percent

Table 36-4shows the generated auto-QoS configuration for the egress queues.

Table 36-4	Auto-QoS Configuration for the Egress Queues
					Queue (Buffer) Size	Queue (Buffer)
				Queue Weight	for Gigabit-Capable	Size for 10/100
Egress Queue		Queue Number	CoS-to-Queue Map	(Bandwidth)	Ports	Ethernet Ports
Priority (shaped)		1	5	10 percent	16 percent	10 percent
SRR shared		2	3, 6, 7	10 percent	6 percent	10 percent
SRR shared		3	2, 4	60 percent	17 percent	26 percent
SRR shared		4	0, 1	20 percent	61 percent	54 percent

When you enable the auto-QoS feature on the first port, these automatic actions occur:

•QoS is globally enabled (mls qos global configuration command), and other global configuration commands are added.

•When you enter the auto qos voip cisco-phoneinterface configuration command on a port at the edge of the network that is connected to a Cisco IP Phone, the switch enables the trusted boundary feature. The switch uses the Cisco Discovery Protocol (CDP) to detect the presence or absence of a Cisco IP Phone. When a Cisco IP Phone is detected, the ingress classification on the port is set to

	Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-02		36-23