Cisco Systems A9014CFD manual Sample QoS Configuration, 24-33

Chapter 24 Configuring QoS

Configuring Quality of Service (QoS)

•On all Cisco ASR 901 routers, you can attach per-port and per-port, per-VLAN policy-maps across all ports on the router until QoS classification resource limitations are reached. Any policy attachment or change that causes this limit to be exceeded fails with a TCAM resources exceeded error message.

Sample QoS Configuration

The following configuration demonstrates how to apply QoS given the hardware limitations. The Cisco ASR 901 processes traffic between interfaces as follows:

•For layer 2 traffic passing between the GigabitEthernet 0/2 interface and the GigabitEthernet 0/0 interface, the output queue is determined by the QoS Group assigned in the in-qos policy map.

•For layer 3 traffic passing between GigabitEthernet 0/2 interface and the GigabitEthernet 0/0 interface, the output queue is determined based on the CoS value assigned in the in-qos policy map. (the CoS value is mapped 1:1 to the QoS group value.)

•For traffic passing between other interfaces, the output queue is determined based on the CS fields (top three bits) of the IP DSCP bits; these bits are copied to the CoS bits, which are mapped 1:1 to the QoS group value.

!

class-map match-all q0 match qos-group 0

class-map match-all q1 match qos-group 1

class-map match-all q2 match qos-group 2

class-map match-all q3 match qos-group 3

class-map match-all q4 match qos-group 4

class-map match-all q5 match qos-group 5

class-map match-all q6 match qos-group 6

class-map match-all q7 match qos-group 7

class-map match-any Voice match dscp ef

class-map match-any Signaling match dscp af41

class-map match-any HSDPA match dscp af11 af12

class-map match-any TCAM1

!translates to 3 TCAM rules because each match in match-any uses one entry match dscp af21

match cos 3

match mpls experimental topmost

class-map match-all TCAM2

!translates to 1 TCAM rules because all the match-all clauses together take only 1 entry match dscp af21

match cos 3

match mpls experimental topmost 1

!

policy-map in-qos

	class Voice
	set cos 5
	set qos-group 5
	class control_plane
	set cos 4
	Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide
OL-23826-09		24-33