Reference Guide

The queue management mechanism used for congestion avoidance raises the priority by dropping trac from lower-priority ows before
trac from higher-priority ows. Policing and shaping provides priority to a ow by limiting the throughput of other ows.
You can congure a guaranteed bandwidth percentage by examining for the egress out ows on the queue. For example, if you have
identied three dierent ows which are egressing out of an interface, you can congure the bandwidth ratio for the ows as 3:2:1 which
means:
• 1st ow—50
• 2nd ow—33.3
• 3rd ow—16.66
The conguration is then:
• Bandwidth percent 50 = bandwidth percent 3
• Bandwidth percent 33 = bandwidth percent 2
• Bandwidth percent 17 = bandwidth percent 1
Bandwidth allocation
You can allocate relative bandwidth to limit large ows and prioritize smaller ows. Allocate the relative amount of bandwidth to nonpriority
queues when priorities queues are consuming maximum link bandwidth.
Each egress queue of an interface can be scheduled as per Weighted Decit Round Robin (WDRR) or by strict-priority (SP), which are
both mutually exclusive. If the bandwidth percent command is present, you cannot congure the priority command as it is used
to assign bandwidth to a queue.
1 Create a class-map of type queuing and congure a name for the class-map in CONFIGURATION mode.
class-map type queuing class-map-name
2 Apply the match criteria for the QoS group in CLASS-MAP mode.
qos-group queue-number
3 Return to the CONFIGURATION mode.
exit
4 Create a policy-map of type queuing and congure a policy-map name in CONFIGURATION mode.
policy-map type queuing policy-map-name
5 Congure a queuing class in POLICY-MAP mode.
class class-name
6 Assign a bandwidth percent (1 to 100) to nonpriority queues in POLICY-MAP-CLASS-MAP mode.
bandwidth percent value
Congure bandwidth allocation
OS10(config)# class-map type queuing solar
OS10(conf-cmap-queuing)# match qos-group 5
OS10(conf-cmap-queuing)# exit
OS10(config)# policy-map lunar
OS10(config)# policy-map type queuing lunar
OS10(conf-pmap-queuing)# class solar
OS10(conf-pmap-c-que)# bandwidth percent 80
View class-map
OS10(conf-cmap-queuing)# do show class-map
Class-map (queuing): solar (match-any)
Match: qos-group 5
View policy-map
OS10(conf-pmap-c-que)# do show policy-map
Service-policy (queuing) output: solar
558
Quality of service