Cisco ME 3800X Command Reference Manual page 246

queue-limit
Command History Release
12.2(52)EY
Usage Guidelines
You use the queue-limit policy-map class command to control output traffic. Queue-limit settings are
not supported in input policy maps.
Use the other classification values to specify the subtype of traffic that needs to be mapped to the unique
threshold on the queue.
The switch supports one output policy map for each interface. Each class of a policy map can have three
unique queue-limit configurations, including an unqualified queue-limit (that is a queue-limit without
any qualifier).
The switch supports a maximum of eight queues per policy map, including the class-default. Queue-limit
configurations are unique for a class of a policy map. There are a total of 256 queue-limit profiles in the
switch, some of which are default profiles. Each profile can have three queue-limit configurations. When
queue-limit configurations are the same across classes, the classes use the same queue-limit profile.
If you try to attach an output policy map that contains a fourth queue-limit configuration to an interface,
you see an error message and the attachment is not allowed.
The queue-limit command is supported only after you first configure a scheduling action, such as
bandwidth, shape-average, or priority, except when you configure queue-limit in the class-default of
an output policy map.
You cannot configure more than two unique threshold values for WTD qualifiers (cos, dscp,
precedence, exp, discard-class, or qos-group) in the queue-limit command. However, you can map
any number of qualifiers to those thresholds. You can configure a third unique threshold value to set the
threshold for the queue, using the queue-limit command with no qualifiers.
You can use these same queue-limit values in multiple output policy maps on the switch. However,
changing one of the queue-limit values in a class would create a new, unique queue-limit configuration.
You can attach only three unique queue-limit configurations in output policy maps to interfaces at any
one time. If you try to attach an output policy map with a fourth unique queue-limit configuration, you
see this error message:
You can verify your settings by entering the show policy-map privileged EXEC command.
Examples This example shows a policy map with a specified bandwidth and queue size. Traffic that is not DSCP 30
or 10 is assigned a queue-limit of 2000 bytes. Traffic with a DSCP value of 30 is assigned a queue-limit
of 1000 bytes, and traffic with a DSCP value of 10 is assigned a queue limit of 1500 bytes. All traffic
not belonging to the class traffic is classified into class-default, which is configured with 10 percent of
the total available bandwidth and a large queue size of 3000 bytes.
Switch(config)# policy-map gold-policy
Switch(config-pmap)# class traffic
Switch(config-pmap-c)# bandwidth percent 50
Switch(config-pmap-c)# queue-limit bytes 2000
Switch(config-pmap-c)# queue-limit dscp 30 bytes 1000
Switch(config-pmap-c)# queue-limit dscp 10 bytes 1500
Switch(config-pmap-c)# exit
Switch(config-pmap)# exit
Switch(config-pmap)# class class-default
Switch(config-pmap-c)# bandwidth percent 10
Cisco ME 3800X and ME 3600X Switch Command Reference
2-222
Modification
This command was introduced.
QoS: Configuration failed. Maximum number of allowable unique queue-limit
configurations exceeded.
Chapter 2 Cisco ME 3800X and ME 3600X Switch Cisco IOS Commands
OL-28238-01