Specifications

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Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches
queue-limit
queue-limit
To specify or modify the maximum number of packets the queue can hold for a class policy configured
in a policy map, use the queue-limit command. To remove the queue packet limit from a class, use the
no form of this command.
queue-limit number-of-packets
no queue-limit number-of-packets
Syntax Description
Defaults By default, each physic al interface on a Catalys t 4500 switch has a defaul t queue based on the number
of slots in a chassis and the number of ports on the linecards.
Command Modes QoS policy-map cl ass configuration mode
Usage Guidelines By default, each physical inter face on a Catalyst 4500 switc h comes up with a default queu e. The size
of this queue is based on the number of slots in a chassis as well as the number of ports on the line card
in each slot. The switc h support s 512K q ueue entries of which 1 00 K are set asid e as a common sharable
pool. The remaining 412 K entries are equa lly distributed among t he slots. Each slot further divides its
allocated queue entries equally a mong its ports.
CBQ creates a queue for every class for which a class map is defined. Packets satisfying the match
criterion for a class accumulate in the queue reserved for the class until they are sent, which occurs when
the queue is serviced by the fair queuing process. When the maximum packet threshold you defined for
the class is reached, queuing of any fur ther packets to the class queue causes tail drop or, if DBL is
configured for the class policy, packet dr op to take effect.
Note The queue-limit command is supported only after you first configure a scheduling action, such as
bandwidth, or priority, except when you configure queue-limit in the class-default class of an output QoS
policy-map.s
Examples This example shows how to configure a policy-map called policy11 to contain policy for a class called
acl203. Policy for this class is set so that the queue reserved for it has a maximum packet limit of 40:
Switch# configure terminal
Switch (config)# policy-map policy11
Switch (config-pmap)# class acl203
Switch (config-pmap-c)# bandwidth 2000
Switch (config-pmap-c)# queue-limit 40
Switch (config-pmap-c)# end
Switch#
number-of-packets Number of packets that the queue for this class can accumulate; valid range
is 16 to 8184. This number must be a multiple of 8.