Queue-Limit - Cisco Catalyst 4500 Series Command Reference Manual

Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches

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.
Syntax Description
number-of-packets
Defaults
By default, each physical interface on a Catalyst 4500 switch has a default queue based on the number
of slots in a chassis and the number of ports on the linecards.
Command Modes
QoS policy-map class configuration mode
Command History Release
12.2(44)SG
Usage Guidelines
This class-based queuing (CBQ) command applies only to the Supervisor Engine 6-E as part of the MQC
support on the Catalyst 4500 Supervisor Engine.
By default, each physical interface on a Catalyst 4500 switch comes up with a default queue. 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 switch supports 512K queue entries of which 100 K are set aside as a common sharable
pool. The remaining 412 K entries are equally distributed among the slots. Each slot further divides its
allocated queue entries equally among 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 further packets to the class queue causes tail drop or, if DBL is
configured for the class policy, packet drop 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
OL-25342 -01
queue-limit number-of-packets
no queue-limit 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.
Modification
This command was introduced on the Catalyst 4500 series switch.
Catalyst 4500 Series Switch Cisco IOS Command Reference—Release IOS XE 3.3.0SG and IOS 15.1(1)SG)
queue-limit
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