Cisco Catalyst 3750 Metro, Command Reference Manual

Page: 400 / 985

2-372
Catalyst 3750 Metro Switch Command Reference
OL-9645-10
Chapter 2 Catalyst 3750 Metro Switch Cisco IOS Commands
queue-limit
queue-limit
Use the queue-limit policy-map class configuration command to configure the maximum threshold for
tail drop in a hierarchical policy map attached to an enhanced-services (ES) port. Use the no form of this
command to return to the default setting.
queue-limit limit
no queue-limit
Syntax Description
Defaults The maximum threshold is 128 packets.
Command Modes Policy-map class configuration
Command History
Usage Guidelines Class-based weighted fair queueing (CBWFQ) creates a queue for every class for which a class map is
defined. Packets satisfying the match criteria 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 queue process. When the
maximum packet threshold you defined for the class is reached, any more packets destined for the class
queue are dropped according to the tail drop or Weighted Random Early Detection (WRED) mechanism.
With tail drop, packets are queued until the maximum threshold is exceeded, and then all the packets are
dropped.
Use the queue-limit command only in a hierarchical policy map attached to an ES port. You can use this
command only in class-level classes.
You must configure the bandwidth or the shape policy-map class configuration command before you
configure either the queue-limit or the random-detect policy-map class configuration command in a
class policy.
You can define a class policy to use either tail drop through the queue-limit policy-map class
configuration command or to use WRED packet drop through the random-detect policy-map class
configuration command. You cannot use the queue-limit and random-detect commands in the same
class policy, but they can be used in two class policies in the same policy map.
You cannot use the bandwidth , queue-limit , random-detect , and the shape policy-map class
configuration commands with the priority policy-map class configuration command in the same class
within the same policy map. However, you can use these commands in the same policy map.
limit Queue maximum threshold on an ES port. The range is 1 to 32768 packets.
Release Modification
12.1(14)AX This command was introduced.
12.2(25)EY Hierarchical service policies can be attached to inbound traffic received on
an ES port.