Cisco Catalyst 3750 Metro

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Catalyst 3750 Metro Switch Command Reference
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Chapter 2 Catalyst 3750 Metro Switch Cisco IOS Commands
priority
priority
Use the priority policy-map class configuration command to enable the strict priority queue
(low-latency queueing [LLQ]) and to give priority to a class of traffic belonging to a hierarchical policy
map attached to an enhanced-services (ES) port. Use the no form of this command to return to the default
setting.
priority
no priority
Syntax Description This command has no arguments or keywords.
Defaults The strict priority queue is disabled.
Command Modes Policy-map class configuration
Command History
Usage Guidelines Use the priority command only in a hierarchical policy map attached to an ES port. You can use this
command only in class-level classes.
This command configures LLQ and provides strict-priority queueing for class-based weighted fair
queueing (CBWFQ). Strict-priority queueing enables delay-sensitive data, such as voice, to be sent
before packets in other queues are sent. The priority queue is serviced first until it is empty.
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.
Within a policy map, you can give priority status to only one class.
When you attach the policy map containing class policy configurations to the port to stipulate the service
policy for that port, the available bandwidth is determined.
To avoid a loss of priority traffic on an ES port when the switch is congested, you can configure both the
strict-priority queueing and egress priority queueing features. Note that when you map certain traffic
classes to the egress priority queue, they are not automatically placed into the strict-priority queue. You
must configure both the priority policy-map class configuration and the priority-queue out interface
configuration commands. For more information, see the
“priority-queue” section on page 2-365.
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.