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This module describes the tasks for configuring priority queueing (PQ) on a device.
A priority list contains the definitions for a set of priority queues. The priority list specifies which queue a packet will be placed in and, optionally, the maximum length of the different queues.
In order to perform queueing using a priority list, you must assign the list to an interface. The same priority list can be applied to multiple interfaces. Alternatively, you can create many different priority policies to apply to different interfaces.
Assign packets to priority queues based on the following qualities:
You can specify multiple assignment rules. The priority-list commands are read in order of appearance until a matching protocol or interface type is found. When a match is found, the packet is assigned to the appropriate queue and the search ends. Packets that do not match other assignment rules are assigned to the default queue.
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Command or Action | Purpose | |
---|---|---|
|
Example: Device> enable |
Enables privileged EXEC mode. |
|
Example: Device# configure terminal |
Enters global configuration mode. |
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Example: Device(config)# policy-list |
Specifies the maximum number of packets allowed in each of the priority queues: |
|
Example: Device(config)# end |
(Optional) Exits global configuration mode. |
Command or Action | Purpose | |
---|---|---|
|
Example: Device> enable |
Enables privileged EXEC mode. |
|
Example: Device# configure terminal |
Enters global configuration mode. |
|
Example: Device(config)# interface ethernet 0 |
Specifies the interface, and then enters interface configuration mode. |
|
Example: Device(config-if)# priority-group 3 |
Assigns a priority list number to the interface. |
|
Example: Device(config-if)# end |
Exits interface configuration mode and returns to privileged EXEC mode. |
Command or Action | Purpose | |
---|---|---|
|
Example: Device> enable |
Enables privileged EXEC mode. |
|
Example: Device# show queue interface-type interface-number |
Displays the contents of packets inside a queue for a particular interface or VC. |
|
Example: Device# show queueing priority |
Displays the status of the priority queueing lists. |
The following example establishes queueing based on protocol type. The example assigns 1 as the arbitrary priority list number, specifies IP as the protocol type, and assigns a high-priority level to traffic that matches IP access list 10.
access-list 10 permit 239.1.1.0 0.0.0.255 priority-list 1 protocol ip high list 10
The following example establishes queueing based on interface. The example sets any packet type entering on Ethernet interface 0 to a medium priority.
priority-list 3 interface ethernet 0 medium
The following example changes the maximum number of packets in the high-priority queue to 10. The medium-limit, normal, and low-limit queue sizes remain at their default 40-, 60-, and 80-packet limits.
priority-list 4 queue-limit 10 40 60 80
The following example assigns priority group list 4 to serial interface 0:
interface serial 0 priority-group 4
Note |
The priority-group list-number command is not available on ATM interfaces that do not support fancy queueing. |
When classifying a packet, the system searches the list of rules specified by priority-list commands for a matching protocol type. The following example specifies four rules:
Remember that when using multiple rules for a single protocol, the system reads the priority settings in the order of appearance.
priority-list 4 protocol decnet medium lt 200 priority-list 4 protocol ip medium tcp 23 priority-list 4 protocol ip medium udp 53 priority-list 4 protocol ip high
Related Topic | Document Title |
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Cisco commands |
|
QoS commands: complete command syntax, command modes, command history, defaults, usage guidelines, and examples |
Cisco IOS Quality of Service Solutions Command Reference |
Description | Link |
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The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password. |
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 1 | Feature Information for Configuring Priority Queueing |
Feature Name | Releases | Feature Information |
---|---|---|
Priority Queueing (PQ) |
11.2(1) 12.2(27)SBB 12.2(33)XNA Cisco IOS XE Release 3.2SE |
The Priority Queueing (PQ) feature allows you to configure priority queueing on a device with the use of priority lists. The following commands were introduced or modified by this feature: priority-group, priority list default, priority list interface, priority list protocol, priority list queue-limit, show queue, show queueing priority. |
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Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.