Configuring Priority Queueing (REMOVED)

Table Of Contents

Configuring Priority Queueing

Finding Feature Information

Priority Queueing Configuration Task List

Defining the Priority List

Assigning Packets to Priority Queues

Specifying the Maximum Size of the Priority Queues

Assigning the Priority List to an Interface

Monitoring Priority Queueing Lists

Priority Queueing Configuration Examples

Priority Queueing Based on Protocol Type: Example

Priority Queueing Based on Interface: Example

Maximum Specified Size of the Priority Queue: Example

Priority List Assigned to an Interface: Example

Priority Queueing Using Multiple Rules: Example

Feature Information for Configuring Priority Queueing

Configuring Priority Queueing

---

This chapter describes the tasks for configuring priority queueing (PQ) on a router.

For complete conceptual information, see the "Congestion Management Overview" module.

Finding Feature Information

For the latest feature information and caveats, see 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 for Configuring Priority Queueing" section.

Use Cisco Feature Navigator to find information about platform support and Cisco IOS, Catalyst OS, and Cisco IOS XE software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Priority Queueing Configuration Task List

To configure PQ, perform the tasks described in the following sections. The tasks in the first two sections are required; the task in remaining section is optional.

•Defining the Priority List (Required)

•Assigning the Priority List to an Interface (Required)

•Monitoring Priority Queueing Lists (Optional)

See the end of this chapter for the section "Priority Queueing Configuration Examples."

Defining the Priority List

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.

To define a priority list, perform the tasks described in the following sections. The task in the first section is required; the task in the remaining section is optional.

•Assigning Packets to Priority Queues (Required)

•Specifying the Maximum Size of the Priority Queues (Optional)

Assigning Packets to Priority Queues

Assign packets to priority queues based on the following qualities:

•Protocol type

•Interface where the packets enter the router

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.

To specify which queue to place a packet in, use the following commands in global configuration mode:

	Command	Purpose
Step 1	Router(config)# priority-list list-number protocol protocol-name {high | medium | normal | low} queue-keyword keyword-value	Establishes queueing priorities based on the protocol type.
Step 2	Router(config)# priority-list list-number interface interface-type interface-number {high | medium | normal | low}	Establishes queueing priorities for packets entering from a given interface.
Step 3	Router(config)# priority-list list-number default {high | medium | normal | low}	Assigns a priority queue for those packets that do not match any other rule in the priority list.

All protocols supported by Cisco are allowed. The queue-keyword argument provides additional options. See the priority-list protocol command syntax description in the Cisco IOS Quality of Service Solutions Command Reference.

Specifying the Maximum Size of the Priority Queues

To specify the maximum number of packets allowed in each of the priority queues, use the following command in global configuration mode:

Command	Purpose
Router(config)# priority-list list-number queue-limit [high-limit [medium-limit [normal-limit [low-limit]]]	Specifies the maximum number of packets allowed in each of the priority queues.

Use the priority-list queue-limit command for each priority list. The default queue limit arguments are listed in Table 1.

Table 1 Default Priority Queue Packet Limits 

Priority Queue Argument	Packet Limits
high-limit	20
medium-limit	40
normal-limit	60
low-limit	80

Assigning the Priority List to an Interface

You can assign a priority list number to an interface. Only one list can be assigned per interface. To assign a priority group to an interface, use the following commands beginning in global configuration mode:

	Command	Purpose
Step 1	Router(config)# interface interface-type interface-number	Specifies the interface, and then enters interface configuration mode.
Step 2	Router(config-if)# priority-group list-number	Assigns a priority list number to the interface.

Monitoring Priority Queueing Lists

To display information about the input and output queues, use the following commands in EXEC mode, as needed:

Command	Purpose
Router# show queue interface-type interface-number	Displays the contents of packets inside a queue for a particular interface or VC.
Router# show queueing priority	Displays the status of the priority queueing lists.

Priority Queueing Configuration Examples

The following sections provide PQ configuration examples:

•Priority Queueing Based on Protocol Type: Example

•Priority Queueing Based on Interface: Example

•Maximum Specified Size of the Priority Queue: Example

•Priority List Assigned to an Interface: Example

•Priority Queueing Using Multiple Rules: Example

For information on how to configure PQ, see the section "Priority Queueing Configuration Task List" in this module.

Priority Queueing Based on Protocol Type: Example

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

Priority Queueing Based on Interface: Example

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

Maximum Specified Size of the Priority Queue: Example

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

Priority List Assigned to an Interface: Example

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.

---

Priority Queueing Using Multiple Rules: Example

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:

•DECnet packets with a byte count less than 200 are assigned a medium priority queue level.

•IP packets originating or destined to TCP port 23 are assigned a medium priority queue level.

•IP packets originating or destined to User Datagram Protocol (UDP) port 53 are assigned a medium priority queue level.

•All IP packets are assigned a high priority queue level.

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

Feature Information for Configuring Priority Queueing

Table 2 lists the features in this module and provides links to specific configuration information.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS XE software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

---

Note Table 2 lists only the Cisco IOS XE software release that introduced support for a given feature in a given Cisco IOS XE software release train. Unless noted otherwise, subsequent releases of that Cisco IOS XE software release train also support that feature.

---

Table 2 Feature Information for Configuring Priority Queueing

Feature Name	Releases	Feature Information
Priority Queueing	Cisco IOS XE Release 2.1	This feature was introduced on Cisco ASR 1000 Series Routers. The following section provides information about this feature: •Priority Queueing Configuration Task List.

CCDE, CCENT, Cisco Eos, Cisco HealthPresence, the Cisco logo, Cisco Lumin, Cisco Nexus, Cisco StadiumVision, Cisco TelePresence, Cisco WebEx, DCE, and Welcome to the Human Network are trademarks; Changing the Way We Work, Live, Play, and Learn and Cisco Store are service marks; and Access Registrar, Aironet, AsyncOS, Bringing the Meeting To You, Catalyst, CCDA, CCDP, CCIE, CCIP, CCNA, CCNP, CCSP, CCVP, Cisco, the Cisco Certified Internetwork Expert logo, Cisco IOS, Cisco Press, Cisco Systems, Cisco Systems Capital, the Cisco Systems logo, Cisco Unity, Collaboration Without Limitation, EtherFast, EtherSwitch, Event Center, Fast Step, Follow Me Browsing, FormShare, GigaDrive, HomeLink, Internet Quotient, IOS, iPhone, iQuick Study, IronPort, the IronPort logo, LightStream, Linksys, MediaTone, MeetingPlace, MeetingPlace Chime Sound, MGX, Networkers, Networking Academy, Network Registrar, PCNow, PIX, PowerPanels, ProConnect, ScriptShare, SenderBase, SMARTnet, Spectrum Expert, StackWise, The Fastest Way to Increase Your Internet Quotient, TransPath, WebEx, and the WebEx logo are registered trademarks of Cisco Systems, Inc. and/or its affiliates in the United States and certain other countries.

All other trademarks mentioned in this document or website are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (0812R)

Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.

© 2007-2009 Cisco Systems, Inc. All rights reserved.