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Applying QoS Features Using the MQC

Table Of Contents

Applying QoS Features Using the MQC

Finding Feature Information

Contents

Restrictions for Applying QoS Features Using the MQC

Information About Applying QoS Features Using the MQC

The MQC Structure

Elements of a Traffic Class

Elements of a Traffic Policy

Nested Traffic Classes

match-all and match-any Keywords of the class-map Command

input and output Keywords of the service-policy Command

Benefits of Applying QoS Features Using the MQC

How to Apply QoS Features Using the MQC

Creating a Traffic Class

Creating a Traffic Policy

Attaching a Traffic Policy to an Interface

Restrictions

Verifying the Traffic Class and Traffic Policy Information

Configuration Examples for Applying QoS Features Using the MQC

Example: Creating a Traffic Class

Example: Creating a Traffic Policy

Example: Attaching a Traffic Policy to an Interface

Example: match not Command

Example: Default Traffic Class Configuration

Example: class-map match-any and class-map match-all Commands

Example: Traffic Class as a Match Criterion (Nested Traffic Classes)

Example: Nested Traffic Class for Maintenance

Example: Nested Traffic Class to Combine match-any and match-all Characteristics in One Traffic Class

Example: Traffic Policy as a QoS Policy (Hierarchical Traffic Policies)

Additional References

Related Documents

Technical Assistance

Feature Information for Applying QoS Features Using the MQC


Applying QoS Features Using the MQC


First Published: April 30, 2007
Last Updated: August 30, 2010

This module contains the concepts about applying QoS features using the Modular quality of service (QoS) Command-Line Interface (CLI) (MQC) and the tasks for configuring the MQC. The MQC allows you to define a traffic class, create a traffic policy (policy map), and attach the traffic policy to an interface. The traffic policy contains the QoS feature that will be applied to the traffic class.

Finding Feature Information

Your software release may not support all the features documented in this module. 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 Applying QoS Features Using the MQC" section.

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

Contents

Restrictions for Applying QoS Features Using the MQC

Information About Applying QoS Features Using the MQC

How to Apply QoS Features Using the MQC

Configuration Examples for Applying QoS Features Using the MQC

Additional References

Feature Information for Applying QoS Features Using the MQC

Restrictions for Applying QoS Features Using the MQC

The MQC does not support Internetwork Packet Exchange (IPX) packets.

The number of QoS class maps supported in a single policy map varies by release, as follows:

For Cisco IOS XE Release 2.1, and Cisco IOS XE Release 2.2, the MQC supports a maximum of 8 class maps in a single policy map.

For Cisco IOS Release 12.4T, Cisco IOS Release 12.2 SR, and Cisco IOS XE Release 2.3, the MQC supports a maximum of 256 class maps in a single policy map.

The number of QoS class maps supported on a router varies by release, as follows:

For Cisco IOS XE Release 2.1, and Cisco IOS XE Release 2.2, the MQC supports no more than 1000 policy maps in the incoming (ingress) direction, outgoing (egress) direction, or a combination of both on a router.

For Cisco IOS Release 12.4T, Cisco IOS Release 12.2 SR, and Cisco IOS XE Release 2.3, the MQC supports no more than 4000 policy maps in the incoming (ingress) direction, outgoing (egress) direction, or a combination of both on a router.

When sessions are created and QoS policy maps are attached in both the ingress and egress directions, only 2000 sessions are supported. Sessions exceeding this limit can still be created, but the QoS policy maps will not be applied to the session.

Information About Applying QoS Features Using the MQC

The MQC Structure

Elements of a Traffic Class

Elements of a Traffic Policy

Nested Traffic Classes

match-all and match-any Keywords of the class-map Command

input and output Keywords of the service-policy Command

Benefits of Applying QoS Features Using the MQC

The MQC Structure

The MQC structure allows you to define a traffic class, create a traffic policy, and attach the traffic policy to an interface.

The MQC structure consists of the following three high-level steps.


Step 1 Define a traffic class by using the class-map command. A traffic class is used to classify traffic.

Step 2 Create a traffic policy by using the policy-map command. (The terms traffic policy and policy map are often synonymous.) A traffic policy (policy map) contains a traffic class and one or more QoS features that will be applied to the traffic class. The QoS features in the traffic policy determine how to treat the classified traffic.

Step 3 Attach the traffic policy (policy map) to the interface by using the service-policy command.


Elements of a Traffic Class

A traffic class contains three major elements: a traffic class name, a series of match commands, and, if more than one match command is used in the traffic class, instructions on how to evaluate these match commands.

The match commands are used for classifying packets. Packets are checked to determine whether they meet the criteria specified in the match commands; if a packet meets the specified criteria, that packet is considered a member of the class. Packets that fail to meet the matching criteria are classified as members of the default traffic class.

Available match Commands

Table 1 lists some of the available match commands that can be used with the MQC. The available match commands vary by Cisco IOS release and platform. For more information about the commands and command syntax, see the command reference for the Cisco IOS release and platform that you are using.

Table 1 match Commands That Can Be Used with the MQC 

Command
Purpose

match access-group

Configures the match criteria for a class map on the basis of the specified access control list (ACL).

match any

Configures the match criteria for a class map to be successful match criteria for all packets.

match class-map

Specifies the name of a traffic class to be used as a matching criterion (for nesting traffic classes [nested class maps] within one another).

match cos

Matches a packet based on a Layer 2 class of service (CoS) marking.

match destination-address mac

Uses the destination MAC address as a match criterion.

match discard-class

Matches packets of a certain discard class.

match [ip] dscp

Identifies a specific IP differentiated service code point (DSCP) value as a match criterion. Up to eight DSCP values can be included in one match statement.

match field

Configures the match criteria for a class map on the basis of the fields defined in the protocol header description files (PHDFs).

match fr-dlci

Specifies the Frame Relay data-link connection identifier (DLCI) number as a match criterion in a class map.

match input-interface

Configures a class map to use the specified input interface as a match criterion.

match ip rtp

Configures a class map to use the Real-Time Transport Protocol (RTP) port as the match criterion.

match mpls experimental

Configures a class map to use the specified value of the Multiprotocol Label Switching (MPLS) experimental (EXP) field as a match criterion.

match mpls experimental topmost

Matches the MPLS EXP value in the topmost label.

match not

Specifies the single match criterion value to use as an unsuccessful match criterion.

Note The match not command, rather than identifying the specific match parameter to use as a match criterion, is used to specify a match criterion that prevents a packet from being classified as a member of the class. For instance, if the match not qos-group 6 command is issued while you configure the traffic class, QoS group 6 becomes the only QoS group value that is not considered a successful match criterion. All other QoS group values would be successful match criteria.

match packet length

Specifies the Layer 3 packet length in the IP header as a match criterion in a class map.

match port-type

Matches traffic on the basis of the port type for a class map.

match [ip] precedence

Identifies IP precedence values as match criteria.

match protocol

Configures the match criteria for a class map on the basis of the specified protocol.

Note There is a separate match protocol (NBAR) command used to configure Network-Based Application Recognition (NBAR) to match traffic by a protocol type known to NBAR.

match protocol citrix

Configures NBAR to match Citrix traffic.

match protocol fasttrack

Configures NBAR to match FastTrack peer-to-peer traffic.

match protocol gnutella

Configures NBAR to match Gnutella peer-to-peer traffic.

match protocol http

Configures NBAR to match Hypertext Transfer Protocol (HTTP) traffic by URL, host, Multipurpose Internet Mail Extension (MIME) type, or fields in HTTP packet headers.

match protocol rtp

Configures NBAR to match Real-Time Transport Protocol (RTP) traffic.

match qos-group

Identifies a specific QoS group value as a match criterion.

match source-address mac

Uses the source MAC address as a match criterion.

match start

Configures the match criteria for a class map on the basis of the datagram header (Layer 2) or the network header (Layer 3).

match tag

Specifies tag type as a match criterion.


If the traffic class contains more than one match command, you need to specify how to evaluate the match commands. You specify this by using either the match-any or match-all keywords of the class-map command. Note the following points about the match-any and match-all keywords:

If you specify the match-any keyword, the traffic being evaluated by the traffic class must match one of the specified criteria.

If you specify the match-all keyword, the traffic being evaluated by the traffic class must match all of the specified criteria.

If you do not specify either keyword, the traffic being evaluated by the traffic class must match all of the specified criteria (that is, the behavior of the match-all keyword is used).

Elements of a Traffic Policy

A traffic policy contains three elements: a traffic policy name, a traffic class (specified with the class command), and the command used to enable the QoS feature.

The traffic policy (policy map) applies the enabled QoS feature to the traffic class once you attach the policy map to the interface (by using the service-policy command).


Note A packet can match only one traffic class within a traffic policy. If a packet matches more than one traffic class in the traffic policy, the first traffic class defined in the policy will be used.


The commands used to enable QoS features vary by Cisco IOS release and platform. Table 2 lists some of the available commands and the QoS features that they enable. For complete command syntax, see the command reference for the Cisco IOS release and platform that you are using.

Table 2 Commands Used to Enable QoS Features 

Command
Purpose

bandwidth

Enables Class-Based Weighted Fair Queuing (CBWFQ).

fair-queue

Specifies the number of queues to be reserved for a traffic class.

drop

Discards the packets in the specified traffic class.

identity policy

Creates an identity policy.

police

Configures traffic policing.

police (control-plane)

Configures traffic policing for traffic that is destined for the control plane.

police (EtherSwitch)

Defines a policer for classified traffic.

police (percent)

Configures traffic policing on the basis of a percentage of bandwidth available on an interface.

police (two rates)

Configures traffic policing using two rates, the committed information rate (CIR) and the peak information rate (PIR).

police rate pdp

Configures Packet Data Protocol (PDP) traffic policing using the police rate.

Note This command is intended for use on the Gateway General Packet Radio Service (GPRS) Support Node (GGSN).

priority

Gives priority to a class of traffic belonging to a policy map.

queue-limit

Specifies or modifies the maximum number of packets the queue can hold for a class configured in a policy map.

random-detect

Enables Weighted Random Early Detection (WRED) or distributed WRED (DWRED).

random-detect discard-class

Configures the WRED parameters for a discard-class value for a class in a policy map.

random-detect discard-class-based

Configures WRED on the basis of the discard class value of a packet.

random-detect ecn

Enables explicit congestion notification (ECN).

random-detect exponential-weighting-constant

Configures the exponential weight factor for the average queue size calculation for the queue reserved for a class.

random-detect precedence

Configure the WRED parameters for a particular IP Precedence for a class policy in a policy map.

service-policy

Specifies the name of a traffic policy used as a matching criterion (for nesting traffic policies [hierarchical traffic policies] within one another).

set atm-clp

Sets the cell loss priority (CLP) bit when a policy map is configured.

set cos

Sets the Layer 2 class of service (CoS) value of an outgoing packet.

set discard-class

Marks a packet with a discard-class value.

set [ip] dscp

Marks a packet by setting the differentiated services code point (DSCP) value in the type of service (ToS) byte.

set fr-de

Changes the discard eligible (DE) bit setting in the address field of a Frame Relay frame to 1 for all traffic leaving an interface.

set mpls experimental

Designates the value to which the MPLS bits are set if the packets match the specified policy map.

set precedence

Sets the precedence value in the packet header.

set qos-group

Sets a QoS group identifier (ID) that can be used later to classify packets.

shape

Shapes traffic to the indicated bit rate according to the algorithm specified.

shape adaptive

Configures a Frame Relay interface or a point-to-point subinterface to estimate the available bandwidth by backward explicit congestion notification (BECN) integration while traffic shaping is enabled.

shape fecn-adapt

Configures a Frame Relay interface to reflect received forward explicit congestion notification (FECN) bits as backward explicit congestion notification (BECN) bits in Q.922 test response messages.


Nested Traffic Classes

The MQC does not necessarily require that you associate only one traffic class to one traffic policy. When packets meet more than one match criterion, multiple traffic classes can be associated with a single traffic policy.

Similarly, the MQC allows multiple traffic classes (nested traffic classes, which are also called nested class maps) to be configured as a single traffic class. This nesting can be achieved with the use of the match class-map command. The only method of combining match-any and match-all characteristics within a single traffic class is with the match class-map command.

For an example of a nested traffic class configuration, see the "Example: Traffic Class as a Match Criterion (Nested Traffic Classes)" section.

match-all and match-any Keywords of the class-map Command

One of the commands used when you create a traffic class is the class-map command. The command syntax for the class-map command includes two keywords: match-all and match-any. The match-all and match-any keywords need to be specified only if more than one match criterion is configured in the traffic class. Note the following points about these keywords:

The match-all keyword is used when all of the match criteria in the traffic class must be met in order for a packet to be placed in the specified traffic class.

The match-any keyword is used when only one of the match criterion in the traffic class must be met in order for a packet to be placed in the specified traffic class.

If neither the match-all keyword nor match-any keyword is specified, the traffic class will behave in a manner consistent with match-all keyword.

input and output Keywords of the service-policy Command

The QoS feature configured in the traffic policy can be applied to packets entering the interface or to packets leaving the interface. Therefore, when you use the service-policy command, you need to specify the direction by using the input or output keyword.

For instance, the service-policy output class1 command would apply the feature in the traffic policy to the interface. All packets leaving the interface are evaluated according to the criteria specified in the traffic policy named class1.

Benefits of Applying QoS Features Using the MQC

The MQC structure allows you to create the traffic policy (policy map) once and then apply it to as many traffic classes as needed. You can also attach the traffic policies to as many interfaces as needed.

How to Apply QoS Features Using the MQC

Creating a Traffic Class

To create a traffic class, use the class-map command to specify the traffic class name. Then use one or more match commands to specify the appropriate match criteria. Packets matching the criteria that you specify are placed in the traffic class. For more information about the match-all and match-any keywords of the class-map comand, see the "match-all and match-any Keywords of the class-map Command" section.

To create the traffic class, complete the following steps.


Note The match cos command is shown in Step 4. The match cos command is simply an example of one of the match commands that you can use. For information about the other available match commands, see Table 1.


SUMMARY STEPS

1. enable

2. configure terminal

3. class-map [match-all | match-any] class-map-name

4. match cos cos-number

5. Enter additional match commands, if applicable; otherwise, continue with Step 6.

6. end

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

class-map [match-all | match-any] class-map-name

Example:

Router(config)# class-map match-any class1

Creates a class to be used with a class map and enters class-map configuration mode. The class map is used for matching packets to the specified class.

Enter the class name.

Note The match-all keyword specifies that all match criteria must be met. The match-any keyword specifies that one of the match criterion must be met. Use these keywords only if you will be specifying more than one match command.

Step 4 

match cos cos-number

Example:

Router(config-cmap)# match cos 2

Matches a packet on the basis of a Layer 2 class of service (CoS) number.

Enter the CoS number.

Note The match cos command is simply an example of one of the match commands you can use. For information about the other match commands that are available, see Table 1.

Step 5 

Enter additional match commands, if applicable; otherwise, continue with Step 6.

Step 6 

end

Example:

Router(config-cmap)# end

(Optional) Exits class-map configuration mode and returns to privileged EXEC mode.

Creating a Traffic Policy


Note The bandwidth command is shown in Step 5. The bandwidth command is simply an example of one of the commands that you can use in a policy map to enable a QoS feature (in this case, CBWFQ). For information about other available commands, see Table 2.


SUMMARY STEPS

1. enable

2. configure terminal

3. policy-map policy-map-name

4. class {class-name | class-default}

5. bandwidth {bandwidth-kbps | percent percent}

6. Enter the commands for any additional QoS feature that you want to enable, if applicable; otherwise, continue with Step 7.

7. end

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

policy-map policy-map-name

Example:

Router(config)# policy-map policy1

Creates or specifies the name of the traffic policy and enters policy-map configuration mode.

Enter the policy map name.

Step 4 

class {class-name | class-default}

Example:

Router(config-pmap)# class class1

Specifies the name of a traffic class and enters policy-map class configuration mode.

Enter the class name created in the "Creating a Traffic Class" section).

Note This step associates the traffic class with the traffic policy.

Step 5 

bandwidth {bandwidth-kbps | percent percent}

Example:

Router(config-pmap-c)# bandwidth 3000

(Optional) Specifies a minimum bandwidth guarantee to a traffic class in periods of congestion. A minimum bandwidth guarantee can be specified in kbps or by a percentage of the overall available bandwidth.

Note The bandwidth command enables CBWFQ. The bandwidth command is simply an example of one of the commands that you can use in a policy map to enable a QoS feature. For information about the other commands available, see Table 2.

Step 6 

Enter the commands for any additional QoS feature that you want to enable, if applicable; otherwise, continue with Step 7.

Step 7 

end

Example:

Router(config-pmap-c)# end

(Optional) Exits policy-map class configuration mode and returns to privileged EXEC mode.


Attaching a Traffic Policy to an Interface

The traffic policy (policy map) applies the enabled QoS feature to the traffic class once you attach the policy map to the interface (by using the service-policy command). For information about the input and output keywords of the service-policy command, see the "input and output Keywords of the service-policy Command" section.

Depending on the platform and Cisco IOS release that you are using, a traffic policy can be attached to an ATM permanent virtual circuit (PVC) subinterface, a Frame Relay data-link connection identifier (DLCI), or another type of interface.

To attach a traffic policy to an interface, complete the following steps.

Restrictions

Multiple traffic policies on tunnel interfaces and physical interfaces are not supported if the interfaces are associated with each other. For instance, if a traffic policy is attached to a tunnel interface while another traffic policy is attached to a physical interface—with which the tunnel interface is associated—only the traffic policy on the tunnel interface works properly.

The amount of bandwidth allocated to the priority traffic cannot exceed the amount of bandwidth available on the interface. If the traffic policy is configured such that the amount of bandwidth allocated to the priority traffic exceeds the amount of bandwidth available on the interface, the traffic policy will be suspended. Previously, the policy map would have been rejected. Now that it is only suspended, you have the option of modifying the traffic policy accordingly and then reattaching the traffic policy to the interface.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface interface-type interface-number

4. service-policy {input | output} policy-map-name

5. end

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

interface interface-type interface-number

Example:

Router(config)# interface serial0

Configures an interface type and enters interface configuration mode.

Enter the interface type and interface number.

Step 4 

service-policy {input | output} policy-map-name

Example:

Router(config-if)# service-policy input policy1

Attaches a policy map to an interface.

Enter either the input or output keyword and the policy map name.

Step 5 

end

Example:

Router (config-if)# end

(Optional) Exits interface configuration mode and returns to privileged EXEC mode.


Verifying the Traffic Class and Traffic Policy Information

SUMMARY STEPS

1. enable

2. show class-map

3. show policy-map policy-map-name class class-name

4. show policy-map

5. show policy-map interface interface-type interface-number

6. exit

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

show class-map

Example:

Router# show class-map

(Optional) Displays all class maps and their matching criteria.

Step 3 

show policy-map policy-map-name class class-name

Example:

Router# show policy-map policy1 class class1

(Optional) Displays the configuration for the specified class of the specified policy map.

Enter the policy map name and the class name.

Step 4 

show policy-map

Example:

Router# show policy-map

(Optional) Displays the configuration of all classes for all existing policy maps.

Step 5 

show policy-map interface interface-type interface-number

Example:

Router# show policy-map interface serial0

(Optional) Displays the statistics and the configurations of the input and output policies that are attached to an interface.

Enter the interface type and number.

Step 6 

exit

Example:

Router# exit

(Optional) Exits privileged EXEC mode.


Configuration Examples for Applying QoS Features Using the MQC

Example: Creating a Traffic Class

In the following example, two traffic classes are created and their match criteria are defined. For the first traffic class called class1, access control list (ACL) 101 is used as the match criterion. For the second traffic class called class2, ACL 102 is used as the match criterion. Packets are checked against the contents of these ACLs to determine if they belong to the class.

Router(config)# class-map class1
Router(config-cmap)# match access-group 101
Router(config-cmap)# exit

Router(config)# class-map class2
Router(config-cmap)# match access-group 102
Router(config-cmap)# exit

Example: Creating a Traffic Policy

In the following example, a traffic policy called policy1 is defined. The traffic policy contains the QoS features to be applied to two classes—class1 and class2. The match criteria for these classes were previously defined (as described in the "Example: Creating a Traffic Class").

For class1, the policy includes a bandwidth allocation request and a maximum packet count limit for the queue reserved for the class. For class2, the policy specifies only a bandwidth allocation request.

Router(config)# policy-map policy1
Router(config-pmap)# class class1
Router(config-pmap-c)# bandwidth 3000
Router(config-pmap-c)# queue-limit 30
Router(config-pmap-c)# exit

Router(config-pmap)# class class2
Router(config-pmap-c)# bandwidth 2000
Router(config-pmap-c)# exit

Example: Attaching a Traffic Policy to an Interface

The following example shows how to attach an existing traffic policy to an interface. After you define a traffic policy with the policy-map command, you can attach it to one or more interfaces by using the service-policy command in interface configuration mode. Although you can assign the same traffic policy to multiple interfaces, each interface can have only one traffic policy attached in the input direction and only one traffic policy attached in the output direction.

Router(config)# interface ethernet1/1
Router(config-if)# service-policy output policy1
Router(config-if)# exit

Router(config)# interface fastethernet1/0/0
Router(config-if)# service-policy output policy1
Router(config-if)# exit

Example: match not Command

The match not command is used to specify a specific QoS policy value that is not used as a match criterion. When using the match not command, all other values of that QoS policy become successful match criteria.

For instance, if the match not qos-group 4 command is issued in class-map configuration mode, the specified class will accept all QoS group values except 4 as successful match criteria.

In the following traffic class, all protocols except IP are considered successful match criteria:

Router(config)# class-map noip
Router(config-cmap)# match not protocol ip
Router(config-cmap)# exit

Example: Default Traffic Class Configuration

Unclassified traffic (traffic that does not meet the match criteria specified in the traffic classes) is treated as belonging to the default traffic class.

If you do not configure a default class, packets are still treated as members of the default class. However, by default, the default class has no QoS features enabled. Therefore, packets belonging to a default class have no QoS functionality. These packets are placed into a first-in, first-out (FIFO) queue managed by tail drop. Tail drop is a means of avoiding congestion that treats all traffic equally and does not differentiate between classes of service. Queues fill during periods of congestion. When the output queue is full and tail drop is in effect, packets are dropped until the congestion is eliminated and the queue is no longer full.

The following example configures a traffic policy for the default class of the traffic policy called policy1. The default class (which is always called class-default) has these characteristics: 10 queues for traffic that does not meet the match criteria of other classes whose policy is defined by the traffic policy policy1, and a maximum of 20 packets per queue before tail drop is enacted to handle additional queued packets.

Router(config)# policy-map policy1
Router(config-pmap)# class class-default
Router(config-pmap-c)# fair-queue 10
Router(config-pmap-c)# queue-limit 20

Example: class-map match-any and class-map match-all Commands

This example illustrates the difference between the class-map match-any command and the class-map match-all command. The match-any and match-all keywords determine how packets are evaluated when multiple match criteria exist. Packets must either meet all of the match criteria (match-all) or meet one of the match criterion (match-any) to be considered a member of the traffic class.

The following example shows a traffic class configured with the class-map match-all command:

Router(config)# class-map match-all cisco1
Router(config-cmap)# match protocol ip
Router(config-cmap)# match qos-group 4
Router(config-cmap)# match access-group 101

If a packet arrives on a router with the traffic class called cisco1 configured on the interface, the packet is evaluated to determine if it matches the IP protocol, QoS group 4, and access group 101. If all three of these match criteria are met, the packet is classified as a member of the traffic class cisco1.

The following example shows a traffic class configured with the class-map match-any command:

Router(config)# class-map match-any cisco2
Router(config-cmap)# match protocol ip
Router(config-cmap)# match qos-group 4
Router(config-cmap)# match access-group 101

In the traffic class called cisco2, the match criteria are evaluated consecutively until a successful match criterion is located. The packet is first evaluated to the determine whether the IP protocol can be used as a match criterion. If the IP protocol can be used as a match criterion, the packet is matched to traffic class cisco2. If the IP protocol is not a successful match criterion, then QoS group 4 is evaluated as a match criterion. Each criterion is evaluated to see if the packet matches that criterion. Once a successful match occurs, the packet is classified as a member of traffic class cisco2. If the packet matches none of the specified criteria, the packet is classified as a member of the default traffic class (class default-class).

Note that the class-map match-all command requires that all of the match criteria be met in order for the packet to be considered a member of the specified traffic class (a logical AND operator). In the first example, protocol IP AND QoS group 4 AND access group 101 must be successful match criteria. However, only one match criterion must be met in order for the packet in the class-map match-any command to be classified as a member of the traffic class (a logical OR operator). In the second example, protocol IP OR QoS group 4 OR access group 101 must be successful match criterion.

Example: Traffic Class as a Match Criterion (Nested Traffic Classes)

There are two reasons to use the match class-map command. One reason is maintenance; if a large traffic class currently exists, using the traffic class match criterion is simply easier than retyping the same traffic class configuration. The more common reason for the match class-map command is to allow users to use match-any and match-all statements in the same traffic class. If you want to combine match-all and match-any characteristics in a traffic policy, create a traffic class using one match criterion evaluation instruction (either match-any or match-all) and then use this traffic class as a match criterion in a traffic class that uses a different match criterion type.

Here is a possible scenario: Suppose A, B, C, and D were all separate match criterion, and you wanted traffic matching A, B, or C and D (A or B or [C and D]) to be classified as belonging to the traffic class. Without the nested traffic class, traffic would either have to match all 4 of the match criterion (A and B and C and D) or match any of the match criterion (A or B or C or D) to be considered part of the traffic class. You would not be able to combine "and" (match-all) and "or" (match-any) statements within the traffic class, and you would therefore be unable to configure the desired configuration.

The solution: Create one traffic class using match-all for C and D (which we will call criterion E), and then create a new match-any traffic class using A, B, and E. The new traffic class would have the correct evaluation sequence (A or B or E, which would also be A or B or [C and D]). The desired traffic class configuration has been achieved.

The only method of mixing match-all and match-any statements in a traffic class is through the use of the traffic class match criterion.

Example: Nested Traffic Class for Maintenance

In the following example, the traffic class called class1 has the same characteristics as the traffic class called class2, with the exception that traffic class class1 has added a destination address as a match criterion. Rather than configuring traffic class class1 line by line, you can enter the match class-map class2 command. This command allows all of the characteristics in the traffic class called class2 to be included in the traffic class called class1, and you can simply add the new destination address match criterion without reconfiguring the entire traffic class.

Router(config)# class-map match-any class2
Router(config-cmap)# match protocol ip
Router(config-cmap)# match qos-group 3
Router(config-cmap)# match access-group 2
Router(config-cmap)# exit

Router(config)# class-map match-all class1
Router(config-cmap)# match class-map class2
Router(config-cmap)# match destination-address mac 00.00.00.00.00.00 
Router(config-cmap)# exit

Example: Nested Traffic Class to Combine match-any and match-all Characteristics in One Traffic Class

The only method of including both match-any and match-all characteristics in a single traffic class is to use the match class-map command. To combine match-any and match-all characteristics into a single class, a traffic class created with the match-any instruction must use a class configured with the match-all instruction as a match criterion (through the match class-map command) or vice versa.

The following example shows how to combine the characteristics of two traffic classes, one with match-any and one with match-all characteristics, into one traffic class with the match class-map command. The result requires a packet to match one of the following three match criteria to be considered a member of traffic class class4: IP protocol and QoS group 4, destination MAC address 00.00.00.00.00.00, or access group 2.

In this example, only the traffic class called class4 is used with the traffic policy called policy1.

Router(config)# class-map match-all class3
Router(config-cmap)# match protocol ip
Router(config-cmap)# match qos-group 4
Router(config-cmap)# exit

Router(config)# class-map match-any class4
Router(config-cmap)# match class-map class3
Router(config-cmap)# match destination-address mac 00.00.00.00.00.00 
Router(config-cmap)# match access-group 2
Router(config-cmap)# exit

Router(config)# policy-map policy1
Router(config-pmap)# class class4
Router(config-pmap-c)# police 8100 1500 2504 conform-action transmit exceed-action 
set-qos-transmit 4
Router(config-pmap-c)# end

Example: Traffic Policy as a QoS Policy (Hierarchical Traffic Policies)

A traffic policy can be nested within a QoS policy when the service-policy command is used in policy-map class configuration mode. A traffic policy that contains a nested traffic policy is called a hierarchical traffic policy.

A hierarchical traffic policy contains a child policy and a parent policy. The child policy is the previously defined traffic policy that is being associated with the new traffic policy through the use of the service-policy command. The new traffic policy using the preexisting traffic policy is the parent policy. In the example in this section, the traffic policy called child is the child policy and traffic policy called parent is the parent policy.

Hierarchical traffic policies can be attached to subinterfaces, Frame Relay PVCs, and ATM PVCs. A hierarchical traffic policy is particularly beneficial when configuring VIP-based distributed FRF.12 (and higher) PVCs. When hierarchical traffic policies are used, a single traffic policy (with a child and a parent policy) can be used to shape and prioritize PVC traffic. In the following example, the child policy is responsible for prioritizing traffic and the parent policy is responsible for shaping traffic. In this configuration, the parent policy allows packets to be sent from the interface, and the child policy determines the order in which the packets are sent.

Router(config)# policy-map child
Router(config-pmap)# class voice
Router(config-pmap-c)# priority 50

Router(config)# policy-map parent
Router(config-pmap)# class class-default
Router(config-pmap-c)# shape average 10000000
Router(config-pmap-c)# service-policy child

With the exception that the values associated with the priority and shape commands can be modified, the example is the required configuration for PVCs using FRF.12 (or higher). The value used with the shape command is provisioned from the committed information rate (CIR) value from the service provider. For more information about FRF.12 (or higher) PVCs, see the "FRF .20 Support" module.

Additional References

Related Documents

Related Topic
Document Title

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

QoS commands: complete command syntax, command modes, command history, defaults, usage guidelines, and examples

Cisco IOS Quality of Service Solutions Command Reference

Packet classification

"Classifying Network Traffic" module

FRF PVCs

"FRF .20 Support" module


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Link

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Feature Information for Applying QoS Features Using the MQC

Table 3 lists the release history for this feature.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which 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 3 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.


Table 3 Feature Information for Applying QoS Features Using the MQC

Feature Name
Releases
Feature Information

Modular QoS CLI (MQC) Unconditional Packet Discard

12.2(13)T

The Modular QoS CLI (MQC) Unconditional Packet Discard feature allows you to classify traffic matching certain criteria and then configure the system to unconditionally discard any packets matching that criteria.

Class-Based Frame Relay Discard Eligible (DE)-Bit Matching and Marking

12.2(2)T

The Class-Based Frame Relay Discard Eligible (DE)-Bit Matching and Marking feature enhances the MQC to support Frame Relay DE bit matching and marking. Packets with FR DE bit set can be matched to a class and the appropriate QoS feature or treatment be applied.

Modular QoS CLI (MQC)

Cisco IOS XE Release 2.1
Cisco IOS XE 3.1.0 SG

This feature was introduced on Cisco ASR 1000 Series Routers.

In Cisco IOS XE 3.1.0 SG, this feature was integrated.