Guest

Cisco IOS Software Releases 12.0 S

QoS: Match ATM OAM

  • Viewing Options

  • PDF (313.4 KB)
  • Feedback
QoS: Match ATM OAM

Table Of Contents

QoS: Match ATM OAM

Contents

Prerequisites for QoS: Match ATM OAM

Restrictions for QoS: Match ATM OAM

Information About QoS: Match ATM OAM

Feature Overview

Matching Packets Using MQC

Benefits

How to Configure QoS: Match ATM OAM

Configuring a Class Map

Configuring Ingress Policing

Creating a Policy Map

Attaching the Policy Map to an Interface or a VC

Restrictions

Verifying the Attached Class Map

Verifying the Policy Map

Verifying the Configuration

Configuration Examples for QoS: Match ATM OAM

Configuring the QoS: Match ATM OAM Feature: Example

Configuring Ingress Policing on L2VPN Tunnels

Verifying the QoS: Match on ATM OAM Feature: Example

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Command Reference

match atm oam

Glossary


QoS: Match ATM OAM


The QoS: Match ATM Operation, Administration, and Maintenance (OAM) feature distinguishes control traffic from data traffic so that the control traffic can be protected from being dropped during interface congestion. Control traffic consists of router-generated ATM OAM protocol packets, used to manage the link status. Data traffic is the network-applications-generated packets, usually from network users. By using Modular Quality of Service (QoS) Command-Line Interface (CLI) (MQC) with this feature, you can label the control traffic as high priority when it travels through a Layer 2 Virtual Private Network (L2VPN) tunnel.

Feature History for QoS: Match ATM OAM

Release
Modification

12.0(30)S

This feature was introduced.


Finding Support Information for Platforms and Cisco IOS Software Images

Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.

Contents

Prerequisites for QoS: Match ATM OAM

Restrictions for QoS: Match ATM OAM

Information About QoS: Match ATM OAM

How to Configure QoS: Match ATM OAM

Configuration Examples for QoS: Match ATM OAM

Additional References

Command Reference

Glossary

Prerequisites for QoS: Match ATM OAM

Ensure that an ATM interface is configured in the network.

Restrictions for QoS: Match ATM OAM

The following restrictions apply to the QoS: Match ATM OAM feature:

It is supported on an ATM interface only.

It is available in MQC classification only.

It is supported on Cisco 12000 Series Routers only.


Note We recommend that you attach policy maps to the ATM interfaces in an input direction only.


Information About QoS: Match ATM OAM

To use the QoS: Match ATM OAM feature, you should understand the following concepts:

Feature Overview

Matching Packets Using MQC

Benefits

Feature Overview

When you enable the QoS: Match ATM OAM feature on an interface, you can match packets on the basis of ATM OAM, and then apply the QoS functionality to those packets.

Control traffic (such as OAM, Interim Local Management Interface [ILMI], Bridge Protocol Data Unit [BPDU]) is not protected from data traffic when the interface is congested. Interface congestion may cause the management packets to be dropped.

The link status is highly dependent on the management packets. The correct link status cannot be maintained on the interface if the management packets are dropped due to interface congestion. In an L2VPN framework, some of the management packets are carried from customer edge (CE) router to CE router for the virtual tunnel link status and the packets need higher priority when they are traveling in the tunnel.

Figure 1 shows a sample topology for QoS: Match ATM OAM.

Figure 1 Sample Topology for QoS: Match ATM OAM

Matching Packets Using MQC

To configure the QoS: Match ATM OAM feature, you must define a traffic class, configure a policy map, and then attach that policy map to the appropriate interface. These three tasks can be accomplished by using MQC.

The MQC is a command-line interface that allows you to define traffic classes, create and configure traffic policies (policy maps), and then attach these traffic policies to interfaces.

The MQC consists of the following three processes:

Defining a traffic class with the class-map command

Creating a traffic policy by associating the traffic class with one or more QoS features by using the policy-map command

Attaching the traffic policy to the interface with the service-policy command

A traffic class contains three major elements: a name, a series of match commands, and, if more than one match command exists in the traffic class, instructions on how to evaluate these match commands (that is, match-all or match-any). The traffic class is named in the class-map command line; for example, if you enter the class-map cisco command while configuring the traffic class in the CLI, the traffic class would be named "cisco".

The match commands are used to specify various criteria for classifying packets. Packets are checked to determine whether they match the criteria specified in the match commands. If a packet matches the specified criteria, that packet is considered a member of the class and is forwarded according to the QoS specifications set in the traffic policy. Packets that fail to meet any of the matching criteria are classified as members of the default traffic class.

Benefits

The QoS: Match ATM OAM feature provides the following benefits:

Allows you to protect the control traffic during interface congestion by using MQC.

Provides a way to distinguish the control traffic from the data traffic on an ATM interface.

Allows you to label the control traffic as high priority when it travels in an L2VPN tunnel.

Allows you to configure policing, which excludes OAM traffic.

How to Configure QoS: Match ATM OAM

This section contains the following procedures:

Configuring a Class Map (required)

Configuring Ingress Policing (required)

Creating a Policy Map (required)

Attaching the Policy Map to an Interface or a VC (required)

Verifying the Attached Class Map (optional)

Verifying the Policy Map (optional)

Verifying the Configuration (optional)

Configuring a Class Map

Perform the following task to configure a class map to match packets on an ATM interface.

SUMMARY STEPS

1. enable

2. configure terminal

3. class-map class-map-name

4. match atm oam

5. exit

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 class-map-name

Example:

Router(config)# class-map class_oam

Specifies the name of the class map to be created and enters class-map configuration mode.

Step 4 

match atm oam

Example:

Router(config-cmap)# match atm oam

Enables packet matching on the basis of the ATM OAM.

Step 5 

exit

Example:

Router(config-cmap)# exit

(Optional) Exits class-map configuration mode.

Configuring Ingress Policing

Perform the following task to configure ingress policing on a L2VPN tunnel.

SUMMARY STEPS

1. enable

2. configure terminal

3. class-map class-map-name

4. match not atm oam

5. exit

6. policy-map policy-map-name

7. class {class-name | class-default}

8. police rate pcr cps delay-tolerance cdvt conform-action action exceed-action action violate-action action

9. exit

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 class-map-name

Example:

Router(config)# class-map not_oam

Specifies the name of the class map to be created and enters class-map configuration mode.

Step 4 

match not atm oam

Example:

Router(config-cmap)# match not atm oam

Enables packet matching on the basis of excluding OAM.

Step 5 

exit

Example:

Router(config-cmap)# exit

Exits class-map configuration mode.

Step 6 

policy-map policy-map-name

Example:

Router(config)# policy-map oam_policy

Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy. Enters policy-map configuration mode.

Enter the policy map name.

Step 7 

class {class-name | class-default}

Example:

Router(config-pmap)# class not_oam

Specifies the name of the class whose policy you want to create or change or specifies the default class before you configure its policy. Enters policy-map class configuration mode.

Enter the class-name argument or enter the class-default keyword.

Step 8 

police rate pcr cps delay-tolerance cdvt conform-action action exceed-action action violate-action action

Example:

Router(config-pmap-c)# police rate 1000 cps delay tolerance 1000 conform transmit exceed set-mpls-exp 3

Specifies a maximum rate usage by a traffic class through the use of a generic cell rate algorithm.

Step 9 

exit

Example:

Router(config-pmap-c)# exit

(Optional) Exits policy-map class configuration mode.

Creating a Policy Map

Perform the following task to create a policy map.

SUMMARY STEPS

1. enable

2. configure terminal

3. policy-map policy-map-name

4. class {class-name | class-default}

5. set mpls experimental imposition {mpls-exp-value}

6. exit

7. class {class-name | class-default}

8. set mpls experimental imposition {mpls-exp-value}

9. exit

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 policy_oam

Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy. Enters policy-map configuration mode.

Enter the policy map name.

Step 4 

class {class-name | class-default}

Example:

Router(config-pmap)# class class_oam

Specifies the name of the class whose policy you want to create or change. Enters policy-map class configuration mode.

Enter the class-name argument or the class-default keyword.

Step 5 

set mpls experimental imposition {mpls-exp-value}

Example:

Router(config-pmap-c)# set mpls experimental imposition 5

Sets the MPLS EXP value for the bits used to define the policy map.

Step 6 

exit

Example:

Router(config-pmap-c)# exit

Exits policy-map class configuration mode.

Step 7 

class {class-name | class-default}

Example:

Router(config-pmap)# class class_default

Specifies the default class before you configure its policy. Enters policy-map class configuration mode.

Step 8 

set mpls experimental imposition {mpls-exp-value}

Example:

Router(config-pmap-c)# set mpls experimental imposition 4

Sets the MPLS EXP value of the bits used to define the default traffic.

Step 9 

exit

Example:

Router(config-pmap-c)# exit

(Optional) Exits policy-map class configuration mode.

Attaching the Policy Map to an Interface or a VC

Perform the following task to attach the policy map to an interface or a virtual circuit (VC).

Restrictions

This feature supports only policy maps attached to an ATM interface in the input direction.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface type number [name-tag]

4. pvc [name] vpi | vci [ilmi | qsaal | smds]

5. service-policy {input} policy-map-name

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 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

interface type number [name-tag]

Example:

Router(config)# interface atm 0/0

Configures the interface type specified and enters interface configuration mode.

Enter interface type.

Step 4 

pvc [name] vpi|vci [ilmi|qsaal|smds]

Example:

Router(config-if)# pvc 0/60 l2transport

Creates or assigns a name to an ATM PVC, specifies the encapsulation type on an ATM PVC, and enters ATM virtual circuit configuration mode.

Step 5 

service-policy {input} policy-map-name

Example:
Router(config-if-atm-l2trans-pvc)# 
service-policy input policy_oam

Specifies the name of the policy map to be attached to the input direction of the interface.

Note Policy maps can be configured on ingress or egress routers. They can also be attached in the input or output direction of an interface. The direction (input or output) and the router (ingress or egress) to which the policy map should be attached varies according your network configuration. For this feature, only the input direction is supported.

Enter the input keyword followed by the policy map name.

Step 6 

exit

Example:

Router(config-if-atm-l2trans-pvc)# exit

(Optional) Exits ATM virtual circuit mode.

Verifying the Attached Class Map

Perform the following task to verify the class maps and their matching criteria on an ATM interface.

SUMMARY STEPS

1. enable

2. show class-map

3. 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

Displays all class maps and their matching criteria.

Step 3 

exit

Example:

Router# exit

(Optional) Exits privileged EXEC mode.

Verifying the Policy Map

Perform the following task to verify the policy maps attached on an ATM interface.

SUMMARY STEPS

1. enable

2. show policy-map policy-map-name

3. 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 policy-map policy-map-name

Example:

Router# show policy-map oam

Displays the packet statistics of all classes that are configured for all service policies either on the specified interface or subinterface or on a specific PVC on the interface.

Enter the interface name.

Step 3 

exit

Example:

Router# exit

(Optional) Exits privileged EXEC mode.

Verifying the Configuration

Perform the following task to verify that the packets of the specified class are being matched and to display the number of matched packets.

SUMMARY STEPS

1. enable

2. show policy-map interface [{interface interface-number} | {null interface-number} | {vlan vlan-id}] [input | output]

3. 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 policy-map interface [{interface interface-number} | {null interface-number} | {vlan vlan-id}] [input | output]

Example:

Router# show policy-map interface atm 3/3

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

Step 3 

exit

Example:

Router# exit

(Optional) Exits privileged EXEC mode.

Configuration Examples for QoS: Match ATM OAM

This section contains the following configuration examples:

Configuring the QoS: Match ATM OAM Feature: Example

Configuring Ingress Policing on L2VPN Tunnels

Verifying the QoS: Match on ATM OAM Feature: Example

Configuring the QoS: Match ATM OAM Feature: Example

There are three tasks for configuring this feature:

Configuring a class map

Creating a policy map

Attaching the policy map to an interface

In the following example, a class map called class_oam is configured to match packets on an ATM interface.

Router# configure terminal 

Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)# class-map class_oam 
Router(config-cmap)# match atm oam 
Router(config-cmap)# exit 

In the following example, a policy map called policy_oam is created by using the policy-map command. Use policy maps to apply one or more QoS features to the packets in your network.

Router# configure terminal 

Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)# policy-map policy_oam 
Router(config-pmap)# class class-oam 
Router(config-pmap-c)# set mpls experiment imposition 5 
Router(config-pmap-c)# exit 
Router(config-pmap)# class class-default 
Router(config-pmap-c)# set mpls experiment imposition 4 
Router(config-pmap-c)# exit 

In the following example, the policy map called policy_oam is attached to an ATM interface by using the service-policy command.

You can attach policy maps to an ATM interface in both directions; however, this feature supports them in the input direction only. Therefore, specify the input keyword when you issue the service-policy command.

Router# configure terminal 

Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)# interface atm 0/0 
Router(config-if)# pvc 0/60 l2transport 
Router(config-if-atm-l2trans-pvc)# service-policy input policy_oam
Router(config-if-atm-l2trans-pvc)# exit

Configuring Ingress Policing on L2VPN Tunnels

In the following example, ingress policing is configured on L2VPN circuits by using the match  not  atm oam command and policy-map oam_policy command.


Note When you configure ingress policing on L2VPN circuits, you can exclude OAM traffic from being policed so that it will not be dropped if the rate on the VC exceeds the peak rate.


Router# configure terminal 

Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)# class-map not_oam
Router(config-cmap)# match not atm oam 
Router(config-cmap)# exit 
Router(config)# policy-map oam_policy 
Router(config-pmap)# class not_oam
Router(config-pmap-c)# police rate 1000 cps delay tolerance 1000 conform transmit exceed 
set-mpls-exp 3 
Router(config-pmap-c)# exit

Verifying the QoS: Match on ATM OAM Feature: Example

In the following example, the configuration of ATM OAM is verified using the show class-map command and the show policy-map interface command.

Use the output from the show class-map command to verify all class maps and their matching criteria.

Router# show class-map

 Class Map match-any class-default (id 0)
   Match any

 Class Map match-all ccc (id 1)
   Match atm oam

 Class Map match-all c (id 2)
   Match none

Use the output from the show policy-map command to verify all policy maps on your network.

Router# show policy-map oam

Policy Map oam
    Class oam
      set mpls experimental imposition 5
    Class class-default
      set mpls experimental imposition 4

Use the output from the show policy-map interface command to verify and monitor the configuration on your network.

Router# show policy-map interface atm 3/3 

ATM3/3: VC 7/100 -

Service-policy input: oam (1072)

Class-map: oam (match-all) (1073/2)
      104 packets, 5512 bytes
      5 minute offered rate 93 bps, drop rate 0 bps
      Match: atm oam (1074)
      Set Policy:
        set mpls experimental imposition 5

    Class-map: class-default (match-any) (1076/0)
      516 packets, 27348 bytes
      5 minute offered rate 181 bps, drop rate 0 bps
      Match: any  (1077)
      Set Policy:
        set mpls experimental imposition 4

Additional References

The following sections provide references related to the QoS: Match ATM OAM feature.

Related Documents

Related Topic
Document Title

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

Cisco IOS Quality of Service Solutions Command Reference, Release 12.3 T

MQC

Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.3


Standards

Standards
Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.


MIBs

MIBs
MIBs Link

No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs


RFCs

RFCs
Title

No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.


Technical Assistance

Description
Link

Technical Assistance Center (TAC) home page, containing 30,000 pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.

http://www.cisco.com/public/support/tac/home.shtml


Command Reference

This section documents a new command. All other commands used with this feature are documented in the Cisco IOS Release 12.3 command reference publications.

match atm oam

match atm oam

To enable the control traffic classification on an ATM interface, use the match atm oam command in class-map configuration mode. To disable the control traffic classification, use the no form of this command.

match atm oam

no match atm oam

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values

Command Modes

Class-map configuration

Command History

Release
Modification

12.0(30)S

This command was introduced.


Usage Guidelines

Use this command for policy maps attached to ATM interfaces or ATM permanent virtual circuits (PVCs). Policy maps containing the match atm oam command attached to ATM interfaces or ATM PVCs can be input policy maps only.

Examples

The following example shows the control traffic classification being configured as the match criterion in a class map. The policy map containing this class map is then applied to the ATM interface.

Router# configure terminal 

Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)# class-map class-oam 
Router(config-cmap)# match atm oam 
Router(config-cmap)# exit

Related Commands

Command
Description

show class-map

Displays all class maps and their matching criteria.

show policy-map

Displays all policy maps.

show policy-map interface

Displays the packet statistics of all classes that are configured for all service policies either on the specified ATM interface or on a specific PVC on the interface.


Glossary

ATM—Asynchronous Transfer Mode. The international standard for cell relay in which multiple service types (such as voice, video, or data) are conveyed in fixed-length (53-byte) cells. Fixed-length cells allow cell processing to occur in hardware, thereby reducing transit delays. ATM is designed to take advantage of high-speed transmission media, such as E3, SONET, and T3.

BPDU—Bridge Protocol Data Unit. A Spanning-Tree Protocol hello packet that is sent out at configurable intervals to exchange information among bridges in the network.

CE router—customer edge router. A router that is part of a customer network and that interfaces to a provider edge (PE) router.

control traffic—Router-generated protocol packets, such as ATM OAM, that are used to manage link status.

data traffic—Packets generated by network applications.

ILMI—Interim Local Management Interface. A specification developed by the ATM Forum for incorporating network-management capabilities into the ATM User-Network Interface (UNI).

MQC—Modular Quality of Service (QoS) Command-Line Interface (CLI).

OAM—Operation, Administration, and Maintenance. An ATM Forum specification for cells used to monitor virtual circuits. OAM cells provide a virtual circuit-level loopback in which a router responds to the cells, demonstrating that the circuit is up and the router is operational.

PE router—provider edge router. A router that is part of a service provider's network and is connected to a customer edge (CE) router.

PVC—permanent virtual circuit (or connection). A virtual circuit that is permanently established. PVCs save bandwidth associated with circuit establishment and teardown in situations where certain virtual circuits must exist all the time. In ATM terminology, called a permanent virtual connection.

VPN—Virtual Private Network. Enables IP traffic to travel securely over a public TCP/IP network by encrypting all traffic from one network to another. A VPN uses "tunneling" to encrypt all information at the IP level.


Note Refer to Internetworking Terms and Acronyms for terms not included in this glossary.