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Cisco IOS Software Releases 12.0 T

MPLS Class of Service

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Table Of Contents

MPLS Class of Service

Feature Overview

Tag Switching/MPLS Terminology

MPLS CoS

LSRs

ATM LSRs

ATM Switches

Benefits

Related Features and Technologies

Related Documents

Supported Platforms

Supported Standards, MIBs and RFCs

Prerequisites

Configuration Tasks

Configuring PVC Mode in a Non-MPLS-Enabled Core

Configuring Multi-VC Mode in a MPLS-Enabled Core

Configuring Multi-VCs Using the Cos-Map Function

Configuring DWFQ and Changing Queue Weights on an Outgoing Interface

Verifying CoS Operation

Configuration Examples

Configuring Cisco Express Forwarding (CEF)

Running IP on Router 2

Running IP on Router 1

Running MPLS on Router 4

Running MPLS on Router 3

Running MPLS on Router 5

Running MPLS on Router 6

Configuring ATM Switch 2

Configuring ATM Switch 1

Command Reference

Command Conventions

boldface font

Commands and keywords are in boldface.

italic font

Arguments for which you supply values are in italics. In contexts that do not allow italics, arguments are enclosed in angle
brackets < >.

[ ]

Elements in square brackets are optional.

{ x | y | z }

Required alternative keywords are grouped in braces and separated by vertical bars.

{ x | y | z ]

Required alternative keywords are grouped in brackets and separated by vertical bars.


class

Syntax Description

Default

Command Mode

Command History

Example

Related Commands

show tag-switching cos-map

Syntax Description

Default

Command Mode

Command History

Example

Related Commands

show tag-switching interfaces

Syntax Description

Default

Command Modes

Command History

Usage Guidelines

Example

Related Command

show tag-switching prefix-map

Syntax Description

Default

Command Mode

Command History

Example

Related Command

tag-switching atm multi-vc

Syntax Description

Default

Command Mode

Command History

Usage Guidelines

Sample Display

tag-switching cos-map

Syntax Description

Default

Command Mode

Command History

Example

Related Command

tag-switching prefix-map

Syntax Description

Default

Command Mode

Command History

Usage Guidelines

Example

Related Command

Debug Commands

debug tag-switching atm-cos

Syntax Description

Default

Command Mode

Command History

Example

Related Commands

Glossary


MPLS Class of Service

Feature Overview

The Class of Service (CoS) feature for Multiprotocol Label Switching (MPLS) enables network administrators to provide differentiated types of service across an MPLS network. Differentiated service satisfies a range of requirements by supplying for each packet transmitted the particular kind of service specified for that packet by its CoS. Service can be specified in different ways, for example, using the IP precedence bit settings in IP packets.

In supplying differentiated service, MPLS CoS offers packet classification, congestion avoidance, and congestion management. lists these functions and their descriptions.

Table 1

Service
CoS Function
Description

Packet classification

Committed access rate (CAR). Packets are classified at the edge of the network before labels are assigned.

CAR uses the type of service (TOS) bits in the IP header to classify packets according to input and output transmission rates. CAR is often configured on interfaces at the edge of a network in order to control traffic into or out of the network. You can use CAR classification commands to classify or reclassify a packet.

Congestion avoidance

Weighted random early detection (WRED). Packet classes are differentiated based on drop probability.

WRED monitors network traffic, trying to anticipate and prevent congestion at common network and internetwork bottlenecks. WRED can selectively discard lower priority traffic when an interface begins to get congested. It can also provide differentiated performance characteristics for different classes of service.

Congestion management

Weighted fair queueing (WFQ). Packet classes are differentiated based on bandwidth and bounded delay.

WFQ is an automated scheduling system that provides fair bandwidth allocation to all network traffic. WFQ uses weights (priorities) to determine how much bandwidth each class of traffic is allocated.


CoS Services and Features

For more information on configuration of the CoS functions (CAR, WRED, and WFQ), see the Cisco IOS Quality of Service Solutions Configuration Guide.

For complete command syntax information for CAR, WRED, and WFQ, see the Cisco IOS Quality of Service Solutions Command Reference.

MPLS CoS lets you duplicate Cisco IOS IP CoS (Layer 3) features as closely as possible in MPLS devices, including label edge routers (LERs), label switch routers (LSRs), and asynchronous transfer mode LSRs (ATM LSRs). MPLS CoS functions map nearly one-for-one to IP CoS functions on all interface types.

Tag Switching/MPLS Terminology

The following table lists the old Tag Switching terms and the new MPLS terms found in this document.

Old Designation
New Designation

Tag Switching

MPLS, Multiprotocol Label Switching

Tag (short for Tag Switching)

MPLS

Tag (item or packet)

Label

TDP (Tag Distribution Protocol)

LDP (Label Distribution Protocol)

Note   Cisco TDP and LDP (MPLS Label Distribution Protocol)) are nearly identical in function, but use incompatible message formats and some different procedures. Cisco will be changing from TDP to a fully compliant LDP.

Tag Switched

Label Switched

TFIB (Tag Forwarding Information Base)

LFIB (Label Forwarding Information Base)

TSR (Tag Switching Router)

LSR (Label Switching Router)

TSC (Tag Switch Controller)

LSC (Label Switch Controller)

ATM-TSR

ATM-LSR (ATM Label Switch Router, for example,
BPX 8650.)

TVC (Tag VC, Tag Virtual Circuit)

LVC (Label VC, Label Virtual Circuit)

TSP (Tag Switch Protocol)

LSP (Label Switch Protocol)

XTagATM (extended Tag ATM port)

XmplsATM (extended mpls ATM port)


MPLS CoS

Several different methods exist for supporting CoS across an MPLS backbone, the choice depending on whether the core has label switch routers (LSRs) or ATM LSRs. In each case, however, the CoS building blocks are the same: CAR, WRED, and WFQ.

Three configurations are described below:

•LSRs used at the core of the network backbone

•ATM LSRs used at the core of the network backbone

•ATM switches without the MPLS feature enabled

LSRs

LSRs at the core of the MPLS backbone are usually either Cisco 7200 and Cisco 7500 series routers running MPLS software. Packets are processed as follows:

1 IP packets enter into the edge of the MPLS network.

2 The edge LSRs invoke CAR to classify the IP packets and possibly set IP precedence. Alternatively, IP packets can be received with their IP precedence already set.

3 For each packet, the router performs a lookup on the IP address to determine the next-hop LSR.

4 The appropriate label is placed on the packet with the IP precedence bits copied into every label entry in the MPLS header.

5 The labeled packet is then forwarded to the appropriate output interface for processing.

6 The packets are differentiated by class. This is done according to drop probability (WRED) or according to bandwidth and delay (WFQ). In either case, LSRs enforce the defined differentiation by continuing to employ WRED or WFQ on each hop.

ATM LSRs

ATM LSRs at the core implement the multiple label virtual circuit model (LVC). In the multiple LVC model, one label is assigned for each service class for each destination. The operation of the edge LSR is the same as that described previously for the LSR case, except that the output is an ATM interface. WRED is used to define service classes and determine discard policy during congestion.

In the multiple LVC model, however, class-based WFQ is used to define the amount of bandwidth available to each service class. Packets are scheduled by class during congestion. The ATM LSRs participate in the differentiation of classes with WFQ and intelligently drop packets when congestion occurs. The mechanism for this discard activity is weighted early packet discard (WEPD).

ATM Switches

When the core network uses ATM switches and the edge of the network uses MPLS-enabled edge LSRs, the edge LSRs are interconnected through a mesh of ATM Forum PVCs (CBR, VBR, or UBR) over the ATM core switches. The edge LSRs invoke WFQ on a per-VC basis to provide differentiation based on the delay of each MPLS CoS multiplexed onto the ATM Forum PVC. Optionally, WRED can also be used on a per-VC basis to manage drop priority between classes when congestion occurs on the edge LSR.

lists the MPLS CoS features supported on packet interfaces in this release.

Table 2 MPLS CoS Features Supported on Packet Interfaces

 
Cisco 7500 Series
Cisco 7200 Series
Cisco 4x00 Series
Cisco 36x0 Series
Cisco 2600 Series
MPLS CoS Packet Feature
         

Per-interface WRED

X

X

X

X

Untested

Per-interface, per-flow WFQ

X

X

X

X

Untested

Per-interface, per-class WFQ

X

X

X

X

Untested


lists the MPLS CoS features supported on ATM interfaces in this release.

Table 3 MPLS CoS Features Supported on ATM Interfaces

 
Cisco 7500 Series
Cisco 7200 Series
Cisco
4x00
Series
Cisco
36x0 Series
Cisco
2600 Series
MPLS CoS ATM Forum PVCs Feature
         

Per-VC WRED

X1

X1

N/A

N/A

N/A

Per-VC WRED and
per VC, per-class WFQ

N/A

X1

N/A

N/A

N/A

MPLS CoS Multi-VC or LBR Feature
         

Per-interface WRED

X2

X2

N/A

N/A

N/A

Per-interface, per-class WFQ

X2

X2

N/A

N/A

N/A

1 This feature is only available on the ATM Deluxe (PA-A3).

2 This feature is only available on the ATM Lite (PA-A1).


lists the MPLS CoS features supported on ATM switches.

Table 4 MPLS CoS Features Supported on ATM Switches and Interfaces

 
BPX 8650 Series
MGX 8800 Series
LightStream 1010 ATM Switch1
Catalyst 8540 MSR1

MPLS CoS ATM Forum PVCs

X

X

X

X

MPLS CoS Multi-VC or LBR—per-class WFQ

X

N/A

N/A

N/A

1 This can be used for the core only.


Benefits

MPLS CoS provides the same benefits as IP CoS when implemented on a backbone built purely of routers. The following benefits are realized when implementing IP CoS on a backbone of ATM switches using MPLS:

Efficient resource allocation—WFQ is used to allocate bandwidth on a per-class and per-link basis. Classes of traffic are guaranteed a percentage of link bandwidth, thereby maximizing the transport of paid traffic.

No connections to configure—Implementing IP CoS with MPLS requires no configuration of end-to-end VCs for each class of service. This advantage is especially beneficial when integrating MPLS CoS support in conjunction with an MPLS VPN service. Traditional methods of configuring IP CoS with ATM would require configuring and provisioning a separate end-to-end VC for each class of service for each VPN.

Flexibility without added overhead—MPLS CoS promotes the efficient use of bandwidth, because unused bandwidth allocated to a class is available to all other classes if needed. Furthermore, MPLS CoS requires no call setup procedure, because reachability and resource allocation are established before the initiation of service.

Related Features and Technologies

You can use MPLS CoS with:

•The MPLS Virtual Private Networks (VPNs) feature

•Any MPLS network

Related Documents

•MPLS Virtual Private Networks Feature Guide

Supported Platforms

The following is a list of router platforms supported at the provider core.

•Cisco 8800 series (MGX) (ATM Forum PVCs and multi VC or LBR - per class WFQ)

•Cisco BPX 8650 IP+ATM switch (ATM Forum PVCs only)

•Cisco 7500 series (ATM Forum PVCs and multi VC or LBR - per class WFQ)

•Cisco 7200 series (ATM Forum PVCs multi VC or LBR - per class WFQ)

The following is a list of router platforms supported at the provider edge.

•Cisco 7500 series routers (Edge LSR or LSR)

•Cisco 7200 series routers (Edge LSR or LSR)

•Cisco 45x0 series routers (POS interfaces only—Edge LSR or LSR)

•Cisco 36x0 series routers (POS interfaces only—Edge LSR or LSR)

Supported Standards, MIBs and RFCs

MIBs

•CISCO-WRED-MIB

•CISCO-CAR-MIB

•CISCO-WRED-MIB

For descriptions of supported MIBs and how to use MIBs, see the Cisco MIB website on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.

RFCs

No new or modified RFCs are supported by this feature.

Standards

No new or modified standards are supported by this feature.

Prerequisites

To use the MPLS CoS feature, your network must be running the following Cisco IOS features:

•CEF switching in every MPLS-enabled router

•MPLS

•ATM functionality (If you are using packet interfaces only, you do not need ATM functionality)

Configuration Tasks

Perform the tasks in the following sections to configure the MPLS CoS feature.

•Configuring PVC Mode in a Non-MPLS-Enabled Core

•Configuring Multi-VC Mode in a MPLS-Enabled Core

•Configuring Multi-VCs Using the Cos-Map Function

•Configuring DWFQ and Changing Queue Weights on an Outgoing Interface

•Verifying CoS Operation

Configuring PVC Mode in a Non-MPLS-Enabled Core

To configure a PVC in a non-MPLS-enabled core, use the following commands in the order specified in configuration mode:

Step
Command
Purpose

1 

Router(config)# interface type number point-to-point

Configures a point-to-point ATM subinterface.

2 

Router(config-subif)# ip unnumbered Loopback0

Assigns IP address to the subinterface.

3 

Router(config-subif)# pvc 4/40

Creates a PVC on the subinterface.

4 

Router(config-if-atm-vc)# random-detect attach groupname

Activates (D)WRED on the interface.

5 

Router(config-if-atm-vc)# encapsulation aal5snap

Sets encapsulation type for the PVC.

6 

Router(config-subif)# exit

Exits from PVC mode and enters subinterface mode.

7 

Router(config-subif)# tag-switching ip

Enables MPLS IP on the point-to-point interface.


Configuring Multi-VC Mode in a MPLS-Enabled Core

To configure multi-VC mode in an MPLS-enabled core, use the following commands in the order specified in configuration mode:

Note   The default for the multi-VC mode creates four VCs for each MPLS destination.

Step
Command
Purpose

1 

Router(config)# interface type number tag-switching

Configures an ATM MPLS subinterface.

2 

Router(config-subif)# ip unnumbered Loopback0

Assigns IP address to the subinterface.

3 

Router(config-subif)# tag-switching atm multi-vc

Enables ATM multi-VC mode on the subinterface.

4 

Router(config-subif)# tag-switching ip

Enables MPLS on the ATM subinterface.


Configuring Multi-VCs Using the Cos-Map Function

If you do not choose to use the default for configuring label VCs, you can configure fewer label VCs by using the CoS map function. To use the CoS map function, perform the following steps:

Step
Command
Purpose

1 

Router(config)# tag-switching cos-map cos-map number

Creates a CoS map.

2 

Router(config-tag-cos-map)# class 1 premium

Enters the cos-map submode and maps premium and standard classes to label VCs.

This CoS map assigns class 1 traffic to share the same label VC as class 2 traffic. The numbers you assign to the CoS map range from 0 to 3.

The defaults are:

•class 0 is available

•class 1 is standard

•class 2 is premium

•class 3 is control

3 

Router(config-tag-cos-map)# exit

Exits the MPLS CoS map submode.

4 

Router(config)# access-list access-list-number permit 
destination

Creates an access list.

The access list acts on traffic going to the specified destination address.

5 

Router(config)# tag-switching prefix-map prefix-map 
access-list access-list cos-map cos-map

Configures the router to use a specified CoS map when a MPLS destination prefix matches the specified access list.


Configuring DWFQ and Changing Queue Weights on an Outgoing Interface

To configure distributed fair queueing and change queue weights on an interface, use the following commands in interface configuration mode after specifying the interface:

Step
Command
Purpose

1 

Router(config)# interface type number

Specifies the interface type and number.

2 

Router(config-if)# fair-queue tos

Configures an interface to use fair queueing

3 

Router(config)# fair-queue tos class weight

Changes the class weight on the specified interface.


Verifying CoS Operation

To verify the operation of MPLS CoS, perform the following steps:

Step
Command
Purpose

1 

Router# show tag-switching interfaces interfaces

Displays detailed information about tag switching interfaces.

2 

Router# show tag-switching cos-map

Displays the CoS map used to assign VCs.

3 

Router# show tag-switching prefix-map

Displays the prefix map used to assign a CoS map to network prefixes.


Configuration Examples

illustrates a sample MPLS topology that implements the MPLS CoS feature. The following sections contain the configuration commands entered on Routers1 to 6 and on Switches 1 and 2 included in this figure.

Figure 1 Sample MPLS Topology Implementing CoS

Configuring Cisco Express Forwarding (CEF)

These configuration commands enable Cisco express forwarding (CEF). CEF switching is a prerequisite for the MPLS feature and must be running on all routers in the network. 

ip cef distributed

tag-switching ip

!

Running IP on Router 2

The following commands enable IP routing on Router 2. All routers must have IP enabled.

Note   Router 2 is not part of the MPLS network. 

!

ip routing

!

hostname R2

!

interface Loopback0

 ip address 10.10.10.10 255.255.255.255

!

interface POS0/3

 ip unnumbered Loopback0

crc 16

 clock source internal

!

router ospf 100

 network 10.0.0.0 0.255.255.255 area 100

!

Running IP on Router 1

The following commands enable IP routing on Router 1.

Note   Router 1 is not part of the MPLS network. 

ip routing 

!

hostname R1

!

interface Loopback0

 ip address 15.15.15.15 255.255.255.255

!

interface POS0/3

 ip unnumbered Loopback0

crc 16

 clock source internal

!

router ospf 100

 network 15.0.0.0 0.255.255.255 area 100

Running MPLS on Router 4

Router 4 is a label edge router. CEF and the MPLS feature must be enabled on this router. Committed Access Rate (CAR) is also configured on Router 4 on interface POS3/0/0 (see the section on Configuring CAR). 

!

hostname R4

!

ip routing

tag-switching ip

tag-switching advertise-tags

!

ip cef distributed

!

interface Loopback0

 ip address 11.11.11.11 255.255.255.255

!

interface Ethernet0/1

 ip address 90.0.0.1 255.0.0.0

tag-switching ip

!

Configuring CAR

Lines 3 and 4 contain the CAR rate policies. It sets the committed information rate (CIR) at 155,000,000 bits and the normal burst/maximum burst size at 200,000/800,000 bytes. The conform action (action to take on packets) sets the IP precedence and transmits the packets that conform to the rate limit. The exceed action sets the IP precedence and transmits the packets when the packets exceed the rate limit. 

!

interface POS3/0/0

 ip unnumbered Loopback0

rate-limit input 155000000 2000000 8000000 conform-action set-prec-transmit 5

exceed-action set-prec-transmit 1

 ip route-cache distributed

!

router ospf 100

 network 11.0.0.0 0.255.255.255 area 100

 network 90.0.0.0 0.255.255.255 area 100

Running MPLS on Router 3

Router 3 is running MPLS. CEF and the MPLS feature must be enabled on this router. Router 3 contains interfaces that are configured for WRED, multi-VC, per VC WRED, WFQ, and CAR. The following sections contain these sample configurations. 

!

hostname R3

!

ip cef distributed

!

interface Loopback0

 ip address 12.12.12.12 255.255.255.255

!

interface Ethernet0/1

 ip address 90.0.0.2 255.0.0.0

tag-switching ip

Configuring Point-to-Point WRED

The following commands configure WRED on an ATM interface. In this example, the commands refer to a PA-A1 (ATM Lite). 

!

interface ATM1/1/0

ip route-cache distributed

 atm clock INTERNAL

 random-detect

!

Configuring an Interface for Multi-VC Mode

The following commands configure interface ATM1/1/0 for multi-VC mode. In this example, the commands refer to a PA-A1 (ATM Lite). 

!

interface ATM1/1/0.1 tag-switching

 ip unnumbered Loopback0

tag-switching atm multi-vc

 tag-switching ip

!

Configuring Per VC WRED

The following commands configure per VC WRED on a PA-A3 (ATM Deluxe) only.

Note   The PA-A1 (ATM Lite) does not support the per-VC WRED drop mechanism. 

!interface ATM2/0/0

 no ip address

ip route-cache distributed


interface ATM2/0/0.1 point-to-point

 ip unnumbered Loopback0

 no ip directed-broadcast

 pvc 10/100 

  random-detect

  encapsulation aal5snap

  exit

 !

 tag-switching ip

Configuring WRED and WFQ

Lines 5 and 6 contain the commands for configuring WRED and WFQ on interface Hssi2/1/0. 

!

interface Hssi2/1/0

 ip address 91.0.0.1 255.0.0.0

ip route-cache distributed

tag-switching ip

 random-detect

fair queue tos

hssi internal-clock

!

Configuring CAR

Lines 3 and 4 contain the CAR rate policies. It sets the committed information rate (CIR) at 155,000,000 bits and the normal burst/maximum burst size at 200,000/800,000 bytes. The conform action (action to take on packets) sets the IP precedence and transmits the packets that conform to the rate limit. The exceed action sets the IP precedence and transmits the packets when the packets exceed the rate limit. 

!

interface POS3/0/0

 ip unnumbered Loopback0

rate-limit input 155000000 2000000 8000000 conform-action set-prec-transmit 2

exceed-action set-prec-transmit 2

 ip route-cache distributed

!

router ospf 100

 network 12.0.0.0 0.255.255.255 area 100

 network 90.0.0.0 0.255.255.255 area 100

 network 91.0.0.0 0.255.255.255 area 100

!

ip route 93.0.0.0 255.0.0.0 Hssi2/1/0 91.0.0.2

!

Running MPLS on Router 5

Router 5 is running the MPLS feature. CEF and the MPLS feature must be enabled on this router. Router 5 has also been configured to create an ATM subinterface in Multi-VC mode and to create a PVC on a Point-to-Point subinterface. The sections that follow contain these sample configurations. 

!

hostname R5

!

ip cef distributed

!

interface Loopback0

 ip address 13.13.13.13 255.255.255.255

!

interface Ethernet0/2

 ip address 92.0.0.1 255.0.0.0

tag-switching ip

Configuring an ATM Interface

The following commands create an ATM interface. 

!

interface ATM1/0/0

 no ip address

ip route-cache distributed

 atm clock INTERNAL

!

Configuring an ATM MPLS Subinterface in Multi-VC Mode

The following commands create an MPLS subinterface in multi-VC mode. 

!

interface ATM1/0/0.1 tag-switching

 ip unnumbered Loopback0

tag-switching atm multi-vc

 tag-switching ip

!

Configuring a PVC on Point-to-Point Subinterface

The following commands create a PVC on a point-to-point subinterface (interface ATM1/0/0.2). 

!

interface ATM1/0/0.2 point-to-point

 ip unnumbered Loopback0

pvc 10/100 

  random-detect

  encapsulation aal5snap

  exit

 !

 tag-switching ip

!

interface Hssi3/0

 ip address 91.0.0.2 255.0.0.0

tag-switching ip

 hssi internal-clock

!

router ospf 100

 network 13.0.0.0 0.255.255.255 area 100

 network 91.0.0.0 0.255.255.255 area 100

 network 92.0.0.0 0.255.255.255 area 100

!

Running MPLS on Router 6

Router 6 is running the MPLS feature. CEF and the MPLS feature must be enabled on this router. 

!

hostname R6

!

ip cef distributed

!

interface Loopback0

 ip address 14.14.14.14 255.255.255.255

!

interface Ethernet0/1

 ip address 93.0.0.1 255.0.0.0

tag-switching ip

!

interface Ethernet0/2

 ip address 92.0.0.2 255.0.0.0

 tag-switching ip

!

interface Ethernet0/3

 ip address 94.0.0.1 255.0.0.0

 tag-switching ip

!

router ospf 100

 network 14.0.0.0 0.255.255.255 area 100

 network 92.0.0.0 0.255.255.255 area 100

 network 93.0.0.0 0.255.255.255 area 100

 network 94.0.0.0 0.255.255.255 area 100

!

Configuring ATM Switch 2 

Switch 2 is configured for MPLS and creates an ATM Forum PVC.

!

hostname S2

!

interface Loopback0

 ip address 16.16.16.16 255.255.255.255

!

interface ATM0/0/0

 ip unnumbered Loopback0

tag-switching ip

!

interface ATM0/0/1

 ip unnumbered Loopback0

 tag-switching ip

atm pvc 10 100 interface ATM0/0/0 10 100


interface ATM0/0/2

 no ip address

 no ip directed-broadcast

!

interface ATM0/0/3

 ip unnumbered Loopback0

tag-switching ip

!

interface ATM1/1/0

ip unnumbered Loopback0

tag-switching ip

!

router ospf 100

 network 16.0.0.0 0.255.255.255 area 100

!

Configuring ATM Switch 1

Switch 1 is configured to create an ATM Forum PVC. 

!

hostname S1

!

interface Loopback0

 ip address 17.17.17.17 255.255.255.255

!

interface ATM0/0/0

 ip unnumbered Loopback0

tag-switching ip

!

Configuring Label VCs and an ATM Forum PVC

Line 3 contains the configuration command for an ATM Forum PVC. 

!

interface ATM0/1/1

 ip unnumbered Loopback0

atm pvc 10 100  interface  ATM0/0/0 10 100 

 tag-switching ip

!

interface ATM1/1/0

 ip unnumbered Loopback0

tag-switching ip

!

router ospf 100

 network 17.0.0.0 0.255.255.255 area 100

!

Command Reference

This section documents new or modified commands supported for the CoS feature. All other commands used with this feature are documented in the Cisco IOS Release 12.0 command references. There are no examples of command output for the configuration commands, because they typically do not generate output. The following commands are described here:

•class

•show tag-switching cos-map

•show tag-switching interfaces

•show tag-switching prefix-map

•tag-switching atm multi-vc

•tag-switching cos-map

In Cisco IOS Release 12.0(1)T or later, you can search and filter the output for show and more commands. This functionality is useful if you must sort through large amounts of output, or if you want to exclude output that you do not need to see.

To use this functionality, enter a show or more command followed by the "pipe" character (|), one of the keywords begin, include, or exclude, and an expression that you want to search or filter on:

command | {begin | include | exclude} regular-expression

Following is an example of the show atm vc command in which you want the command output to begin with the first line where the expression "PeakRate" appears:

show atm vc | begin PeakRate

For more information on the search and filter functionality, refer to the Cisco IOS Release 12.0(1)T feature module titled CLI String Search.

Command Conventions

boldface font

Commands and keywords are in boldface.

italic font

Arguments for which you supply values are in italics. In contexts that do not allow italics, arguments are enclosed in angle
brackets < >.

[ ]

Elements in square brackets are optional.

{ x | y | z }

Required alternative keywords are grouped in braces and separated by vertical bars.

{ x | y | z ]

Required alternative keywords are grouped in brackets and separated by vertical bars.


class

To configure an MPLS CoS map which specifies how classes map to label VCs (LVCs) when combined with a prefix map, use the class cos-map submode command. To disable this option, use the no form of this command.

class class [available standard premium control]

no class class [available standard premium control]

Syntax Description

class

The precedence of identified traffic to classify traffic.

available

Means low precedence (In/Out plus lower two bits = 0,4).

standard

Means next precedence (In/Out plus lower two bits = 1,5).

premium

Means high precedence (In/Out plus lower two bits = 2,6).

control

Means highest precedence pair (In/Out plus lower two
bits = 3,7). These bits are reserved for control traffic.


Default

No default behavior or values.

Command Mode

CoS map submode

Command History

Release
Modification

12.0(5)T

This command was introduced.


Example

The following commands configure a CoS map: 

Router(config)# tag-switching cos-map 55

Router(config-tag-cos-map)# class 1 premium

Router(config-tag-cos-map)# exit

Related Commands

Command
Description

tag-switching cos-map

Configures a class map, which specifies how classes map to LVCs when combined with a prefix map.

show tag-switching cos-map

Displays a CoS map.

tag-switching prefix-map

Configures a router to use a specific CoS map for a specified destination.

access-list

Establishes MAC address access lists.


show tag-switching cos-map

To display the CoS map used to assign quantity of label VCs and associated class of service of those LVCs, use the show tag-switching cos-map EXEC command.

show tag-switching cos-map

Syntax Description

This command has no arguments or keywords.

Default

No default behavior or values.

Command Mode

EXEC

Command History

Release
Modification

12.0(5)T

This command was introduced.


Example

The following example shows output from this command: 

Router# show tag-switching cos-map 

cos-map 2    class  tag-VC 

             3      control 

             2      control 

             1      available

             0      available

lists the fields displayed.

Table 5 Show Tag-Switching Cos-Map Field Descriptions

Field
Description

cos-map

Configures a class map, which specifies how classes map to MPLS VCs when combined with a prefix map.

class

The IP precedence.

tag-VC

An ATM virtual circuit that is set up through ATM LSR label distribution procedures.


Related Commands

Command
Description

class

Enters the cos-map submode.

tag-switching cos-map

Configures a class map.


show tag-switching interfaces

To display information about one or more interfaces with the MPLS feature enabled, use the
show tag-switching interfaces EXEC command.

show tag-switching interfaces [interface] [detail]

Syntax Description

interface

Optional. The interface about which to display MPLS information.

detail

Optional. Displays information in long form.


Default

No default behavior or values.

Command Modes

EXEC

Command History

Release
Modification

11.1 CT

This command was introduced.


Usage Guidelines

You can show information about the requested interface or about all interfaces on which the MPLS feature is enabled.

Example

The following example shows the interface in multi-VC LVC mode 

Router# show tag-switching interfaces detail


Interface ATM3/0/0.1:

        IP tagging enabled

        TSP Tunnel tagging not enabled

        Tagging operational

        Tagswitching feature vector

        MTU = 4470

        ATM tagging: Tag VPI = 1, Control VC = 0/32, multi-vc tag-vc mode

lists the fields displayed in this example.

Table 6 Show Tag-Switching Interfaces Field Descriptions

Field
Description

Interface

Interface type and number

IP tagging enabled

Status of IP MPLS on an interface.

TSP Tunnel tagging not enabled

Status of tag tsp-tunnels on the interface.

Tagging operational

Operational status of MPLS on an interface.

Tagswitching feature vector

Specifies the MPLS feature vector on an interface.

MTU

Maximum number of data bytes per labeled packet that will be transmitted.

ATM tagging

The interface uses TC-ATM procedures.


Related Command

Command
Description

tag-switching ip interface

Enables MPLS on an interface.


show tag-switching prefix-map

To show the prefix map used to assign a CoS map to network prefixes matching a standard IP access list, use the show tag-switching prefix-map EXEC command.

show tag-switching prefix-map [prefix-map]

Syntax Description

prefix-map

Specifies the prefix-map number.


Default

No default behavior or values.

Command Mode

EXEC

Command History

Release
Modification

12.0(5)T

This command was introduced.


Example

The following is sample output from the show tag-switching prefix-map command: 

Router# show tag-switching prefix-map 

prefix-map 2 access-list 2 cos-map 2

lists the fields displayed.

Table 7 show tag-switching prefix-map Field Description