Cisco IOS Software Releases 12.0 S

Table Of Contents

Any Transport over MPLS

Contents

Prerequisites for Any Transport over MPLS

Cisco 7200 and 7500 Series Routers: Required Chassis, Processors, and VIPs

Cisco 7200 and 7500 Series Routers: Supported Port Adapters

Cisco 12000 Series Routers: Supported Line Cards

Restrictions for Any Transport over MPLS

ATM AAL5 over MPLS Restrictions

ATM Cell Relay over MPLS Restrictions

Ethernet over MPLS Restrictions

Frame Relay over MPLS Restrictions

HDLC over MPLS Restrictions

PPP over MPLS Restrictions

Restrictions Specific to the Cisco 12000 Series Routers

Information About Any Transport over MPLS

How AToM Transports Layer 2 Packets

Compatibility with Previous Releases of AToM

Benefits of AToM

How to Configure Any Transport over MPLS

Prerequisites

How to Configure the Pseudowire-Class

Configuration Guidelines

How to Configure ATM AAL5 over MPLS

Configuring OAM Cell Emulation for ATM AAL5 over MPLS

How to Configure ATM Cell Relay over MPLS

Varieties of ATM Cell Relay over MPLS

Configuring ATM Relay over MPLS with the Cisco 12000 Series Router Engine 2 8-Port OC-3 STM-1 ATM Line Card

Configuring ATM Cell Relay over MPLS: VC Mode

Configuring ATM Cell Relay over MPLS: VP Mode

Configuring ATM Cell Relay over MPLS: Port Mode

Configuring ATM Cell Relay over MPLS: Single Cell Relay

Configuring ATM Cell Relay over MPLS: Packed Cell Relay

OAM Support with ATM Cell Relay over MPLS

How to Configure Ethernet over MPLS

Configuring Ethernet over MPLS: VLAN Mode

Configuring Ethernet over MPLS: Port Mode

Configuring Ethernet over MPLS: VLAN ID Rewrite

How to Configure Frame Relay over MPLS

How Frame Relay PDUs Move Between PE Routers

Configuring Frame Relay over MPLS with DLCI-to-DLCI Connections

Configuring Frame Relay over MPLS with Port-to-Port Connections

Enabling Other PE Devices to Transport Frame Relay Packets

Local Management Interface and Frame Relay over MPLS

How to Configure HDLC and PPP over MPLS

Configuring HDLC and PPP over MPLS

How to Configure Distributed CEF Mode

Enabling Distributed CEF

How to Configure MPLS Traffic Engineering Fast Reroute

Configuring MPLS TE Fast Reroute

Fast Reroute Configuration Example

Verifying Fast Reroute

Troubleshooting Tips

How to Configure Tunnel Selection

Configuring Tunnel Selection

Tunnel Selection Configuration Guidelines

Tunnel Selection Configuration Example

Verifying Tunnel Selection

Troubleshooting Tunnel Selection

How to Estimate the Size of Packets Traveling Through the Core Network

Example of Estimating Packet Size

Changing the MTU Size on the P and PE Routers

How to Configure QoS with AToM

How to Set Experimental Bits with AToM

ATM AAL5 over MPLS and EXP Bits

ATM Cell Relay over MPLS and EXP Bits

Ethernet over MPLS and EXP Bits

Frame Relay over MPLS and EXP Bits

HDLC over MPLS and PPP over MPLS and EXP Bits

Setting the EXP Bits

Using 802.1Q P Bits to Determine the Experimental Bit Settings

How to Configure QoS Features with the Cisco 12000 Series Routers

Configuring Traffic Policing with the Cisco 12000 Series Routers

Configuration Guidelines

Configuring Traffic Policing for ATM AAL5 and ATM Cell Relay on the Cisco 12000 Series Routers

Configuring Traffic Policing for Frame Relay on the Cisco 12000 Series Routers

How to Configure QoS Features with the Cisco 7200 and 7500 Series Routers

Setting the Frame Relay Discard Eligibility Bit on the Cisco 7200 and 7500 Series Routers

Matching the Frame Relay DE Bit on the Cisco 7200 and 7500 Series Routers

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Command Reference

Obsolete and Replaced Commands

atm mode cell-relay

atm route interface

debug mpls atm-transport control

debug mpls atm-transport distributed

debug mpls atm-transport switching

match fr-de

mpls atm-transport

mpls atm-transport cos-map

mpls l2transport cos-map

random-detect discard-class-based

set discard-class

show atm route

show mpls atm-transport cos-map

show mpls atm-transport disposition

show mpls atm-transport imposition

Any Transport over MPLS

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Any Transport over MPLS (AToM) transports Layer 2 packets over a Multiprotocol Label Switching (MPLS) backbone. AToM enables service providers to connect customer sites with existing data link layer (Layer 2) networks, by using a single, integrated, packet-based network infrastructure — a Cisco MPLS network. Instead of separate networks with network management environments, service providers can deliver Layer 2 connections over an MPLS backbone. AToM provides a common framework to encapsulate and transport supported Layer 2 traffic types over an MPLS network core.

AToM supports the following like-to-like transport types:

•ATM AAL5 over MPLS

•ATM Cell Relay over MPLS

•Ethernet over MPLS (VLAN and port modes)

•Frame Relay over MPLS

•PPP over MPLS

•HDLC over MPLS

Feature Specifications for Any Transport over MPLS

Feature History
Release	Modification
12.0(10)ST	Any Transport over MPLS: ATM AAL5 over MPLS was introduced on the Cisco 12000 series routers.
12.1(8a)E	Any Transport over MPLS: Ethernet over MPLS was introduced on the Cisco 7600 series Internet router.
12.0(21)ST	Ethernet over MPLS was introduced on the Cisco 12000 series routers. ATM AAL5 over MPLS was updated.
12.0(22)S	Ethernet over MPLS was integrated into this release. Support for the Cisco 10720 router was added. ATM AAL5 over MPLS was integrated into this release for the Cisco 12000 series routers.
12.0(23)S	The following new features were introduced: •ATM Cell Relay over MPLS (single cell relay, VC mode) •Frame Relay over MPLS •HDLC over MPLS •PPP over MPLS These features were supported on the Cisco 7200 and 7500 series routers. The Cisco 12000, 7200, and 7500 series routers supported the following features: •ATM AAL5 over MPLS •Ethernet over MPLS (VLAN mode) The Cisco 10720 Internet router continued support for Ethernet over MPLS.
12.2(14)S	This feature was integrated into Cisco IOS Release 12.2(14)S.
12.2(15)T	This feature was integrated into Cisco IOS Release 12.2(15)T.
12.0(25)S	The following new features were introduced: •New commands for configuring AToM •Ethernet over MPLS: port mode •ATM Cell Relay over MPLS: packed cell relay •ATM Cell Relay over MPLS: VP mode •ATM Cell Relay over MPLS: port mode •Distributed CEF mode for Frame Relay, PPP, and HDLC over MPLS •Fast reroute with AToM •Tunnel selection •Traffic policing •QoS support
12.0(26)S	The following new features were introduced: •Support for connecting disparate attachment circuits. See L2VPN Interworking for more information. •QoS functionality with AToM for the Cisco 7200 series routers. •Support for FECN and BECN marking with Frame Relay over MPLS. (See BECN and FECN Marking for Frame Relay over MPLS for more information.)
Supported Platforms
Cisco 7200 series, Cisco 7500 series, Cisco 12000 series, Cisco 10720 Internet router See the sections that describe the features to determine the platforms that support the features. See Prerequisites for Any Transport over MPLS for the supported port adapters and line cards.

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 Any Transport over MPLS

•Information About Any Transport over MPLS

•How to Configure Any Transport over MPLS

•How to Configure QoS with AToM

•Additional References

•Command Reference

Prerequisites for Any Transport over MPLS

On the provider edge (PE) routers, AToM requires the hardware specified in the following sections:

•Cisco 7200 and 7500 Series Routers: Required Chassis, Processors, and VIPs

•Cisco 7200 and 7500 Series Routers: Supported Port Adapters

•Cisco 12000 Series Routers: Supported Line Cards

Cisco 7200 and 7500 Series Routers: Required Chassis, Processors, and VIPs

•Cisco 7200 series routers

–Chassis: All 7200-VXR chassis types

–Processors: NPE-225, NPE-300, and NPE-400

•Cisco 7500 series routers

–Chassis: All 7500 chassis types

–Processors: RSP4, RSP4+, RSP8, and RSP16

–VIPs: VIP2-50, VIP4-50, VIP4-80, and VIP6-80

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Note The chassis, processors, and VIPs listed have been tested and are supported for use with MPLS AToM. All other chassis, processors, and VIPs have not been tested and therefore are not supported. In future releases, you will not be able to configure AToM on unsupported hardware.

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Cisco 7200 and 7500 Series Routers: Supported Port Adapters

The following port adapters are supported for the Cisco 7200 and 7500 series routers for each transport type.

Transport Type	Supported Port Adapters
ATM AAL5 over MPLS	PA-A3-OC3 PA-A3-E3 Note AAL5 over MPLS is not supported on hardware version 1.0 of the PA-A3-OC3 and PA-A3-E3 line cards. PA-A3-DS3 PA-A3-OC12 PA-A3-8T1IMA PA-A3-8E1IMA
ATM Cell Relay over MPLS Note ATM Cell Relay over MPLS is not supported on the following port adapters: PA-A1-OC3 PA-A2-OC3
ATM single cell relay: VC mode	PA-A3-OC3 PA-A3-E3 PA-A3-T3 PA-A3-8T1IMA PA-A3-8E1IMA Note ATM Cell Relay is not supported on hardware version 1.0 of the PA-A3-OC3, -E3, and -T3 port adapters.
ATM single cell relay: VP mode	PA-A3-OC3 PA-A3-E3 PA-A3-T3 PA-A3-8T1IMA PA-A3-8E1IMA Note ATM Cell Relay is not supported on on hardware version 1.0 of the PA-A3- OC3, -E3, and -T3 port adapters.
ATM packed cell relay: VP or VC mode	PA-A3-OC3 PA-A3-E3 PA-A3-T3 Note ATM Cell Relay is not supported on hardware version 1.0 of these port adapters.
Ethernet over MPLS (Port and VLAN modes)	7200 and 7500 PA-2FE PA-FE 7200 only C7200-I/O-2FE C7200-I/O-GE+E (Only the Gigabit Ethernet port of this port adapter is supported.) c7200-I/O-FE PA-GE 7500 only GEIP GEIP+
Frame Relay over MPLS HDLC over MPLS PPP over MPLS Note: Starting in Cisco IOS Release 12.0(25)S, channelized port adapters are supported for HDLC and PPP over MPLS.	PA-MC-8T1 PA-MC-8E1 PA-MC-2T3+ PA-MC-T3 PA-T3 PA-2T3 PA-T3+ PA-4T+ PA-2T3+ PA-8T-V35 PA-E3 PA-2E3 PA-MC-E3 PA-MC-2E1 PA-MC-4T1 PA-MC-STM1 PA-MC-8TE1+ PA-POS-OC3 PA-HSSI PA-2HSSI PA-4E1G120 PA-8T-232 PA-8T-X21

Cisco 12000 Series Routers: Supported Line Cards

The following line cards are supported for the Cisco 12000 series routers for each transport type.

Transport Type	Supported Line Cards
ATM AAL5 over MPLS	Label imposition: All Engine 0 and 2 ATM line cards Label disposition: All line cards
ATM single cell relay over MPLS: VC mode	Label imposition: •All Engine 0 ATM line cards •Engine 2: 8-Port OC-3 STM-1 ATM line card Label disposition: All line cards
ATM single cell relay over MPLS: VP mode	Label imposition: •Engine 2: 8-Port OC-3 STM-1 ATM line card Label disposition: All line cards
ATM single cell relay over MPLS: port mode	Label imposition: •Engine 2: 8-Port OC-3 STM-1 ATM line card Label disposition: All line cards
Ethernet VLAN over MPLS	Label imposition: All Engine 2, 3, and 4+ Ethernet line cards Label disposition: All line cards
Ethernet Port Mode over MPLS	Label imposition: All Engine 2, 3, and 4+ Ethernet line cards Label disposition: All line cards
Frame Relay over MPLS	Label imposition: •All Engine 0 POS and channelized line cards •All Engine 2 POS line cards •All Engine 3 POS and channelized line cards Label disposition: All line cards
HDLC over MPLS	Label imposition: •All Engine 0 POS and channelized line cards •All Engine 2 POS line cards •All Engine 3 POS and channelized line cards •All Engine 4+ POS line cards Label disposition: All line cards
PPP over MPLS	Label imposition: •All Engine 0 POS and channelized line cards •All Engine 2 POS line cards •All Engine 3 POS and channelized line cards Label disposition: All line cards

Restrictions for Any Transport over MPLS

The following general restrictions pertain to all transport types under AToM:

•Sequencing: AToM does not support detecting of out-of-order packets.

•Address format: Configure the LDP router ID on all PE routers to be a loopback address with a /32 mask. Otherwise, some configurations might not properly function.

ATM AAL5 over MPLS Restrictions

The following restrictions pertain to the ATM AAL5 over MPLS feature:

•PVC configuration: You can configure ATM AAL5 over MPLS on permanent virtual circuits (PVCs) only. You cannot configure AAL5 over MPLS on main interfaces.

•SDU mode: AAL5 over MPLS is supported only in SDU mode.

ATM Cell Relay over MPLS Restrictions

The following restrictions pertain to the ATM Cell Relay over MPLS feature:

•TE tunnels: If you have TE tunnels running between the PE routers, you must enable label distribution protocol (LDP) on the tunnel interfaces.

Ethernet over MPLS Restrictions

The following restrictions pertain to the Ethernet over MPLS feature:

•Packet format: Ethernet over MPLS supports VLAN packets that conform to the IEEE 802.1Q standard. The 802.1Q specification establishes a standard method for inserting VLAN membership information into Ethernet frames. The Inter-Switch Link (ISL) protocol is not supported between the PE and customer edge (CE) routers.

Frame Relay over MPLS Restrictions

The following restrictions pertain to the Frame Relay over MPLS feature:

•Traffic shaping: Frame Relay traffic shaping is not supported with AToM switched VCs.

HDLC over MPLS Restrictions

The following restrictions pertain to the HDLC over MPLS feature:

•Asynchronous interfaces: Asynchronous interfaces are not supported.

•Interface configuration: You must configure HDLC over MPLS on router interfaces only. You cannot configure HDLC over MPLS on subinterfaces.

PPP over MPLS Restrictions

The following restrictions pertain to the PPP over MPLS feature:

• Zero hops on a PE router: Zero hops on one router is not supported. However, you can have back-to-back PE routers.

•Asynchronous interfaces: Asynchronous interfaces are not supported. The connections between the CE and PE routers on both ends of the backbone must have similar link layer characteristics. The connections between the CE and PE routers must both be synchronous.

•Multilink PPP: Multilink PPP (MLP) is not supported.

•Interface configuration: You must configure PPP on router interfaces only. You cannot configure PPP on subinterfaces.

Restrictions Specific to the Cisco 12000 Series Routers

Fast Reroute

Fast Reroute uses three or more labels, depending on where the Traffic Engineering (TE) tunnel ends:

•If the TE tunnel is from PE router to PE router, three labels are used.

•If the TE tunnel is from PE router to P router, four labels are used.

Engine 0 ATM line cards support three or more labels, although performance degrades. Engine 2 Gigabit Ethernet line cards and Engine 3 line cards support three or more labels and can work with the Fast Reroute feature.

Frame Relay over MPLS

If you configure Frame Relay over MPLS and the core-facing interface is an Engine 4 or 4+ line card and the edge facing interface is an Engine 0 or 2 line card, then the FECN, BECN, CR, and DE bit information is stripped from the PVC.

ATM Cell Relay over MPLS

If you configure the Engine 2 8-Port OC-3 STM-1 ATM line card for ATM single cell relay over MPLS, you cannot configure other Layer 3 features on those ports reserved for ATM cell relay over MPLS.

Information About Any Transport over MPLS

To configure AToM, you must understand the following concepts:

•How AToM Transports Layer 2 Packets

•Compatibility with Previous Releases of AToM

•Benefits of AToM

How AToM Transports Layer 2 Packets

AToM encapsulates Layer 2 frames at the ingress PE and sends them to a corresponding PE at the other end of a pseudowire, which is a connection between the two PE routers. The egress PE removes the encapsulation and sends out the Layer 2 frame.

The successful transmission of the Layer 2 frames between PE routers is due to the configuration of the PE routers. You set up the connection, called a pseudowire, between the routers. You specify the following information on each PE router:

•The type of Layer 2 data that will be transported across the pseudowire, such as Ethernet, Frame Relay, or ATM

•The IP address of the loopback interface of the peer PE router, which enables the PE routers to communicate

•A unique combination of peer PE IP address and VC ID that identifies the pseudowire

The following example shows the basic configuration steps on a PE router that enable the transport of Layer 2 packets. Each transport type has slightly different steps.

Step 1 defines the interface or subinterface on the PE router.

Router# interface interface-type interface-number

Step 2 specifies the encapsulation type for the interface, such as dot1q.

Router(config-if)# encapsulation encapsulation-type

Step 3 does the following:

•Makes a connection to the peer PE router by specifying the LDP router ID of the peer PE router.

•Identifies a unique identifier that is shared between the two PE routers. The vcid is a 32-bit identifier.

The combination of the peer-router-id and the VC ID must be a unique combination on the router. Two circuits cannot use the same combination of peer-router-id and VC ID.

•Specifies the tunneling method used to encapsulate data in the pseudowire. For AToM, the tunneling method used to encapsulate data is mpls.

Router(config-if)# xconnect peer-router-id vcid encapsulation mpls

As an alternative, you can set up a pseudowire class to specify the tunneling method and other characteristics. See the "How to Configure the Pseudowire-Class" section for more information.

Compatibility with Previous Releases of AToM

In previous releases of AToM, the command used to configure AToM circuits was mpls l2 transport route. This command has been replaced with the xconnect command.

No new CLI enhancements will be made to the mpls l2transport route command. CLI enhancements will be made to either the xconnect command or pseudowire-class command. Therefore, we recommend that you use the xconnect command to configure AToM circuits.

Configurations from previous releases that use the mpls l2transport route command are still supported.

Benefits of AToM

The following list explains some of the benefits of enabling Layer 2 packets to be sent in the MPLS network:

•The AToM product set accommodates many types of Layer 2 packets, including Ethernet and Frame Relay, across multiple Cisco router platforms, such as the Cisco 7200 and 7500 series routers. This enables the service provider to transport all types of traffic over the backbone and accommodate all types of customers.

•AToM adheres to the standards developed for transporting Layer 2 packets over MPLS. (See the "Standards" section for the specific standards that AToM follows.) This benefits the service provider who wants to incorporate industry-standard methodologies in the network. Other Layer 2 solutions are proprietary, which can limit the service provider's ability to expand the network and can force the service provider to use only one vendor's equipment.

•Upgrading to AToM is transparent to the customer. Because the service provider network is separate from the customer network, the service provider can upgrade to AToM without disruption of service to the customer. The customers assume that they are using a traditional Layer 2 backbone.

How to Configure Any Transport over MPLS

This section explains how to perform a basic AToM configuration and includes the following procedures:

•How to Configure the Pseudowire-Class

•How to Configure ATM AAL5 over MPLS

•How to Configure ATM Cell Relay over MPLS

•How to Configure Ethernet over MPLS

•How to Configure Frame Relay over MPLS

•How to Configure HDLC and PPP over MPLS

•How to Configure Distributed CEF Mode

•How to Configure MPLS Traffic Engineering Fast Reroute

•How to Configure Tunnel Selection

•How to Estimate the Size of Packets Traveling Through the Core Network

Prerequisites

Before configuring AToM, ensure that the network is configured as follows:

•Configure IP routing in the core so that the PE routers can reach each other via IP.

•Configure MPLS in the core so that a label switched path (LSP) exists between the PE routers.

•Enable IP CEF or IP CEF distributed before configuring any Layer 2 circuits.

•Configure a loopback interface for originating and terminating Layer 2 traffic. Make sure the PE routers can access the other router's loopback interface. Note that the loopback interface is not needed in all cases. For example, tunnel selection does not need a loopback interface when AToM is directly mapped to a TE tunnel.

How to Configure the Pseudowire-Class

The successful transmission of the Layer 2 frames between PE routers is due to the configuration of the PE routers. You set up the connection, called a pseudowire, between the routers.

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Note In simple configurations, this task is optional. You do not need to specify a pseudowire class if you specify the tunneling method as part of the xconnect command.

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The pseudowire-class configuration group specifies the characteristics of the tunneling mechanism, including:

•Encapsulation type

•Control protocol

•Payload-specific options

For more information about the pseudowire-class command, see the feature module Layer 2 Tunnel Protocol Version 3 at the following location:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120limit/120s/120s24/l2tpv3.htm

Once you specify the encapsulation mpls command, you cannot remove it using the no encapsulation mpls command. Nor can you change the command's setting using the encapsulation l2tpv3 command. Those methods result in the following error message:

Encapsulation changes are not allowed on an existing pw-class.

To remove the command, you must delete the pseudowire with the no pseudowire-class command. To change the type of encapsulation, remove the pseudowire with the no pseudowire-class command and re-establish the pseudowire and specify the new encapsulation type.

SUMMARY STEPS

1. enable

2. configure terminal

3. pseudowire-class name

4. encapsulation mpls

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	pseudowire-class name Example: Router(config)# pseudowire-class atom	Establishes a pseudowire class with a name that you specify.
Step 4	encapsulation mpls Example: Router(config-pw)# encapsulation mpls	Specifies the tunneling encapsulation. For AToM, the encapsulation type is mpls.

Configuration Guidelines

You must specify encapsulation mpls as part of the xconnect command or as part of a pseudowire class for the AToM VCs to work properly. If you omit encapsulation mpls as part of the xconnect command, you receive the following error:

% Incomplete command.

How to Configure ATM AAL5 over MPLS

ATM AAL5 over MPLS encapsulates ATM AAL5 SDUs in MPLS packets and forwards them across the MPLS network. Each ATM AAL5 SDU is transported as a single packet. Perform this task to enable ATM AAL5 over MPLS.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface atmslot/port

4. pvc vpi/vci l2transport

5. encapsulation aal5

6. xconnect peer-router-id vcid encapsulation mpls

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 atmslot/port Example: Router(config)# interface atm1/0	Specifies an ATM interface.
Step 4	pvc vpi/vci l2transport Example: Router(config-if)# pvc 1/200 l2transport	Assigns a virtual path identifier (VPI) and virtual circuit identifier (VCI). The l2transport keyword indicates that the PVC is a switched PVC instead of a terminated PVC. You can configure ATM AAL5 on PVCs only. You cannot configure AAL5 over MPLS on main interfaces.
Step 5	encapsulation aal5 Example: Router(config-if-atm-l2trans-pvc)# encapsulation aal5	Specifies ATM AAL5 encapsulation for the PVC. Make sure you specify the same encapsulation type on the PE and CE routers.
Step 6	xconnect peer-router-id vcid encapsulation mpls Example: Router(config-if-atm-l2trans-pvc)# xconnect 13.13.13.13 100 encapsulation mpls	Binds the attachment circuit to a pseudowire VC.

Configuring OAM Cell Emulation for ATM AAL5 over MPLS

Supported Platforms:

•Cisco 7200 series routers

•Cisco 7500 series routers

•Cisco 12000 series routers

Overview of OAM Cell Emulation

If a PE router does not support the transport of OAM cells across an LSP, you can use OAM cell emulation to locally terminate or loopback the OAM cells. You configure OAM cell emulation on both PE routers, which emulates a VC by forming two unidirectional LSPs. You use the oam-ac emulation-enable command and the oam-pvc manage command on both PE routers to enable OAM cell emulation.

After you enable OAM cell emulation on a router, you can configure and manage the ATM VC in the same manner as you would a terminated VC. A VC that has been configured with OAM cell emulation can send loopback cells at configured intervals toward the local CE router. The endpoint can be either of the following:

•End-to-end loopback, which sends OAM cells to the local CE router.

•Segment loopback, which responds to OAM cells to a device along the path between the PE and CE routers.

The OAM cells include the following:

•Alarm indication signal (AIS)

•Remote defect indication (RDI)

These cells identify and report defects along a VC. When a physical link or interface failure occurs, intermediate nodes insert OAM AIS cells into all the downstream devices affected by the failure. When a router receives an AIS cell, it marks the ATM VC down and sends an RDI cell to let the remote end know about the failure.

Enabling OAM Cell Emulation for ATM AAL5 over MPLS

To enable OAM cell emulation on the PE routers, issue the oam-ac emulation-enable and oam-pvc manage commands in AToM VC configuration mode.

Specifying the Rate at Which AIS Cells Are Sent

The oam-ac emulation-enable command lets you specify the rate at which AIS cells are sent. The default is one cell every second. The range is 0 to 60 seconds.

Configuration Examples for OAM Cell Emulation

The following example enables OAM cell emulation on an ATM PVC:

Router# interface ATM 1/0/0

Router(config-if)# pvc 1/200 l2transport

Router(config-if-atm-l2trans-pvc)# oam-ac emulation-enable

Router(config-if-atm-l2trans-pvc)# oam-pvc manage

The following example sets the rate at which an AIS cell is sent to every 30 seconds:

Router# interface ATM 1/0/0

Router(config-if)# pvc 1/200 l2transport

Router(config-if-atm-l2trans-pvc)# oam-ac emulation-enable 30

Router(config-if-atm-l2trans-pvc)# oam-pvc manage

Verifying OAM Cell Emulation

The following show atm pvc command shows that OAM cell emulation is enabled and working on the ATM PVC:

Router# show atm pvc 5/500

ATM4/1/0.200: VCD: 6, VPI: 5, VCI: 500                    

UBR, PeakRate: 1                                         

AAL5-LLC/SNAP, etype:0x0, Flags: 0x34000C20, VCmode: 0x0 

OAM Cell Emulation: enabled, F5 End2end AIS Xmit frequency: 1 second(s) 

OAM frequency: 0 second(s), OAM retry frequency: 1 second(s)

OAM up retry count: 3, OAM down retry count: 5

OAM Loopback status: OAM Disabled

OAM VC state: Not ManagedVerified

ILMI VC state: Not Managed

InPkts: 564, OutPkts: 560, InBytes: 19792, OutBytes: 19680

InPRoc: 0, OutPRoc: 0

InFast: 4, OutFast: 0, InAS: 560, OutAS: 560

InPktDrops: 0, OutPktDrops: 0

CrcErrors: 0, SarTimeOuts: 0, OverSizedSDUs: 0

Out CLP=1 Pkts: 0

OAM cells received: 26

F5 InEndloop: 0, F5 InSegloop: 0, F5 InAIS: 0, F5 InRDI: 26

OAM cells sent: 77

F5 OutEndloop: 0, F5 OutSegloop: 0, F5 OutAIS: 77, F5 OutRDI: 0 

OAM cell drops: 0

Status: UP

How to Configure ATM Cell Relay over MPLS

This section contains the following concepts and procedures:

•Varieties of ATM Cell Relay over MPLS

•Configuring ATM Relay over MPLS with the Cisco 12000 Series Router Engine 2 8-Port OC-3 STM-1 ATM Line Card

•Configuring ATM Cell Relay over MPLS: VC Mode

•Configuring ATM Cell Relay over MPLS: VP Mode

•Configuring ATM Cell Relay over MPLS: Port Mode

•Configuring ATM Cell Relay over MPLS: Single Cell Relay

•Configuring ATM Cell Relay over MPLS: Packed Cell Relay

Varieties of ATM Cell Relay over MPLS

ATM cell relay over MPLS provides several configuration options:

•Virtual circuit (VC) mode, which enables you to configure ATM circuits on the permanent virtual circuits.

•Virtual path (VP) mode, which enables you to configure ATM circuits on the permanent virtual paths.

•Port mode, which enables you to configure ATM circuits on an interface.

•Single cell relay, which contains one ATM cell per packet.

•Packed cell relay, which contains multiple concatenated ATM cells per MPLS packet.

Table 1 shows the platforms that support the new ATM cell relay features. The following sections explain how to configure each feature.

Table 1 Platforms that Support the ATM Cell Relay Features

Transport Type	7200	7500	12000
VC mode, single cell relay	Y	Y	Y
VP mode, single cell relay	Y	Y	Y
Port Mode, single cell relay	N	N	Y
VC mode, packed cell relay	Y	Y	N
VP mode, packed cell relay	Y	Y	N

Configuring ATM Relay over MPLS with the Cisco 12000 Series Router Engine 2 8-Port OC-3 STM-1 ATM Line Card

In Cisco IOS Release 12.0(25)S, there were special instructions for configuring ATM cell relay on the Cisco 12000 series router with an engine 2 8-port OC-3 STM-1 ATM line card. The special configuration instructions are no longer needed. You no longer need to use the atm mode cell-relay command.

In Cisco IOS Release 12.0(25)S, when you configured the Cisco 12000 Series 8-Port OC-3 STM-1 ATM line card for ATM Cell Relay over MPLS, two ports were reserved. That is no longer true. Only one port is reserved now.

In addition, in Cisco IOS Release 12.0(25)S, if you configured an 8-port OC-3 STM-1 ATM port for ATM AAL5 over MPLS and then configured ATM single cell relay over MPLS on that port, the VCs and VPs for AAL5 on the port and its corresponding port were removed. Starting in Cisco IOS Release 12.0(26)S, this behavior no longer occurs. ATM AAL5 over MPLS and ATM single cell relay over MPLS are supported on the same port. The Cisco 12000 Series 8-Port OC-3 STM-1 ATM line cards now support, by default, the ATM single cell relay over MPLS feature in both virtual path (VP) and virtual circuit (VC) mode and ATM AAL5 over MPLS on the same port.

Configuring ATM Cell Relay over MPLS: VC Mode

Supported Platforms:

•Cisco 7200 series routers

•Cisco 7500 series routers

•Cisco 12000 series routers

Perform this task to configure ATM Cell Relay on the permanent virtual circuits.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface atmslot/port

4. pvc vpi/vci l2transport

5. encapsulation aal0

6. xconnect peer-router-id vcid encapsulation mpls

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 atmslot/port Example: Router(config)# interface atm1/0	Specifies an ATM interface.
Step 4	pvc vpi/vci l2transport Example: Router(config-if)# pvc 0/100 l2transport	Assigns a virtual path identifier (VPI) and virtual circuit identifier (VCI). The l2transport keyword indicates that the PVC is a switched PVC instead of a terminated PVC.
Step 5	encapsulation aal0 Example: Router(config-if-atm-l2trans-pvc)# encapsulation aal0	For ATM Cell Relay, this command specifies raw cell encapsulation for the interface. Make sure you specify the same encapsulation type on the PE and CE routers.
Step 6	xconnect peer-router-id vcid encapsulation mpls Example: Router(config-if-atm-l2trans-pvc)# xconnect 13.13.13.13 100 encapsulation mpls	Binds the attachment circuit to a pseudowire VC.

VC Mode Configuration Example

Example 1 shows the configuration for carrying single ATM cells over PVCs.

Example 1 VC Mode Configuration Example

PE1	PE2
mpls label protocol ldp mpls ldp router-id Loopback0 force ! interface Loopback0 ip address 12.12.12.12 255.255.255.255 ! interface ATM4/0 pvc 0/100 l2transport encapsulation aal0 xconnect 13.13.13.13 100 encapsulation mpls ! interface ATM4/0.300 point-to-point no ip directed-broadcast no atm enable-ilmi-trap pvc 0/300 l2transport encapsulation aal0 xconnect 13.13.13.13 300 encapsulation mpls	mpls label protocol ldp mpls ldp router-id Loopback0 force ! interface Loopback0 ip address 13.13.13.13 255.255.255.255 interface ATM4/0 pvc 0/100 l2transport encapsulation aal0 xconnect 12.12.12.12 100 encapsulation mpls ! interface ATM4/0.300 point-to-point no ip directed-broadcast no atm enable-ilmi-trap pvc 0/300 l2transport encapsulation aal0 xconnect 12.12.12.12 300 encapsulation mpls

Verifying ATM Cell Relay VC Mode

The following show atm vc command shows that the interface is configured for VC mode cell relay:

Router# show atm vc 7

ATM3/0: VCD: 7, VPI: 23, VCI: 100

UBR, PeakRate: 149760

AAL0-Cell Relay, etype:0x10, Flags: 0x10000C2D, VCmode: 0x0

OAM Cell Emulation: not configured

InBytes: 0, OutBytes: 0

Status: UP

Configuring ATM Cell Relay over MPLS: VP Mode

Supported Platforms:

•Cisco 7200 series routers

•Cisco 7500 series routers

•Cisco 12000 series routers

Virtual Path (VP) mode allows cells coming into a predefined permanent virtual path (PVP) on the ATM interface to be transported over the MPLS backbone to a predefined PVP on the egress ATM interface. You can use VP mode to send single cells or packed cells over the MPLS backbone.

To configure VP mode, you must specify the following:

•The VP is for transporting cell relay cells.

•The IP address of the peer PE router and the VC ID.

Perform this task to transport ATM cells over a PVP.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface atmslot/port

4. atm pvp vpi l2transport

5. xconnect peer-router-id vcid encapsulation mpls

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 atmslot/port Example: Router(config)# interface atm1/0	Defines the interface.
Step 4	atm pvp vpi l2transport Example: Router(config-if)# atm pvp vpi 1 l2transport	Specifies that the PVP is dedicated to transporting ATM cells. The l2transport keyword indicates that the PVP is for cell relay. Once you enter this command, you enter l2transport PVP submode. This submode is for Layer 2 transport only; it is not for regular PVPs.
Step 5	xconnect peer-router-id vcid encapsulation mpls Example: Router(cfg-if-atm-l2trans-pvp)# xconnect 10.0.0.1 123 encapsulation mpls	Binds the attachment circuit to a pseudowire VC. The syntax for this command is the same as for all other Layer 2 transports.

VP Mode Configuration Guidelines

When configuring ATM Cell Relay over MPLS in VP mode, use the following guidelines:

•You do not need to enter the encapsulation aal0 command in VP mode.

•One ATM interface can accommodate multiple types of ATM connections. VP cell relay, VC cell relay, and ATM AAL5 over MPLS can coexist on one ATM interface. On the Cisco 12000 series router, this is true only on the Engine 0 ATM line cards.

•If a VPI is configured for VP cell relay, you cannot configure a PVC using the same VPI.

•VP trunking (mapping multiple VPs to one emulated vc label) is not supported in this release. Each VP is mapped to one emulated VC.

•Each VP is associated with one unique emulated VC ID. The AToM emulated VC type is ATM VP Cell Transport.

•The AToM control word is supported. However, if a peer PE does not support the control word, it is disabled. This negotiation is done by LDP label binding.

•VP mode (and VC mode) drop idle cells.

VP Mode Configuration Example

The following example transports single ATM cells over a virtual path:

pseudowire-class vp-cell-relay

  encapsulation mpls

int atm 5/0 

    atm pvp 1 l2transport 

        xconnect 10.0.0.1 123 pw-class vp-cell-relay

Verifying ATM Cell Relay VP Mode

The following show atm vp command shows that the interface is configured for VP mode cell relay:

Router# show atm vp 1

ATM5/0  VPI: 1, Cell Relay, PeakRate: 149760, CesRate: 0, DataVCs: 1, CesVCs: 0, Status: 
ACTIVE

  VCD    VCI   Type   InPkts   OutPkts   AAL/Encap     Status

  6      3     PVC    0        0         F4 OAM        ACTIVE  

  7      4     PVC    0        0         F4 OAM        ACTIVE  

TotalInPkts: 0, TotalOutPkts: 0, TotalInFast: 0, TotalOutFast: 0,

TotalBroadcasts: 0 TotalInPktDrops: 0, TotalOutPktDrops: 0

Configuring ATM Cell Relay over MPLS: Port Mode

Supported Platforms:

•Cisco 12000 series routers

Port mode cell relay allows a single cell coming into an ATM interface to be packed into an MPLS packet and transported over the MPLS backbone to an egress ATM interface.

To configure port mode, you issue the xconnect command from an ATM main interface and specify the destination address and the VC ID. The syntax and semantics of the xconnect command are the same as for all other transport types. Each ATM port is associated with one unique pseudowire VC label.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface atmslot/port

4. xconnect peer-router-id vcid encapsulation mpls

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. •Enter your password if prompted.
Step 2