MPLS LDP—Autoconfiguration

First Published: November 8, 2004
Last Updated: May 4, 2009

The MPLS LDP —Autoconfiguration feature enables you to globally configure Label Distribution Protocol (LDP) on every interface associated with a specified Interior Gateway Protocol (IGP) instance.

Finding Feature Information

For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the "Feature Information for MPLS LDP—Autoconfiguration" section.

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

Contents

•Restrictions for MPLS LDP—Autoconfiguration

•Information About MPLS LDP—Autoconfiguration

•How to Configure MPLS LDP—Autoconfiguration

•Configuration Examples for MPLS LDP—Autoconfiguration

•Additional References

•Feature Information for MPLS LDP—Autoconfiguration

Restrictions for MPLS LDP—Autoconfiguration

This feature has the following restrictions:

•If LDP is disabled globally, the mpls ldp autoconfig command fails and generates a console message explaining that LDP must first be enabled globally by means of the global mpls ip command.

•If the mpls ldp autoconfig command is configured for an IGP instance, you cannot issue the global no mpls ip command. To disable LDP, you must first issue the no mpls ldp autoconfig command.

•For interfaces running IS-IS processes, you can enable Multiprotocol Label Switching (MPLS) for each interface, using the router mode command mpls ldp autoconfig or mpls ldp igp autoconfig at the interface level.

•You specify that the default label distribution protocol is LDP for a router or for an interface. Tag Distribution Protocol (TDP) is not supported.

•The MPLS LDP—Autoconfiguration feature is not supported on traffic engineering tunnel interfaces.

Information About MPLS LDP—Autoconfiguration

You should understand the following concept before you configure the MPLS LDP—Autoconfiguration feature:

•MPLS LDP—Autoconfiguration Overview

MPLS LDP—Autoconfiguration Overview

To enable LDP, you should configure it globally and on each interface where it is needed. Configuring LDP on many interfaces can be time consuming.

The MPLS LDP—Autoconfiguration feature enables you to globally enable LDP on every interface associated with an IGP instance. This feature is supported on OSPF and IS-IS IGPs. Further, it provides a means to block LDP from being enabled on interfaces that you do not want enabled. The goal of the MPLS LDP—Autoconfiguration feature is to make configuration easier, faster, and error free.

You issue the mpls ldp autoconfig command to enable LDP on each interface that is running an OSPF or IS-IS process. If you do not want some of the interfaces to have LDP enabled, you can issue the no form of the mpls ldp igp autoconfig command on those interfaces.

How to Configure MPLS LDP—Autoconfiguration

This section contains the following procedures:

•Configuring MPLS LDP—Autoconfiguration with OSPF Interfaces (required)

•Disabling MPLS LDP—Autoconfiguration from Selected OSPF Interfaces (optional)

•Verifying MPLS LDP—Autoconfiguration with OSPF (optional)

•Configuring MPLS LDP—Autoconfiguration with IS-IS Interfaces (required)

•Disabling MPLS LDP—Autoconfiguration from Selected IS-IS Interfaces (optional)

Configuring MPLS LDP—Autoconfiguration with OSPF Interfaces

The following steps explain how to configure LDP for interfaces running OSPF processes.

SUMMARY STEPS

1. enable

2. configure terminal

3. mpls ip

4. mpls label protocol ldp

5. interface type slot/subslot/port[.subinterface-number]

6. ip address prefix mask

7. exit

8. router ospf process-id

9. network ip-address wildcard-mask area area-id

10. mpls ldp autoconfig [area area-id]

11. exit

12. 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 

mpls ip

Example:

Router(config)# mpls ip

Globally enables hop-by-hop forwarding.

Step 4 

mpls label protocol ldp

Example:

Router(config)# mpls label protocol ldp

Specifies LDP as the default label distribution protocol.

Step 5 

interface type slot/subslot/port[.subinterface-number]

Example:

Router(config)# interface POS0/3/0

Specifies the interface to configure and enters interface configuration mode.

Step 6 

ip address prefix mask

Example:

Router(config-if)# ip address 10.0.0.11 255.255.255.255

Assigns an IP address to the interface.

Step 7 

exit

Example:

Router(config-if)# exit

Exits interface configuration mode.

Step 8 

router ospf process-id

Example:

Router(config)# router ospf 1

Enables OSPF routing and enters router configuration mode.

Step 9 

network ip-address wildcard-mask area area-id

Example:

Router(config-router)# network 10.0.0.0 0.0.255.255 area 3

Specifies the interface on which OSPF runs and defines the area ID for that interface.

Step 10 

mpls ldp autoconfig [area area-id]

Example:

Router(config-router)# mpls ldp autoconfig area 3

Enables the MPLS LDP—Autoconfiguration feature to enable LDP on interfaces belonging to an OSPF process.

•If no area is specified, the command applies to all interfaces associated with the OSPF process. If an area ID is specified, then only interfaces associated with that OSPF area are enabled with LDP.

Step 11 

exit

Example:

Router(config-router)# exit

Exits router configuration mode and returns to global configuration mode.

Step 12 

exit

Example:

Router(config)# exit

Exits global configuration mode and returns to privileged EXEC mode.

Disabling MPLS LDP—Autoconfiguration from Selected OSPF Interfaces

When you issue the mpls ldp autoconfig command, all the interfaces that belong to an OSPF area are enabled for LDP. To remove LDP from some interfaces, use the no mpls ldp igp autoconfig command on those interfaces. The following configuration steps show how to disable LDP from some of the interfaces after they were configured with MPLS LDP—Autoconfiguration with the mpls ldp autoconfig command.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface type slot/subslot/port[.subinterface-number]

4. no mpls ldp igp autoconfig

5. exit

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 slot/subslot/port[.subinterface-number]

Example:

Router(config)# interface POS0/3/0

Specifies the interface to configure and enters interface configuration mode.

Step 4 

no mpls ldp igp autoconfig

Example:

Router(config-if)# no mpls ldp igp autoconfig

Disables LDP for that interface.

Step 5 

exit

Example:

Router(config-if)# exit

Exits interface configuration mode and returns to global configuration mode.

Step 6 

exit

Example:

Router(config)# exit

Exits global configuration mode and returns to privileged EXEC mode.

Verifying MPLS LDP—Autoconfiguration with OSPF

The following steps explain how to verify the MPLS LDP—Autoconfiguration feature.

SUMMARY STEPS

1. enable

1. show mpls interfaces [detail]

2. show mpls ldp discovery [detail]

3. exit

DETAILED STEPS

Step 1 enable

Use this command to enter privileged EXEC mode. Enter your password if requested. For example: 

Router> enable

Router#

Step 2 show mpls interfaces detail

The show mpls interfaces command lists the method that was used to enable LDP on an interface.

•If LDP is enabled by the mpls ldp autoconfig command, the output displays: 

IP labeling enabled (ldp):

   IGP config

•If LDP is enabled by the mpls ip command, the output displays: 

IP labeling enabled (ldp):

  Interface config

•If LDP is enabled by the mpls ip command and the mpls ldp autoconfig command, the output displays: 

IP labeling enabled (ldp):

  Interface config

  IGP config

The following example shows that LDP was enabled on the interface by both the mpls ip and mpls ldp autoconfig commands: 


Router# show mpls interfaces S2/0 detail 


Interface Serial2/0/0:

        IP labeling enabled (ldp):

          Interface config

          IGP config

        LSP Tunnel labeling enabled

        BGP labeling not enabled

        MPLS operational

        Fast Switching Vectors:

          IP to MPLS Fast Switching Vector

          MPLS Turbo Vector

        MTU = 1500

Step 3 show mpls ldp discovery

The show mpls ldp discovery details command also show how LDP was enabled on the interface. In the following example, LDP was enabled by both the mpls ip and mpls ldp autoconfig commands: 

Router# show mpls ldp discovery detail


Local LDP Identifier:

    10.11.11.11:0

    Discovery Sources:

    Interfaces:

        Serial2/0/0 (ldp): xmit/recv

            Enabled: Interface config, IGP config;

            Hello interval: 5000 ms; Transport IP addr: 10.11.11.11 

            LDP Id: 10.10.10.10:0

              Src IP addr: 10.0.0.1; Transport IP addr: 10.10.10.10

              Hold time: 15 sec; Proposed local/peer: 15/15 sec

Step 4 exit

Use this command to exit privileged EXEC mode and return to user EXEC mode. For example: 

Router# exit

Router>

Configuring MPLS LDP—Autoconfiguration with IS-IS Interfaces

The following steps explain how to configure the MPLS LDP—Autoconfiguration feature for interfaces running IS-IS processes.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface type slot/subslot/port[.subinterface-number]

4. ip address prefix mask

5. ip router isis

6. exit

7. mpls ip

8. mpls label protocol ldp

9. router isis

10. mpls ldp autoconfig [level-1 | level-2]

11. exit

12. 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 slot/subslot/port[.subinterface-number]

Example:

Router(config)# interface POS0/2/0

Specifies the interface to configure and enters interface configuration mode.

Step 4 

ip address prefix mask

Example:

Router(config-if)# ip address 10.50.72.4 255.0.0.0

Assigns an IP address to the interface.

Step 5 

ip router isis

Example:

Router(config-if)# ip router isis

Enables IS-IS for IP on the interface.

Step 6 

exit

Example:

Router(config-if)# exit

Exits interface configuration mode.

Step 7 

mpls ip

Example:

Router(config)# mpls ip

Globally enables hop-by-hop forwarding.

Step 8 

mpls label protocol ldp

Example:

Router(config)# mpls label protocol ldp

Specifies LDP as the default label distribution protocol.

Step 9 

router isis

Example:

Router(config)# router isis

Enables an IS-IS process on the router and enters router configuration mode.

Step 10 

mpls ldp autoconfig [level-1 | level-2]

Example:

Router(config-router)# mpls ldp autoconfig

Enables the LDP for interfaces belonging to an IS-IS process.

Step 11 

exit

Example:

Router(config-router)# exit

Exits router configuration mode and returns to global configuration mode.

Step 12 

exit

Example:

Router(config)# exit

Exits global configuration mode and returns to privileged EXEC mode.

Disabling MPLS LDP—Autoconfiguration from Selected IS-IS Interfaces

When you issue the mpls ldp autoconfig command, all the interfaces that belong to an IS-IS process are enabled for LDP. To remove LDP from some interfaces, you can use the no form of the mpls ldp igp autoconfig command on those interfaces. The following configuration steps show how to disable LDP from some of the interfaces after they were configured with the MPLS LDP—Autoconfiguration through the mpls ldp autoconfig command.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface type slot/subslot/port[.subinterface-number]

4. no mpls ldp igp autoconfig

5. exit

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 slot/subslot/port[.subinterface-number]

Example:

Router(config)# interface POS0/3/0

Specifies the interface to configure and enters interface configuration mode.

Step 4 

no mpls ldp igp autoconfig

Example:

Router(config-if)# no mpls ldp igp autoconfig

Disables LDP for that interface.

Step 5 

exit

Example:

Router(config-if)# exit

Exits interface configuration mode and returns to global configuration mode.

Step 6 

exit

Example:

Router(config)# exit

Exits global configuration mode and returns to privileged EXEC mode.

Configuration Examples for MPLS LDP—Autoconfiguration

The following sections show examples for MPLS LDP—Autoconfiguration with OSPF and IS-IS processes.

•MPLS LDP—Autoconfiguration Examples with OSPF

•MPLS LDP—Autoconfiguration Examples with IS-IS

MPLS LDP—Autoconfiguration Examples with OSPF

The following configuration commands enable LDP for OSPF process 1 area 3. The mpls ldp autoconfig area 3 command and the OSPF network commands enable LDP on interfaces POS0/0/0, POS0/1/0, and POS1/1/0. The no mpls ldp igp autoconfig command on interface POS1/0/0 prevents LDP from being enabled on interface POS1/0/0, even though OSPF is enabled for that interface. 

configure terminal

 interface POS0/0/0

  ip address 10.0.0.1

!

 interface POS0/1/0

  ip address 10.0.1.1

!

 interface POS1/1/0

  ip address 10.1.1.1

!

 interface POS1/0/0

  ip address 10.1.0.1

  exit

!

 router ospf 1

  network 10.0.0.0 0.0.255.255 area 3

  network 10.1.0.0 0.0.255.255 area 3

  mpls ldp autoconfig area 3

  exit

 interface POS1/0/0

  no mpls ldp igp autoconfig

MPLS LDP—Autoconfiguration Examples with IS-IS

The following example shows the configuration of MPLS LDP—Autoconfiguration on interfaces POS0/2/0 and POS0/3/0, which are running IS-IS processes: 

configure terminal

 interface POS0/2/0

  ip address 10.0.0.1

  ip router isis

!

 interface POS0/3/0

  ip address 10.1.1.1

  ip router isis

  exit

 mpls ip

 mpls label protocol ldp

 router isis 

  mpls ldp autoconfig

Additional References

The following sections provide references related to the MPLS LDP—Autoconfiguration feature.

Related Documents

Related Topic
Document Title

MPLS LDP

MPLS Label Distribution Protocol

The MPLS LDP-IGP Synchronization feature

MPLS LDP-IGP Synchronization

MPLS LDP commands

Cisco IOS Multiprotocol Label Switching Command Reference

Configuring integrated IS-IS

Integrated IS-IS Routing Protocol Overview

IS-IS commands

Cisco IOS IP Routing Protocols Command Reference

Configuring OSPF

Configuring OSPF

OSPF commands

Cisco IOS IP Routing Protocols Command Reference


Standards

Standard
Title

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

—


MIBs

MIB
MIBs Link

MPLS LDP MIB

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

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


RFCs

RFC
Title

RFC 3036

LDP Specification

RFC 3037

LDP Applicability


Technical Assistance

Description
Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

http://www.cisco.com/techsupport


Feature Information for MPLS LDP—Autoconfiguration

Table 1 lists the features in this module and provides links to specific configuration information.

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

Note Table 1 lists only the Cisco IOS XE software release that introduced support for a given feature in a given Cisco IOS XE software release train. Unless noted otherwise, subsequent releases of that Cisco IOS XE software release train also support that feature.

Table 1 Feature Information for MPLS LDP—Autoconfiguration 

Feature Name
Releases
Feature Information

MPLS LDP—Autoconfiguration

Cisco IOS XE Release 2.1

This feature enables you to globally configure LDP on every interface associated with a specified Interior Gateway Protocol (IGP) instance.

The following sections provide information about this feature:

•MPLS LDP—Autoconfiguration Overview

•Configuring MPLS LDP—Autoconfiguration with OSPF Interfaces

•Disabling MPLS LDP—Autoconfiguration from Selected OSPF Interfaces

•Verifying MPLS LDP—Autoconfiguration with OSPF

•Configuring MPLS LDP—Autoconfiguration with IS-IS Interfaces

•Disabling MPLS LDP—Autoconfiguration from Selected IS-IS Interfaces

•Configuration Examples for MPLS LDP—Autoconfiguration

In Cisco IOS XE Release 2.1, this feature was implemented on the Cisco ASR 1000 Series Aggregation Services Router.

The following commands were introduced or modified: debug mpls ldp autoconfig, mpls ldp autoconfig, mpls ldp igp autoconfig, show isis mpls ldp, show mpls ldp discovery.


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