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Example: Configuring LDP-Signaled LSPs

This example shows how to create and configure LDP instances within an MPLS network.

Requirements

Before you begin:

  • Configure network interfaces. See Interfaces User Guide for Security Devices.

  • Configure an IGP across your network. (The LDP configuration is added to the existing IGP configuration and included in the MPLS configuration.)

  • Configure a network to use LDP for LSP establishment by enabling MPLS on all transit interfaces in the MPLS network.

    Note:

    Because LDP runs on top of an IGP such as IS-IS or OSPF, you must configure LDP and the IGP on the same set of interfaces.

Overview

To configure LDP-signaled LSPs, you must enable the MPLS family on all transit interfaces in the MPLS network and include all the transit interfaces under the [protocols mpls] and [protocols ldp] hierarchy levels.

In this example, you enable the MPLS family and create an LDP instance on all the transit interfaces. Additionally, you enable the MPLS process on all the transit interfaces in the MPLS network. In this example, you configure a sample network as shown in Figure 1.

Figure 1: Typical LDP-Signaled LSP Network diagram of LDP signaled LSPs between routers R1, R2, and R3 with loopback addresses 200.0.0.1, 200.0.0.2, 200.0.0.3 respectively.

Configuration

Procedure

CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, copy and paste the commands into the CLI at the [edit] hierarchy level and then enter commit from configuration mode.

R1

R2

R3

Step-by-Step Procedure

To enable LDP instances within an MPLS network:

  1. Enable the MPLS family on the transit interface on Router R1.

  2. Enable the MPLS process on the transit interface.

  3. Create the LDP instance on the transit interface.

Results

Confirm your configuration by entering the show command from configuration mode. If the output does not display the intended configuration, repeat the configuration instructions in this example to correct it.

For brevity, this show output includes only the configuration that is relevant to this example. Any other configuration on the system has been replaced with ellipses (...).

If you are done configuring the device, enter the commit command from the configuration mode to activate the configuration.