(Optional) Configuring an LDP Transport Address

An LDP session is established over a TCP connection. To set up an LDP session, two LSRs need to confirm the LDP transport address of each other and then set up a TCP connection.

Context

LDP transport addresses are used to set up a TCP connection and need to be configured on both nodes of a local LDP session. The default transport address is the loopback interface address used as an LSR ID.

If LDP sessions are to be established over multiple links connecting two LSRs, LDP-enabled interfaces of either LSR must use the default transport address or the same transport address. If multiple transport addresses are configured on an LSR, only one transport address can be used to establish only one LDP session.
A change in an LDP transport address will terminate an LDP session. Exercise caution when running the mpls ldp transport-address command.

Using the default LDP transport address is recommended.

Procedure

Access the system view.
```
system-view
```
Specify the interface to participate in MPLS forwarding.
```
interface interface-type interface-number
```
Specify an LDP transport address.
```
mpls ldp transport-address { interface-type interface-number | interface }
```
Either of the following settings can be used:
- interface-type interface-number: specifies the type and number of an interface. These parameters allow LDP to use the primary IP address of a specified interface as a transport address.
- interface: allows LDP to use the IP address of the current interface as a transport address.
The default transport address for a node on a public network is the local LSR ID of the current LDP session, and the default transport address for a node on a private network is the primary IP address of an interface on the node.