(Optional) Configuring a Policy for Triggering Transit LSP Establishment

A policy for triggering transit LSP establishment can be configured to allow LDP to use a specified route to establish a transit LSP.

Context

After MPLS LDP is enabled, LDP LSPs will be automatically established, leading to a large number of transit LSPs and resulting in resource wastes. A policy for triggering transit LSP establishment can be configured to allow LDP to only send Label Mapping messages upstream for routes that match specified conditions to establish a transit LSP. This reduces the number of unwanted LSPs and efficiently uses network resources.

Procedure

Access the system view.
```
system-view
```
Access the MPLS-LDP view.
```
mpls ldp
```
Configure a policy for triggering transit LSP establishment.
```
propagate mapping for ip-prefix ip-prefix-name
```
LDP uses all routes without filtering them to establish transit LSPs by default.

The policy for triggering transit LSP establishment cannot be modified during the LDP GR process.