Configuring LDP session protection
If two LDP peers have both a direct link and an indirect link in between, you can configure this feature to protect their LDP session when the direct link fails.
LDP establishes both a Link Hello adjacency over the direct link and a Targeted Hello adjacency over the indirect link with the peer. When the direct link fails, LDP deletes the Link Hello adjacency but still maintains the Targeted Hello adjacency. In this way, the LDP session between the two peers is kept available, and the FEC-label mappings based on this session are not deleted. When the direct link recovers, the LDP peers do not need to re-establish the LDP session or re-learn the FEC-label mappings.
When you enable the session protection feature, you can also specify the session protection duration. If the Link Hello adjacency does not recover within the duration, LDP deletes the Targeted Hello adjacency and the LDP session. If you do not specify the session protection duration, the two peers will always maintain the LDP session over the Targeted Hello adjacency.
LDP session protection is applicable only to IPv4 networks.
To configure LDP session protection:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter LDP view. | mpls ldp | N/A |
3. Enable the session protection feature. | session protection [ duration time ] [ peer peer-prefix-list-name ] | By default, session protection is disabled. |