Protocols, Ldp configuration task list, Ldp messages – H3C Technologies H3C S12500-X Series Switches User Manual

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restarter goes down, it marks the FEC-label mappings learned from the session as stale and starts

the Reconnect timer received from the GR restarter.

After LDP completes restart, the GR restarter re-establishes an LDP session with the GR helper. If the
LDP session is not set up before the Reconnect timer expires, the GR helper deletes the stale

FEC-label mappings and the corresponding MPLS forwarding entries. If the LDP session is

successfully set up before the Reconnect timer expires, the GR restarter sends the remaining time of

the MPLS Forwarding State Holding timer as the LDP Recovery time to the GR helper.

After the LDP session is re-established, the GR helper starts the LDP Recovery timer.

The GR restarter and the GR helper exchange label mappings and update their MPLS forwarding
tables.
The GR restarter compares each received label mapping against stale MPLS forwarding entries. If

a match is found, the restarter deletes the stale mark for the matching entry. Otherwise, it adds a
new entry for the label mapping.
The GR helper compares each received label mapping against stale FEC-label mappings. If a
match is found, the helper deletes the stale mark for the matching mapping. Otherwise, it adds the

received FEC-label mapping and a new MPLS forwarding entry for the mapping.

When the MPLS Forwarding State Holding timer expires, the GR restarter deletes all stale MPLS
forwarding entries.

When the LDP Recovery timer expires, the GR helper deletes all stale FEC-label mappings.

Protocols

RFC 5036, LDP Specification

LDP configuration task list

Tasks at a glance

Enable LDP:

(Required.)

Enabling LDP globally

(Required.)

Enabling LDP on an interface