Configuring LDP Graceful Restart

The graceful restart mechanism minimizes the negative effect on MPLS forwarding across an LSR restart by enabling neighbors to wait for the LSR to restart and causing the LSR itself to restart gracefully.

Note: Successful operation of LDP graceful restart requires that stateful SRP switchover (high availability) be configured on the router. Although you can configure LDP graceful restart if stateful SRP switchover is not configured on the router, the graceful restart capability will not function.

To configure LDP graceful restart:

  1. Enable LDP graceful restart and graceful restart helper mode.
    host1(config)#mpls ldp graceful-restart
  2. (Optional) Specify the length of time you want the neighbors to wait for the gracefully restarting router to resume sending LDP messages to neighbors after the LDP connection between them fails.
    host1(config)#mpls ldp graceful-restart reconnect-time 130
  3. (Optional) Specify the length of time the router retains its MPLS forwarding state across a restart.
    host1(config)#mpls ldp graceful-restart recovery-time 150
  4. (Optional) Specify the maximum length of time that the router waits for a neighbor to complete a graceful LDP restart after the LDP session is reestablished.
    host1(config)#mpls ldp graceful-restart timers max-recovery 150
  5. (Optional) Specify the length of time the router waits for a neighbor to reestablish the LDP session.
    host1(config)#mpls ldp graceful-restart timers neighbor-liveness 150

Note: For information about configuring hold timers for LDP graceful restart in scaled environments, see the Configuring Hold Timers for Successful Graceful Restart in Scaled Scenarios section in the JunosE BGP and MPLS Configuration Guide

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