Graceful Restart Helper advertises to its LDP neighbors by carrying the fault tolerant (FT) session TLV in the LDP initialization message, assisting the LDP in preserving its IP forwarding state across the restart. The 7705 SAR recovery is self-contained and relies on information stored internally to self-heal.
Maximum recovery time is the time (in seconds) that the sender of the TLV would like the receiver to wait, after detecting the failure of LDP communication with the sender.
Neighbor liveness time is the time (in seconds) that the LSR is willing to retain its MPLS forwarding state. The time should be long enough to allow the neighboring LSRs to resynchronize all the LSPs in a graceful manner, without creating congestion in the LDP control plane.
Use the following syntax to configure graceful restart parameters:
config>router>ldp
[no] graceful-restart
[no] maximum-recovery-time interval
[no] neighbor-liveness-time interval
config>router>ldpconfig>router>ldp# graceful-restartconfig>router>ldp>graceful-restart# maximum-recovery- time 120
config>router>ldp>graceful-restart# neighbor-liveness- time 60
config>router>ldp# exitconfig>router# The following example displays the import policy configuration output.
ALU-1>config>router>ldp>graceful-restart# info
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maximum-recovery-time 120
neighbor-liveness-time 60
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ALU-1>config>router>ldp>graceful-restart#