Ldp Frr; Protocols; Ldp Configuration Task List - HP MSR2000 Configuration Manual

If a notification delay is configured, LDP notifies IGP of the LDP-IGP synchronization states in bulk
•
when one of the following events occurs:
LDP recovers to the status before the restart or switchover.
The maximum delay timer expires.

LDP FRR

A link or router failure on a path can cause packet loss until LDP establishes a new LSP on the new path.
LDP FRR enables fast rerouting to minimize the failover time. LDP FRR is based on IP FRR and is enabled
automatically after IP FRR is enabled.
You can use one of the following methods to enable IP FRR:
• Configure an IGP to automatically calculate a backup next hop.
Configure an IGP to specify a backup next hop by using a routing policy.
•
Figure 14 Network diagram for LDP FRR
As shown in
or it specifies a backup next hop through a routing policy. LDP creates a primary LSP and a backup LSP
according to the primary route and the backup route calculated by IGP. When the primary LSP operates
correctly, it forwards the MPLS packets. When the primary LSP fails, LDP directs packets to the backup
LSP.
When packets are forwarded through the backup LSP, IGP calculates the optimal path based on the new
network topology. When IGP route convergence occurs, LDP establishes a new LSP according to the
optimal path. If a new LSP is not established after IGP route convergence, traffic forwarding might be
interrupted. Therefore, HP recommends that you enable LDP-IGP synchronization to work with LDP FRR to
reduce traffic interruption.

Protocols

RFC 5036, LDP Specification

LDP configuration task list

Tasks at a glance
Enable LDP:
1. (Required.)
2. (Required.)
Figure 14, configure IP FRR on LSR A. The IGP automatically calculates a backup next hop
Enabling LDP globally
Enabling LDP on an interface
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