Graceful Restart: Standard And Interface-Based - Cisco ASR 9000 Series Configuration Manual

Graceful Restart
• Control plane of a node fails but the node preserves its data forwarding states. This is called node failure.
The procedure for RSVP graceful restart is described in the "Fault Handling" section of RFC 3473, Generalized
MPLS Signaling, RSVP-TE Extensions. One of the main advantages of using RSVP graceful restart is recovery
of the control plane while preserving nonstop forwarding and existing labels.

Graceful Restart: Standard and Interface-Based

When you configure RSVP graceful restart, Cisco IOS XR software sends and expects node-id address based
Hello messages (that is, Hello Request and Hello Ack messages). The RSVP graceful restart Hello session is
not established if the neighbor router does not respond with a node-id based Hello Ack message.
You can also configure graceful restart to respond (send Hello Ack messages) to interface-address based Hello
messages sent from a neighbor router in order to establish a graceful restart Hello session on the neighbor
router. If the neighbor router does not respond with node-id based Hello Ack message, however, the RSVP
graceful restart Hello session is not established.
Cisco IOS XR software provides two commands to configure graceful restart:
• signalling hello graceful-restart
• signalling hello graceful-restart interface-based
By default, graceful restart is disabled. To enable interface-based graceful restart, you must first enable
Note
standard graceful restart. You cannot enable interface-based graceful restart independently.
Related Topics
Enabling Graceful Restart, on page 76
Enable Graceful Restart: Example, on page 100
Enable Interface-Based Graceful Restart: Example, on page 100
Cisco ASR 9000 Series Aggregation Services Router MPLS Configuration Guide, Release 4.3.x
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Implementing RSVP for MPLS-TE
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