RSVP-TE graceful shutdown provides a method to reroute transit LSPs in a bulk fashion away from a node prior to maintenance of that node. A PathErr message with the error code ‟Local Maintenance on TE Link required Flag” (if the affected network element is a link) or the error code ‟Local node maintenance required” (if the affected network element is the node) is sent before the links or node are taken out of service.
When an LER receives the message, it performs a make-before-break on the LSP path to move the LSPs away from the links/nodes whose IP addresses are indicated in the PathErr message and reroute them. Affected link/node resources are flagged in the TE database so that other routers will signal LSPs using the affected resources only as a last resort.
Graceful shutdown can be enabled on a per-interface basis or on all interfaces on the node if the whole node must be taken out of service.