The mpls rsvp-te hello command in the MPLS view globally enables the Hello mechanism. The mpls rsvp-te hello command in the interface view enables the Hello mechanism on an interface after it is enabled in the MPLS view.
The undo mpls rsvp-te hello command in the interface view disables the Hello mechanism globally and on interfaces.
This command varies in transport and router modes. For detailed differences, see Differences Between Commands in Transport and Router Modes. This topic describes the command configuration in router mode.
By default, the RSVP Hello extension is disabled.
Usage Scenario
The Hello mechanism rapidly detects neighbor connectivity. Avoid overuse because it increases communication costs.
Prerequisites
RSVP-TE has been enabled using the mpls rsvp-te command in the MPLS view.
Precautions
The undo mpls rsvp-te hello command in the MPLS view disables the Hello function from all interfaces, disables GR on the local node, and deletes all sessions with the specified node ID.