Once a signaled LSP is enabled at the ingress LER, the router persistently attempts to establish the LSP through periodic retries until the LSP is successfully established. To maintain the forwarding states and resource reservations on the routers in an LSP, Path and Resv messages are exchanged between neighboring LSRs at regular intervals. When these refresh messages are not received on the routers in the LSP, the RSVP forwarding states and resource reservations are removed. You can also use refresh reduction to reduce RSVP message bandwidth and improve the dependability of RSVP paths and reservations states.