A service provider runs LDP with an IGP across their core. An intermittent physical link between routers P1 and P2 flaps several times per hour. Each flap causes the LDP session to tear down and all associated labels to be purged, triggering a full label re-exchange and brief traffic loss once the link recovers. The operator wants to keep the LDP session and its label bindings intact across short link outages, provided an alternate IGP path exists between the two LSRs. Which LDP feature should be configured to achieve this?