This read-create Unsigned32, in seconds and ranging 0-65535, sets how often this router, when it is the assert winner, resends PIM Assert messages on this interface, and it must be set less than rlPimInterfaceAssertHoldtime. It keeps the router's forwarder status refreshed on a shared multi-access segment. For example, setting this too close to rlPimInterfaceAssertHoldtime risks the assert winner's refresh messages arriving too late to prevent losers from re-triggering an assert election.