For an L2TP tunnel this object represents the failover resync
mechanism:
disable(0) - Disable failover resync
failoverProtocol(1) - Use the L2TP Failover Protocol
silentFailover(2) - Use the JUNOSe Silent Failover Mechanism
failoverProtocolFallbackToSilentFailover(3) - (Default) Use the
L2TP Failover Protocol and fall back to Silent Failover.