The value of vRtrLdpIfKeepAliveTimeout specifies the time interval,
in seconds, that LDP waits before tearing down a session. If no LDP
messages are exchanged during this time interval, the LDP session
is torn down. Generally the value of vRtrLdpIfKeepAliveTimeout is
configured to be 3 times the keepalive time (the time interval
between successive LDP keepalive messages).