The value of vRtrLdpIfBackoffTime specifies the initial value
for the backoff interval.
The backoff interval is the time, in seconds, that LDP waits
after an LDP session setup has failed before it attempts to
setup the session again. After the LDP session startup fails
the first time, the backoff interval is set to the value of
vRtrLdpIfBackoffTime. Thereafter, if session startup fails
again the backoff interval increases exponentially.