Patent ID: 7694167

Claim:
At a subject node in a federation infrastructure of a ring of nodes configured for bi-directional routing, the ring of nodes including at least the subject node and a monitor node, the subject node having a clock, a method for monitoring the subject node for a failure, the method comprising: an act of the subject node generating a subject side time-to-live duration value for use in monitoring of the subject node; an act of the subject node sending an establish request to the monitor node, the establish request indicative of the subject node requesting that the monitor node monitor the subject node, the establish request including at least the subject side time-to-live duration value; an act of the subject node establishing an existing subject side time-to-die time based on the subject side time-to-live duration value and the time the establish request was sent, wherein the subject node's clock reaching the existing subject side time-to-die time, prior to receiving an establish grant from the monitor node, is an indication of the subject node having to transition to a failure state; an act of the subject node receiving an establish grant from the monitor node, the establish grant indicative of the monitor node monitoring the subject node; an act of the subject node sending a renew request to the monitor node prior to the subject node clock reaching the existing subject side time-to-die time; an act of the subject node receiving a renew grant from the monitor node subsequent to sending the renew request and prior to the subject node clock reaching the existing subject side time-to-die time, the renew grant message indicative of the monitor node continuing to monitor the subject node; an act of the subject node transitioning to a previously calculated updated subject side time-to-die time in response to receiving the renew grant, wherein the subject node clock reaching the updated subject side time-to-die time, prior to receiving another renew grant from the monitor node, is an indication of the subject node having to transition to a failure state.