Study on a Fast OSPF Route Reconstruction Method under Network Failures

OSPF (Open Shortest Path First), which is used widely on networks, has a Router Dead Interval problem. If a (backup) designated router has stopped operation due to failure, the OSPF routers await a hello packet acknowledgment for the router dead interval to recognize that the designated router has ceased the operation. The Router Dead Interval is 40 sec This interval time is not only long for many real-time applications but also involves huge buffering of data and a burst of traffic after the router reconstruction. To avoid the Router Dead Interval, we propose a fast method of designated router detection by enhanced OSPF. In this report, we show how our method reduces the route reconstruction time from 45 sec to 10 or less on OSPF networks.