Author:
Hiroki Doi
Affiliation:
Central Research Institute of Electric Power Industry, Japan
Keyword(s):
OSPF, Router Dead Interval, Delay Time, Route, Designated Router.
Related
Ontology
Subjects/Areas/Topics:
Data Communication Networking
;
Fault Detection and Management
;
Routing and Flow Control in Lans, Wans and Pans
;
Sensor Networks
;
Signal Processing
;
Telecommunications
Abstract:
The Great East Japan Earthquake occurred onMarch 11, 2011. Many Japanese people and Japanese companies were damaged by the disaster. Also, network failures occurred over a wide area because many facilities of commercial ISPs (Internet Service Providers) were damaged. Thus, there is a need to reexamine the disaster estimation and reconstruct a robust network system against disasters in Japan. The network must have higher reliability and fast recovery. Although OSPF (Open Shortest Path First) is used widely on networks, it has a
router dead interval problem. If a (backup) designated router has stopped operation due to failure, the other OSPF routers miss the designated router and try to find it by multiple hello packets. The OSPF routers await a hello packet acknowledgment from the designated router for the router dead interval. After the router dead interval, those routers can recognize that the designated router has ceased the operation. The router dead interval is 40 seconds. This i
nterval 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 seconds to 10 or less on OSPF networks.
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