Methods for Determining the Restoration Order of Base Nodes in the Virtual Segment Network

Virtual Segment (VS) is an architecture design for delay tolerant network to efficiently perform the store-carry-and-forward routing along traffic flows of vehicles on roadway networks. VS network consists of three types of node: Corresponding Node (CN), Relay Node (RN), and Base Node (BN). CN is a stationary node as the roles of a sender and a receiver of messages, RN is a movable node as a vehicle to relay the messages, and BN is a stationary gateway to the core backbone network connecting all the BNs as a reliable high-speed communication network. The VS network is considered to be effective for message forwarding in disaster situations since RNs are flexible to transfer messages between CNs and BNs. However, effects of breakdown of BNs by disaster have not been well studied even though the failure of message transfer between BNs seriously degrade the performance of the arrival rate of forwarding messages. In this paper, we investigate some disaster scenarios using our traffic simulator of vehicles and also our mathematical model of the VS network to simulate the effects of the disruption of BNs on the performance. We consider some methods to determine the restoration order of broken BNs and numerically compare the performance of the arrival rate. As a result, we found that the performance of the arrival rate is quickly recovered by the preferential restoration of frequently used BNs.