Performance Evaluation of Virtual Segment Method Based on Actual Road Network Topology at the Time of the Great East Japan Earthquake

The message deliveries based on the store-carry-forward routing schemes, such as Epidemic Routing(ER), are one of useful methods for communication under challenged environments. However, these methods commonly have their own limitations in reach ability of messages to destinations and scalability. For example, as the distance to the destination increases, the delivery delay of a message between source and destination nodes generally becomes longer and even the reach ability decreases. To overcome these problems, the Virtual Segment(VS) method was proposed, which combines the ER method and a wired/wireless high-speed network connecting all base nodes(BN) located on the area. This can improve the reach ability and solve the scalability problem. In this paper, we evaluate the effectiveness of the VS method by simulation with the use of actual road network topology after the Great East Japan Earthquake in 2011. The results show that the VS method achieve higher successfully delivered probability and shorter delivery delay than the ER method, even if the traffic volume is much smaller than an usual one. It follows that the VS method is effective not only qualitatively but also quantitatively even in a challenged network environment such as in a disaster.