Virtual Segment: Store-Carry-Forward Relay-Based Support for Wide-Area Non-Real-time Data Exchange

In the Internet of the future, a flexible, dynamic combination of wireless and wired access networks is expected to be a key driver for enlarging the broadband communication service area. However, in general, the number of broadband wireless access points is limited due to their cost, and hence, they cannot cover the whole network. On the other hand, various message delivery schemes based on store-carry-forward routing with some extensions have been studied to support nonreal- time communication in sparse or intermittent networks. However, communication services based solely on the storecarry- forward schemes covering a large area are inefficient because the delay time for message delivery increases in proportion to the size of the service area. Therefore, to extend the communication service area with controllable performance in a cost-effective manner, the authors have proposed a concept of Virtual Segment (VS) in which global communication service is provided by combining a store-carry-forward scheme with broadband wireless/wired network infrastructures connected to the Internet to deploy the supplementary infrastructure. Along this line, in the present paper, the issues on the addressing and the message transfer methods in VS approach are considered which are essential for designing a practical framework for non-real-time, asynchronous data communication, especially for large-sized message transfer. A logical architecture for implementation is also presented. Finally, the message transmission methods are examined using computer simulation.