—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-...