## 1 Introduction  
The DTN (delay/disruption tolerant networking) [1; 2] is being studied intensively as a network that provides a means of communication when base stations in a mobile network are damaged by a disaster. However, there is a concern about whether a service that is not used in normal times can really work in an emergency. If we are to ensure that a DTN works in an emergency, it is desirable to promote general use of the DTN, so that it will also be used in normal times. Most studies on the DTN for use in times of disaster assume the use of mobile terminals owned by users or rescuers as relay nodes [3; 4; 5]. Since the DTN capability needs to be installed in these mobile terminals, any service that is designed only for use in times of disaster cannot be cost effective. If a DTN is to use devices that are not dedicated to networking, such as mobile terminals and vehicles, as relay nodes, it is important to use a routing protocol that does not impose a large processing load on relay nodes. DTN routing methods that do not require dedicated relay nodes include epidemic routing [6], spray and wait routing [7], location-based routing [8] and motion vector routing (MoVe) [8]. None of these sufficiently reduces the processing load on relay nodes. An existing routing that uses traveling nodes that are dedicated to relay nodes is the message ferry routing [9; 10; 11]. However, it has a problem with feasibility, because the DTN is dedicated to a specific purpose, and thus, the ferry nodes must travel to all nodes or clusters in the network. Many DTN protocols have also been proposed in the field of vehicular networks (VNs) [12; 13]. These protocols focus on use in intelligent transport systems (ITSs). As such, their application is limited to the promotion of and support for safe driving and P2P data communication between vehicles. They have been studied for unicast communication and dissemination. No studies on these protocols have been made for the application to point-to-multipoint, multicast communication.  
In this paper, we consider the use of a DTN for a day-to-day service of delivering content to a specific area and propose a routing that is based on information about the routes of fixed route-traveling nodes and the concept of \"destination area\". The destination of a bundle is specified not by a terminal identifier, but by an area, which is identified by its location information. This makes it possible to multicast data to multiple terminals in the destination area. Public transportation vehicles that travel fixed routes are used as relay nodes. We present an outbound-type bundle protocol, which is used by relay nodes when they have received a forwarding-bundle request from a sending terminal and try to determine whether the bundle can reach its destination area. Using simulation, we have evaluated the proposed routing in terms of the bundle arrival rate and factors that affect the network load on relay nodes, such as the number of bundle copies, the number of hops and the maximum required buffer size of relay nodes. The evaluation results indicate that the proposed routing is better than existing routing methods at reducing the network load. Section 2 summarizes existing routing methods. Section 3 proposes a new routing method that is based on information about the routes of fixed-route traveling nodes. Section 4 presents the outbound-type bundle protocol, which makes the proposed routing possible. Section 5 describes the simulation system used to evaluate the proposed routing and protocol. Section 6 presents the evaluation conditions used. Section 7 discusses evaluation results. Section 8 gives conclusions and future issues.