Moon Jeong Kim

DHT-Based Mobile Service Discovery Protocol for Mobile Ad Hoc Networks

Service discovery to search for a service available in a mobile ad-hoc network is an important issue. Although mobile computing technologies grow ever more powerful and accessible, MANET, consisting of mobile devices without any fixed infrastructure, has such features as high mobility and resource constraints. In this paper, we propose an effective service discovery protocol which is based on the concept of peer-to-peer caching of service information and DHT-based forwarding of service requests to solve these problems. Neighboring information, such as services and power is shared not only through logical neighbors but also through physically nearby neighboring nodes. Our protocol is that physical hop counts and the number of messages exchanged have been significantly reduced, since it does not require a central lookup server and does not rely on multicasting and flooding. The results of the simulation show that our proposed scheme works very well on dynamic MANET.

An adaptive routing protocol for supporting reliable communication in wireless ad-hoc network environments

A multi-hop wireless ad-hoc network is a temporal network formed by a collection of wireless mobile nodes without the aid of any existing network infrastructure or centralized administration. Each mobile host participating in the multi-hop wireless ad-hoc network should also be willing to forward packets for other mobile hosts in the ad-hoc network. The proposed protocol, called DSMR protocol, supports seamless communication services between the mobile hosts within a multi-hop wireless ad-hoc network and provides fixed network services to the mobile hosts in multi-hop wireless ad-hoc network environments, if necessary. With the DSMR protocol, each mobile host need not broadcast routing messages periodically, and mobile hosts that want to send data packets can initiate route request and establishment procedures. In particular, the DSMR protocol makes faster route re-establishment possible by maintaining multiple paths in each mobile host, and the protocol also provides reliable communication environments.

Cross-Layer Service Discovery Using Multi-Path for Wireless Environments

Efficient service discovery mechanism is a crucial feature for the usability of a wireless ad-hoc network. A wireless ad-hoc network is a temporal network formed by a collection of wireless mobile nodes without the aid of any existing network infrastructure or centralized administration. We propose an efficient service discovery mechanism using link/node non-disjoint multi-path source routing protocol for pervasive environments. Multi-path routing techniques can operate more quickly and adaptively when route failure occurs. Cross-layer technique can reduce the number of messages because nodes perform to search a service and to find the route at once. Our scheme has advantages of not only multi-path routing protocol but also cross-layer service discovery. This scheme provides faster route recovery and lower route maintenance overhead by limiting the number of multiple routing paths and by maintaining link/node non-disjoint multi-path.

A nested token-based delegation scheme for cascaded delegation in mobile agent environments

In mobile agent environments, cascaded delegation occurs frequently among places due to the mobility of agents. Because the existing scheme considers only the delegation between two places which participate in migration of an agent, it is inadequate in the situation that needs cascaded delegation. In this paper, we propose a delegation scheme that provides agents with secure cascaded delegation. The proposed scheme achieves the goal by nesting each delegation token within the signed part of the next immediate delegation token. We prove that the proposed scheme is secure against the attack of replaying a message and the attack of substituting a delegation token.