Koichi Asatani

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One of the main issues of mobile IPv6 is handover latency that causes service disruption time. Although plenty of proposals significantly reduce the service disruption time, they suffer from redundant routing that causes packet misordering and excess bandwidth consumption. In this paper, we propose a new scheme that minimizes the redundant routing during(More)
One of the main issues of Mobile IPv6 is handover latency that causes service disruption time. Although plenty of proposals significantly reduce the service disruption time, they suffer from redundant routing that causes packet misordering and bandwidth consumption during the process of inter-domain handover. In this paper, we propose R-MIP, a routing-aware(More)
The Internet real-time applications are growing rapidly, and available bandwidth estimation is required. Available bandwidth estimation methods by end host have been studied e.g. Pathload and pathChirp. These methods parameterize probe packets volume and observe the delay variation to estimate available bandwidth. In these methods, probe packets give heavy(More)
Call admission control (CAC) is essential for the QoS guarantee communications. VoIP services require QoS guarantee as the existing telephony services. This paper proposes a new CAC scheme for VoIP to achieve efficient use of network resources by adopting a dynamic routing and a routing history table. This scheme chooses the better route out of two(More)
The registration process stores presence information in the presence server, which includes ID for authorization, registered date and time, and location. The reference process loads the presence information using the ID as a search key. Safety confirmation service registers a user's presence and refers to his/her friend's presence. However, existing systems(More)
Uneven traffics may too much concentrate on specific nodes and the path requests will be blocked at these nodes in wavelength division multiplexing (WDM). This paper proposes a new load-balancing method applying link-cost adjustment based on betweenness centrality in WDM networks with wavelength converters. It is clarified that the proposed method(More)