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Tomohiro INOUE Takayuki NAKAMURA Motonori NAKAMURA Masayasu YAMAGUCHI
Communications in locally structured wireless networks, such as ad hoc networks, will play an important role for network services and applications in the ubiquitous networking environments of the future. Most of the time, however, mobile networks are used in much the same way as fixed networks: most of the time, mobile terminals merely access information which is stored in the backbone network. Applications based on the local exchange of information gathered or generated by mobile terminals will open up many novel possibilities. A new online storage system named CAOSS facilitates such exchange and constitutes a building block for various new applications. CAOSS is a server-less system that provides high availability of data in mobile and wireless network environments. We describe CAOSS and its application in a mobile video-information-sharing system named GT. Thanks to the good performance of CAOSS, the GT system gives users a convenient and easy way to share and accumulate video data in a wireless environment. We confirm that CAOSS has strong enough performance to deal with large volumes of video data.
Shigeo URUSHIDANI Shunji ABE Kenjiro YAMANAKA Kento AIDA Shigetoshi YOKOYAMA Hiroshi YAMADA Motonori NAKAMURA Kensuke FUKUDA Michihiro KOIBUCHI Shigeki YAMADA
This paper describes an architectural design and related services of a new Japanese academic backbone network, called SINET5, which will be launched in April 2016. The network will cover all 47 prefectures with 100-Gigabit Ethernet technology and connect each pair of prefectures with a minimized latency. This will enable users to leverage evolving cloud-computing powers as well as draw on a high-performance platform for data-intensive applications. The transmission layer will form a fully meshed, SDN-friendly, and reliable network. The services will evolve to be more dynamic and cloud-oriented in response to user demands. Cyber-security measures for the backbone network and tools for performance acceleration and visualization are also discussed.
Shigeya SUZUKI Motonori NAKAMURA
Domain Name System--DNS is a key service of the Internet. Without DNS, we cannot use any useful Internet applications. At the beginning of the Internet, email or file transfer applications were provided. DNS provides key service to them--resource discovery. Nowadays, there are broad range of software making use of DNS as basis of their application. In this paper, we explain the evolution of DNS, how DNS works and recent activities including operational issues. Then, we describe EPC network which make use of RFID to bridge real world and the Internet, and how DNS helps to organize EPC network.
Hiroshi ESAKI Naoaki YAMANAKA Youki KADOBAYASHI Kaori MAEDA Kenichi NAGAMI Motonori NAKAMURA Koji OKAMURA Atsushi SHIONOZAKI Suguru YAMAGUCHI
Hiroshi ESAKI Naoaki YAMANAKA Youki KADOBASHI Kaori MAEDA Kenichi NAGAMI Motonori NAKAMURA Koji OKAMURA Atsushi SHINOZAKI Suguru YAMAGUCHI
Yutaka ARAKAWA Keiichiro KASHIWAGI Takayuki NAKAMURA Motonori NAKAMURA
The number of networked devices of sensors and actuators continues to increase. We are developing a data-sharing mechanism called uTupleSpace as middleware for storing and retrieving ubiquitous data that are input or output by such devices. uTupleSpace enables flexible retrieval of sensor data and flexible control of actuator devices, and it simplifies the development of various applications. Though uTupleSpace requires scalability against increasing amounts of ubiquitous data, traditional load-distribution methods using a distributed hash table (DHT) are unsuitable for our case because of the ununiformity of the data. Data are nonuniformly generated at some particular times, in some particular positions, and by some particular devices, and their hash values focus on some particular values. This feature makes it difficult for the traditional methods to sufficiently distribute the load by using the hash values. Therefore, we propose a new load-distribution method using a DHT called the dynamic-help method. The proposed method enables one or more peers to handle loads related to the same hash value redundantly. This makes it possible to handle the large load related to one hash value by distributing the load among peers. Moreover, the proposed method reduces the load caused by dynamic load-redistribution. Evaluation experiments showed that the proposed method achieved sufficient load-distribution even when the load was concentrated on one hash value with low overhead. We also confirmed that the proposed method enabled uTupleSpace to accommodate the increasing load with simple operational rules stably and with economic efficiency.