Hitachi, Ltd.

Hitachi Communication Technologies, Ltd.

Nippon Telegraph and Telephone Corporation

Fujitsu Corporation

Nec Corporation

Hitachi Ulsi Engineering Corp.

Hitachi Communication System, Inc.

Yoshihiro Ashi

Yukio Nakano

Masahiko Mizutani

Masahiro Takatori

Masayuki Takase

Tohru Kazawa

Hideki Endo

Shinya Sasaki

Naohiro Sakakida

Hiroyuki Nakano

Satoshi Aoki

Shin Nishimura

Hironari Matsuda

Toru Kazawa

Keiji Tomooka

Ryoji Takeyari

Nobuyuki Yamamoto

Kenichi Sakamoto

Takayuki Kanno

Hiroyuki Fujita

Takahiko Kozaki

Atsushi Iwamura

Masanobu Kobayashi

Akihiko Tanaka

Tadayuki Kanno

Yusuke Yajima

Akihiko Takase

Takeshi Shibata

Shinobu Gohara

Hiromi Ueda

Kiyotaka Takahashi

Ryosuke Nishino

Shinya Fujioka

Toshiki Sugawara

Takashi Mori

Masaru Murakami

Taisuke Ueta

Junichirou Yanagi

Morihito Miyagi

Katsuyoshi Tanaka

Naohisa Hamaguchi

Kazutaka Sakai

Takao Fukushima

Yozo Oguri

Atsushi Kubotera

Taishi Shinagawa

Hiroki Koyama

Michael A Wright

Takashi Seki

Hideaki Tsushima

Kenji Takeda

Takafumi Chujo

Kazuhiro Watanabe

Shigeo Amemiya

Takeshi Yasuda

Masatoshi Shibasaki

Takumi Oishi

Norihiro Sakamoto

Ryuichi Ikematsu

Hiroaki Nakazawa

Takatoshi Kurano

Youichi Igarashi

Takaaki Toyama

Hiroshi Hashimoto

Kenji Fujihira

Yasuo Murakami

Yoshio Nogi

Haruhiko Matsunaga

Masafumi Kamakura

Masao Nakayama

Toshihiko Fujita

Kenji Akutsu

Takashi Nakashima

Yoshihiro Yano

Kouichi Asao

Yasuhiko Numagami

Shikou Matsushima

Keiichi Ishida

Norio Miyazaki

Kenji Tomooka

Ryoji Tateyari

Kyoji Takeyari

Ken Mutou

Noriko Saitoh

Daiji Mitsunaga

Kenichirou Tomizawa

Taichi Hiramatsu

Hideyuki Nakanishi

Shuuichi Maruyama

Hiroyuki Mukouyama

A data transport system comprises transport apparatus and at least one computer. The transport apparatus construct a second network coupled to a first network which is constructed by a communication apparatus. A logical path is built between a first transport apparatus and the computer. The first transport apparatus is configured to: hold management information, which associates identification information of a port with logical path identification information; refer to the management information to identify the logical path identification information that is associated with the port through which the control information has been received; and assign the identified logical path identification information to the control information, and transmit the control information over the logical path. The computer assigns the logical path identification information assigned to the control information to response information, and transmits the response information to the second network.

Data transport system, transmission method, and transport apparatus

In an extensive distribution system with no delay guarantee network used as a relay network, an influence of a fluctuation of a communication delay time is avoided to conduct a high-precision time synchronization. First and second delay control devices installed in junctions between communication networks and a relay network, respectively, have functions of retaining first and second time information, and setting a first relay network passing time of a first communication signal directed from a time dissemination device toward a time receiving device through a relay network, and a second relay network passing time of a second communication signal directed from the time receiving device toward the time dissemination device, respectively. In measurement of communication delay time of the first communication network and the second communication network prior to time synchronization, the first and second relay network passing times are unified in advance to exclude uncertainty of the communication time.

Communication system and time synchronization method

When a communication path between a user site and a dual-homed data center is made redundant, a communication between the user site and a server within a data center can be continued. An edge node DCE-1 of a data center-and edge nodes TPE-1, TPE-2 of a transport network are connected to each other by a link TPE-1-1 and a link TPE-2-1, respectively. The edge nodes TPE-3 and TPE-1, TPE-2 that hold a node AEof a user siteare set with an LSPof an active system, and an LSPof a backup system, respectively. One of the links is active, and the other link is backup, and the LSP of the TPE node having the active link in the LSPand the LSPis made active. The respective links are prioritized, and the links are switched to an active state in order from the links higher in the order of priority when a link failure or an LSP failure occurs.

Communication system, path switching method and communication device

A transmission device uses transmission delay time of reciprocation with the terminal and time information of the transmission device to create a correction value of time information of the terminal and transmits it to the terminal. The terminal includes expected arrival time information based on the time information of the terminal and the correction value received from the transmission device in a frame transmitted to the transmission device. The transmission device compares reception time of the frame with the expected arrival time information in the frame. If they match, the time information of the terminal synchronizes with the time information of the transmission device. If they do not match, the transmission device transmits a new correction value to the terminal. The terminal transmits a frame including expected arrival time information using the new correction value to the transmission device.

Communication system and its device

A transmission network system includes a network terminating device connected to a user terminal and an authentication information device connected to the network terminating device through a transmission network. The transmission network is connected to a reference clock that holds a reference time. The network terminating device includes a terminating internal clock that synchronizes with the reference clock, when receiving a first frame from the user terminal, generates a second frame including a time outputted from the terminating internal clock as a request time on the basis of the first frame, and transmits the second frame to the authentication information device. The authentication information device generates time authentication information based on the request time included in the received second frame, generates a third frame including the generated time authentication information, and transmits the third frame to the transmission network.

Transmission network system, transmission method, and authentication information device

A communication device on a time equivalence assurance network that guarantees the receiving sequence of packets sent to all users so that even if a user session is re-sent, a function operates to alleviate the resultant effects and make the send and receive timing approach the initial timing. An edge communication device on a provider network identifies the sessions of each user subscriber terminal, and stores and monitors the time information attached by a sequence information attachment function. Even if a packet is resent, the packet will at this time be resent with attached sequence information based on the past time originally attached to the packet, and not sequence information based on the current resending time.

Network system and communication device

Provided is a communication system which is provided with a plurality of communication devices and transfers a packet between the plurality of communication devices through a communication path. When a packet is looped back at any of the communication devices on the communication path to verify connectivity of the communication path, a first communication device of the plurality of communication devices stores, in a first region of header information of the packet, first information for designating the communication device at which the packet is looped back, further stores, in a second region of the header information of the packet, second information on a loopback point in the designated communication device at which the packet is looped back, and sends the packet to which the first information and the second information have been added.

Communication system and communication device

A shelf of a network synchronization device includes: a clock input reception unit which receives an input of a clock signal; a clock output unit which outputs a clock signal; a clock interruption detection unit which detects a clock interruption if the clock input reception unit does not receive a clock; an AIS signal detection unit which detects an AIS signal if the AIS signal is received through the clock input reception unit; an AIS signal generation unit which generates the AIS signal; an alarm control unit which outputs a predetermined alarm notification when the AIS signal detection unit does not detect the AIS signal if the clock interruption detection unit detects the clock interruption; and an output signal selection unit which outputs the AIS signal generated by the AIS signal generation unit to the clock output unit if the clock interruption detection unit detects the clock interruption.

Shelf of a network synchronization device, and network synchronization device

A packet transfer apparatus connects two networks of different protocols. The packet transfer apparatus, connected to a first communication network and a second communication network, performs the steps of: storing first destination correspondence information; receiving a packet of the first communication protocol; based on the first destination correspondence information, determining destination information of a packet of the second communication protocol corresponding to destination information of the received packet of the first communication protocol; generating the header of the packet of the second communication protocol, based on the determined destination information of the packet of the second communication protocol; converting the received one or more packets of the first communication protocol into one or more packets of the third communication protocol; and adding the generated header of the packet of the second communication protocol to the packets of the third communication protocol.

Packet transfer apparatus

An identifier management apparatus capable of setting identifier conversion information of a new user without affecting identifier conversion processings of other users, and an identifier management method. The identifier management apparatus converts an identifier given to communication data. Its memory stores multiple hash functions, output values of the hash functions corresponding to the respective plurality of hash functions, multiple entry tables that manage the identifier conversion information indicating a correspondence between the input identifier being an input value of the hash function and an output identifier obtained by converting the input identifier, and a management table for managing a setting status of the identifier conversion information in each entry table. When registering the new identifier conversion information in any entry table, its processor selects an entry table that should register new identifier conversion information depending on setting statuses of the identifier conversion information in the entry tables.

Apparatus and method for identifier management

It is ensured to prevent a user from misrepresenting a time stamp, and to send out packets in sequence in which the packets are accepted to all users who are geographically isolated from each other. A unique time stamp impartation function is realized by respective communication devices on a net inside an administrative responsibility range of a communication common carrier, hardly accessible by a user. If a packet with a time stamp imparted by a subscriber terminal, provided thereto, is received, the respective communication devices positioned on the net inside the administrative responsibility range nullify the relevant time stamp in order to prevent misrepresentation of the time stamp, by a user outside the administrative responsibility range, and restores the packet from the subscriber together with the time stamp when transferring the packet to the outside of the administrative responsibility range.

In order to specify a data discarding point in a network, provided is a network system for collecting, in the network including an access network and a transport network, pieces of statistical information including a traffic amount of the network, including: an access terminal coupled to the access network; and an edge node for interconnecting the access network and the transport network, in which: the access terminal is configured to: measure pieces of statistical information including a traffic amount in the access terminal; and notify the edge node of the measured pieces of statistical information; and the edge node collects the pieces of statistical information notified by the access terminal.

Network system, edge node, and access device

When data is disclosed to a plurality of users by using a transfer network and a transfer apparatus, data disclosure time control which cannot be adversely affected by the users is performed to reduce the difference in data disclosure time among the users. A transfer network system includes a distribution server serving as a data-distribution-source transfer apparatus, and a network terminal connected to distribution-destination user equipment. The distribution server and the network terminal each have a time keeping function and a time synchronization function for matching the time of the time keeping function with a master clock. The distribution server sends in advance disclosure data and disclosure time to the network terminal. When the time of the time keeping function of the network terminal matches the disclosure time, the network terminal sends the disclosure data to the user equipment.

Transfer apparatus, transfer network system, and transfer method

An interconnection between fully synchronous networks and next-generation frame communications networks is disclosed. A means of bidirectional frame format conversion between a synchronous multiplexing system and a logical multiplexing system is provided, along with a method of transmitting data between different networks on a path as if it were being transmitted in the same network. Further, when converting network control information in an STM network into data suitable for a packet network, even across the boundary of a synchronous multiplexing system and a logical multiplexing system, a unified communication management means is provided over the whole path.

System apparatus and method for interconnecting TDM and frame/packet communication networks

When multiple SDH/SONET frame are accumulated and then lower-order path information removed from multiple frames is multiplexed into the same packet to achieve better transmission efficiency during packetization, the delay for accumulating increases. Disclosed is a transmission device that packetizes an SDH/SONET lower-order path with timing which is an integer factor of 1 cycle of the SDH frame. In this case, the destination loads the same multiple lower-order path in one packet. The result is that delay time accompanying lower-order path packetization is kept to less than the time of 1 cycle of the SDH frame, and the efficiency with which lower-order paths are accommodated in packets is further increased. The result is that improved transmission efficiency is realized.

Transmission device with function of packetizing and transmitting

Growing community of inventors

Yokohama, Japan

Yoshihiro Ashi