Canon Kabushiki Kaisha

Hitachi, Ltd.

Hitachi Communication Technologies, Ltd.

Hiroaki Nakazawa

Katsuhisa Ogawa

Naohiko Suzuki

Tetsuhiko Hirata

Atsushi Tachikawa

Yoshihiro Ashi

Makoto Hirota

Yasuo Murakami

Masahiko Mizutani

Hiroaki Miyata

Masashi Yano

Takashi Aso

Keisuke Takeuchi

Tsuyoshi Yagisawa

Kazue Kaneko

Kazuko Suzuki

Mitsuhiro Wada

Noriyuki Sueyoshi

Masaya Hayashi

Masahiko Kosaka

Daiji Mitsunaga

Hideyuki Nakanishi

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

A boundary node router determines whether a received packet includes a SIP message and a REGISTER message, and, if so, adds its router identifier to a REGISTER message which includes a user identifier and a user terminal identifier, sent from a user terminal, and sends the message to a SIP server. The SIP server has a user management table which stores the user terminal identifier, the router identifier of a router which serves the user terminal, and a predetermined Quality of Service type, in association with each user identifier. The SIP server extracts a user identifier, a user terminal identifier, and a router identifier from a received REGISTER message, and updates the user terminal identifier and the router identifier corresponding to the extracted user identifier, to the extracted user terminal identifier and the extracted router identifier.

Router and SIP server

A transmission apparatus connected to a first network obtains information on a device connected to a third network, to which a destination of communication with a communication device connected to a second network is connected, and transmits the obtained information to a device connected to the second network via the first network.

Transmission apparatus, method and program

A providing apparatus that provides information required for a secure communication to first and second devices includes a receiving unit for receiving candidates for parameters used for the secure communication from the first and second devices; a generating unit for generating the information required for the secure communication based on the candidates for the parameters received from the first and second devices; and a transmitting unit for transmitting the information required for the secure communication, generated by the generating unit, to the first and second devices.

Providing apparatus, providing method, communication device, communication method, and program

A providing apparatus provides information required for secure communication to first and second devices. The providing apparatus includes a receiving unit that receives a first parameter used by the first device for the secure communication and a second parameter used by the second device for the secure communication from a connection apparatus via which the first device is connected to the second device, a generating unit that generates the information required for the secure communication based on the parameters received from the connection apparatus, and a transmitting unit that transmits the information required for the secure communication, generated by the generating unit, to the first and second devices.

Providing apparatus, communication device, method, and program

An access server starts the individual collection of communication statistics information on each of LCP sessions upon the establishment of a data link, individually collects communication statistics information on each of NCP sessions established on the LCP session, notifies a RADIUS server of the statistics information on the LCP session when the data link is released, and notifies, when the NCP session is released, the RADIUS server of the statistics information on the released NCP session.

Access server with function of collecting communication statistics information

Upon reception of a query about the address of a server from a client, a DNS server sends a query about the address of that server to an external DNS server. The DNS server checks based on the address obtained from the external DNS server if connection to the server can be established. If connection to the server cannot be established, and the DNS server receives a query about the address of the server, the DNS server returns a response indicating that the address is not available. When the address is returned before the check process, the DNS sever sets an expiration time shorter than that of the address of the server obtained from the external DNS server as the expiration time of the address of the server.

Address query response method, program, and apparatus, and address notification method, program, and apparatus

There is provided an address translator having the functions to prevent, in the communications via the address translation, transmission of packets having no correct destination and transmission source addresses which will cause troubles in the networks and to urge an administrator take adequate measures for reception of the relevant packets. This address translator stores discriminator to discriminate temporary addresses. Moreover, when the original address is registered as the temporary address at the time of assignment of the temporary address of the receiving side host started when the name solution is performed, assignment is rejected to prevent transmission of packet from the transmitting side host by returning a response for name solution error to the transmitting side host. In addition, when transmission source address before translation and destination address after translation are registered as the temporary address, the received packet is discarded. Moreover, assignment of the temporary address is rejected and the packet is discarded, a message is transmitted to an alarm device or external host to notifying the event to an administrator.

Address translator and method for management of address translation rules

Router and sip server

A mobile data communication system capable of shortening the interruption time of communication includes an HA device, advertising routers, base stations, routers, and mobile terminal devices. Each base station advertises an address having '1' set in a different bit of an interface ID of a routing address. When a mobile terminal has received radio waves from a plurality of base stations in the vicinity of a boundary between cells, the mobile terminal combines a plurality of received routing addresses by logical summation and registers a resultant routing address with the HA device. As for a packet delivered from the HA device to the routing address and having '1' in a plurality of bits of the host section, a router resolves the address of the host section into destination addresses each having &#x201c;1&#x201d; in one bit, generates packets each having one of resultant addresses, and transmits the generated packets.

Mobile communication system

In a character provision service system for providing users with characters such as interface agents and virtual characters in virtual spaces on computers or in TV games, charges for use of a provided character is computed according to a motion made by the character. This system enables each user to easily purchase with security a character capable of moving according user's need, and also enables character data providers to collect charges according to motions made by provided characters and to provide various characters without anxiety about unauthorized use of the characters.

Growing community of inventors

Kanagawa, Japan

Hiroaki Nakazawa