Hitachi, Ltd.

Alaxala Networks Corporation

Hidehiro Fukushima

Shigeki Morimoto

Naoya Ikeda

Kenji Kawakita

Tohru Setoyama

Masato Tsukakoshi

Masashi Kamegaya

Kenichi Sakamoto

Takeshi Shibata

Osamu Takada

Tatsuya Watanuki

Toshihiko Murakami

Masatoshi Takihiro

Atsushi Kimoto

Nagayuki Hirota

Toshiyuki Kubo

Yoshihiro Kaya

Keisuke Kadowaki

A relay device comprises: a routing controller configured to perform learning of routing information, which includes area information used to identify a relay area of communication packets and a network address of one or more other relay devices, and to determine a relay route of the communication packets, based on the learnt routing information; and a relay module configured to send the communication packets received by the relay device to a destination address of the received communication packets, based on the determined relay route. When the relay device receives a disaster notification packet notifying of a disaster area and when the determined relay route includes the disaster area, the routing controller changes the relay route to an alternative relay route that does not include the disaster area.

Relay device, network system and computer program product

In a network relay router, a multicast routing protocol processing moduleA sequentially sends a join request message (CP) to a routerfunctioning as a rendezvous point via an interface, based on the settings of a multicast group address or destination address and a sender VRF name. The network relay routerreceives a multicast packet (DP) from the routervia the interfaceand acquires a sender address or source address of a transmission device SE from the received multicast packet. The network relay routersends a join request message (CP) via an interfaceon the side of the transmission device SE and receives a multicast packet via the interface. This establishes an optimum multicast route (MR) between the transmission device SE and the network relay router

Network relay apparatus and inter-network relay method

For continuing multicast data transfer according to path control information after being switched from an active status to a standby status, it is necessary that the standby status hold the same path control information as the active status. However, a synchronization of the path control information thereof is not guaranteed. To solve the above-mentioned problem, this invention provides a data transfer apparatus coupled to a network, including a plurality of interfaces for transmitting and receiving data, in which the data transfer apparatus is configured to: create transfer destination information for correlating a destination of the data with the interfaces for transmitting the data to be transmitted to the destination; and transmit, upon reception of multicast data via one of the interfaces before being judged that the transfer destination information has been created, the multicast data from at least one of the interfaces irrespective of the transfer destination information.

Network apparatus for redundant multicast

Packets of mobile communication protocol which a mobile terminal sends and receives are monitored and when it is detected that a mobile terminal to which a multicast data packet is transferred moved to another network, a multicast gateway apparatus connected to the moving destination network makes a group attend request and transfers the multicast data packet to the moved mobile terminal.

Method, apparatus and system for distributing multicast data

A multicast communication device receives data packets multicast for receiving terminals which terminals do not support multicast communication and that are requesting multicast data packets. The multicast communication device then forwards the data packets to the receiving terminals. Communication from the receiving terminal accessing the sending terminal sending data packets to obtain information is monitored. Based on the access contents, a join group request is issued for the group address used by the multicast delivery. The multicast communication device stores service information such as the address of the sending terminal and the destination address of data packets sent by the sending terminal. If the service to be accessed by the receiving terminal is present, multicast delivery of data packets is requested. The multicast communication device forwards received multicast data packets to the receiving terminal.

Device and system for multicast communication

A multiplex router device, having a multiplex configuration, is instrumental in reducing internal and external traffic flows for a routing protocol process that occurs at a time of system switchover. A data base integration module, in a route calculation unit in the active mode, stores network link-state information collected by a routing protocol packet transmission-reception module in a link-state data base, and at the same time sends the information to a route calculation unit, but does not send routing protocol information collected. In the route calculation unit in the standby mode, a data base integration module that received the network link-state information stores its contents into its own link-state data base. When a failure occurs in the route calculation unit in the active mode, the route calculation unit performs the routing protocol process by using the stored link-state data base.

System and method for using active and standby routers wherein both routers have the same ID even before a failure occurs

A router device facilitates management of connection of a manager and assures communication quality of each of the connections. The router device determines a communication quality required by the communication of the packet in reference to a protocol information, an application acknowledging information and a priority information, transmits the control packet having the determined communication quality set therein to another router device contained in the same connection and further performs a traffic control (a preferential processing of a packet or the like) satisfying a communication quality indicated by the transmitted or received control packet in respect to the packet of the aforesaid connection.

Router device and network system using the same

Multiplex router device comprising a function for controlling a traffic

An ATM switch for providing an electrical interconnection between a connection-oriented ATM LAN of an ATM system and a connectionless legacy LAN is provided. The ATM switch includes a switch fabric electrically connected to the ATM LAN, a segmentation and reassembly block electrically connected to the switch fabric, for providing an interchange between one of cells transmitted over the ATM LAN and a packet transmitted over the legacy LAN, a management and control block electrically connected to the switch fabric through the segmentation and control block so as to manage and control operations for electrical connections between networks, a first bridging/routing processor having a legacy LAN interface for providing electrical connections between the legacy LAN and the first bridging/routing processor, a second bridging/routing processor electrically connected to the switch fabric through at least one ATM interface, and a bus for providing electrical connections between the management and control block, the first bridging/routing processor and the second bridging/routing processor. A LAN emulation configuration server function for managing configurations of a plurality of virtual LAN segments on the ATM LAN, which are required upon LAN emulation, a LAN emulation server function for obtaining an address resolution to an ATM address from a media access address, and a broadcast and unknown server function for making a broadcast to a terminal in the LAN are provided so as to be distributed to the management and control block or the second bridging/routing processor.

Growing community of inventors

Fujisawa, Japan

Hidehiro Fukushima