Abstract: A data generating device is installed more upstream than a switching device for switching based on data of a first layer. The data generating device reads forward management information relating to a forwarding process of forward data from data of a second layer higher than the first layer, determines one or more clients corresponding to destinations of the forward data on the basis of the forward management information, and generates the same number of pieces of transmission data as the number of identified clients, and forwards each of the pieces of transmission data to the switching device in order to transmit the transmission data to each of the clients.

Abstract: In a network relaying method and device at a time of distributing data from a server to a client by multicast, join/leave information transmitted by the client to a multicast group is discriminated, the join/leave information of the client is processed into multicast join/leave notifying information and the multicast join/leave notifying information is transferred to the server.

Abstract: A multicast processing section constructs, when it is determined that a received packet is a packet on a multicast packet and multicast group management protocol, a table showing a correlation between a host device and a multicast group in a port number-multicast physical address correlation storing section as well as in a multicast router-connected port storing section according to the received packet, and controls to transfer a packet for each multicast group between a multicast router and host devices according to the table.

Abstract: A multicast processing section constructs, when it is determined that a received packet is a packet on a multicast packet and multicast group management protocol, a table showing a correlation between a host device and a multicast group in a port number-multicast physical address correlation storing section as well as in a multicast router-connected port storing section according to the received packet, and controls to transfer a packet for each multicast group between a multicast router and host devices according to the table.

Abstract: A multicast processing section constructs, when it is determined that a received packet is a packet on a multicast packet and multicast group management protocol, a table showing a correlation between a host device and a multicast group in a port number-multicast physical address correlation storing section as well as in a multicast router-connected port storing section according to the received packet, and controls to transfer a packet for each multicast group between a multicast router and host devices according to the table.

Abstract: A Multicast processing section constructs, when it is determined that a received packet is a packet on a multicast packet and multicast group management protocol, a table showing a correlation between a host device and a multicast group in a port number-multicast physical address correlation storing section as well as in a multicast router-connected port storing section according to the received packet, and controls to transfer a packet for each multicast group between a multicast router and host devices according to the table.

Abstract: A multicast processing section constructs, when it is determined that a received packet is a packet on a multicast packet and multicast group management protocol, a table showing a correlation between a host device and a multicast group in a port number-multicast physical address correlation storing section as well as in a multicast router-connected port storing section according to the received packet, and controls to transfer a packet for each multicast group between a multicast router and host devices according to the table.

Abstract: A network system, enabling the quality of the data to be ensured and efficient use can be made of the network, including at least one network relay apparatus provided with a discriminating unit for discriminating the type of data transmitted, a selecting unit for selecting the optimal route for each string of data in accordance with the discriminated type and destination, and a holding unit for holding the optimal routing information for each type of data and destination and sending received data toward the optimal route.

Abstract: In a delay failure test circuit, a delay failure test between two clock domains among a plurality of clock domains having different operation clock rates is performed. The delay failure test circuit inputs, to a first clock domain, a clock signal having only a launch edge for transferring data from the first clock domain to a second clock domain, and to input, to the second clock domain, a clock signal having only a capture edge for capturing the data.

Abstract: In a network system comprising an upper relay and a plurality of lower relays connected to the upper relay with working links, the lower relays are connected with redundant links, and communication is performed through the redundant links when the working links are unavailable. Also, frames passing through a same lower relay are distributed and transmitted to the working link and the detour path (working link—lower relay—redundant link).

Abstract: In a wireless LAN system chiefly using a millimeter wave, a satellite station is provided with an active phased planar-array antenna, the radiating directivity characteristic of which can be freely changed. When a master station receives a control frame transmitted from the satellite station prior to the commencement of normal communication, the master station transmits a carrier wave. The satellite station determines such a directivity characteristic of an antenna as to receive this carrier wave with the strongest intensity, and fixes the characteristic. Thus, an optimal communication environment can be secured. When the number of errors in a received data frame or the receiving electric field intensity received by the satellite station in normal communication is inferior to a respective predetermined threshold, the deterioration of the communication environment can be coped with by determining again.

Abstract: A communication device connectable to an IP network includes a congestion monitor unit monitoring whether the communication device is congested, and a congestion information creating unit creating congestion information concerning a congested state of the communication device when the congestion monitor unit detects the congested state thereof, the congestion information being sent to other devices connected to the IP network.

Abstract: An IP communications network system comprises a first QoS guaranteeing apparatus including a distinguishing unit for classifying target traffics in order to guarantee, based on a QoS guarantee protocol, a quality of a set of specified data packets accordant with a specified condition among data packets transmitted from a multiplicity of data communications terminals, an encapsulating unit for encapsulating the specified data packets defined as a QoS guarantee target on the basis of addresses of QoS guaranteeing apparatuses existing on the sides opposite to each other in a QoS guarantee target area in an IP packet switching network so that a set of the traffics appear as if being one session, and a resource reserving unit for reserving resources in accordance with the QoS guarantee protocol with respect to the set of encapsulated specified data packets. With this architecture, the QoS as to a delay, etc.

Abstract: In a network relaying method and device at a time of distributing data from a server to a client by multicast, join/leave information transmitted by the client to a multicast group is discriminated, the join/leave information of the client is processed into multicast join/leave notifying information and the multicast join/leave notifying information is transferred to the server.

Abstract: There are disclosed a network routing system and a routing apparatus. In a network having one routing apparatus to which one or more communication devices are connected, and another routing apparatus to which one or more communication devices are connected, a network routing system reserves a network resource using a service quality set-up protocol with bit sequence between these two routing apparatuses.

Abstract: A data generating device is installed more upstream than a switching device for switching based on data of a first layer. The data generating device reads forward management information relating to a forwarding process of forward data from data of a second layer higher than the first layer, determines one or more clients corresponding to destinations of the forward data on the basis of the forward management information, and generates the same number of pieces of transmission data as the number of identified clients, and forwards each of the pieces of transmission data to the switching device in order to transmit the transmission data to each of the clients.

Abstract: In a network system comprising an upper relay and a plurality of lower relays connected to the upper relay with working links, the lower relays are connected with redundant links, and communication is performed through the redundant links when the working links are unavailable. Also, frames passing through a same lower relay are distributed and transmitted to the working link and the detour path (working link—lower relay—redundant link).

Abstract: A device for multicast-session management provided in a network including one or more servers and a plurality of clients includes a data-exchange interface which receives an original data flow from a server, and multicasts a multicast data flow to the network, a usable-multicast-address-registration unit which stores therein usable multicast addresses, and a destination-address-conversion unit which converts a destination address of the original data flow into a multicast address, the multicast address being selected from the usable multicast addresses stored in said usable-multicast-address-registration unit, wherein said data-exchange interface multicasts the original data flow having the multicast address as the multicast data flow.

Abstract: A network system, enabling the quality of the data to be ensured and efficient use can be made of the network, including at least one network relay apparatus provided with a discriminating unit for discriminating the type of data transmitted, a selecting unit for selecting the optimal route for each string of data in accordance with the discriminated type and destination, and a holding unit for holding the optimal routing information for each type of data and destination and sending received data toward the optimal route.

Abstract: A multicast processing section constructs, when it is determined that a received packet is a packet on a multicast packet and multicast group management protocol, a table showing a correlation between a host device and a multicast group in a port number-multicast physical address correlation storing section as well as in a multicast router-connected port storing section according to the received packet, and controls to transfer a packet for each multicast group between a multicast router and host devices according to the table.