Abstract: A loop locating apparatus and method enabling simple and fast identification of a Layer 3 loop fault occurring in a network, wherein, when the possibility of a Layer 3 loop is detected, a loop locating command function unit makes a packet transmission/reception function unit send a series of inspection packets (Pis) with successively incremented TTLs and monitors the return packets (te) of the inspection packets (Pis) by a return number counting function unit and wherein a loop location decision function unit finds the routers returning packets (te) with remarkably larger return numbers than the others and identifies the routers with return numbers over a predetermined threshold as the location of occurrence of the loop.

Abstract: A network monitoring device that monitors a network state, includes a receiving unit that receives a packet passing through the network; a processing unit that performs analysis of the network state with respect to the packet received; and a determining unit that determines whether a failure has occurred in the network, based on the result obtained by the processing unit.

Abstract: Disclosed is a network system capable of transferring data at a high speed between multicast-supported networks via a L2 network. The network system includes a multicast-unsupported L2 network, two multicast-supported network, two gateway devices for connecting one of the multicast-supported networs to the multicast-unsupported L2 network, and each of witch is capble of assembling, when a multicast data packet is transmitted from the side of thet multicast-supported network, a L2-network packet in which a destination MAC address of the multicast data packet is translated into a MAC address of the other gateway device, and transmitting the L2-network packet over the L2 network.

Abstract: The invention relates to a package starting control device determining a moment and a sequence of starting a package corresponding to an individual wavelength to be wavelength-division-multiplexed in a wavelength division multiplex transmission device. An object of the invention is to provide a package starting control device capable of effectively increasing or decreasing the number of wavelengths at low cost without changing a basic structure drastically.

Abstract: An intensive management apparatus for managing a time-sharing multiplexing network, comprises: a path-information-creating unit for creating path information including a group identifier, termination information of terminating connection points, a path management number assigned to a path connecting the terminating connection points at which time slots in a communication apparatus are allocated and an allocated-time-slot number; a time-slot-allocating unit for creating time-slot-allocation information describing allocation of the time slots to a path identified by the path management number included in the time-slot-allocation information for each of the terminating connection points; a path-information-checking unit for forming a judgment on validity of each of a plurality of paths identified by the same group identifier assigned to a path-information group comprising pieces of path information describing the paths on the basis of the path information; and a result display unit for displaying results of the

Abstract: A multicast network system is provided with a multicast network unit that delivers data between independent multicast network domains. The multicast network unit includes an extraction part for extracting a multicast delivery destination address from received data, a holder part for holding conversion data where the multicast delivery destination address corresponds to a delivery source address, and a judgment part for judging whether the multicast delivery destination address is held and outputting the result of a judgment. The multicast network unit also includes a filtering part which, when the result of the judgment is holding, converts the multicast delivery source address to an arbitrary delivery destination address and, when it is non-holding, discards the received data. The multicast network unit further includes a transmitter part for transmitting data containing the converted multicast address to the domain.

Abstract: A monitoring apparatus and apparatuses to be monitored each have an address holding unit which holds the address of a group to which each apparatus belongs. A data frame to be transmitted between the monitoring apparatus and each of the apparatuses to be monitored includes an identifier which specifies communication between two apparatuses or group broadcast. When the identifier specifies the group broadcast, a group address is put in the data frame. In this manner, a large number of apparatuses which form a large-scale network can be divided into groups, and the group broadcast can be carried out when a plurality of monitoring apparatuses are used for monitoring the apparatuses, thereby eliminating the need of polling.

Abstract: A transmitter equipped with a plurality of transmission path ports and a relay section. The relay section has a routing table and a router. In the routing table, information about the relay of the received packet to one of the transmission path ports connected to a relay transmission path is stored, correlated with both a port identifier of each the transmission path port and the source address of the transmitter that transmitted the packet. The router extracts the port identifier of the transmission path port that received the packet and the source address contained in the received packet, and routes the received packet to the transmission path port connected to the relay transmission path by referring to the routing table for the extracted port identifier and the extracted source address.

Abstract: A network integrated management system transferring monitor/control information by e-mail using the Internet (40) between a monitor/control apparatus (50) having a network (14) to be monitored and controlled under it and a network integrated management apparatus (30) integratedly managing the network through the monitor/control apparatus.

Abstract: An intensive management apparatus for managing a time-sharing multiplexing network, comprises: a path-information-creating unit for creating path information including a group identifier, termination information of terminating connection points, a path management number assigned to a path connecting the terminating connection points at which time slots in a communication apparatus are allocated and an allocated-time-slot number; a time-slot-allocating unit for creating time-slot-allocation information describing allocation of the time slots to a path identified by the path management number included in the time-slot-allocation information for each of the terminating connection points; a path-information-checking unit for forming a judgment on validity of each of a plurality of paths identified by the same group identifier assigned to a path-information group comprising pieces of path information describing the paths on the basis of the path information; and a result display unit for displaying results of the