Abstract: An access node run as a packet switching apparatus enables IP connection services for a plurality of access methods; e.g., relatively low-speed IP connection, high-speed IP connection, and mobile network IP connection. By using this apparatus of the present invention, cost can be reduced and upgrading to advanced access networks and access services is easily carried out. Provision of the above access nodes implements upgrade-type network services common for diverse protocols. Each access node retains a pathfinding table to which input port, input tunnel identifier and input session identifier entries in a set are registered per session. When routing a packet, by looking up the set of these entries matching with the packet, the associated output port, output tunnel identifier, and output session identifier are obtained. After processing for the packet, appropriate for one of the plurality of access methods and network services, the node forwards the packet over the routed path.

Abstract: 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.

Abstract: An access node run as a packet switching apparatus enables IP connection services for a plurality of access methods; e.g., relatively low-speed IP connection, high-speed 1P connection, and mobile network IP connection. By using this apparatus of the present invention, cost can be reduced and upgrading to advanced access networks and access services is easily carried out. Provision of the above access nodes implements upgrade-type network services common for diverse protocols. Each access node retains a pathfinding table to which input port, input tunnel identifier and input session identifier entries in a set are registered per session. When routing a packet, by looking up the set of these entries matching with the packet, the associated output port, output tunnel identifier, and output session identifier are obtained. After processing for the packet, appropriate for one of the plurality of access methods and network services, the node forwards the packet over the routed path.

Abstract: An access node run as a packet switching apparatus enables IP connection services for a plurality of access methods; e.g., relatively low-speed IP connection, high-speed IP connection, and mobile network IP connection. By using this apparatus of the present invention, cost can be reduced and upgrading to advanced access networks and access services is easily carried out. Provision of the above access nodes implements upgrade-type network services common for diverse protocols. Each access node retains a pathfinding table to which input port, input tunnel identifier and input session identifier entries in a set are registered per session. When routing a packet, by looking up the set of these entries matching with the packet, the associated output port, output tunnel identifier, and output session identifier are obtained. After processing for the packet, appropriate for one of the plurality of access methods and network services, the node forwards the packet over the routed path.

Abstract: 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 “1” in one bit, generates packets each having one of resultant addresses, and transmits the generated packets.

Abstract: A mobile communication system with a packet switching function which enables sharing of radio resources among mobile stations, wherein a mobile station which has generated a request for communication quality assurance periodically sends a packet for requesting preferential use of a radio channel in order to prevent timeout of the state transition timer, timeout of which would cancel radio channel assignment to the mobile station and bring it into a dormant state if a certain period elapses without transmission or reception of a signal, so that it can remain in the active state and hold the radio channel continuously. In addition, when the mobile station requesting communication quality assurance moves from one cell to another or requests radio channel assignment, the base station controller controls the radio base station so that the mobile station can be assigned a radio channel by sending a priority request packet.

Abstract: In a mobile IP network system including a plurality of radio access networks for connecting with mobile stations via radio links and an IP network connected with a plurality of packet nodes for transferring IP packets, each of the radio access networks has at least one base station controller and at least one radio base station connected to the base station controller. Each of the base station controllers in the radio access network is connected to the plurality of packet nodes to each other via a network and selects one of the plurality of packet nodes in accordance with a state of each mobile station to establish a logical connection to be used in IP packet communication of the mobile station.

Abstract: In a mobile IP network system containing a plurality of radio access networks 2 for connecting with mobile stations 1 via radio links and an IP network 102 connected with a plurality of packet nodes for transferring IP packets, each of the radio access networks has at least one base station controller 7 and at least one radio base station 6 connected to the base station controller. Each of the base station controllers 7 in the radio access network is connected to the plurality of packet nodes to each other via a network 104 and selects one of the plurality of packet nodes in accordance with a state of each mobile station to establish a logical connection to be used in IP packet communication of the mobile station.

Abstract: 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.

Abstract: A mobile communication system that can obtain mobile station location information repeatedly at short intervals, without depending on whether base stations are synchronous or asynchronous, with lower loads and suppressed use of radio resources. For obtaining location information, a mobile station receives a paging channel periodically sent from a base station (Step 100), obtains the contents and the reception timing of this paging channel. Further, if it is necessary to obtain the transmission timing of the paging channel, that transmission timing is obtained (Steps 105, 106). The propagation delay of the paging channel or propagation delay differences between a plurality of periodic paging channels are calculated from the transmission timing and the reception timing of the paging channel (Step 107). The mobile station location information is calculated from the propagation delay or propagation delay difference, and outputted (Steps 108, 109, 110).

Abstract: 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 “1” in one bit, generates packets each having one of resultant addresses, and transmits the generated packets.

Abstract: An access node run as a packet switching apparatus enables IP connection services for a plurality of access methods; e.g., relatively low-speed IP connection, high-speed IP connection, and mobile network IP connection. By using this apparatus of the present invention, cost can be reduced and upgrading to advanced access networks and access services is easily carried out. Provision of the above access nodes implements upgrade-type network services common for diverse protocols. Each access node retains a pathfinding table to which input port, input tunnel identifier and input session identifier entries in a set are registered per session. When routing a packet, by looking up the set of these entries matching with the packet, the associated output port, output tunnel identifier, and output session identifier are obtained. After processing for the packet, appropriate for one of the plurality of access methods and network services, the node forwards the packet over the routed path.

Abstract: A mobile communication system with a packet switching function which enables sharing of radio resources among mobile stations, wherein a mobile station which has generated a request for communication quality assurance periodically sends a packet for requesting preferential use of a radio channel in order to prevent timeout of the state transition timer, timeout of which would cancel radio channel assignment to the mobile station and bring it into a dormant state if a certain period elapses without transmission or reception of a signal, so that it can remain in the active state and hold the radio channel continuously. In addition, when the mobile station requesting communication quality assurance moves from one cell to another or requests radio channel assignment, the base station controller controls the radio base station so that the mobile station can be assigned a radio channel by sending a priority request packet.

Abstract: It is designed to connect a duplicated LAN to a network terminal such as a controller having a standard serial or parallel interface, a computer having only one LAN interface, or a computer having only one communication line interface.The network interface apparatus for connecting a network terminal and a duplicated LAN comprises a device for controlling interfaces with the network terminal and the LAN transmission line of each of the duplicated LAN, a buffer, and a sending device to both, and the data from the network terminal is buffered in the buffer, and when the buffered data reaches a fixed amount, the data is sent to both LANs of the duplicated LAN. On the other hand, with respect to the data received from each LAN transmission line of the duplicated LAN, only the data which is judged as earlier arrival data is sent to the network terminal.

Abstract: A network interface apparatus connected between a LAN adaptor possessed by a computer and a transceiver provided on a network includes a buffer memory for storing data, a first control circuit for communicating with the LAN adaptor, a second control circuit for communicating with the transceiver, and a processor for controlling the first and second control circuits to control the transfer of data between the LAN adaptor and the transceiver. The processor causes the buffer memory to store transmit data transmitted from the LAN adaptor and transmits the stored transmit data in the buffer memory to the transceiver in a transmission time zone which is allotted beforehand. The transmission time zone is determined by the processor on the basis of the reception of a synchronizing packet which is transferred on the network. Receive data received from the transceiver is selected by the processor so that only the selected receive data is sent to the LAN adaptor.

Abstract: A distributed memory computer system periodically performs memory copy among a plurality of computers by using general-purpose communication control devices and a transmission line of the CSMA/CD type. A master computer periodically generates a synchronizing packet, and transmits data for memory copy and normal data in a time slot immediately after the transmission of the synchronizing packet. Each computer other than the master computer transmits the data for memory copy and the normal data in its own time slot after the elapse of a predetermined time. The respective computers complete their transmissions within predetermined times. Since the time slots are assigned to the respective computers, the number of computers which may compete with each other on a transmission line can be restricted and each computer can be assured a periodic opportunity to transmit data.

Abstract: Communication control equipment for connecting a computer system to a network and supporting the computer system to set a plurality of connections on the network and perform parallel communication between computers.

Abstract: In a communication control equipment for transmitting data in an external predetermined memory to a network, there are provided a buffer memory unit for temporarily holding the data transferred thereto, a data transfer unit for performing a data transfer between the predetermined memory and the buffer memory unit, a unit for executing a protocol processing with regard to data held in the buffer memory unit, a control unit for controlling a transmission of the data processed by the protocol processing to the network, and a unit for producing a transmission start instruction at a start time instant within a range defined from a time instant when 1-packet data transfer from the predetermined memory to the buffer memory unit is commenced until a time instant when this data transfer is completed.

Abstract: An arithmetic-logic unit ALU having three data input ports A, B and C, a modulo adder/subtracter for executing an arithmetic-logic operation of (A.+-.B) mod (C+1), a comparator for determining whether the input data A, B and C satisfy at least one of the relationship of A.ltoreq.B.ltoreq., A.ltoreq.B<C, A<B.ltoreq.C and A<B<C from a modulo operation viewpoint, and outputting a comparison judgment signal, a two-input ALU for executing an arithmetic-logic operation of two data, and one data output port for outputting operation results.

Abstract: A communication control equipment connected between a computer and a network so as to perform protocol processing at a high speed, has a buffer memory connected between a computer interface circuit and a network interface circuit through a first path for data transfer, so as to temporarily store communication data, and a protocol processor connected between the computer interface circuit and the network interface circuit through a second path for control information transfer. The protocol processor is also connected to the buffer memory through a third path so as to effect protocol processing on the communication data within the buffer memory.