Abstract: A network system is comprised of a learning management program in a CPU to send and receive a learning frame, a frame transfer unit which transfers a learning frame, and a learning frame transmission management unit which judges whether learning has completed or not.

Abstract: A node of a spanning tree system operating on a network connecting a plurality of nodes, comprises two transfer units which determines an output destination port, based on the destination MAC address of an input frame, two tree managers which configures a spanning tree according to a spanning tree protocol, and a virtual port of connecting the tree manager and the transfer unit.

Abstract: The one-to-plural communication system for realizing the time slot allocation control method of the invention comprises the terminal-side apparatus 800˜830 provided with the buffer 801, the Queue length report function 802, and the output control function 803, and the network-side apparatus 840 provided with the necessary buffer capacity reduction type time slot allocation control function 141. The necessary buffer capacity reduction type time slot allocation control function 141, by using the Queue length information reported from the Queue report function 802, allocates time slots so that Queue lengths in the buffer 801 may become constant as nearly as possible among the terminal-side apparatus 800˜830, and reports the results to the output control circuit 803 which controls the output of cells from the buffer 801.

Abstract: A semiconductor apparatus comprises a resistor formed in a driver to connect a driving device to a transmission line connecting the driver to a receiver. The resistor has resistance considerably larger than on-state resistance of the driving device on condition that the resistor matches output impedance of the driver with impedance of the transmission line. The transmission line has length decided so that a reflected wave from a receiver-side end of the transmission line reaches the driver while a driving signal supplied to the driver has a logical high or low level.

Abstract: A node that configures a spanning tree over a network to which a plurality of nodes are connected generates a tree after a cost change using another LAN while continuing to operate the tree that existed before the change, and switches the tree that is used for forwarding after the new tree has been stable.

Abstract: In frame transfer in a network for transferring an Ethernet frame sent from a source on the network to a predetermined destination, to an applied Ethernet frame, an expansion tag containing information about forwarding to an egress edge node to a host as a destination is added to make an expansion frame, and each node on the network relays the data frame based on the forwarding information of the added expansion tag to transfer the frame to the egress edge node.

Abstract: A node to relay the Ethernet frame provided with means to insert, in the relay process of the frame, two or more VLAN tags into the frame at a time and to remove the inserted VLAN tags wherein a TTL area to show the frame survival time is provided in the VLAN tag to be inserted to the frame so that whether the survival time has been elapsed or not is checked by the value in the TTL area and the frame after elapse of the survival time is discarded without being relayed.

Abstract: The invention enables protection of a ring frame transferred via an inter-ring bridge ring node when a fault occurs at the node in a multiring. Ring nodes form a ring protection domain to enable one ring node to be bypassed by using other ring nodes when a fault occurs at this ring node. The TTL value of ring frame to be transferred through the bypass is set to a value obtained by adding the number of hops h to the faulty ring node to a common initial value A in the same two-fiber ring to enable detection of a characteristic TTL value at a bypassing ring node. The bypass for the ring frame is selected with reference to the characteristic TTL value at the bypassing ring node. The bypassing ring node is set to a value obtained by adding a certain number of hops h to the next bypassing ring node to the initial value A of the two-fiber ring at the other end of the bypass.

Abstract: In a communication system for transmitting and receiving communication frames between a plurality of communication terminals and a server, a control frame which is indicative of control information necessary for communication between the communication terminals and the server and whose size is smaller than the size of the communication frame is transferred being included in a preamble portion of each communication frame and when no communication frame to be transmitted exists, the control frame is transferred as an independent frame.

Abstract: In a communication system in which a plurality of communication terminals sequentially transfer data to a server during the respective transmission permissible periods assigned to the respective communication terminals, the communication terminal transfers a preamble for synchronization to the server at a time of starting the transmission permissible period, converts a data frame for every 8 bits into every 10 bit-code, and transmits to the server, the signal string with a code indicating the head added there, during the transmission permissible period, and turns a communication to the server into a zero signal state, during a period other than the transmission permissible period, while the server establishes a synchronization by reading the preamble for synchronization inserted into the signal string received from each of the communication terminals, converts a portion of the zero signal state of the signal string into a predetermined special code string, and inversely transforms the received signal string i

Abstract: A node in an asynchronous transfer mode exchange network comprises a bandwidth monitor circuit for calculating a bandwidth used for a virtual path by measuring a cell amount entered into each virtual path, cell stored buffers for respectively storing an input cell for every virtual path, a bandwidth allocation control circuit for deciding a bandwidth allocation ratio, in accordance with a used bandwidth ratio obtained by reference to each bandwidth used for every virtual path from the bandwidth monitor circuit, depending on a change of the Queue length in a cell within the cell stored buffer, and an output bandwidth control circuit for controlling output of the respective cell stored buffers, in accordance with the bandwidth allocation ratio decided by the bandwidth allocation control circuit.

Abstract: A remote station creates a transfer frame with one synchronous bit string added to at least one or more client frames and sends this transfer frame to a base station, when multiplexing the client frame received from a client system through an optical fiber and transferring the same to the base station.

Abstract: A node in an asynchronous transfer mode exchange network comprises a bandwidth monitor circuit for calculating a bandwidth used for a virtual path by measuring a cell amount entered into each virtual path, cell stored buffers for respectively storing an input cell for every virtual path, a bandwidth allocation control circuit for deciding a bandwidth allocation ratio, in accordance with a used bandwidth ratio obtained by reference to each bandwidth used for every virtual path from the bandwidth monitor circuit, depending on a change of the Queue length in a cell within the cell stored buffer, and an output bandwidth control circuit for controlling output of the respective cell stored buffers, in accordance with the bandwidth allocation ratio decided by the bandwidth allocation control circuit.

Abstract: A packet communication system is constructed with a plurality of terminal side devices and a network side device including a dynamic identifier assigning portion 141 and a time slot allocation portion 1242. The dynamic identifier assigning portion 141 transmits an identifier information assigned to the respective terminal side devices in an initial setting state to the respective terminal side devices by means of a control signal. When an identifier assignment release request is received from an identifier control portion 100 of the terminal side device in a usual state, the dynamic identifier assigning portion changes the state of an identifier assigned to the terminal side device to the non-assigned state.

Abstract: The present invention comprises a plurality of terminal-side apparatuses each having a buffer, a queue length notification module, and an output control module, and a network-side apparatus having a fairness guarantee/high efficiency hybrid time slot assignment control module (FG/HE HTSAC module). The FG/HE HTSAC module assigns time slots to all or a part of the terminal-side apparatuses in accordance with a fairness criteria. If the number of the time slots assigned exceeds a queue length for one or more terminal-side apparatuses, leftover time slots are reassigned among the terminal-side apparatus(es) where the number of the time slots assigned thereto does not exceed a queue length. The result of reassignment is notified to an output control circuit that controls output of cells from the buffer.

Abstract: In a communication network, end-user systems are connected via a common transmission medium to a timeslot assignment unit. Each end-user system has a buffer for storing packets, and a queue length detector for detecting a queue length of the stored packets. The end-user system forwards packets on assigned timeslots to the network and transmits a signal for indicating the detected queue length to the assignment unit. The timeslot assignment unit maintains timeslot records to store count numbers of assigned timeslots, determines a total count number of timeslots assigned to each end-user system during a period corresponding to the delay time of the unit, and receives a queue length signal from each end-user system. From the total count number and the queue length a virtual queue length is determined for indicating the number of packets to which timeslots are still not assigned. Based on the virtual queue length, timeslots are assigned to each end-user system.