Abstract: A repeater stores retrieval situation of an address retrieved as an address identical with the transmission destination address of the reception frame in association with each address registered in the learning table, refers to, when the transmission source address of the received frame is registered in the learning table, the retrieval situation of the address stored in association with a port identical with the port that receives the frame from among retrieval situations, specifies an address to be overwritten by the transmission source address of the reception frame, overwrites and registers the transmission source address of the reception frame on the specified address, and updates, when the address identical with the transmission destination address of the received frame is retrieved from the learning table, the retrieval situation stored in association with the retrieved address.

Abstract: A packet forwarding device reads each packet from a common buffer at a predetermined band velocity and transfers the readout packet; detects passage of a re-transmission request packet requesting re-transmission of a packet having been transmitted, from a receiving terminal to a packet transmission source; and limits a writing band of writing a packet transmitted from the packet transmission source terminal, which is a receiving terminal to which the re-transmission request packet is destined, into the common buffer when the re-transmission request packet is detected.

Abstract: A surplus amount of token calculating unit calculates a surplus amount of token for a station in which a residual amount of output buffer is smaller than a residual amount of token. A necessary amount of token calculating unit calculates a necessary amount of token for a station in which the residual amount of output buffer is larger than the residual amount of token. A token distributing unit distributes a token within a range of the surplus amount of token to a token counter of a station in which the necessary amount of token has been calculated, from a station in which the surplus amount of token has been calculated.

Abstract: A repeater stores retrieval situation of an address retrieved as an address identical with the transmission destination address of the reception frame in association with each address registered in the learning table, refers to, when the transmission source address of the received frame is registered in the learning table, the retrieval situation of the address stored in association with a port identical with the port that receives the frame from among retrieval situations, specifies an address to be overwritten by the transmission source address of the reception frame, overwrites and registers the transmission source address of the reception frame on the specified address, and updates, when the address identical with the transmission destination address of the received frame is retrieved from the learning table, the retrieval situation stored in association with the retrieved address.

Abstract: A communication device simplified in circuit configuration and capable of shortening the time required to copy packets for broadcasting or multicasting. A packet separator separates an incoming packet into a data part and a header part, and a memory stores the data part. An internal packet generator attaches, to the header part, an internal header of a fixed length including the address of the stored data part, to generate an internal packet. A route searcher searches for a route for the internal packet based on the header part. Queues are associated with packet input/output ports, respectively, for temporarily storing the internal packet routed by the route searcher. A reader reads out the data part from the memory in accordance with the address included in the internal header of the internal packet. A packet generator generates an output packet from the data part and the header part of the internal packet.

Abstract: A packet forwarding device reads each packet from a common buffer at a predetermined band velocity and transfers the readout packet; detects passage of a re-transmission request packet requesting re-transmission of a packet having been transmitted, from a receiving terminal to a packet transmission source; and limits a writing band of writing a packet transmitted from the packet transmission source terminal, which is a receiving terminal to which the re-transmission request packet is destined, into the common buffer when the re-transmission request packet is detected.

Abstract: The disclosed apparatus and method include transmitting and receiving frame(s) to/from another transmission apparatus, storing header information of user frames that are currently being transmitted to the other transmission apparatus, detecting whether the maintenance frame was received, splitting user frames and interrupting the transmission processing of the user frames, adding to subsequent user frames combination information, performing a transmission processing on response maintenance frames, resuming transmission processing of the subsequent user frames, and adding combination information and header information.

Abstract: A surplus amount of token calculating unit calculates a surplus amount of token for a station in which a residual amount of output buffer is smaller than a residual amount of token. A necessary amount of token calculating unit calculates a necessary amount of token for a station in which the residual amount of output buffer is larger than the residual amount of token. A token distributing unit distributes a token within a range of the surplus amount of token to a token counter of a station in which the necessary amount of token has been calculated, from a station in which the surplus amount of token has been calculated.

Abstract: A communication device simplified in circuit configuration and capable of shortening the time required to copy packets for broadcasting or multicasting. A packet separator separates an incoming packet into a data part and a header part, and a memory stores the data part. An internal packet generator attaches, to the header part, an internal header of a fixed length including the address of the stored data part, to generate an internal packet. A route searcher searches for a route for the internal packet based on the header part. Queues are associated with packet input/output ports, respectively, for temporarily storing the internal packet routed by the route searcher. A reader reads out the data part from the memory in accordance with the address included in the internal header of the internal packet. A packet generator generates an output packet from the data part and the header part of the internal packet.