Abstract: The disclosed apparatus includes a MAC learning table storing a MAC address and port identification information that uniquely identifies a port for transferring a frame to which the MAC address is assigned. The apparatus includes updating the MAC learning table, reading a MAC address of a link trace frame, transferring the link trace frame via a port determined based on the MAC learning table, storing a correspondence relationship of a predetermined MAC address and port identification information, saving a correspondence relationship set as an object to be deleted at a time of updating the MAC learning table, transferring the link trace frame, if there is no correspondence relationship relevant to the MAC address of the link trace frame in the MAC learning table, and sending a response frame to a switching hub which is an originator of the link trace frame with transfer of the link trace frame.

Abstract: A frame transmission device having a port for transmitting and receiving a frame and a learning table for storing a transmission source address included in the frame received at the port and the receiving port in association with each other includes: a port detector for detecting whether learning data coincident with the transmission source address included in the frame received at the port is stored in the learning table; a port judging unit for comparing a port learned in the learning data detected by the port detector to the receiving port; and a loop judging unit for judging on the basis of a time lapse from the storage of the learning data whether the frame is in a loop or not when the port learned in the learning data is not coincident with the receiving port.

Abstract: A frame transmission device having a port for transmitting and receiving a frame and a learning table for storing a transmission source address included in the frame received at the port and the receiving port in association with each other includes: a port detector for detecting whether learning data coincident with the transmission source address included in the frame received at the port is stored in the learning table; a port judging unit for comparing a port learned in the learning data detected by the port detector to the receiving port; and a loop judging unit for judging on the basis of a time lapse from the storage of the learning data whether the frame is in a loop or not when the port learned in the learning data is not coincident with the receiving port.

Abstract: The disclosed apparatus includes a MAC learning table storing a MAC address and port identification information that uniquely identifies a port for transferring a frame to which the MAC address is assigned. The apparatus includes updating the MAC learning table, reading a MAC address of a link trace frame, transferring the link trace frame via a port determined based on the MAC learning table, storing a correspondence relationship of a predetermined MAC address and port identification information, saving a correspondence relationship set as an object to be deleted at a time of updating the MAC learning table, transferring the link trace frame, if there is no correspondence relationship relevant to the MAC address of the link trace frame in the MAC learning table, and sending a response frame to a switching hub which is an originator of the link trace frame with transfer of the link trace frame.

Abstract: Network load is reduced by combining packets by considering the MTU of a transmission path. When a routing processing unit detects the transmission of a large number of packets addressed to the same destination network, a routing information gathering unit determines the MTU of a transmission path along which the packets are to be transmitted. A combining unit assembles a combined packet by combining packets up to a length that does not exceed the MTU of the transmission path, and sends out the combined packet.

Abstract: A disclosed download method for downloading software to a transmission device constituting a network includes the steps of: searching for an unused channel between the transmission device and an adjacent transmission device and setting up a cross-connect for the unused channel so as to set up a communication channel for transferring software; transmitting the software stored in a software storage unit to the adjacent transmission device via the communication channel; and receiving software transferred from the adjacent transmission device via the communication channel and storing the software in the software storage unit.

Abstract: In a method and a device for notifying a server failure recovery which notify a failure recovery of a server or the like to a client, a server failure detector detects a client having tried but failed to access a server due to a failure, a server recovery detector detects a failure recovery, and a server recovery notifier gives a failure recovery notification to the client having failed to access. Also, the server failure recovery notification device is mounted on a router. The server failure detector detects the client having failed to access based on a destination unreachable message of an ICMP of the router 40, or detects the client having failed to access by determining the failure is being occurred in the server, in the absence of a reply IP packet to the IP packet addressed to the server from the client.

Abstract: In a method and a device for notifying a server failure recovery which notify a failure recovery of a server or the like to a client, a server failure detector detects a client having tried but failed to access a server due to a failure, a server recovery detector detects a failure recovery, and a server recovery notifier gives a failure recovery notification to the client having failed to access. Also, the server failure recovery notification device is mounted on a router. The server failure detector detects the client having failed to access based on a destination unreachable message of an ICMP of the router 40, or detects the client having failed to access by determining the failure is being occurred in the server, in the absence of a reply IP packet to the IP packet addressed to the server from the client.

Abstract: Network load is reduced by combining packets by considering the MTU of a transmission path. When a routing processing unit detects the transmission of a large number of packets addressed to the same destination network, a routing information gathering unit determines the MTU of a transmission path along which the packets are to be transmitted. A combining unit assembles a combined packet by combining packets up to a length that does not exceed the MTU of the transmission path, and sends out the combined packet.