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: 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: Network interconnection apparatus and method capable of efficiently guaranteeing optimum QoS suited to the status of actual traffic and network, whereby high-performance network interconnection is achieved without entailing lost calls. Routing information managing means manages routing information of an ATM network, and statistical information managing means manages statistical information on the traffic of a LAN. QoS setting means sets QoS which the ATM network ought to guarantee, based on the statistical information, and QoS guarantee determining means determines based on the routing information whether or not the set QoS can be guaranteed. If it is judged that the QoS cannot be guaranteed, QoS adjusting means adjusts the QoS so that the QoS can be guaranteed. Call connection control means connects call according to the QoS which can be guaranteed.

Abstract: A synchronous transmission network system has a plurality of nodes including a plurality of clock supply nodes and all the nodes synchronize with a clock supplied from one of clock supply nodes as a master, wherein each clock supply node includes a transmission module for transmitting a quality request message toward all other nodes, a receiving module for receiving quality response messages from all the other nodes, a quality determination module for determining clock supply quality information, a notifying module for notifying other clock supply node serving as the master of the clock supply quality information, and a node determination module for determining an optimum clock supply node exhibiting the best clock supply quality on the basis of the notified clock supply quality information and the clock supply quality information of the self-node.

Abstract: In a node device having a function of recognizing route information of a network, a route selector selects a connection setting route based on the dynamic route information of the network, and generates a reservation request of a predetermined optimum route unless the connection setting route is the predetermined optimum route, a route switchover reservation portion monitors whether or not the predetermined optimum route becomes available based on the route information during the communication, and makes switchover instructions toward the predetermined optimum route to a call processor. The call processor sets a connection in a selected connection setting route, and sets another connection in the predetermined optimum route by the switchover instructions.