Switching hub, line card and frame relay method

摘要

A switching hub includes a plurality of ports including receiving ports for receiving a frame from outside and transmitting ports for transmitting the frame to outside, a distributed ID calculation portion for calculating a distributed ID based on the frame received by one of the receiving ports of the plurality of ports and adding the distributed ID to the frame, a first distribution table that stores a port ID for identifying the transmitting port for transmitting the frame associated with the distributed ID to outside, a second distribution table that stores the port ID associated with the distributed ID so that the correspondence relation is different from that of the first distribution table, a distribution table identification information adding portion for adding first table identification information for identifying the first distribution table or second table identification information for identifying the second distribution table to the frame, and a transmission distribution table access portion for obtaining the port ID stored in the first or second distribution table so as to be associated with the distributed ID that is added to the frame by referring to the first distribution table when the first table identification information is added to the frame and by referring to the second distribution table when the second table identification information is added to the frame.