Patent attributes
When a signal cable is connected between communication nodes 0, 1 which comply with a communication protocol that inhibits loop connection, communication node 0 detecting connection of the signal cable transmits a loop test signal LT having information of a port where connection was detected (e.g., information of a transfer rate between ports). In response to the loop test signal LT, a communication node 2 adds information of its own port that received the loop test signal LT, that is, P(2, 1), to the received loop test signal LT, and repeats the loop test signal LT. Similarly, communication node 1 adds information of its own port that received the loop test signal LT, that is, P(1, 0), to the loop test signal LT. Communication node 0 specifies a suitable disconnection point of a loop (e.g., a port having a low transfer rate between ports) based on the port information thus accumulated. Accordingly, even if a loop is formed accidentally, the disconnection point of the loop can be specified in view of the signal transfer efficiency on the network, and the port corresponding to the disconnection point can be logically disabled.
