Constructing multiple spanning trees at a node device in a ring network

摘要

In a multiple spanning tree system, a plurality of spanning trees are constructed in a ring system to effectively use a band of the ring system. A plurality of bridge protocol processing sections are provided in a node device to enable a plurality of bridge protocol processings to be performed in a transmission path connected to one node device. Thereby, a plurality of spanning trees can be constructed, and a root bridge can be placed at each node device.