Patent ID: 7855981

Claim:
A node that configures a spanning tree over a network to which a plurality of nodes are connected, comprising: a plurality of tree managers that generate a plurality of independently operating spanning trees; a tag table that returns a tag corresponding to a spanning tree that is used for forwarding; a tag insertion unit that inserts the tag that has been returned from said tag table into a frame; a tree selector that determines the spanning tree used for forwarding; a forwarding table in which a forwarding output destination of the frame is recorded by destination; a frame forwarding unit that forwards the frame to the forwarding output destination that is specified in said forwarding table; and a separator that determines a tree manager of the forwarding output destination of said frame according to said tag, wherein said tree selector comprises: a main controller that performs a switching of the spanning tree used for forwarding; a stable timer that notifies of an expiration of the timer for a specified time, which indicates a stabilization of the spanning tree; a tag remove unit that removes the tag that has been added to the frame; a GVRP (i.e. generic or GARP VLAN registration protocol) transmitter/receiver that transmits a control frame to switch spanning trees; and a tag insertion unit that adds a tag to the frame.