Apparatus and method for configuring spanning tree and spanning tree protocol system and bridge system

An apparatus for configuring a spanning tree used for a network in which a plurality of virtual LANs coexist, the apparatus comprising:

• at least two bridges each having a plurality of ports, the bridges each being capable of configuring a plurality of virtual LANs by logically combining the plurality of ports;
• holding means for holding on the bridge for each of the plurality of virtual LANs, information that is a combination between a code for identifying each of the plurality of virtual LANs configured by the bridge and a code for identifying a root bridge in a spanning tree for each of the plurality of virtual LANs;
• output means for, when there is outputted plural items of spanning tree configuration information containing a code in which one of the bridges identifies a root bridge for each of the plurality of virtual LANs, bundling in one packet at least two items of spanning tree configuration information contained in the plurality of spanning tree configuration information and outputting them;
• and
• control means for acquiring the spanning tree configuration information on each of the plurality of virtual LANs from the packet in a bridge which receives the packet, thereby controlling opening and closing of each of the plurality of ports that the bridge has for each of the plurality of virtual LANs.

A method for configuring a spanning tree used for a network in which a plurality of virtual LANs coexist, the method comprising the steps of:

• providing at least two bridges each having a plurality of ports, the bridges each being capable of configuring a plurality of virtual LANs by logically combining the plurality of ports;
• holding on the bridge for each of the plurality of virtual LANs, information that is a combination between a code for identifying each of the plurality of virtual LANs configured by the bridge and a code for identifying a root bridge in a spanning tree for each of the plurality of virtual LANs;
• when there is outputted plural items of spanning tree configuration information containing a code in which one of the bridges identifies a root bridge for each of the plurality of virtual LANs, bundling in one packet at least two items of spanning tree configuration information contained in the plurality of spanning tree configuration information and outputting them;
• and
• acquiring the spanning tree configuration information on each of the plurality of virtual LANs from the packet in a bridge which receives the packet, thereby controlling opening and closing of each of the plurality of ports that the bridge has for each of the plurality of virtual LANs.

A bridge system used for a network in which there exists a plurality of VLANs to which a spanning tree protocol is applied, the bridge system comprising:

• at least two bridges each having a plurality of ports, the bridges each being capable of configuring a plurality of virtual LANs by logically combining the plurality of ports;
• a spanning tree protocol instance having a VLAN-ID of at least the VLAN of the plurality of VLANs and an MAC address of a root bridge in the VLAN for each of the plurality of VLANs;
• output means for, when one of the bridges outputs plural items of spanning tree configuration information containing a code for identifying a root bridge for each of the plurality of virtual LANs, bundling in one packet at least two items of spanning configuration information contained in the plural items of spanning tree configuration information and outputting them;
• and
• control means for acquiring the spanning tree configuration information on each of the plurality of virtual LANs from the packet in a bridge which receives the packet, thereby controlling opening and closing of each of the plurality of ports that the bridge has for each of the plurality of virtual LANs.