Patent ID: 8165043

Claim:
A device comprising: a plurality of ports for interconnecting the device to a computer network having a plurality of virtual local area networks (VLANs), each VLAN associated with a corresponding VLAN identifier (VID); a spanning tree engine in communicating relationship with the plurality of ports, the spanning tree engine configured to exchange bridge protocol data unit (BPDU) messages with one or more neighboring devices to establish a plurality of loop-free paths through the computer network independent of any VLANs in the computer network, each loop-free path associated with a respective spanning tree instance identifier of a plurality of spanning tree instance identifiers, the spanning tree engine configured to elect a root bridge for each spanning tree instance identifier, each BPDU message to specify one of the spanning tree instance identifiers of the plurality of spanning tree instance identifiers and to include information regarding the loop-free path associated with that the specified spanning tree instance identifier; mapping logic configured to map each VID to one spanning tree instance identifier of a loop free path, wherein the root bridge for a given spanning tree instance identifier specifies which VIDs are mapped to the given spanning tree instance identifier, wherein at least some VIDs are mapped to the same spanning tree instance identifier; and at least one forwarding engine configured to forward a network message associated with a given VID from at least one port that is in the forwarding spanning tree port state for the spanning tree instance identifier to which the given VID is mapped.