Patent ID: 8531991

Claim:
A method for configuring a system of devices including a spanning tree device connected to two or more edge switches in a network of layer 2 switches, the method comprising: creating an emulated switch between the spanning tree device and the two or more edge switches, wherein a first link connects the spanning tree device to a first edge switch among the two or more edge switches and a second link connects the spanning tree device to a second edge switch among the two or more edge switches, the emulated switch appearing to be connected to the first link between the first edge switch and the spanning tree device, the emulated switch further appearing to be connected to the second link between the second edge switch and the spanning tree device, links to the emulated switch appearing as a single port of the emulated switch to the network of layer 2 switches; configuring each of the two or more edge switches such that the emulated switch is viewed as equidistant from each of the two or more edge switches and as part of the network of layer 2 switches; and if the first link between the first edge switch and the spanning tree device is inoperable, transferring a frame received at the first edge switch to the second edge switch for forwarding of the frame to the spanning tree device, stripping a header from the frame, the header including a switch identification corresponding to the emulated switch, and forwarding the frame from the second edge switch to the spanning tree device based, at least in part, upon a subswitch or local identification within the header of the frame; wherein the configuring includes configuring each of the two or more edge switches to, upon receipt of a unicast frame from another switch in the network of layer 2 switches, determine if the unicast frame is for the emulated switch, and if so, examine the subswitch or local identification within the header of the unicast frame and forward the unicast frame to the spanning tree device based, at least in part, upon the subswitch or local identification.