Configuring the WSM using Device Manager

Understanding multiple spanning trees    

To create the spanning tree, the root bridge (switch) generates a bridge protocol data unit (BPDU), to forward out of its ports. BPDUs are messages used by bridges implementing STP to learn about the existence of other bridges for the purpose of calculating and maintaining the spanning tree. By exchanging BPDUs, all switches in the Layer 2 network participating in the spanning tree gather information about other switches in the network. The BPDU is used to establish a path, much like a Hello packet in IP routing. The figure below shows the information contained in a BPDU about the transmitting bridge and its ports.

See also:

• About Spanning Tree protocol
• VLANs and spanning tree protocol
• Why multiple Spanning Trees?
• Root cost comparison
• Example--four-WSM topology with single spanning tree
• Example--four-WSM topology with multiple spanning trees
• Multiple spanning tree example--determining root cost
• Configuring spanning tree protocol