
BPDU. After exchanging enough BPDUs, a root bridge is elected by the bridges
participating in the STP. The redundant links are disabled from forwarding traffic
(i.e., user data frames) by putting the ports connecting the link ends into the
blocked state so that each LAN is connected to the root bridge only through a
designated port on a designated bridge. Bridges elect the root bridge, designated
bridge and designated ports based on a set of priority criterions such as port speed,
bridge and port IDs, and/or manually provisioned cost parameters. For space
reasons, the details of the spanning tree algorithm will not be discussed here.
Interested readers ...