ABSTRACT
This chapter looks at all the advantages of the spanning tree protocol (STP), but also the scalability limits that its adversaries underline to discourage its use in the carrier network. The STP is used to determine the best path from source to destination for Ethernet frames in a switched Ethernet network. It creates a hierarchical tree spanning the entire network, including all bridges and switches. Searching such a tree, the STP determines all possible paths between two network users and, when needed, it activates only one of them. If a network node becomes unreachable for some reason, the spanning-tree algorithm reconfigures the logical topology, reestablishing the connection by activating the standby path. A network administrator can reduce the cost of a spanning tree, if necessary, by altering some of the configuration parameters in such a way as to affect the choice of the root of the spanning tree.
