Cisco LAN Switching Fundamentals

Introducing Spanning Tree Protocol

As with traditional shared Ethernet, transparent bridges inherently lack the capability to provide redundancy. The Spanning Tree Protocol (STP) inserts a mechanism into the Ethernet transparent bridge environment to dynamically discover the network topology and ensure only one path through the network. Without STP, there is no way to make a transparent bridge environment redundant. STP also protects a network against accidental miscablings because it prevents unwanted bridging loops in the transparent bridging environment. A bridge loop is similar to a wrestling match. At first, everything appears orderly, but pandemonium soon ensues. The normal referee and rules do not work. The pandemonium does not stop until ...