In Transparent bridging, Spanning Tree must be used to prevent data loops (since in an Ethernet environment, a packet propagated down multiple paths would cause higher volumes of trafÞc and collisions that would cripple a network that relied on carrier sense and collision detection).
In a network designed with multiple bridges placed in parallel, Spanning Tree selects a controlling Root Bridge and Port for the entire bridged local area network, and a Designated Bridge and Port for each individual network segment. The Root bridge is the one that selects one of two or more available bridge paths between two end stations, basing its decision on factors associated with each of the bridges in the path. A Designated Port/Bridge for a network segment relays frames toward the Root Bridge, or from the Root Bridge onto the network segment. When data passes from one end station to another across a bridged local area network, it is forwarded through the Designated Bridge/Port for each network segment towards the Root Bridge, which in turn forwards frames towards Designated Bridges/Ports on its opposite side.
During the Root Bridge selection process, all bridges on the network communicate STA information via Bridge Protocol Data Units (BPDUs). It is with BPDUs that the bridges collectively determine the current network topology and ensure that all bridges have current topology information.
To access the Bridge Spanning Tree window:
1.From the
2.Click on Spanning Tree.... The Bridge Spanning Tree window, Figure
Figure 3-6. Bridge Spanning Tree Window
Bridge Spanning Tree |
