Cabletron Systems 7C04-R User Manual

Using the 7C0x SmartSwitch Bridge View

6-20

The Spanning Tree Protocol Window

To find a source address in the Filtering Database:

1.

In the Filtering Database window, click on the 

 button to open the 

Find MAC Address window.

In the Bridge Traffic View, display the Device menu by clicking on the Front 
Panel 

 button. Drag down to Find MAC Address.

Figure 6-10. Find MAC Address Window

Bridges in a network collectively implement a Spanning Tree Algorithm (STA) to 
detect and eliminate data loops in a network containing parallel bridges. 

In a network designed with multiple bridges placed in parallel (i.e., attached to 
the same network segment), 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. 

2.

In the edit box, enter a valid MAC 
address and then press the 
Return key. If the address is found 
in the Filtering Database, its port 
location and status will appear in 
the list box. If it is not found, a 
separate window will appear with 
a “Not Found” message.