3com 9000 SX Manual De Usuario

If the link through Bridge C fails, as shown in Figure 7-3, the STP 
system reconfigures the network so that traffic from segment 2 flows 
through Bridge B.

Figure 7-3   Traffic flowing through Bridge B

STP has the following three stages of operation:

■

Initialization

■

Stabilization

■

Reconfiguration

Initially, the STP system requires the following before it can configure 
the network:

■

All bridges exchange information by way of Bridge Protocol Data 
Units (BPDUs), which are transmitted in packets with a known 
multicast address

■

To determine a single root bridge as a result of BPDU exchange

The Root Bridge is selected on the basis of it having the lowest Bridge 
Identifier value. This value is a combination of the unique MAC address 
of the bridge and a priority component defined for the bridge.

SW9000.BK  Page 3  Wednesday, April 1, 1998  11:00 AM