3Com SuperStack 3C17300 Implementation Manual page 40

42 C 4: U R F
HAPTER SING ESILIENCE EATURES
Figure 8 Traffic flowing through Bridges C and A
If a link failure is detected, as shown in Figure 9, the STP process
reconfigures the network so that traffic from LAN segment 2 flows
through Bridge B.
Figure 9 Traffic flowing through Bridge B
STP determines which is the most efficient path between each bridged
segment and a specifically assigned reference point on the network. Once
the most efficient path has been determined, all other paths are blocked.
Therefore, in Figure 7, Figure 8, and Figure 9, STP initially determined that
the path through Bridge C was the most efficient, and so blocked the
path through Bridge B. After the failure of Bridge C, STP re-evaluated the
situation and opened the path through Bridge B.