3Com 4210 PWR Configuration Manual page 145

The following is an example of how the STP algorithm works. The specific
network diagram is shown in Figure 47. The priority of Device A is 0, the
priority of Device B is 1, the priority of Device C is 2, and the path costs of these
links are 5, 10 and 4 respectively.
Figure 47 Network diagram for STP algorithm
Device A
With priority 0
AP 1
5
BP 1
BP 2
Device B
With priority 1
Initial state of each device
■
The following table shows the initial state of each device.
Table 98 Initial state of each device
Device
Device A
Device B
Device C
Comparison process and result on each device
■
The following table shows the comparison process and result on each device.
AP 2
10
4
CP 1
CP 2
Device C
With priority 2
Port name
AP1
AP2
BP1
BP2
CP1
CP2
STP Overview 143
BPDU of port
{0, 0, 0, AP1}
{0, 0, 0, AP2}
{1, 0, 1, BP1}
{1, 0, 1, BP2}
{2, 0, 2, CP1}
{2, 0, 2, CP2}