QTECH
Software Configuration Manual
15-187
For the convenience of description, the description and examples below involve only four
parts of a configuration BPDU :
·
Root bridge ID (in the form of device priority)
·
Root path cost
·
Designated bridge ID (in the form of device priority)
·
Designated port ID (in the form of port name)
1) Specific computing process of the STP algorithm
·
Initial state
Upon initialization of a device, each port generates a BPDU with itself as the root, in which the root path
cost is 0, designated bridge ID is the device ID, and the designated port is the local port.
·
Selection of the optimum configuration BPDU
Each device sends out its configuration BPDU and receives configuration BPDUs from other devices.
The process of selecting the optimum configuration BPDU is as follows :