HP 1910 User Manual page 208

Figure 177 STP network
Initial state of each device
•
Table 57 Initial state of each device
Device
Device A
Device B
Device C
Comparison process and result on each device
•
Table 58 Comparison process and result on each device
Device Comparison process
•
Port AP1 receives the configuration BPDU of Device B {1, 0, 1,
BP1}. Device A finds that the configuration BPDU of the local
port {0, 0, 0, AP1} is superior to the received configuration
BPDU, and discards the received configuration BPDU.
•
Port AP2 receives the configuration BPDU of Device C {2, 0, 2,
CP1}. Device A finds that the BPDU of the local port {0, 0, 0,
AP2} is superior to the received configuration BPDU, and
Device A
discards the received configuration BPDU.
•
Device A finds that both the root bridge and designated bridge
in the configuration BPDUs of all its ports are itself, so it assumes
itself to be the root bridge. It does not make any change to the
configuration BPDU of each port, and starts sending out
configuration BPDUs periodically.
Port name
AP1
AP2
BP1
BP2
CP1
CP2
147
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}
BPDU of port after
comparison
AP1: {0, 0, 0, AP1}
AP2: {0, 0, 0, AP2}