H3C S7500E Series Ethernet Switches Operation Manual

Operation Manual – MSTP
H3C S7500E Series Ethernet Switches Chapter 1 MSTP Configuration
1-7
Table 1-4 Initial state of each device
Device Port name BPDU of port
AP1 {0, 0, 0, AP1}
Device A
AP2 {0, 0, 0, AP2}
BP1 {1, 0, 1, BP1}
Device B
BP2 {1, 0, 1, BP2}
CP1 {2, 0, 2, CP1}
Device C
CP2 {2, 0, 2, CP2}
z Comparison process and result on each device
The following table shows the comparison process and result on each device.
Table 1-5 Comparison process and result on each device
Device Comparison process
BPDU of port
after
comparison
Device A
z 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 configuration received message,
and discards the received configuration BPDU.
z 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 discards the
received configuration BPDU.
z Device A finds that both the root bridge and
designated bridge in the configuration BPDUs of all
its ports are Device A itself, so it assumes itself to
be the root bridge. In this case, it does not make
any change to the configuration BPDU of each port,
and starts sending out configuration BPDUs
periodically.
AP1: {0, 0, 0,
AP1}
AP2: {0, 0, 0,
AP2}