H3C Technologies H3C S12500 Series Switches - Manual (Page 71)

58
Device Port name
Configuration BPDU on the
port
Port A2 {0, 0, 0, Port A2}
Device B
Port B1 {1, 0, 1, Port B1}
Port B2 {1, 0, 1, Port B2}
Device C
Port C1 {2, 0, 2, Port C1}
Port C2 {2, 0, 2, Port C2}
NOTE:
In Table 8 , each configuration BPDU contains the following fields: root bridge ID, root path cost,
designated bridge ID, and designated port ID.
5. Comparison process and result on each device
Table 9 Comparison process and result on each device
Device Comparison process
Configuration BPDU
on ports after
comparison
Device A
• Port A1 receives the configuration BPDU of Port B1 {1, 0, 1,
Port B1}, finds that its existing configuration BPDU {0, 0, 0,
Port A1} is superior to the received configuration BPDU, and
discards the received one.
• Port A2 receives the configuration BPDU of Port C1 {2, 0, 2,
Port C1}, finds that its existing configuration BPDU {0, 0, 0,
Port A2} is superior to the received configuration BPDU, and
discards the received one.
• Device A finds that it is both the root bridge and designated
bridge in the configuration BPDUs of all its ports, and
considers itself as the root bridge. It does not change the
configuration BPDU of any port and starts to periodically
send out configuration BPDUs.
• Port A1: {0, 0, 0, Port
A1}
• Port A2: {0, 0, 0, Port
A2}
Device B
• Port B1 receives the configuration BPDU of Port A1 {0, 0, 0,
Port A1}, finds that the received configuration BPDU is
superior to its existing configuration BPDU {1, 0, 1, Port B1},
and updates its configuration BPDU.
• Port B2 receives the configuration BPDU of Port C2 {2, 0, 2,
Port C2}, finds that its existing configuration BPDU {1, 0, 1,
Port B2} is superior to the received configuration BPDU, and
discards the received one.
• Port B1: {0, 0, 0, Port
A1}
• Port B2: {1, 0, 1, Port
B2}