HP 3100 Series Configuration Manual page 61

Table 11 Comparison process and result on each device
Device Comparison process
•
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
Device A
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 configuration BPDUs.
•
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.
•
Device B compares the configuration BPDUs of all its ports,
decides that the configuration BPDU of Port B1 is the
Device B
optimum, and selects Port B1 as the root port with the
configuration BPDU unchanged.
•
Based on the configuration BPDU and path cost of the root
port, Device B calculates a designated port configuration
BPDU for Port B2 {0, 5, 1, Port B2}, and compares it with the
existing configuration BPDU of Port B2 {1, 0, 1, Port B2}.
Device B finds that the calculated one is superior, decides
that Port B2 is the designated port, replaces the
configuration BPDU on Port B2 with the calculated one, and
periodically sends the calculated configuration BPDU.
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Configuration BPDU
on ports after
comparison
•
Port A1: {0, 0, 0, Port
A1}
•
Port A2: {0, 0, 0, Port
A2}
•
Port B1: {0, 0, 0, Port
A1}
•
Port B2: {1, 0, 1, Port
B2}
•
Root port (Port B1):
{0, 0, 0, Port A1}
•
Designated port
(Port B2): {0, 5, 1,
Port B2}