IP-COM G3210P, Руководство пользователя

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Advanced Settings
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BPDU Comparison
Each switch sends out configuration BPDUs and receives a configuration BPDU on one of
its ports from another switch. The following table shows the comparing operations.
Step Operation
1 If the priority of the BPDU received on the port is lower than that of the BPDU if
of the port itself, the switch discards the BPDU and does not change the BPDU
of the port.
If the priority of the BPDU is higher than that of the BPDU of the port itself, the
switch replaces the BPDU of the port with the received one and compares it
with those of other ports on the switch to obtain the one with the highest
priority.
2 The switch selects the best BPDU by comparing BPDUs on all ports.

Select the root bridge
The root bridge is selected by BPDU comparing. The switch with the smallest root ID will
be chosen as the root bridge.
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Select the root port and designated port
The operation is taken in the following way:
Step Operation
1 For each switch (except the one chosen as the root bridge) in a network, the
port that receives the BPDU with the highest priority is chosen as the root port
of the switch.
2 Using the root port BPDU and the root path cost, the switch generates a
designated port BPDU for each of its ports.

Root ID is replaced with that of the root port;

Root path is replaced with the sum of the root path cost of the root port
and the path cost between this port and the root port;
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The ID of the designated bridge is replaced with that of the switch;

The ID of the designated port is replaced with that of the port.
3 The switch compares the resulting BPDU with the BPDU of the desired port
whose role you want to determine.

If the resulting BPDU takes the precedence over the BPDU of the port, the
port is chosen as the designated port and the BPDU of this port is
replaced with the resulting BPDU. The port regularly sends out the