Bridge Port Stp Parameters; Port State; Port Path Cost; Port Priority - 3Com 4007 Implementation Manual

186 C 9: B
HAPTER RIDGE
Bridge Port
STP Parameters
-W B P P
IDE AND RIDGE ORT ARAMETERS
You can modify these STP parameters on each port:

Port state

Port path cost

Port priority

Port State
You can enable, disable, or remove STP for each bridge port on a module.
This setting affects the operation of a port only if bridge-wide STP is
enabled. Table 42 summarizes the forwarding behavior of bridge ports
based on the bridge-wide STP and per-port STP states:
Table 42 Port Forwarding Behavior Depends on Bridge and Port STP States
Bridge STP State
Disabled
Enabled
Port Path Cost
The algorithm adds the path cost to the root cost field in a configuration
message that is received on this port. The module uses this value to
determine the path cost to the root through this port. You can set this
value individually on each port.
A higher path cost value makes the LAN that is reached through the port
more likely to be low in the STP topology. The lower the LAN is in the
topology, the less through traffic it carries. For this reason, assign a high
path cost to a LAN that has a lower bandwidth or to one on which you
want to minimize traffic.
Port Priority
The STP port priority influences the choice of port when the bridge has
two ports connected to the same LAN, which creates a loop. The port
with the lowest port priority is used by STP.
Port Participates
Port STP State in STP?
Disabled No
Enabled No
Removed No
Disabled No
Enabled Yes
Removed No
Port Forwards
Frames?
Yes, if link state is up.
Yes, if link state is up.
Yes, if link state is up.
No
Determined by STP
provided that the
port link state is up.
Yes, if link state is up.