PT-7828 User’s Manual
Featured Functions
3-41
Hello Time (sec.)
Setting
Description
Factory Default
Numerical value input by
user
This specifies the time interval between "hello"
messages broadcast by the root of the Spanning
Tree topology. The "hello" message is used to
check if the topology is healthy.
2
Max. Age (sec.)
Setting
Description
Factory Default
Numerical value input by
user
This specifies the amount of time to wait for a
"hello" message from the root before the
PT-7828 will reconfigure itself as a root. When
two or more devices on the network are
recognized as a root, the devices will
renegotiate to set up a new Spanning Tree
topology.
20
Enable STP per Port
Setting
Description
Factory Default
Enable/Disable
This includes the selected port as a node on the
Spanning Tree topology.
Disabled
NOTE
We suggest that you disable the Spanning Tree Protocol for ports that are connected directly to a
device (PLC, RTU, etc.) as opposed to network equipment. This will prevent unnecessary
negotiation.
Port Priority
Setting
Description
Factory Default
Numerical value selected
by user
This specifies the port’s priority as a node on
the Spanning Tree topology. Lower values
correspond to higher priority.
128
Port Cost
Setting
Description
Factory Default
Numerical value input by
user
This specifies the port cost. Higher costs
correspond to lower suitability as a node for the
Spanning Tree topology.
200000
Port Status
Indicates the current Spanning Tree status of this port.
Forwarding
indicates normal transmission
and
Blocking
indicates blocked transmission.
Configuration Limits of RSTP/STP
The Spanning Tree Algorithm places limits on three of the configuration items:
[Eq. 1]: 1 sec Hello Time 10 sec
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[Eq. 2]: 6 sec Max. Age 40 sec
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[Eq. 3]: 4 sec Forwarding Delay 30 sec
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These three variables are further restricted by the following two inequalities:
