IE-SW-VL08M Series User’s Manual
Featured Functions
3-40
Max. Age (sec.)
Setting
Description
Factory Default
Numerical value
input by user
If this device is not the root, and it has not
received a hello message from the root in an
amount of time equal to
Max. Age
, then this
device will reconfigure itself as a root. Once
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
Select to enable the port as a node on the
Spanning Tree topology.
Disabled
NOTE
We suggest not enabling the Spanning Tree Protocol once the port is connected to a device (PLC,
RTU, etc.) as opposed to network equipment. The reason is that it will cause unnecessary
negotiation.
Port Priority
Setting
Description
Factory Default
Numerical value
selected by user
Increase this port’s priority as a node on the
Spanning Tree topology by entering a lower
number.
128
Port Cost
Setting
Description
Factory Default
Numerical value
input by user
Input a higher cost to indicate that this port is
less suitable as a node for the Spanning Tree
topology.
200000
Port Status
This indicates the current Spanning Tree status of this port. The status values are
Forwarding
for
normal transmission, and
Blocking
to block transmission.
Configuration Limits of RSTP/STP
The Spanning Tree Algorithm places limits on three of the configuration items previously described:
[Eq. 1]: 1 sec
≦
Hello Time
≦
10 sec
[Eq. 2]: 6 sec
≦
Max. Age
≦
40 sec
[Eq. 3]: 4 sec
≦
Forwarding Delay
≦
30 sec
These three variables are further restricted by the following two inequalities:
