Moxa Technologies Moxa EtherDevice Switch EDS-508 - Manual (Page 45)

EDS-508 Series User’s Manual Featured Functions
3-29
Max. Age (sec.)
Setting Description Factory Default
User adjustable
numbers
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.
Disable
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
User selectable
number
Increase this port’s priority as a
node on the Spanning Tree
topology by inputting a lower
number.
128
Port Cost
Setting Description Factory Default
User adjustable
number
Input a higher cost to indicate that
this port is less suitable as a node
for the Spanning Tree topology.
200000
Port Status
Indicates the current Spanning Tree status of this port. “Forwarding” for normal transmission,
“Blocking” to block transmission.
Configuration Limits of RSTP/STP
We should point out that the Spanning Tree Algorithm places certain limits on three of the
configuration items described above:
[Eq. 1]: 1 sec ≦ Hello Time ≦ 10 sec
[Eq. 2]: 6 sec ≦ Max. Age ≦ 40 sec
[Eq. 3]: 4 sec ≦ Forwarding Delay ≦ 30 sec