NPort 6000 Series
Module Settings
6-8
Configuration Limits of RSTP/STP
The Spanning Tree Algorithm places 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
These three variables are further restricted by the following two inequalities:
[Eq. 4]: 2 x (Hello Time + 1 sec)
≦
Max. Age
≦
2 x (Forwarding Delay – 1 sec)
The NPort 6000’s firmware will alert you immediately if any of these restrictions are violated. For example,
setting
Hello Time = 5 sec, Max. Age = 20 sec, and Forwarding Delay = 4 sec does not violate Eqs. 1 through 3, but
does violate Eq. 4, since in this case,
2 x (Hello Time + 1 sec) = 12 sec, and 2 x (Forwarding Delay – 1 sec) = 6 sec.
You can remedy the situation in any number of ways. One solution is simply to increase the Forwarding Delay
value to at least 11 sec.
HINT: Take the following steps to avoid guessing:
Step 1: Assign a value to “Hello Time” and then calculate the left most part of Eq. 4 to get the lower limit of
“Max. Age”.
Step 2: Assign a value to “Forwarding Delay” and then calculate the right most part of Eq. 4 to get the upper
limit for “Max. Age”.
Step 3: Assign a value to “Forwarding Delay” that satisfies the conditions in Eq. 3 and Eq. 4.
Configuring Turbo Ring
The Turbo Ring Concept
Moxa developed the proprietary Turbo Ring protocol to optimize communication redundancy and achieve a
faster recovery time on the network. The Turbo Ring and Turbo Ring V2 protocols identify one NPort 6000 as
the master of the network, and then automatically block packets from traveling through any of the network’s
redundant loops.
In the event that one branch of the ring gets disconnected from the rest of the network, the protocol
automatically readjusts the ring so that the part of the network that was disconnected can reestablish contact
with the rest of the network.
Initial setup of a “Turbo Ring” or “Turbo Ring V2” ring
1.
Select any two ports as redundant ports.
2.
Connect the redundant ports to form the Turbo Ring.
