Westermo ODW-720-F2 - Manual (Page 32)

32 6651-2235
Reconfiguration time under faulty condition
The reconfiguration time is determined by the time it takes to detect a faulty fibre seg-
ment plus the time it takes to transport an error status message through to the ODW-
720 Ring Focal Point unit. The time to transport an error status message to the Ring
Focal Point unit is dependent on how many units the error status message has to be
repeated through and the total fibre length delay.
The time to detect a faulty fibre segment is less or equal to 3 µs.
The time to repeat an error status message through any unit is 0.8 µs
During reconfiguration data may be corrupted or lost.
Example: Calculate the maximum reconfiguration time in a network comprising of
10 ODW-720 units and a total fibre length of 40 km.
1. Error detection: The time it takes to detect a faulty fibre segment.
Always 3 µs.
2. Fibre: The total optical fibre length delay.
40 x 5 µs = 200 µs
3. Optical repeaters: The optical repeater delay x Number of optical repeaters
(excluding the ODW-720 units connected to the communication devices that are
exchanging data).
(10 – 2) x 0.8 µs = 6.4 µs.
4. The reconfiguration time is calculated by summing the delays in item 1 to 3
above:
3 µs + 200 µs + 6.4 µs = 209.4 µs