2 - 18 ONline Ethernet 10BASE-FL Installation and Operation Guide
Network Distance Calculation Examples
The following examples demonstrate how to calculate network distances
for various all-10BASE-FL networks.
Example: A Network with 3 Concentrators
Refer to Figure 2-5, which shows a network with 3 concentrators.
To determine the maximum allowable link distance between Concentrators
A and C:
1. Begin with 4200 meters (Ethernet Rule 3).
2. Subtract the fiber equivalent of the three concentrators with
10BASE-FL Modules that occur on the path between the two
transceivers:
3 * 560 meters for each 10BASE-FL module = 1680 meters (Ethernet
Rule 4)
3. Subtract the known amount of fiber cable between the two
transceivers:
500 m + 500 m + 1 km = 2 km (Ethernet Rule 5)
4. The remainder is the maximum allowable distance of the link
between concentrators A and C:
4200 m - 1680 m - 2000 m = 520 meters
5. Verify that the optical power budget is able to drive all of the link
distances in the example. Because all link distances are only 1 km or
less, and do not have any splices, this is not a problem.
Example: A Network with 6 Concentrators
Six concentrators are connected in Figure 2-6. Use this example to
determine if the distances between transceivers are all within the 4200
meter maximum network diameter restriction for Ethernet networks.
