Designing and Expanding the Network 2 - 3
2
(con’t) Wire the backbone in a
star topology to isolate
faults.
The star topology conforms to
FDDI wiring. Run at least two
fiber strands to each backbone
connection.
3 Do not exceed the
maximum Fiber Ethernet
network diameter of
4200 meters of fiber
cable.
The 4200 meters is the
maximum distance between
any two transceivers on the
network.
The 4200 meters does not
include the transceiver cable
that connects a device with an
external transceiver.
Transceiver cable can extend up
to 50 meters. Thus, total
network diameter can be as
much as 4300 meters (4200 m +
2 * 50 m) between any two
modes.
4 Certain LAN products
on the network shrink
the maximum Fiber
Ethernet network
diameter to less than
4200 meters.
Each microsecond delay
through a device on the
network shrinks the network
diameter by approximately 2 00
meters of fiber cable. This
reduction is known as
equivalent distance. Table 2-2
lists the equivalent fiber
distances for 3Com ONline LAN
products.
Table 2-1. Basic Network Rule s (Continued)
Rule Definition Recommendations/Notes