Designing and Expanding the Network 2 - 3
2 Wire the backbone in
a star topology to
isolate faults.
Make sure to lay extra fiber cables. The
extra cost is small and you will find you
need them as your network grows.
The star topology conforms to FDDI
wiring as well -- just make sure to run at
least two fiber strands to every
backbone connection.
3 The maximum Fiber
Ethernet network
diameter is 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 is, drop or patch
cable) that connects a device with an
external transceiver. Transceiver cables
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 nodes.
4 Certain LAN devices
on the network shrink
the maximum Fiber
Ethernet network
diameter to less than
4200 meters.
Many LAN products delay the signal
that goes through them. This is known
as equivalent distance. Every
microsecond delay reduces the
maximum link distance. In fact, every
microsecond delay shrinks the network
diameter by approximately 200 meters
of fiber cable. Table 2-2 lists the
Equivalent Distances for other 3Com
products.
Table 2-1. Seven Basic Network Rules (Continued)
Rule Definition Recommendations/Notes
