Table 2-1. Seven Basic Network Rules (Continued)

Rule

Definition

Recommendations/Notes

 

 

 

2

Wire the backbone in

Make sure to lay extra fiber cables. The

 

a star topology to

extra cost is small and you will find you

 

isolate faults.

need them as your network grows.

 

 

 

 

 

The star topology conforms to FDDI

 

 

wiring as well -- just makesure to run at

 

 

least two fiber strands to every

 

 

backbone connection.

 

 

 

3

The maximum Fiber

The 4200 meters is the maximum

 

Ethernet network

distance between any two transceivers

 

diameter is 4200

on the network.

 

meters of fiber cable.

 

 

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

Many LAN products delay the signal

 

on the network shrink

that goes through them. This is known

 

the maximum Fiber

as equivalent distance. Every

 

Ethernet network

microsecond delay reduces the

 

diameter to less than

maximum link distance. In fact, every

 

4200 meters.

microsecond delay shrinks the network

 

 

diameter by approximately 200 meters

 

 

of fiber cable. Table 2-2 lists the

 

 

Equivalent Distances for other 3Com

 

 

products.

 

 

 

Designing and Expanding the Network 2 - 3

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3Com 5104M-FL1 installation and operation guide As equivalent distance. Every