Sample Configuration Distance Calculation - 3Com CoreBuilder 5000 User Manual

2-6 D E
ESIGNING AND
Fiber Backbone, Twisted
Pair To-The-Desk
Fiber
backbone
1000 m
N
XPANDING THE ETWORK
In the sample configuration shown in
transceivers are within legal Ethernet distance limits. Note that
24-gauge unshielded twisted-pair cable is used to connect 10BASE-T
transceivers to the 24-Port modules in the hubs.
The first step is to identify the two transceivers that are the greatest
fiber equivalent distance apart. In this case, they are 10BASE-T
transceivers A and B.
Hub A
100 m
Hub B
75 m
500 m
Fiber backbone
Hub C
Figure 2-1

Sample Configuration Distance Calculation

Use the following steps to determine whether your network
configuration is legal:
1 Begin with 4.2 km (4200 m) since this is the maximum network
diameter for a pure fiber network (Rule 3).
2 Determine the sum of each hub's equivalent distance based on the
figures in Table
470 m. This total represents the sum of the incoming signal to the UTP
port (420 m) and the outgoing signal from the fiber port (50 m). Refer
to Figure 2-1 for further details.
Unshielded twisted pair
A
Unshielded twisted pair
B
Unshielded twisted pair
C
2-2. For example, Hub A has an equivalent distance of
Figure 2-1, we determine if the
Configuration Distance
1. Maximum Diameter:
2. Equivalent Distances:
Hub A: 470 m
Hub B: 305 m
Hub C: 190 m
Total: 965 m
3. Amount of cable between
transceivers:
1000 m
100 m
500 m
75 m
Total:
4. Remaining Distance:
4200 m
1675 m
1560 m