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B.3.1 Network Performance Requirements
The overall cabling system used in a Token Ring network must meet the
performance requirements listed in
Table B-1 Token Ring Network Performance Requirements
Maximum
Total Signal
Attenuation
14.5 dB
B.3.2 Signal Interference
Some of the conditions that degrade Token Ring signals are:
Crosstalk
•
Noise
•
•
Temperature
Crosstalk
Crosstalk is interference caused by signal coupling between different
cable pairs contained within a multi-pair cable bundle. Multi-pair cabling
jackets should not be used for routing Token Ring trunk cabling,
especially at 16 Mbps. Avoid mixing Token Ring cabling with other
cabling systems (e.g., telephone) within the same multi-pair bundle.
Noise
Noise can be caused by crosstalk or other energy sources. If
noise-induced errors are suspected, ensure that the electrical circuitry in
the area is properly wired and grounded and/or try re-routing cabling
away from potential noise sources (motors, switching equipment,
fluorescent lighting, high amperage equipment).
Temperature
The attenuation level of PVC-insulated cable varies significantly with
temperature. So check the cable manufacturer's specifications.
Plenum-rated cables are strongly recommended in areas where
temperatures exceed 40 C (104 F). Under such conditions, plenum-rated
cables ensure that cable attenuation tolerance remains within
specifications.
Table
B-1.
.
Maximum
Total Ambient
Noise
20 dBmV
Minimum
NEXT loss
per 100 m
30.5 dB
CABLING
B-3
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