Nortel Communication Server 1000 Series Manual page 35

Assume a 12 km length of fiber made from twelve 1 km lengths of cable
with eleven splices in the cable (one splice every 1 km).
Calculations:
Example 4 - High quality single-mode cable and splices
High quality single-mode cable provides a loss of 0.5 dB per km. High
quality splices provide 0.1 dB loss per splice.
Assumptions:
•
•
•
Assume a 25 km length of fiber made from twenty-five 1 km lengths of
cable with twenty-four splices in the cable (one splice every 1 km).
Calculations:
System selection
In some applications where non-blocking or low blocking traffic
considerations are important, you have to limit the number of peripheral
cards supported by each superloop. For a non-blocking condition, the 120
voice/data timeslots (one superloop) support seven or eight 16-port line
cards. Each additional line card in the IPE module increases call blocking
under high traffic conditions. Refer to Communication Server 1000M and
Meridian 1 Large System Planning and Engineering (NN43021-220) () to
calculate traffic.
A Remote IPE module supports 16 line cards and provides a maximum
of 256 ports (different IPE cards provide different number of ports).
This column can be expanded by adding more IPE modules to support
Copyright © 2007-2009 Nortel Networks
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dB loss = (12km) x (1.0 dB per km) + (11 splices) x (0.2 dB per splice)
dB loss = 12.0dB + 2.2 dB = 14.2 dB
Safety margin = 15 dB - 14.2 dB = 0.8 dB
dB loss allowed over single-mode fiber by the Fiber Remote Multi-IPE
Interface: 15 dB
dB loss per km of fiber: 0.5 dB
dB loss per splice: 0.1 dB
dB loss = (25km) x (0.5 dB per km) + (24 splices) x (0.1 dB per splice)
dB loss = 12.5dB + 2.4 dB = 14.9 dB
Safety margin = 15 dB - 14.9 dB = 0.1 dB
Nortel Communication Server 1000
Fiber Remote Multi-IPE Interface Fundamentals
NN43021-556 03.01
11 May 2009
Engineering guidelines 35