Avaya 8800 Planning And Engineering, Network Design page 51

Table 15: Mesh ring signal loss values
Parameter
Loss budget
OADM insertion loss for Add port
OADM insertion loss for Through port
OADM insertion loss for Drop port
System margin
Fiber attenuation
The equations and calculations used to determine the maximum transmission distance for this
network example are:
Passthrough nodes = nodes – 2 Passive loss = OADM add + OADM drop + (passthrough
nodes*OADM passthrough loss) Implied fiber loss = loss budget – passive loss – system margin
Maximum transmission distance = implied fiber loss/attenuation
In this case:
Passthrough nodes = 8 - 2 = 6 nodes Passive loss = 1.9 + 2.3 + (6*2.0)= 16.2 dB Implied fiber loss
= 30 - 16.2 - 3 = 10.8 dB Maximum reach = (10.8 dB) / (0.25 dB/km) = 43.2 km
Hub-and-spoke reach example
Hub-and-spoke topologies are complex. The characteristics of all components designed into the
network must be considered in calculating the transmission distance. The following factors
determine the maximum transmission distance for the configuration shown in the following figure.
• OADM insertion loss for Add port
• OADM insertion loss for Drop port
• OADM insertion loss for Through port for intermediate nodes
• Fiber attenuation of 0.25 dB/km
June 2016
Value
30 dB
1.9 dB
2.0 dB
2.3 dB
3.0 dB
0.25 dB/km
Planning and Engineering — Network Design
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Transmission distance
51