Table 57: Estimated Values For Factors Causing Link Loss - Juniper QFX10016 Hardware Manual

Table 57: Estimated Values for Factors Causing Link Loss

Link-Loss Factor
Higher-order mode losses
Modal and chromatic
dispersion
Connector
Splice
Fiber attenuation
Clock Recovery Module
(CRM)
Copyright © 2017, Juniper Networks, Inc.
as provided in Table 57 on page 133
the (P ) is 13 dBm).
B
Estimated Link Loss Value
Multimode—0.5 dBm
Single-mode—None
Multimode—None, if product of
bandwidth and distance is less
than 500 MHz/km
Single-mode—None
0.5 dBm
0.5 dBm
Multimode—1 dBm/km
Single-mode—0.5 dBm/km
1 dBm
NOTE: For information about the actual amount of signal loss caused by
equipment and other factors, see your vendor documentation for that
equipment.
Calculate the (P ) by subtracting (LL) from (P
2.
M
P – LL = P
B M
13 dBm – 0.5 dBm [HOL] – 5 (0.5 dBm) – 2 (0.5 dBm) – 2 km (1.0 dBm/km) – 1 dB
[CRM] = P
M
13 dBm – 0.5 dBm – 2.5 dBm – 1 dBm – 2 dBm – 1 dBm = P
P = 6 dBm
M
The calculated power margin is greater than zero, indicating that the link has sufficient
power for transmission. Also, the power margin value does not exceed the maximum
receiver input power. Refer to the specifications for your receiver to find the maximum
receiver input power.
Chapter 10: Transceiver and Cable Specifications
(here, the link is 2 km long and multimode, and
Sample Link Loss (LL) Calculation Values
0.5 dBm
0 dBm
0 dBm
0 dBm
This example assumes five connectors. Loss for five
connectors: 5 (0.5 dBm) = 2.5 dBm.
This example assumes two splices. Loss for two splices:
2 (0.5 dBm) = 1 dBm.
This example assumes the link is 2 km long. Fiber
attenuation for 2 km: 2 km (1 dBm/km) = 2 dBm.
This example assumes the link is 2 km long. Fiber
attenuation for 2 km: 2 km (0.5 dBm/km) = 1 dBm.
1 dBm
):
B
M
133