Qfx10000 Console And Management Cable Specifications And Pinouts; Qfx10000 Cable Specifications For Console And Management - Juniper QFX10008 Hardware Manual

Table 58: Estimated Values for Factors Causing Link Loss (continued)
Link-Loss Factor
Fiber attenuation
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QFX10000 Console and Management Cable Specifications and Pinouts

Copyright © 2019, Juniper Networks, Inc.
Estimated Link-Loss Value
Single-mode—0.5 dB/km
Multimode—1 dB/km
The following sample calculation for a 2-km-long multimode link with a power budget
(P ) of 13 dB uses the estimated values from
B
(LL) as the sum of fiber attenuation (2 km @ 1 dB/km, or 2 dB) and loss for five connectors
(0.5 dB per connector, or 2.5 dB) and two splices (0.5 dB per splice, or 1 dB) as well as
higher-order mode losses (0.5 dB). The power margin (P
P = P – LL
M B
P = 13 dB – 2 km (1 dB/km) – 5 (0.5 dB) – 2 (0.5 dB) – 0.5 dB
M
P = 13 dB – 2 dB – 2.5 dB – 1 dB – 0.5 dB
M
P = 7 dB
M
The following sample calculation for an 8-km-long single-mode link with a power budget
(P ) of 13 dB uses the estimated values from
B
(LL) as the sum of fiber attenuation (8 km @ 0.5 dB/km, or 4 dB) and loss for seven
connectors (0.5 dB per connector, or 3.5 dB). The power margin (P
follows:
P = P – LL
M B
P = 13 dB – 8 km (0.5 dB/km) – 7(0.5 dB)
M
P = 13 dB – 4 dB – 3.5 dB
M
P = 5.5 dB
M
In both examples, the calculated power margin is greater than zero, indicating that the
link has sufficient power for transmission and does not exceed the maximum receiver
input power.
QFX10000 Line Cards on page 71
Maintaining QFX10000 Line Cards on page 221
QFX10000 Cable Specifications for Console and Management Connections on page 136
RJ-45 to DB-9 Serial Port Adapter Pinout Information on page 136
RJ-45 Management Port Connector Pinout Information on page 137
Chapter 2: Site Planning, Preparation, and Specifications
Table 58 on page 134
) is calculated as follows:
M
Table 58 on page 134
M
to calculate link loss
to calculate link loss
) is calculated as
135