Juniper QFX10016, Руководство по оборудованию

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P
M
= 13 dB – 2 km (1 dB/km) – 5 (0.5 dB) – 2 (0.5 dB) – 0.5 dB
P
M
= 13 dB – 2 dB – 2.5 dB – 1 dB – 0.5 dB
P
M
= 7 dB
The following sample calculation for an 8-km-long single-mode link with a power budget (P
B
) of 13 dB
uses the estimated values from Table 70 on page 185 . This example calculates link loss (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
M
) is calculated as follows:
P
M
= P
B
– LL
P
M
= 13 dB – 8 km (0.5 dB/km) – 7(0.5 dB)
P
M
= 13 dB – 4 dB – 3.5 dB
P
M
= 5.5 dB
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.
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Maintaining QFX10000 Line Cards
QFX10000 Console and Management Cable
Specifications and Pinouts
IN THIS SECTION
QFX10000 Cable Specifications for Console and Management Connections | 187
RJ-45 to DB-9 Serial Port Adapter Pinout Information | 188
RJ-45 Management Port Connector Pinout Information | 188
Console Port Connector Pinout Information | 189
186