Juniper MX2010, Hardware Manual

Page: 173 / 825

CHAPTER 10
Transceiver and Cable Specifications
IN THIS CHAPTER
Calculating Power Budget and Power Margin for Fiber-Optic Cables | 151
Understanding Fiber-Optic Cable Signal Loss, Attenuation, and Dispersion | 153
CB-RE and RCB Interface Cable and Wire Specifications for MX Series Routers | 155
Routing Engine Interface Cable and Wire Specifications for MX Series Routers | 156
Calculating Power Budget and Power Margin for Fiber-Optic Cables
Use the information in this topic and the specifications for your optical interface to calculate the power
budget and power margin for fiber-optic cables.
TIP: You can use the Hardware Compatibility Tool to find information about the pluggable
transceivers supported on your Juniper Networks device.
To calculate the power budget and power margin, perform the following tasks:
1.
Calculating Power Budget for Fiber-Optic Cable | 151
2.
Calculating Power Margin for Fiber-Optic Cable | 152
Calculating Power Budget for Fiber-Optic Cable
To ensure that fiber-optic connections have sufficient power for correct operation, you need to calculate
the link's power budget, which is the maximum amount of power it can transmit. When you calculate the
power budget, you use a worst-case analysis to provide a margin of error, even though all the parts of an
actual system do not operate at the worst-case levels. To calculate the worst-case estimate of power
budget (P
B
), you assume minimum transmitter power (P
T
) and minimum receiver sensitivity (P
R
):
P
B
= P
T
– P
R
151