Calculating The Ex Series Switch Fiber-Optic Cable Power Margin; Table 43: Estimated Values For Factors Causing Link Loss - Juniper EX4500 Hardware Manual

EX4500 Switch Hardware Guide
Related
Documentation

Calculating the EX Series Switch Fiber-Optic Cable Power Margin

Table 43: Estimated Values for Factors Causing Link Loss

Link-Loss Factor
Higher-order mode losses (HOL)
Modal and chromatic dispersion
Connector
86
Calculating the EX Series Switch Fiber-Optic Cable Power Margin on page 86
Understanding EX Series Switches Fiber-Optic Cable Signal Loss, Attenuation, and
Dispersion on page 98
Pluggable Transceivers Supported on EX Series Switches on page 90
Calculate the link's power margin when planning fiber-optic cable layout and distances
to ensure that fiber-optic connections have sufficient signal power to overcome system
losses and still satisfy the minimum input requirements of the receiver for the required
performance level. The power margin (P
attenuation or link loss (LL) has been subtracted from the power budget (P
When you calculate the power margin, 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 worst-case
levels. A power margin (P
M
to operate the receiver and that it does not exceed the maximum receiver input power.
This means the link will work. A (P
to operate the receiver. See the specification for your receiver to find the maximum
receiver input power.
Before you begin to calculate the power margin:
Calculate the power budget. See
Power Budget" on page
To calculate the worst-case estimate for the power margin (P
Determine the maximum value for link loss (LL) by adding estimated values for
1.
applicable link-loss factors—for example, use the sample values for various factors
as provided in Table 43 on page 86
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
) is the amount of power available after
M
) greater than zero indicates that the power budget is sufficient
) that is zero or negative indicates insufficient power
M
"Calculating the EX Series Switch Fiber-Optic Cable
85.
(here, the link is 2 km long and multimode, and
Sample (LL) Calculation Values
This example assumes 5 connectors.
Loss for 5 connectors:
(5) * (0.5 dBm) = 2.5 dBm
).
B
) for the link:
M
0.5 dBm
0 dBm
0 dBm
0 dBm
Copyright © 2017, Juniper Networks, Inc.