Table 55: Estimated Values For Factors Causing Link Loss - Juniper EX6210 Complete Hardware Manual

Table 55: Estimated Values for Factors Causing Link Loss

Link-Loss Factor
Higher-order mode losses (HOL)
Modal and chromatic dispersion
Connector
Splice
Fiber attenuation
Clock Recovery Module (CRM)
Copyright © 2014, Juniper Networks, Inc.
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 55 on page 123
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
13 dBm – 0.5 dBm – 2.5 dBm – 1 dBm – 2 dBm – 1 dBm = P
"Calculating the EX Series Switch Fiber-Optic Cable
122.
(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
This example assumes 2 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:
1 dBm
):
B
M
Chapter 7: Planning Power Requirements
) for the link:
M
0.5 dBm
0 dBm
0 dBm
0 dBm
(2 km) * (1.0 dBm/km) = 2 dBm
(2 km) * (0.5 dBm/km) = 1 dBm
M
123