Juniper EX4600 Series User Manual

of component attenuation, power penalties (including those from dispersion), and a
safety margin for unexpected losses.
Related
Documentation
Calculating the EX Series Switch Fiber-Optic Cable Power Budget on page 76•
• Calculating the EX Series Switch Fiber-Optic Cable Power Margin on page 76
Calculating the EX Series Switch Fiber-Optic Cable Power Budget
Calculate the link's power budget when planning fiber-optic cable layout and distances
to ensure that fiber-optic connections have sufficient power for correct operation. The
power budget is the maximum amount of power the link 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 for fiber-optic cable power budget (P
B
) for the
link:
1. Determine values for the link's minimum transmitter power (P
T
) and minimum receiver
sensitivity (P
R
). For example, here, (P
T
) and (P
R
) are measured in decibels, and
decibels are referred to one milliwatt (dBm).
P
T
= –15 dBm
P
R
= –28 dBm
NOTE: See the specifications for your transmitter and receiver to find the
minimum transmitter power and minimum receiver sensitivity.
2. Calculate the power budget (P
B
) by subtracting (P
R
) from (P
T
):
–15 dBm – (–28 dBm) = 13 dBm
Related
Documentation
Calculating the EX Series Switch Fiber-Optic Cable Power Margin on page 76•
• Understanding EX Series Switches Fiber-Optic Cable Signal Loss, Attenuation, and
Dispersion on page 74
• Pluggable Transceivers Supported on EX Series Switches
Calculating the EX Series Switch Fiber-Optic Cable Power Margin
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
M
) is the amount of power available after
attenuation or link loss (LL) has been subtracted from the power budget (P
B
).
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
Copyright © 2014, Juniper Networks, Inc.76
EX4600 Switch Hardware Guide

Juniper EX4600 Series Specifications

General

Product Series	EX4600
10GbE ports	24 or 48
Cooling	Front-to-back or back-to-front airflow
Rack Units	1 U
Virtual Chassis	Up to 10 members
MAC address table size	288, 000 entries
Memory	8 GB DRAM
Layer 3 Routing	Yes
AC Power Input	100-240V AC
Ports	24 or 48 x 10GbE ports
40GbE ports	4
100GbE ports	0
Power Supply	Dual redundant, hot-swappable AC or DC
Jumbo frames	9216 bytes
Operating temperature	0°C to 45°C
Input voltage	100-240 VAC, -40 to -72 VDC
Operating relative humidity	5% to 90% noncondensing
Fans	Redundant
JUNOS OS	Junos OS
Storage	16 GB flash
DC Power Input	-40 to -72 VDC