Juniper EX9208, Руководство по оборудованию, Страница: 168 / 396

Related
Documentation
Installing a Transceiver in a Switch on page 255
•
•
Removing a Transceiver from a Switch on page 257
Management Cable Specifications
Table 59 on page 144 lists the specifications for the cables that connect the console ( CON )
and management ( MGMT ) ports to management devices.
Table 59: Specifications of Cables to Connect to Management Devices
Additional Information Receptacle Cable Specifications Ports
Connecting a Switch to a
Management Console RJ-45 CAT5e UTP (unshielded
twisted pair) cable RJ-45 Console (
CON2
) port
Connecting a Device to a
Network for Out-of-Band
Management – – Management (
MGMT
)
Ethernet port (10/100/1000)
– – Mini-USB Type-B Console
(
CON1
) port
Understanding EX Series Switches Fiber-Optic Cable Signal Loss, Attenuation, and
Dispersion
To determine the power budget and power margin needed for fiber-optic connections,
you need to understand how signal loss, attenuation, and dispersion affect transmission.
EX Series Switches use various types of network cable, including multimode and
single-mode fiber-optic cable.
• Signal Loss in Multimode and Single-Mode Fiber-Optic Cable on page 144
• Attenuation and Dispersion in Fiber-Optic Cable on page 145
Signal Loss in Multimode and Single-Mode Fiber-Optic Cable
Multimode fiber is large enough in diameter to allow rays of light to reflect internally
(bounce off the walls of the fiber). Interfaces with multimode optics typically use LEDs
as light sources. However, LEDs are not coherent light sources. They spray varying
wavelengths of light into the multimode fiber, which reflects the light at different angles.
Light rays travel in jagged lines through a multimode fiber, causing signal dispersion.
When light traveling in the fiber core radiates into the fiber cladding (layers of lower
refractive index material in close contact with a core material of higher refractive index),
higher-order mode loss (HOL) occurs. Together, these factors reduce the transmission
distance of multimode fiber compared to that of single-mode fiber.
Single-mode fiber is so small in diameter that rays of light reflect internally through one
layer only. Interfaces with single-mode optics use lasers as light sources. Lasers generate
a single wavelength of light, which travels in a straight line through the single-mode fiber.
Copyright © 2017, Juniper Networks, Inc. 144
EX9208 Switch Hardware Guide