Black Box 100 mbps Compact Media Converter Computer Hardware User Manual


 
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About FiberAlert and LinkLoss
The Compact Media Converter comes with the following troubleshooting fea-
tures:
FX LinkLoss (LinkLoss over a Fiber cable)
TX LinkLoss (LinkLoss over a Twisted Pair cable)
FiberAlert (including Pulsing FiberAlert)
LinkLoss and FiberAlert are advanced troubleshooting features that can help
locate "silent failures" on a network. Users should understand how FiberAlert and
LinkLoss work, and how they will act in a network environment, before attempt-
ing to install the Compact Media Converter.
About Link Integrity
During normal operation, link integrity pulses are transmitted by all point-to-
point Ethernet devices. When a Compact Media Converter receives valid link puls-
es, it knows that the device to which it is connected is functioning, and that the cop-
per or fiber cable coming from that device is intact. The appropriate “LINK” LED
is lit to indicate this. The Compact Media Converter also sends out link pulses
from its copper and fiber transmitters, but normally has no way of knowing
whether the cable to the other device is intact and the link pulses are reaching the
other end. FiberAlert and LinkLoss allow this information to be obtained from the
fiber, even when physical access to a remote device (and its link integrity LED) is
not available.
What Is FX LinkLoss?
FX LinkLoss is a troubleshooting feature that allows users to detect failures over
the fiber connection. When a fault occurs on the fiber segment of a conversion, FX
LinkLoss detects the fault and passes this information to the twisted pair segment.
If a Compact Media Converter is not receiving a fiber link, FX LinkLoss disables
the transmitter on the Compact Media Converter 's twisted pair port. This results
in a loss of link on the device connected to the twisted pair port.
What Is TX LinkLoss?
TX LinkLoss is a troubleshooting feature that allows users to detect failures
over the twisted-pair connection. When a fault occurs on the twisted pair segment
of a conversion, TX LinkLoss detects the fault and passes this information to the
fiber segment. If a Compact Media Converter is not receiving a twisted pair link,
TX LinkLoss disables the transmitter on the media converter's fiber port. This
results in a loss of link on the device connected to the fiber port.
What is FiberAlert?
FiberAlert is a troubleshooting feature that minimizes the problems associ-
ated with the loss of one strand of fiber. If a strand is unavailable, the
Compact
Media Converter
notes the lost link and will stop transmitting data and the link
signal until a signal or link pulse is received. The result is that the link LED
on BOTH sides of the fiber connection will go out indicating a fault somewhere
in the fiber loop. Using
FiberAlert, a local site
administrator is notified
of a fault and can quick-
ly determine the location
of a cable fault.
Using FiberAlert and LinkLoss
The following table provides an overview of the troubleshooting features,
their functionality and the recommended settings for a pair of media convert-
ers in a typical central/main site to remote site application:
NOTE
Without understanding LinkLoss and FiberAlert, the 100 Mbps Compact Media
Converter could appear flawed or even malfunctioning.
LinkLoss/FiberAlert Comparison Table
Feature Fault Location Disabled LEDs Enable At
FX LinkLoss Fiber Twisted Pair Main Site Only
TX LinkLoss Twisted Pair Fiber Remote Site Only
FiberAlert Fiber Fiber Remote Site Only
NOTE
FiberAlert is not available/applicable on single-strand fiber versions of
Compact Media Converter.