CompTIA exam study guide presentations by instructor Brian Ferrill, PACE-IT (Progressive, Accelerated Certifications for Employment in Information Technology)
"Funded by the Department of Labor, Employment and Training Administration, Grant #TC-23745-12-60-A-53"
Learn more about the PACE-IT Online program: www.edcc.edu/pace-it
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Instructor, PACE-IT Program – Edmonds Community College
Areas of Expertise Industry Certifications
PC Hardware
Network Administration
IT Project Management
Network Design
User Training
IT Troubleshooting
Qualifications Summary
Education
M.B.A., IT Management, Western Governor’s University
B.S., IT Security, Western Governor’s University
Entrepreneur, executive leader, and proven manger
with 10+ years of experience turning complex issues
into efficient and effective solutions.
Strengths include developing and mentoring diverse
workforces, improving processes, analyzing
business needs and creating the solutions
required— with a focus on technology.
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– Summary of troubleshooting methodology.
– Common copper wire problems.
PACE-IT.
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Seven-step troubleshooting methodology.
1) Identify the problem.
» A mistake in identifying the problem can negate the rest of the steps!
» Remember, the problem is not the symptom; the problem is what is
causing the symptom to occur.
2) Establish a theory of probable cause.
3) Test the theory of probable cause.
4) Establish a plan of action to resolve the problem.
5) Implement the solution, or escalate as necessary.
6) Verify full system functionality.
7) Document findings, actions, and outcomes.
Troubleshooting copper wire networks I.
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– Electromagnetic interference (EMI)/radio
frequency interference (RFI).
» Becausecopperwiretransmissionsareelectricalinnature,theirelectricalsignals
canbedegradedbysourcesofEMIandRFI.
• Sources of EMI/RFI may corrupt the network signal, leading to
loss of communication or poor communication between end
nodes.
» Sources of EMI/RFI include:
• Other electrical wires; network cables should be kept separate
from normal electrical runs and, if possible, network cabling
should cross electrical wires at a 90⁰ angle.
• Other electrical components may inject EMI and RFI into the
environment; manufacturing environments often have a lot of
EMI and RFI present.
• One major source of EMI/RFI is fluorescent lights.
» EMI/RFI problems can often be identified by when they occur;
for instance, does the problem only happen when somebody
turns on all the lights?
• The solution may be to move from UTP to STP or to re-route
the network cable to avoid the source of the EMI/RFI.
Troubleshooting copper wire networks I.
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– Distance limitations.
» All network transmission media experience attenuation—loss of
signal strength over distance—which can lead to poor
communication or loss of communication between end nodes.
• A decibel (dB) logarithmic scale is used to measure the
amount of acceptable and unacceptable attenuation.
• As network transmission speeds increase, the attenuation
also increases—as a ratio of signal-to-signal loss.
» Possible attenuation issues can be identified when a cable
cannot handle the higher transmission speeds for which it is
rated.
» A cable certifier or time-domain reflectometer (TDR) will usually
identify this problem.
• Possible solutions are to install a network switch to boost the
signal strength, or to re-route the network run to create a
shorter run of cable.
Troubleshooting copper wire networks I.
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– Crosstalk.
» Even with the steps taken to reduce it, all cables experience
crosstalk between the pairs, which can lead to intermittent or
constant transmission issues.
• More crosstalk is present at the near end (where the
transmission originates) than at the far end (where the
transmission is received).
• As network transmission speeds increase, the opportunity for
crosstalk increases.
» A good cable certifier or TDR will identify the problem.
• Possible solutions include replacing the network run with
cable rated for a higher transmission speed, replacing the
cable with one that has better shielding, or reducing the
transmission rate of the network.
Troubleshooting copper wire networks I.
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– Bad connectors.
» Once a good cable is in use, the end connectors may still
become broken—especially after repeated use, leading to a
loss in connectivity.
• The locking tabs on an RJ45 can be easily broken, leading to
a loose connection—creating an open connection.
» A cable tester may identify this problem as an open connection,
a thorough inspection of the cable ends can help to identify the
problem.
• The solution is to replace the bad connector with a good one.
– Bad cable.
» Cables can go bad—especially if they are in places susceptible
to damage—leading to loss in connectivity or poor network
communication.
» A cable tester can be used to identify the problem as either an
open connection or a short.
• An open connection indicates a broken wire.
• A short indicates an electrical signal is traveling down an
unintended path—down the wrong wire.
• The solution is to replace the bad network cable.
Troubleshooting copper wire networks I.
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Troubleshooting copper wire networks I.
A seven-step troubleshooting methodology involves: identifying the
problem, establishing a theory of probable cause, testing the theory of
probable cause, establishing a plan of action to resolve the problem,
implementing the solution or escalating, verifying full system functionality,
and documenting findings, actions, and outcomes. Misidentifying the
problem can negate the rest of the troubleshooting steps.
Topic
Summary of troubleshooting
methodology.
Summary
Possible copper wire network problems include: EMI/RFI, cables exceeding
their distance limitations, too much crosstalk, bad connectors, and bad
cabling.
Common copper wire
problems.
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U.S. Department of Labor's Employment and Training Administration. The solution was
created by the grantee and does not necessarily reflect the official position of the U.S.
Department of Labor. The Department of Labor makes no guarantees, warranties, or
assurances of any kind, express or implied, with respect to such information, including
any information on linked sites and including, but not limited to, accuracy of the
information or its completeness, timeliness, usefulness, adequacy, continued availability
or ownership. Funded by the Department of Labor, Employment and Training
Administration, Grant #TC-23745-12-60-A-53.
PACE-IT is an equal opportunity employer/program and auxiliary aids and services are
available upon request to individuals with disabilities. For those that are hearing
impaired, a video phone is available at the Services for Students with Disabilities (SSD)
office in Mountlake Terrace Hall 159. Check www.edcc.edu/ssd for office hours. Call
425.354.3113 on a video phone for more information about the PACE-IT program. For
any additional special accommodations needed, call the SSD office at 425.640.1814.
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