PACE-IT: Troubleshooting Copper Wire Networks (part 2)

Troubleshooting copper wire networks II.

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.

Brian K. Ferrill, M.B.A.

Troubleshooting copper wire networks II.PACE-IT.

– What constitutes a bad cable?

– Common copper wire problems.

What constitutes a bad cable?Troubleshooting copper wire networks II.

Network cables can go bad, or be bad, without any visible indication. Additionally, a cable may be inappropriate for a particular application.

Anything that makes a cable fall outside of specifications will make it a bad cable. How long is the cable? Is the cable over its maximum run length? Is the cable rated for the amount of data being run over the wire? All of these, plus more, can constitute a bad cable.

By using the proper tools and methodology, a bad cable can be identified and any problems associated with the bad cable can be rectified.



– Copper wire termination standards.» The TIA/EIA (Telecommunications Industry

Association/Electronics Industry Alliance) has developed a set of termination standards for twisted pair copper wire.

• The standards ensure that network transmission is consistent across networks.

» The standards involve how the pairs of wires are ordered when placed in the termination device—usually either an RJ45 or punchdown block.

» The current termination standards are:• T568B: white orange-orange, white green-blue, white

blue-green, white brown-brown.• T568A: white green-green, white orange-blue, white

blue-orange, white brown-brown.» Not following the standards may lead to network

problems.• Cable testers and certifiers can be used to determine

if a twisted pair copper wire network cable meets the standards.

Common copper wire problems.Troubleshooting copper wire networks II.


– Twisted pair termination standards.» A straight-through cable is used to connect different

types of devices (e.g., a computer to a switch, or a switch to a router).

• Both ends of the cable are terminated to the same standard.

» A crossover cable is used to connect similar types of devices (e.g., a computer to a computer, or a switch to a switch).

• One end will be terminated to the T568A standard and the other end will be terminated to the T568B standard.

– Mismatched cabling standards.» Using the wrong type of cable (e.g., using a straight-

through cable when a crossover cable is specified) can lead to network problems.

• Many IT devices use a process called auto-MDI/MDI-X in which they can auto-sense the type of device on the other end of a cable and electronically change their send/receive setup to match the cable used. Reliance on this may contribute to the problem.

» Cable testers can be used to help identify the problem.


– Split pairs.» The problem occurs during the termination process.

• At least two pairs of wires that should be grouped together in the termination device (e.g., the RJ45 or punchdown block) get separated.

» The problem may not be identifiable with the most basic of cable testers.

• If the split pairs are due to a misunderstanding of the termination standards, it may still test as a straight-through or crossover cable. This often leads to a crosstalk issue.

• A good cable certifier can identify the problem.

– Tx/Rx (transmit/receive) reverse.» A PC type device uses pins 1 and 2 (one pair of wires) to

transmit a signal and pins 3 and 6 (another pair of wires) to receive a signal.

• The receiving device must be configured to either receive on pins 1 and 2 and transmit on pins 3 and 6 or the proper cable must be used. If not, the link will not be created—Tx/Rx reverse.

» If the link fails to be created, check the pinout on the cables to ensure that a Tx/Rx reverse has not occurred.

What was covered.Troubleshooting copper wire networks II.

Anything that makes a network cable fall out of its specifications constitutes a bad cable. The TIA/EIA created a set of specifications on how to terminate twisted pair copper wire—the T568B and T568A standards. Following these standards will help to reduce the probability of copper wire network problems.

Topic

What constitutes a bad cable?

Summary

A straight-through cable is terminated to the same standard on both ends. A crossover cable is terminated to the T568A standard on one end and the T568B standard on the other. Mismatched termination standards can lead to problems in network communication. Split pairs can still test as good but lead to problems with crosstalk. A Tx/Rx reverse problem will prevent a transmission link between devices.

Common copper wire problems.

THANK YOU!

This workforce solution was 100 percent funded by a $3 million grant awarded by the 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. Edmonds Community College does not discriminate on the basis of race; color; religion; national origin; sex; disability; sexual orientation; age; citizenship, marital, or veteran status; or genetic information in its programs and activities.

PACE-IT: Troubleshooting Copper Wire Networks (part 2)

Education

Transcript of PACE-IT: Troubleshooting Copper Wire Networks (part 2)