Troubleshooting Physical Networks

Question 1

Network Troubleshooting Methodology: Step 1

Answer 1

1. Identify the problem

Question 2

Network Troubleshooting Methodology: Step 2

Answer 2

2. Establish a theory to determine the cause

Question 3

Network Troubleshooting Methodology: Step 3

Answer 3

3. Test the theory to determine the cause

Question 4

Network Troubleshooting Methodology: Step 4

Answer 4

4. Establish a plan of action to resolve the problem and identify potential effects

Question 5

Network Troubleshooting Methodology: Step 5

Answer 5

5. Implement the solution or escalate as necessary

Question 6

Network Troubleshooting Methodology: Step 6

Answer 6

6. Verify the whole system functionality and if applicable, implement preventive

Question 7

Network Troubleshooting Methodology: Step 7

Answer 7

7. Document findings, actions, outcomes, and lesson learned
▪ Gather more details
▪ Identify symptoms
▪ Check for changes
▪ Duplicate problem

Question 8

Riser Cable

Answer 8

▪ Used to run network cables vertically between floors in a building in a
cable riser or elevator shaft
▪ Riser cables cannot be used in plenum spaces since they are not made
from PVC or FEP

Question 9

Rollover/Console Cable

Answer 9

A cable that is used to connect a

computer to a router

Question 10

Snips or Cutters

Answer 10

▪ Used to simply cut a piece of cable off a larger spool or run of cable
▪ Looks a lot like a pair of scissors, but uses stronger blades to cut twisted
copper cables, coaxial, cables, or even larger cable bundles

Question 11

Cable strippers

Answer 11

▪ Strips the end of the cable to prepare it the attachment of a RJ-45 or
other type of connector

Question 12

Cable Crimper

Answer 12

▪ Used to attach the connector to the end of the cable
▪ support both RJ-45 and RJ-11 connectors
▪ If you are working with coaxial cables, then you will need a cable crimper
that supports an RG-6 or RG-59 connector

Question 13

Cable Tester

Answer 13

▪ Verifies continuity for each wire in the cable to ensure there are no
breaks
▪ Verifies the pinouts of the connectors
▪ Different testers for different cable types

Question 14

Multi-tester

Answer 14

▪ Supports not just ethernet cables using RJ-45, but also BNC connectors
for coaxial cables, as well as IDE, PATA, SATA, RJ-45, fiber, DB25, DB9s
and anything else that you might need to test

Question 15

Wire Map tool

Answer 15

Like a cable tester, but it works specifically for twisted pair ethernet
cables
▪ It can diagnose any issues with that cable
Open, short, reversed, crossed, split pairs

Question 16

Cable Certifier

Answer 16

Used with an existing cable to determine its Category or data throughput

Question 17

Multimeter

Answer 17

▪ Checks the voltage or the amperage or the resistance of a copper cable
▪ Used to verify if a cable is broken or not
▪ Used to check coaxial cables to ensure there is no cuts or breaks in the
middle of a patch cable, or test power sources or power cords

Question 18

Punch-Down Tool

Answer 18

▪ Used to terminate wires on a punch-down block without stripping off the
insulation
▪ Used with 66 block or 110 block, network jacks, and patch panels

Question 19

Toner Generator/Probe

Answer 19

▪ Allows technicians to generate a tone at one end of a connection and use
the probe to audibly detect the wire pair connected to the tone
generator
▪ Often called a “Fox and Hound”
▪ Fox is a tone generator
▪ Hound is a toner probe

Question 20

Loopback Adapter

Answer 20

▪ Connects transmit pins (or fibers) to receive pins (or fiber) to test a
network interface

Question 21

Time-domain Reflectometer (TDR)

Answer 21

▪ Locate breaks in a copper cable and provide an estimate of the severity
and the distance to the break

Question 22

Optical Time-domain Reflectometer (OTDR)

Answer 22

Locate breaks in a fiber able and provide an estimate of the severity
and the distance to the break

Question 23

Fiber Light Meter

Answer 23

A device that provides a continuous wave of stable source of energy for
attenuation measurements

Question 24

Fusion Splicer

Answer 24

A machine that is used to permanently join two fibers together

Question 25

Tap

Answer 25

▪ A simple device that connects directly to the cabling infrastructure to split or copy packets for use in analysis, security, or general network management ▪ Spectrum analyzer is a device that measures and displays signal amplitude (strength) as it varies by frequency within its frequency range

Question 26

Attenuation

Answer 26

▪ Loss of signal strength on a network cable or connection over the length of the cable ▪ Twisted pair cables can transmit data over a maximum distance of 100 meters ▪ Coaxial cables can transmit data over a maximum distance of 500 meters ▪ The higher the frequency, the higher the bandwidth

Question 27

Noise

Answer 27

Additional electrical or radio frequency noise in the areas where your network cables are operating o Use the proper cables for the physical environment you are operating in o Shorten the distance o Use an amplifier or repeater

Question 28

Fiber cleaning

Answer 28

Clean and polish both ends of fiber cable and connectors or switch to a cable with higher quality

Question 29

Interference

Answer 29

▪ Occurs when multiple cables in the same frequency band are operating in close proximity to each other ▪ Use high quality twisted pair cables or higher category rated cables ▪ Plan cable runs to operate in parallel to any high power cables

Question 30

Decibel (dB) Loss

Answer 30

``` ▪ Measures the amount of signal deterioration we are experiencing on a given connection ● Copper o decrease in voltage ● Fiber o amount of lost light ```

Question 31

Copper Cable Issues

Answer 31

Incorrect pinouts Bad port Open Short

Question 32

Bad port

Answer 32

If you suspect a bad port on a switch or router, you should connect a loopback plug to the port on that device and run a test using specialized software

Question 33

Open

Answer 33

There is nothing on the other end of the connection or there’s a break in the wires between the source and the destination

Question 34

Short

Answer 34

Indicates there are two wires are connected together somewhere in the connection

Question 35

Fiber Cable Issues

Answer 35

Transceiver Dry Cleaning Wet Cleaning

Question 36

Transceiver

Answer 36

▪ A transmitter and a receiver combined into a single device that converts a network connection from one type to another ▪ They are designed to support a certain type of connection and a certain cable type

Question 37

Dry Cleaning

Answer 37

▪ Using light pressure while rubbing the end face of a fiber cable or connector with a dry-cleaning cloth in one direction

Question 38

Wet Cleaning

Answer 38

▪ Moistening a piece of lint-free cloth with a fiber optic cleaning solution and wiping the end face of the cable or connector

Question 39

Ethernet Issues

Answer 39

Duplex Mismatch ▪ When one device thinks the connection is full duplex and the other thinks it is half duplex ▪ Ensure both devices are configured to auto negotiate the connection properly