Troubleshooting & Tools

Question 1

Network Troubleshooting Process

Answer 1

1. Identify the problem
   a) Info gathering, identify symptoms, question users
2. Establish a theory
3. Test the theory to determine cause
4. Establish a plan of action to resolve the problem and
   identify potential effects.
5. Implement the solution or escalate as necessary
6. Verify full system functionality and, if applicable,
   implement preventative measures
7. Document findings, actions and outcomes

Question 2

NEXT

Answer 2

Near End Crosstalk

Interference measured at the transmitting end (near end)

Question 3

FEXT

Answer 3

Far End Crosstalk

Interference measured away from the transmitter

Question 4

AXT

Answer 4

Alien Crosstalk

Interference from other cables

Question 5

ACR

Answer 5

Attenuation to Crosstalk Ratio

Difference btween insertion loss and NEXT
Signal-to-Noise Ratio (SNR)

Question 6

Lineman’s Handset/Butt Set

Answer 6

Connect to a circuit from the closet

Used to confirm or troubleshoot an installation

Question 7

Cable Tester

Answer 7

Measure the quality of a cable installation

Near end crosstalk, attenuation, etc.

Question 8

Loopback Plug

Answer 8

Used for diagnostics and troubleshooting

Determine if a received signal is the same as the sent signal

Question 9

Punch-down tool

Answer 9

Forces wires into a wiring block

Trims the wires and breaks the insulation

Question 10

Crimper

Answer 10

“Pinches” the connector onto the wire

the final step of a cable installation

Question 11

Multimeter

Answer 11

Measures voltage, current, resistance

Check AC/DC voltage, cable continuity

Question 12

Toner Probe

Answer 12

Find specific wire

2 pieces: tone generator and inductive probe

Question 13

Protocol Analyzer

Answer 13

Capture data from the network

Decodes and analyzes the packets

Question 14

TDR/OTDR

Answer 14

(Optical) Time Doman Reflectometer

Estimate cable lengths, identify splice locations, measure impedance, measure signal loss

Question 15

Environmental Monitor

Answer 15

Temperature, humidity, water
Measure power voltages
Network connectivity
Multiple sensor inputs

Question 16

Throughput Tester

Answer 16

Network throughput

Application performance

Question 17

Hypervisor

Answer 17

Bridges the virtual world to the physical

Manages virtual machine resources

Question 18

Hypervisor Types

Answer 18

Type 1- Bare metal

Type 2- Runs on existing OS

Question 19

ping

Answer 19

Tests reachability
Provides round-trip timing
Uses ICMP

Question 20

traceroute/tracert

Answer 20

Determine the path a packet takes to a destination
Uses ICMP Time to Live Exceeded
Traces all routers between two points

Question 21

NSLookup/dig

Answer 21

Lookup information from DNS servers

Canonical names, IP addresses, cache timers, etc.

Question 22

ipconfig/ifconfig

Answer 22

ipconfig - Windows TCP/IP configuration

ifconfig - Linux interface configuration

Question 23

ARP

Answer 23

Address Resolution Protocol

View local ARP table
View local ARP results

Question 24

nbstat

Answer 24

NetBIOS name resolution
Query local an dremote devices
Useful for legacy networks

Question 25

netstat

Answer 25

View network statistics
Works on many different OS
Many, many options

Question 26

route

Answer 26

Manage local IP routing table
Print, add, delete change
Available on different OS