5.7 Troubleshooting Networks Flashcards
Name some external sources that could interfere with wired connections.
- Power lines
- Fluorescent lighting
- Motors
- Generators
When does the activity light blink?
When sending or receiving data
What device would you use to increase the connectivity signal?
A repeater
Name four possible connectivity issues with wired networks.
- Physical connection
- Cable length
- Interference
- Port flapping
What network cables always use fiber optic connections and why?
Network cables near power lines, because they are immune to EMI
What causes port flapping?
Intermittent connectivity issue between the client and the network switch
Define a half duplex
A network that sends or receives information, but not simultaneously.
Define data exfiltration.
Sending data in the background without the user seeing it.
What is a full duplex?
A network that facilitates the simultaneous sending and receiving of information.
How are NICs set in a full duplex?
They are set to auto-negotiation.
What does the auto-negotiation setting on an NIC do?
It allows the port to communicate with the other device to determine the optimal duplex mode and speed for the connection.
List four possible causes of data exfiltration.
- Mismatch in the duplex setting
- Mismatch in the speed setting
- Network adapter drivers are out of date
- Malware infection
Which wireless standards are less prone to signal interference?
a, n, ac and ax
Give four things that could cause wireless connectivity issues.
- Intermittent wireless connectivity
- Signal interference
- Low signal strength
- Standards mismatch
What does a received signal strength indicator (RSSI) do?
Measures the signal strength based on an index level and gives a value in decibels
How could you improve the signal strength if the RSSI is displaying negative decibels?
- Increase the power of transmission
- Increase the antenna size
- Move closer to the source
Which wireless standards use 2.4 GHz?
b, g and n
Which wireless standards use 5 GHz?
a, n, ac, and ax
What are three questions you could ask to troubleshoot wireless issues?
What frequency is being used?
What is the maximum speed of that frequency?
Which versions of wireless networking are being used?
Give two possible VoIP issues.
Latency and jitter
Define latency and give the ideal measurement.
The time it takes for a signal to reach the intended client; ideally 50-100ms or less
Define jitter and when it starts to occur.
A measurement of the variation in delay over time; it starts to occur when latency increases by up to 30-50 ms.
What do the settings for quality of service (QoS) affect?
Only things inside the network
How do you allow prioritisation of voice traffic?
By setting the quality of service
How could you reduce or eliminate jitter?
By increasing network performance or implementing QoS
What does limited connectivity mean?
That a computer is not receiving incoming signals from the network.
