5.7 Troubleshooting Wired and Wireless Networks

Question 1

Intermittent wireless connectivity

Answer 1

• frequency interference
• check signal strength
• incorrect channel: try manual tuning to look for other channels
• change access point location

Question 2

Slow network speeds

Question 3

Limited connectivity

Answer 3

• check the local IP address
• an APIPA address means that the DHCP server is not available
• APIPA will only have local connectivity

Question 4

Jitter

Answer 4

• the time between frames
• real-time media is sensitive to jitter

Question 5

Poor VoIP quality

Answer 5

• other applications can cause latency
• check internet connection
• replace old equipment
• perform a packet capture to better understand where the problem is occuring

Question 6

Port flapping

Answer 6

• network interface goes up and down repeatedly
• usually a physical issue between two devices
• verify the cable: does it support the ethernet standards and speed you are using
• test a different interface/port on the device
• replace bad hardware and/or cables

Question 7

High latency

Answer 7

• delay between a request and a response
• packet captures can provide detailed analysis

Question 8

External interference

Answer 8

Other devices that use the same frequency as the access point
- fluorescent lights, microwaves, cordless phones

• buildings with many tenants may experience this
• check the signal to noise ratio

Question 9

No network connection

Answer 9

Is the network device plugged in?
- link light shows connection status

Perform ping tests to see where we lose connectivity
1. ping loopback (127.0.0.1)
2. ping local IP address
3. ping default gateway
4. ping a device on the internet
- ex. Google’s DNS server at 8.8.8.8