5.7 Given a scenario, troubleshoot problems with wired and wireless networks.

Question 1

Intermittent wireless
connectivity

Answer 1

• Interference– Something else is using our frequency
• Signal strength– Transmitting signal, transmitting antenna,
  receiving antenna, etc.
• Incorrect channel– Usually automatic; look for manual tuning
• Bounce and latency– Multipath interference; flat surfaces
• Incorrect access point placement

Hardware components that cause connectivity issues are a network cable, network interface card (NIC), Interference, DHCP Issues, DNS problems.

Question 2

Slow network speeds

Answer 2

Caused by hardware and software issues. Can be caused by incorrect cabling, Malfunctioning NIC. From software viewpoint it can be caused by router misconfiguration and switch misconfiguration.

Question 3

Limited connectivity

Answer 3

• Windows alert in the system tray– “Limited or No connectivity”– “No Internet Access”
• Check the local IP address– An APIPA address will only have local connectivity
• If DHCP address is obtained,perform the ping tests– Local gateway, remote IP addre

Issues that reside on other layers of the OSI model include authentication issues, and DNS issues,

Question 4

Jitter

Answer 4

• Most real-time media is sensitive to delay– Data should arrive at regular intervals– Voice communication, live video
• If you miss a packet, there’s no retransmission– There’s no time to “rewind” your phone call
• Jitter is the time between frames– Excessive jitter can cause you to miss information,
  “choppy” voice calls

Solutions include upgrading the router, Increasing the bandwidth and implementing a jitter buffer.

Question 5

Poor Voice over Internet
Protocol (VoIP) quality

Answer 5

• High speed and low latency– Real-time applications are demanding
• Check the Internet connection– A speed test can identify slow links
• Verify the local networking equipment– An old router can cause significant problems
• View the network performance– A packet capture would be useful

Question 6

Port flapping

Answer 6

• Network interface goes up and down– Over and over again
• Verify the cable– Check the wiring
• Move between switch interfaces– Is the flapping associated with the switch
  interface or the device?
• Replace bad hardware or cables– May require additional purchase

Question 7

High latency

Answer 7

Means the network is slow. Use Tracert to determine where the slow subnets resides and then concentrate your troubleshooting effort there.

Question 8

External interference

Answer 8

Effects wireless and wired networks. EMI will degrade network performance. Run cables around (not over) ballasts and other items that can cause EMI.