Network Troubleshooting | Ethernet Troubleshooting | NETSCOUT

Network Troubleshooting: Ethernet Network Troubleshooting

Local area networks (LAN) are integral to the operation of many businesses today. The most common LANs use Ethernet, a data link layer protocol, and Internet Protocol (IP), a network layer protocol.

A LAN is comprised of many elements: printers, monitors, PCs, IP phones, servers, storage hardware, networking equipment, security software, network applications, enterprise applications, office productivity applications, and more. Devices on the network are linked physically by twisted pair copper, fiber or wireless access points.

LAN Network Troubleshooting is typically the job for the frontline network support staff - engineers and technicians. Common Ethernet network troubleshooting problems include user connection issues and slow networks.

Root causes of Ethernet network troubleshooting problems are frequently caused by one of these three sources:

1. Physical layer: copper, fiber or wireless

Possible causes:

  • Damaged or dirty cabling or terminations
  • Excessive signal attenuation
  • Insufficient cable bandwidth
  • Wireless interference

2. Network Layer: Ethernet and IP

Possible causes:

  • Damaged networking devices
  • Incorrect or sub-optimal device configurations
  • Authentication and association issues
  • Insufficient network bandwidth

3. Switches and VLANs

Possible causes:

  • Excessive utilization
  • Too many errors
  • Incorrectly assigned VLAN membership
  • Traffic priority (CoS/QoS) issues

Best practices for successful network Ethernet troubleshooting include these steps:

1. Identify the exact issue or problem: Have the person who reported the problem explain how normal operation appears, and then demonstrate the perceived problem.

2. Recreate the problem if possible: Ask yourself if you understand the symptoms, and verify the reported problem yourself if possible.

3. Localize and isolate the cause: Attempt to isolate the problem to a single device, connection, or software application.

4. Formulate a network troubleshooting plan for solving the problem: Research and/or consider the possible solutions to the problem. Consider the possibility that some solutions to the problem at hand may introduce other problems.

5. Implement the network troubleshooting plan: Your actual solution to the problem may be replacing hardware, implementing a software patch, reinstalling the application or component or cleaning a virus infected file. If the problem is the user account, the user’s security settings or logon scripts may need to be adjusted.

6. Test to verify that the problem has been resolved: After you have implemented the solution, ensure that the entire problem has been resolved by having the user test for the problem again.

7. Document the problem and solution: Documentation can be used for future reference to help you troubleshoot the same or similar problem. You can also use the documentation to prepare reports on common network problems for management and/or users, or to train new network users, network troubleshooters, or members of the network support team.

8. Provide feedback to the user: This encourages users to report similar situations in the future, which will improve the performance of your network. If the user could have done something to correct or avoid the issue, providing feedback may reduce the number of future network problems.

Importance of LAN troubleshooting tools and training
Giving frontline network support staff the proper training, the right tools, and a solid network troubleshooting methodology results in faster LAN problem solving - saving staff time, closing trouble tickets quicker, minimizing downtime, and getting network users back to productivity faster.