Network Troubleshooting

Documentation

Document the network installation and configuration.

• Cable installation information - Cable types with network diagrams showing jacks.
• Equipment information - Where the equipment was purchased with serial numbers, vendors and warranty information.
• Network resources - Document commonly used resources including drive mappings.
• Network addressing - Record the allocation of network addresses with diagrams.
• Network connections - Document or diagram how your network is connected to other networks.
• Software configuration - Software is installed on each network node outlining the sequence of software and driver installation required. Also document configuration files.
• User administration - Determine methods and policies for user names, passwords, and groups.
• Policies and procedures - Be sure network policies and procedures are defined and necessary personnel are aware of them.
• Base network performance - Determine normal traffic levels on the network.
• Hardware or software changes - document all changes to the network and record dates.
• Software licenses - Be sure you have valid software licenses for all software with license serial numbers recorded.
• Keep a history of troubleshooting - Record network problems and their solutions.

Troubleshooting and network management tools

• SMS - Systems Management Server from Microsoft can collect information of software on each computer and can install and configure new software on the client computers. It will also monitor network traffic.

Performance Monitoring Benefits

• Identify network bottlenecks.
• Identifying network traffic pattern trends.
• Provide information to help develop plans for increasing network performance.
• Determine the effects of hardware or software changes.
• Provide information to help forecast future needs.

Microsoft Complex Problem Structured Approach

1. Set the problem’s priority
2. Identify the symptoms.
3. Determine possible causes.
4. Perform tests to determine the problem cause.
5. Identify a solution by studying the test results.

Troubleshooting Tools

• DVM - Digital volt meter.
• TDR - Time-domain reflectometer sends a sonar like electrical pulse down a cable and can determine the location of a break in the cable. The pulse is reflected back to the TDR and the TDR can tell where the break is by timing the time it takes for the pulse to return.
• Protocol analyzers - They are usually a mix of hardware and software and may also be referred to as network analyzers. They monitor network traffic and examining packets, collecting data that helps determine the network performance. They can locate:
• Faulty NICs or components
• Network bottlenecks
• Abnormal network traffic from a computer
• Conflicting applications
• Connection errors

Windows NT Server 4.0 includes the Network Monitor tool which is a software based protocol analyzer.

• Advanced cable testers - Can determine a cable's impedance, resistance, attenuation, and if the cable is broke or shorted. Advanced cable testers can acquire information about message network collisions, frame counts, and congestion errors.

If Thinnet cable is broken its resistance would go from the normal of 50 ohms to infinity.

• Network monitors - Used to monitor network traffic. They can examine network packets, where they are from and where they are going. They can also generate reports and shows graphic statistics about the network. The network monitors work through all layers of the OSI model except the hardware layer. Windows NT provides the Performance Monitor tool software as a network monitor.
• Terminators - They are placed on one end of a network cable so the cable will have proper impedance. This is also a way to check the cable to be sure it is not broken.