Chapter 13 Troubleshooting Network Problems

Chapter 13 Troubleshooting Network Problems
If you see a bumper sticker that says, “User are losers” and you aren’t thinking about someone using drugs most likely you are a Network Administrator. Users come in many forms from button pushers, knob twisters or the indecisive user who doesn’t want to do anything that may screw up. With this in mind we need to look at every user issue as an opportunity to further the security policies, and the users’ basic understanding of the data …

Troubleshooting Methodology the following troubleshooting steps:
1. –Identify symptoms, problems
2. –Identify affected area
3. –Determine what has changed
4. –Establish most probable cause
5. –Determine if escalation necessary
6. –Create action plan, solution
7. –Implement solution, test result
8. –Identify results, effects
9. –Document solution, process

Troubleshooting Tools

Tone Generator and Tone Locator are used to located wiring from where begins to in telecommunications closet to where wire pair terminates.

Multimeters are used to tests cables for faults and measuring electric circuit characteristics (Resistance and voltage).

Cable Continuity Testers are used to tests whether cable carrying signal to destination. There are also Fiber optic continuity testers that issues light pulses onto the fiber cable to test.

Cable Performance Testers can do the same functions of a Cable Continuity tester however it is also do the following:
• Measure the distance to a connectivity device.
• Measure attenuation along a cable.
• Measure near-end cross talk between wires.
• Measure terminations resistance and impedance.
• Issue pass/fail ratings for Cat3, Cat 5, Cat 5e, Cat 6 or Cat 7 Standards.
• Store and print cable testing results or directly save data to a computer database.
• Graphically depict a cable’s attenuation and cross talk characteristics over the length of the cable.
Copper wire tester uses TDR(time domain reflectometers) where Fiber-optic connections testers use OTDRs (optical time domain reflectometers)

Voltage Event Recorders record voltage events any condition where voltage exceeds or drops below predefined levels and collects data about power quality.

Butt Set is a lineman’s handset, telephone test set giving the line man to butt into telephone conversations.

Network Monitors Software-based tools continually monitoring network traffic from server, workstation attached to network. It interprets up to Layer 3 can determine protocols passed by each frame however it cannot interpret frame data. To run it on the full network all Network adapters must support promiscuous mode. Common terms for abnormal data patterns, packets are local collisions, late collisions, runts, giants, jabber, negative frame sequence checks and ghosts.

Protocol Analyzers (network analyzer) captures traffic, analyzes frames typically to Layer 7. They have the same features as network monitor but it also generates traffic. Before using network monitor or protocol analyzer learn what network traffic normally looks like capturing data for time period on regular basis

Wireless Network Testers are tools containing wireless NICs, running wireless protocols.