Overview
This lecture gives a high-level overview of the network troubleshooting process, emphasizing a systematic, step-by-step approach that can be applied to any network issue.
Troubleshooting Process Overview
- Start by clearly identifying the problem, including symptoms and affected systems.
- Gather detailed information from users and system metrics to understand the issue.
- Consider recent changes in the system or environment that could have caused the problem.
- Attempt to duplicate the issue, possibly in a lab environment.
- Break down complex problems into smaller components to isolate the fault.
Establishing and Testing Theories
- Develop theories about possible causes, starting with obvious and easy-to-test issues.
- Use methods like swapping cables or checking configurations to quickly eliminate potential causes.
- Use the OSI model to approach problems from top-down (application to network) or bottom-up (network to application).
- Test theories systematically, adjusting only one variable at a time.
- If a theory fails, return to the previous step and establish a new hypothesis.
Planning and Implementation
- Create a plan of action for implementing the identified fix, considering organizational change control policies.
- Prepare backup plans (Plan B, Plan C) and rollback options in case the initial fix fails.
- Implement changes during scheduled maintenance windows if required.
- Separate teams may handle troubleshooting and actual implementation.
Verification and Documentation
- Verify full system functionality after the change, involving end users to confirm the issue is resolved.
- Discuss preventative measures with users and IT staff to avoid recurrence.
- Document the entire troubleshooting process, including the fix, in a searchable knowledge base or help desk system for future reference.
Key Terms & Definitions
- OSI Model — A conceptual framework used to understand network interactions in seven layers, from physical to application.
- Change Control — A formal process for requesting, approving, and implementing changes in a production environment.
- Rollback Process — A predefined procedure to revert a system to its previous state if a change fails.
- Knowledge Base — A centralized resource for storing and retrieving troubleshooting steps and solutions.
Action Items / Next Steps
- Practice duplicating network problems in a lab setting.
- Review your organization’s change control policies.
- Begin documenting troubleshooting steps and solutions for future use.