Difference between revisions of "CCNP TSHOOT 642-832/Chapter 2"

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Fin a balance between
 
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*What ''is'' occurring on the network?
 
*What ''is'' occurring on the network?
*what ''should be'' occurring on the network?
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*What ''should be'' occurring on the network?
  
 
=== Eliminate Potential Causes===
 
=== Eliminate Potential Causes===

Revision as of 11:34, 6 June 2010

Introduction to Troubleshooting Processes

Troubleshooting Methods

Defining Troubleshooting

  • Step 1: Problem Report
  • Step 2: Problem Diagnosis
  • Step 3: Problem resolution

Diagnosing a Problem

Diagnosing a Problem
Step Description
Collect Information A problem report often lacks sufficient information. Collect additional information from. fx. Network Management tolls or interviewing the user.
Examine Collected Information Examine collected information. Fx. comparing to baseline information.
Eliminate Potential causes Based on knowledge of network and collected information - start to eliminate causes.
Hypothesize Underlying Cause After eliminating causes hypothesize the most likely cause of the problem.
Verify Hypothesis Test if the hypothesize resolve the problem

The Value of a Structured Troubleshooting Approach

Structured Troubleshooting Approach
Shoot from the hip Troubleshooting Approach

Popular Troubleshooting Methods

Top-down, Bottom-up or Divide and conquer approaches
Follow the Path of Traffic
Component Swapping

Structured Troubleshooting Procedure

By combining the previously mentioned Three-step troubleshooting procedure and the subprocesses of Problem Diagnosis steps you get

  1. Problem Report
  2. Collect Information
  3. Examine Collected Information
  4. Eliminate Potential Causes
  5. Hypothesize Underlying Cause
  6. Verify Hypothesize
  7. Problem resolution

Problem Report

  • Often lacks information
  • Are you authorized to resolve the problem or need to forward it.
  • Interview the user who reported the problem.

Collect Information

  • Collect information from routers and switches... (show debug commands, log, NMS etc)

Examine Collected information

  • Identify indicators pointing to the underlying cause of the problem
  • Find evidence that can be used to eliminate potential causes

Fin a balance between

  • What is occurring on the network?
  • What should be occurring on the network?

Eliminate Potential Causes

  • Is OSPF running etc.

Hypothesize Underlying Cause

  • If problem can't be resolved (Lack of authority, devices) a temporary fix could resolve the problem here and now.

Verify Hypothesis

  • Implementing the fix. (Make a plan)

Problem resolution

  • Document the resolved problem.

Including Troubleshooting in Routine Network Maintenance