Monday, August 8, 2011

CCNP - ENTERPRISE - OSPF Troubleshooting targets

When troubleshooting OSPF look for the following:

  1. What routes are present in the routing table
  2. Check the status of OSPF adjacencies
  3. Check the networks are advertised properly (in subnets)
  4. Check your virtual-links are configured correctly
  5. Check your timers match at each end of your links
  6. Check you have OSPF configured to use the correct network type for your media

Friday, August 5, 2011

CCNP - ENTERPRISE - Troubleshooting Methodology...

Regardless of the particular issue at hand trouble shooting generally flows as follows:

Problem Reported ---------> Diagnosis ---------> Resolution

You'll find the bulk of your time concentrating around the Diagnosis part of the process.

For the CCNP TSHOOT exam you need to know process of troubleshooting an issue, which is:

  1. Collect information - from users/reports/monitoring
  2. Examine the information - such as comparing your gathered information with that of a baseline measurement
  3. Eliminate potential causes - this is where you'll use your knowledge about your local network
  4. Hypothesise a cause - Consider the most likely cause based on the information you have gathered
  5. Verify the hypothesis - Test/reject the theory regarding the cause

It's important to note that your should always be methodical. Do not jump about the steps otherwise you'll lose track of what you've done and cause further delay.

Experience engineers may proceed straight to step 4 if they have a good hunch about what is causing the issue however such action (known as 'Shoot from the Hip') can cause time delays if the hypothesis is wrong.