Trust But Verify


By the time you are ready to sit in the torture chambers that house the CCIE lab, you are practiced with live configuration to the point of it being subconscious.  Configuring VLANs and routing processes happen without a second thought.  The candidate can do simple tasks quickly and spend more time focusing on difficult areas and weak points.  After walking out of the lab and waiting for the score report, tough areas are replayed over and over again trying to dissect any bright spots.  Whether or not you are confident about your results, when the unsuccessful score report arrives there is usually a shock.  Areas that the candidate believed they passed with authority show missed points and lost opportunity.  The most often heard phrase after this situation is, “I know I did better than that!”

I uttered these very words more than once.  I thought to myself, “How could I get that wrong?  I typed everything in right.  It looked like it was working.”  The fault here wasn’t only in my configuration skill.  Instead, the additional fault was in my failure to verify what I had configured.  Typing commands into a terminal for a lab configuration task is easy, relatively speaking.  It is equally important to prove that you’ve done what you think you’ve done.  Without verification, there is no way to make sure that your configuration tasks are behaving like they should.

Every time I have sat down in the lab, I take one of the two pieces of paper that you are given and I write down a number for every task in the troubleshooting and configuration sections of the lab.  When I configure something, I make a check mark next to that task.  If I can’t get it working right away, I leave it blank.  Once I have a list full of single check marks, I know it’s time to verify.  I sit down with the configuration tasks and I forget everything I’ve done up to that point.  I do this because in the past I’ve been known to say to myself, “I did that right.  No need to check it.”  That attitude couldn’t be more wrong.  If you assume that you’ve done something correctly and don’t bother to check it, you might as well have gotten the question wrong.

When I begin verifying, I read the question again and make sure there were no omitted words or phrases that could affect the configuration.  I then use a variety of “show” commands to prove that I typed everything in the right way the first time.  Nothing is taken for granted.  Neighbor statements are checked.  VLAN descriptions are checked.  Routing tables are poured over.  On lab attempts 6 & 7 (where I passed the configuration section), I found simple mistakes both times that would have cost me a large number of points.  The kind of simple mistakes that a lot of people assume that they couldn’t possibly screw up because they were so easy.  The grading script doesn’t assume you meant “neighbor 1.1.1.1 remote-as 254” instead of what you typed “neighbor 1.1.1.1 remote-as 245“.  Don’t give the script the chance to punch you out for lapses in typing skill.

Once I’ve verified a task the second time, I put a second check mark next to that task.  Once I have a page full of double checks I can relax just a little knowing that I’ve looked at every question twice.  If there’s enough time remaining before I head out, I look over the particularly hairy tasks and add perhaps a third check mark if necessary to really be sure I got them working correctly.  These are usually single tasks that stand alone in the configuration and shouldn’t have an impact on core reachability.  Screwing up your core with less than an hour to go is a great way to get high blood pressure quickly.

Tom’s Take

There’s a reason why they call it “double checking”.  I feel that having a running total of the tasks in your lab keep you focused on the macro task instead of getting bogged down in the micro sections.  It helped in my passing attempt by forcing my to keep moving in the troubleshooting section.  It always helped me in the configuration section so that I didn’t miss the forest for the trees.  Hopefully those of you out there going after your lab will find this useful.  After all, since you can’t use the paper to dispose of your gum you might as well put it to good use.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s