Common operational misconceptions

Steve Clark sclark at
Fri Feb 17 15:18:57 UTC 2012

I agree with this 100%.

Having worked with many people over the last 40 years, the good trouble shooters understood how things
were suppose to work. This helps immeasurably in determining where to start looking.

On 02/17/2012 10:12 AM, Mario Eirea wrote:
> Well, I will argue this. I think the important factor in any troubleshooting is having a real understanding of how the system works. That is, how different things interact with each others to achieve a specific goal. The biggest problem I see is that many people understand understand the individual parts but when it comes to understanding the system as a whole they fall miserably short.
> A short example, probably not the best but the one that comes to mind right now:
> Someone replaces a device on the network with a new one. They give it the same IP address as the old device. They don't understand why the router cant communicate with it at first and then starts working. The people "understand" ARP, but cant correlate one event with another.
> I guess if your 35 you have seen this at least once and can fix it. But what happens if you have never seen this problem or a related one? At this point your going to have to really troubleshoot, not just go on experience.
> Mario Eirea
> ________________________________________
> From: -Hammer- [bhmccie at]
> Sent: Friday, February 17, 2012 9:52 AM
> To: nanog at
> Subject: Re: Common operational misconceptions
> Let me simplify that. If you are over 35 you know how to troubleshoot.
> Yes, I'm going to get flamed. Yes, there are exceptions in both directions.
> -Hammer-
> "I was a normal American nerd"
> -Jack Herer
> On 2/17/2012 8:29 AM, Leo Bicknell wrote:
>> In a message written on Thu, Feb 16, 2012 at 08:50:11PM -1000, Paul Graydon wrote:
>>> At the same time, it's shocking how many network people I come across
>>> with no real grasp of even what OSI means by each layer, even if it's
>>> only in theory.  Just having a grasp of that makes all the world of
>>> difference when it comes to troubleshooting.  Start at layer 1 and work
>>> upwards (unless you're able to make appropriate intuitive leaps.) Is it
>>> physically connected? Are the link lights flashing? Can traffic route to
>>> it, etc. etc.
>> I wouldn't call it a "misconception", but I want to echo Paul's
>> comment.  I would venture over 90% of the engineers I work with
>> have no idea how to troubleshoot properly.  Thinking back to my own
>> education, I don't recall anyone in highschool or college attempting
>> to teach troubleshooting skills.  Most classes teach you how to
>> build things, not deal with them when they are broken.
>> The basic skills are probably obvious to someone who might design
>> course material if they sat down and thought about how to teach
>> troubleshooting.  However, there is one area that may not be obvious.
>> There's also a group management problem.  Many times troubleshooting
>> is done with multiple folks on the phone (say, customer, ISP and
>> vendor).  Not only do you have to know how to troubleshoot, but how
>> to get everyone on the same page so every possible cause isn't
>> tested 3 times.
>> I think all college level courses should include a "break/fix"
>> exercise/module after learning how to build something, and much of that
>> should be done in a group enviornment.

Stephen Clark
Director of Technology
Phone: 813-579-3200
Fax: 813-882-0209
Email: steve.clark at

More information about the NANOG mailing list