Common operational misconceptions

Brandt, Ralph ralph.brandt at
Fri Feb 17 19:47:58 UTC 2012

I just pulled the humorous point about Mary the accountant out, pasted its link into an email and sent it to our staff with the suggestion they read it. I was going to past it here but decided to let someone who wants to read it go to the site, they may learn something by accident if they do.

I have been unable to get our group to read anything else, maybe they will read this very well written document.  It really is a "comm oriented" Cliff Notes of Kepner Trego Problem Analysis.  I would love them to read the text book, but will settle for anything.

Ralph Brandt
Communications Engineer
HP Enterprise Services
Telephone +1 717.506.0802
FAX +1 717.506.4358
Email Ralph.Brandt at
5095 Ritter Rd
Mechanicsburg PA 17055

-----Original Message-----
From: Marcel Plug [mailto:marcelplug at] 
Sent: Friday, February 17, 2012 12:01 PM
To: -Hammer-
Cc: nanog at
Subject: Re: Common operational misconceptions

I often struggle with the concept of teaching someone how to
troubleshoot.  We have young guys coming in all the time and it is
often an area in which they need to hone their skills.  I found this
article a while back and I keep it bookmarked, its the best article
I've seen that lays it all out pretty clearly.


I'm guessing, but I believe the author would fall into the under 35 category ;-)

On Fri, Feb 17, 2012 at 10:51 AM, -Hammer- <bhmccie at> wrote:
> Mario,
>    I was kinda having fun and kinda not. My point is that the 40-50 year
> olds that were doing this 30 years ago grew up understanding things in
> order. Bits. Bytes. KiloBits. KiloBytes. (Some folks still get those
> confused). Hex. etc. Move on to the OSI model and it's the same thing.
> Voltage. Amplitude. Binary. etc. I think that this generation that I'm
> referring to is a great generation because we were at the beginning of the
> Internet blooming. There are folks on this forum that go back further. Into
> DARPA. Before DARPA was just chapter 1 one every single Cisco Press book.
> They have a unique understanding of the layers. I had that understanding in
> my 20s. The technology is so complicated these days that many folks miss
> those fundamentals and go right into VSS on the 6500s or MPLS over Juniper.
> In the end, it all comes in time.
> -Hammer-
> "I was a normal American nerd"
> -Jack Herer
> On 2/17/2012 9:12 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.

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