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Re: Common operational misconceptions
From: Owen DeLong <owen () delong com>
Date: Fri, 17 Feb 2012 10:49:13 -0800

Now, come on... If you're in the 40-50 range, you should have put octal before hex. :p

Owen
(Who grew up on a PDP-11 in his high-school and still remembers 1777300 and its significance to anyone who has used a 
larger PDP system)

On Feb 17, 2012, at 7:51 AM, -Hammer- 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 () gmail com]
Sent: Friday, February 17, 2012 9:52 AM
To: nanog () nanog org
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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