[150199] in North American Network Operators' Group
RE: Common operational misconceptions
daemon@ATHENA.MIT.EDU (George Bonser)
Sat Feb 18 15:37:50 2012
From: George Bonser <gbonser@seven.com>
To: Paul Graydon <paul@paulgraydon.co.uk>, "nanog@nanog.org" <nanog@nanog.org>
Date: Sat, 18 Feb 2012 20:36:50 +0000
In-Reply-To: <4F3FF418.2000009@paulgraydon.co.uk>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
> Yes I'm serious, they were CCNP qualified, hired as a NOC engineer for
> an ISP & Hosting company. =20
There was a time a new hire with all the right holes punched in his ticket =
deleted an item in an access-list in a PIX that was running an older versio=
n of the software than he was familiar with. The entire access-list disapp=
eared and he was locked out, production stopped, like a train hitting a bri=
ck wall. =20
> For the company the NOC team was the top
> tier of customer support (3rd line+), they looked after routers,
> switches, firewalls, servers, leased lines, and so on.
> This individual was perfectly capable of regurgitating all the facts,
> figures and technical details you can imagine, probably pretty much the
> entire CCNP syllabus. What they didn't seem that capable of was
> actually applying that to anything.
You might be surprised at how common that is. If you present them with ALL=
the diagrams and ALL of the configs on paper, they can figure it out. In =
other words, if you recreate the same environment they had in their trainin=
g class, they can do fine. But what some can't seem to be able to do is vi=
sualize in their head how things are. It is that layer of abstraction that=
separates them out. They are fine for maintaining documentation or even f=
or participating in a design review but you don't want them designing some =
new addition to the network or working on something "live". My first clue =
often comes from the quality of diagrams they produce. If the diagrams are =
accurate as far as what connects to what but do not reflect the actual flow=
of the network, that's a telltale sign. Sort of like an electronic schema=
tic. If they sort of have random components/stages at random locations in =
the drawing that doesn't really reflect the functional flow through the dev=
ice, that is my clue that I am likely dealing with a concrete thinker and n=
ot an abstract thinker. Ditto if they demand that the symbol representing =
a particular piece of gear actually be a picture of that piece of gear. If=
they get lost when gear is represented by a square box then they are proba=
bly part of the normal 85% of people who find it more difficult (actually h=
ave to try) to translate a square box on a diagram to a router in the rack =
in their head vs the 15% who do that naturally without any effort.
The access-list guy mentioned above would be great for looking at the confi=
g and producing a new one with the correct access control, but you wouldn't=
want him to be the one to apply it in production on a live network. So ev=
en in that guy's case, there is a place where their skills can be quite use=
ful and there are other places where their chance of making a costly mistak=
e increase. It is a matter of matching the person's role to their skills.
> I'd bet good money that if I'd
> asked him at the time what the 1918 network ranges are he'd have been
> able to tell me.
You'll be surprised how many people "forget" that 172.28.0.0 is rfc1918 spa=
ce. They are so used to seeing 172.16 that they tend to forget 172.17-31. =
I've had to change null routes and access controls to include the entire /1=
2. They "know" that it is a /12 but seem to forget in practice when they s=
ee a second octet that isn't "16".
> This is exactly what we're teaching kids to do these days (makes me
> feel so old that I've already been saying this for several years and
> I'm only
> 31) standardised tests aren't marked based on ability to apply
> knowledge, just the knowledge itself.=20
Yes. We teach them facts but now how to FIND facts. Part of teaching is i=
n teaching how to teach yourself. It started with me when I was a kid. Wh=
en I had a question, my father would always say "look it up and tell me" ev=
en if he knew the answer perfectly well. He had invested in an encyclopedi=
a and the annual updates and was determined that I would use it. It taught=
me how to research to find my own answers and it taught me to learn it wel=
l enough to explain it to someone else because Pop would always throw in a =
couple of questions for me after I explained it to him just to see if I act=
ually "got" the underlying concept. Besides, often in the course of resear=
ching one thing, I happened across a completely unrelated thing that caught=
my interest in that volume of the book and learned something I hadn't even=
been looking for. Forget the Internet, for people with kids at home, I wo=
uld recommend a hard copy set of World Book with the Year Book and Science =
Year annual additions. That one in particular because the style in which t=
hey are written, they are actually pretty fun to read and have a lot of ill=
ustrations. http://www.worldbook.com/browse-all-products/item/953-advanced-=
research-package-2012 (no affiliation at all with them, just a satisfied "c=
ustomer"). Soon, going to the books when a question arose became natural.
It is one thing to produce a "teachable" child, something quite different t=
o produce the ability to learn independently and allow their own natural cu=
riosity to "pull" them to that knowledge.
