Networking is like physics or math, not history

Every so often I stumble across a blog post (or receive an e-mail) complaining how hard it is to learn the material needed to pass a certification exam. That’s definitely true if you try the memorization approach to networking: trying to cram as many facts as possible into your grey matter. However, it’s impossible to make any reasonable progress that way; to move forward, you have to handle networking like you would math or physics: having a firm basic foundation, you slowly expand it, all the time trying to fit the new concepts into a coherent model (let’s call it “the big picture”).

Every single internetworking technology (or solution) was invented and introduced for a very good reason; it was trying to solve a particular set of problems within an environment that posed a unique set of restrictions. Trying to memorize how something works (or how you configure a particular device feature) is close to impossible if you don’t have the big picture; it’s like trying to learn history by memorizing the years of important events, without understanding their correlation (yes, that’s how I was taught history ... and I promptly managed to forget most of it).

To really progress in your networking studies, you have to focus on understanding how various technologies work and why they work that way ... and then, if you’re at least a little bit devious, you start to experiment: imagine a crazy scenario that your theory (your mental “big picture”) predicts will fail, try it out in the lab, observe whether the results match with your mental model predictions, and try to fix it.


  1. Sorry, networking is not even close to any science. It is not even high-tech engineering. Its approach and methodology is more like those of plumbing.
  2. I can't disagree with you ... however, I wanted to emphasize the need to build an understanding of what's going on and what different technologies do (and don't do) versus jumping head-on into configuration stuff.
  3. As Narbik Kocharians says in his classes "every command has as story." Great reminder of that on this post Ivan. You understand the story you'll know what to configure.
  4. I think that's true of becoming good at networking, in a general sense. The problem with certification exams, however, is that they are often written to cater to this memorization model (at least good portions of many exams).

    For example, the only way that I know an ASA can perform NAT and PAT on SIP inspection traffic, but cannot PAT on LDAP inspection traffic, is via memorization. Cisco tests are filled with that sort of insanity. I think the general concept exams are not as bad, but the exams on certain products (e.g., ASA, IPS, etc) require lots of memorization because no one has the specific experience these exams require (I've never tried to perform PAT on LDAP only to discover it didn't work, nor have I tried to NAT SIP to see if it worked).
  5. Isn't plumbing the practical application of a science?
  6. Certification -should be- like physics and sience, but [often] is like history.

    This is done to give absolute beginners a change to pass the exams, this is why I could not care less about particular certified people when they can't answer simple logic-questions.
  7. Great explanation, I definitely agree! Every time I study a new topic it really helps to know the history behind it and how it evolved during the years, BGP is a great example of it.
  8. Understanding networking and passing a certification test are two different things. One "can" lead to the other but, they aren't the same. Understanding networking fundamentals and theory, is actually closer to math or a science...BUT unfortunately passing a Cisco Exam is like history. Its more based on memorizing obscure timers, and obscure pieces of information.
Add comment