BlueWolf's Howl

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September 14, 2003

Routing all the way...

Yes, my absence indicates that I've actually been ~~sleeping~~ studying....

It may have been the BSCN book that I read, but the chapters are flowing smoothly. I'm getting all the "Do I Know This Already?" material correct...and still reading the chapter. And naturally, I'm doing well on the quiz at the end of the chapter (so far). If the studying continues (and in this manner), I should be prepared for the exam at the end of the month.

The exciting part (well, exciting to me) is that I'm seeing a difference. I'm very aware that I know more now than I did last year or the year before. There's a number of things that I can now look back at and say "I didn't know that then...but I DO know that now."

Two of those things are subnetting and supernetting. They are some very confusing and difficult subjects. Looking back on my studies... I first learned subnetting when it was all dotted decimal. The common method for learning subnets involved memorizing tables of subnet masks, networks and hosts. It was rote. I hate rote. I hate memorizing lists of things. The 2n-2 formula for the number of hosts or the number of networks was easy. I can learn and apply a formula. But, the list of subnets was hard to learn and easy to forget.

Subnetting is something that crops up in almost every network-type exam. You'll find subnetting and supernetting questions on both Microsoft and Cisco exams (and many others too). After I first learned subnetting, the shortcut way of displaying subnet masks started to gain popularity. I was used to 255.255.240.0 or 255.255.255.0 .... and now they're throwing addresses at me that have a /27 or /21 at the end of them! When I first started dealing with this, I had a hard time. I would translate it into what I knew and then went from there... It added an extra step or two and took more time to answer the questions than was allowed. It was grueling and I had to fight my way through it.

Then I had to recertify for the CCNA. It was something that I really didn't want to do. I had hoped to attain the next level (CCNP) and not have to recertify. But, things didn't turn out that way. So, I bought the latest CCNA book and began to prepare. [I passed that exam last year.] I know I've posted about "subnetting in your head" before... Well, it's true. Once I landed on that, I was free of rote. I no longer had to memorize anything to do with subnetting. I could just figure it out. And I could just figure it out very quickly.

The wonderful part is: once you know subnetting in that manner...it also applies to supernetting (address aggregation). It's almost like I can just look at it and *SEE* the answer... And I shortcut right to the heart of the matter and get the answer much more quickly!

It's really a joy to know that you've mastered something like that. I can now count those type of questions as "cakewalk" questions. Now...what *else* do I need to know for this exam....???

*sticking my head back in the book* Only 15 more days until T-Day (Testing Day). Let's see what other routing concepts I can claim mastery over by that time...

Posted by BlueWolf on September 14, 2003 03:06 PM