Monday, February 28, 2005

On the CCNA Road

This morning I began training to test for the Cisco Certified Network Associate certification. I am in a class offered by GlobalNet Training in northern Virginia. My company ManTech agreed to pay my way, as they support sending engineers to a week's worth of training per year.

My instructor is Todd Lammle, author of the recently updated CCNA: Cisco Certified Network Associate, Deluxe Edition (640-801) study guide. Two weeks ago I saw Todd was personally teaching this class, so I immediately signed up. I'm probably not the easiest student to have in a networking class. When Todd asked if HTTP uses TCP, I felt it necessary to mention Universal Plug and Play Protocol (UPNP) which runs HTTP over UDP. I also mentioned that DNS uses TCP to answer queries when the response is larger than the 512 byte limit on UDP responses. Todd's tolerating me so far, but he said I have to provide a copy of my book. :)

Why am I studying for the CCNA? Once in a while I find myself working on Cisco routers and switches, and it's been almost seven years since my last formal training on either platform. I believe the CCNA is a fairly well-respected certification, as far as entry-level certs go. By attending this class I also get a free copy of the latest deluxe study guide edition, which is tough to pass up when you're a book reader and reviewer!

Todd told me today that he's sold somewhere between 600,000-700,000 copies of his study guides over the last five years. That is absolutely amazing, considering that a technical book which sells more than 10,000 copies is regarded as a big hit. I will be reading and studying this book in preparation for my CCNA exam, which I plan to take some time next week. Todd is an excellent instructor, and he's already improved my subnet addressing skills by an order of magnitude. In other words, subnet questions which might have taken 60 seconds to answer will probably take about 6 seconds. This speed increase is important, as candidates have about a minute to answer each question. They can't return to skipped questions, so it pays to answer as rapidly as possible.


Anonymous said...

How does your lab look like?

Anonymous said...

You will certainly have to keep us posted on your adventure towards the CCNA! I look forward to hearing how things go, and basically living vicariously through your own workshop. ;)

Anonymous said...

Way to go Richard, I used the first edition Lamle book to prepare for the CCNA. What a treat that you actually get to be trained by him!


Alastair said...

Good luck with it, certainly sounds like you're going about it the right way.
By all accounts it's a hard exam.

I'm also studying for my CCNA using the Lammle book (not the Lammle person).

Anonymous said...

Please post some highligts.

Scott said...

I just picked up Todd's books as well (my company won;t pay for formal training but they'll pay for books). Good luck Richard

Anonymous said...


Does this 6-second method have anything to do w/ the "magic number" method? I'm currently reading the Cisco Press CCNA book which teaches this method.


Richard Bejtlich said...

Re: lab set-up -- GlobalNet Training provided each student with his/her own 2621 router, 2500 router, 804 router, and 2950 switch. Each pair of students also shared a 3550 switch and another 2500 router. This arrangement beats any other CCNA class I've researched.

Re: subnetting -- I'm not familiar with the "magic number" method. Can you elaborate?

Anonymous said...

(not the same as the original "magic number" poster)

The magic number is just a quick way to calculate the subnet mask & broadcast address without converting to binary and back.

To calculate the magic number for networking, you calculate how many hosts that a given subnet uses.
For example, if the Class C subnet mask was, the total # of hosts would be (2^6)-2. But the magic number would be just the 2^6 (ie 64). Given any ip address, you can figure out the subnet number by multiplying the magic number and finding the closest number that does not exceed the IP address. Then the broadcast number by adding the magic number minus 1 to that number.
Given IP address:
You would know that the possible subnets are 0,64,128,192. (64x0, 64x1, 64x2...). Since 64 is the highest number without going over, it is the winner.
The Broadcast address would be 127 (64x1 from above + 64-1)

Anonymous said...

Sorry. It was just by dumb luck that 64 was the magic number and also the subnet mask.

Anonymous said...

To calculate the magic number, subtract the subnet mask from 256.

From the example given above:
256 - 192 = 64

Anonymous said...
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Divine said...

I've been been following/reading lammle and bejtich for years, go figures they run into each other lol.