Subnetting

Subnetting is a topic that every networking professional needs to know, and know very well. Even though thre are programs out there that will do all the work for you it is a good skill to have. There are many diffrent "shortcut" ways to learn subnetting, the best way I was taught was just learn the correct way to do it, meaning do it the full way with no shortcuts.

Lets say for example you are asked what is the binary equivilant of 231. What I like to do is wrie down all powers of 2 upto 128

128 64 32 16 8 4 2 1

From here I would see if I can subtract 231 by 128, which I can so I would put a 1 under 128

128
1

This would give us 103. Next can you subtrac 103 by 64, yes you can. That gives you 39

128 64
1 1

Next can you subtract 39 by 32? Yes, we then have 7

128 64 32
1 1 1

Now can you subtract 7 by 16? No so under the 8 you would put a 0, also do this for 8 as you can not subtract 7-8.

128 64 32 16 8
1 1 1 0 0

Finally, can you subtract 7-4? Yes, now we are left with 3. Can you subtract 3-2?, yes we are left with 1 and you an subtract 1-1. So under 4, 2 and 1 we will put 1's

128 64 32 16 8 4 2 1
1 1 1 0 0 1 1 1

So 11100111 is the binary equivalent to 231. Your end result should always equal 0. If it does not then there is something wrong with your math and you need to go back and recheck your work.

Welcome All!!

Welcome to my journey on becoming a Cisco Certified Network Professional! Let me start off by introducing myself, my name is Mike and I am a Network Administrator for a import/export company in New Jersey. I have a Masters Degree in Computer Science and currently hold the following certifications;

• A+
• Network+
• MCP
• MCSA
• MCSE
• MCTS
• MCITP
• CCENT
• CCNA

I already started my CCNP journey by passing 642-812 (BCMSN) this past Saturday. I did not think of using a blog as a medium to help learn and reinforce what I have read or practiced in labs.

I hope you find this blog informative and intresting and if you have any questions or comments, please post them in the comments section.

Thanks for stopping by!

Mike