Help me understand IP adress subnetting

[funguy11]

I am taking a college course on computer networking as a part of my PC Maintenance & Repair and Networking degree and I have had a little trouble understanding how to subnet an IP address when configuring a new network. Could somebody try to explain it to me in as simple a way as possible.

[DaveLembke]

Pretty simple tutorial linked. Its about as simple as it can be without losing context on important details.

http://www.techopedia.com/6/28587/internet/8-steps-to-understanding-ip-subnetting


Useful tables at this link showing which subnets are best for specific applications. But I would suggest reading everything from beginning to end and multiple times if needed to grasp the concepts!

http://www.techopedia.com/6/28587/internet/8-steps-to-understanding-ip-subnetting/5


*When I got my computer science degree I had to do the math to show why I chose to go with a specific subnet mask etc. Not sure if your professor wants you to know how to do the math or not, but it would be best to familiarize yourself with the process even though as seen in the above table, lots of people can use cheat sheets with the above info to avoid the redundant math. I ended up making an excel spreadsheet back in 1998 that did the conversions even though I had to manually do the work in class on paper. Then I found online tools that made it even easier.

For my computer science degree, the networking course had a test with word problems of a scenario and the scenario went into depth on the network that a corporation or smaller business needed and you then had to show all work and give the answer to all network info which also stated the subnet mask and class A, B, or C, etc and why, and you couldnt just go with an overkill subnet as the easy way out, it had to be exact to the needs of that network, so if you couldnt do the math, or didnt have a table to refer to, then you wouldnt have the answer and would fail. I got a 100% with the 5 problem test but it wasnt a easy test if you didnt study and know how to work it all out!!!

This info below might also be helpful to you if you have to calculate it all like I and many others had to. Not sure if they allow you to use reference table cheat sheets these days or not, but they didnt allow them when I went and got my degree. I had to do it all out manually   :

http://www.dslreports.com/faq/cisco/30.1_Quick_subnet_calculating_techniques