22 February 2014

Ken Long - klong13@cnm.edu or kenglong@gmail.com

# Subnetting as Taught at Central New Mexico Community College

One of the most important skills one needs to learn to become
a
Network Administrator is subnetting. These pages show what I've learned
at CNM on this subject. In all of my classes so far, I've been taught
the bare-bones way to subnet. That means using binary math, bit-wise
ANDing, and conversion between binary and decimal. While this may
appear extremely complicated to some people, learning to do it this way
illustrates the "why" of the process in ways that those shortcuts and
tricks can never do. If you learn how it works you'll be way ahead of
the game.

### Here are some pages that I threw together during the Spring
2013 semester while taking Cisco 1:

The step-by-step
procedure I learned.

A practical subnetting problem.

A challenging
subnetting problem from the book.

### Fast forward to August 2013 and I find
myself reviewing subnetting
for the Cisco 2 and Cisco 3 courses I'll be taking this fall. While
doing some practice problems, I found I had forgotten a few things.
Here are some pages that show my mistakes and explains how I should
have done it.

Mistake
#1 from David Clauss' IP Subnet Problem Generator

Mistake #2 from David Clauss'
IP Subnet Problem Generator

I now find myself in
Spring 2014, my last semester, and I need to review some new subnetting
subjects I learned last fall and some new subjects.

Subnetting
Charts

Route
Summarization

Route
Summarization in Reverse

ACL Wildcard Masking

Lastly, here are links to other subnetting
sites:

IP Subnet
Problem
Generator (David Clauss)

Multi-mask Subnet Problems (David Clauss)

A basic GNU Subnet Calculator (this one does wildcard masks!)

A more full-featured Subnet Calculator

Subnetting Practice and Game

Subnetting Tutorial

Old CNMNorth

New CNM North (as of April 2014)

*Thanks to David Clauss, James Hart, David
Beach, Steve Perry, and Bob Hennigan at Central New Mexico Community College
for taking me this far. I'm sure I'll refine this as more of the steps
become second nature and I more fully understand the underlying
mechanics of it all.*