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Subnetting Fundamentals


Intro Video

Photo of Michael Christian

Michael Christian

Course Development Director in Content







Course Details

This course will provide the prospective student with the fundamentals of network segmentation. By the end of this course, the student will have a thorough understanding of subnetting and network masking.

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Getting Started

About the Training Architect


Lesson Description:

Meet Michael Christian, the Subnetting Fundamentals Training Architect.

Course Intro and Overview


Lesson Description:

An introduction and overview of the course.

What is Subnetting?

Networking Basics


Lesson Description:

Why do we network computers and what are the basic components to do so? In this lesson, we take a very basic look at networking to answer these questions.

Networking Traffic


Lesson Description:

In this lesson, we examine the various methods of how data moves through the network. Additionally, we look at the OSI layers, and how data is broken into bits to move across the wire.

Networking Segmentation


Lesson Description:

Why do we segment a network? In this lesson, we assess why breaking a network into small sections for the purpose of security and/or limiting makes sense.



Lesson Description:

For information to travel across a network, there must be a source and a destination. This means everything on the network must be addressable. In this lesson, we examine the components of network addresses.



Lesson Description:

Binary is the base-two number system computers use for their calculations. If we're to understand subnetting, we must understand using binary to represent the numbers of the IPv4 octet.

Binary IPs


Lesson Description:

Every IP address can be written as a binary number. In this lesson, we examine binary representation of IP addresses and why the octet range limits exist. This is a necessary step to understanding network masking in upcoming lessons.

Subnetting Strategies

Network Masks


Lesson Description:

What is a network mask and how is it applied? In this lesson, we examine masking off a portion of the host address for the purpose of giving the network itself an address. Using what we've learned about binary, we can further examine the host bits and network bits.

Subnetting Calculation


Lesson Description:

It's import to be able to calculate the number of host addresses available in a subnet, as well as the address range. In this lesson, we perform these calculations against several examples.

Classful Networking


Lesson Description:

What is a class A network? In this lesson, we examine classful networking, and why classful networks were used in network design. While all but replaced by CIDR, understanding classful networks gives us the needed context to understand why CIDR is such an improvement.

All-Ones and Subnet Zero


Lesson Description:

When subnetting a classful network, both the first and last available subnet in a range presented particular challenges. In this lesson we examine the all-zeros subnet, as well as the all-ones subnet, and how they imposed a unique challenge to subnetting classful networks.



Lesson Description:

In this lesson, we examine CIDR and the flexibility of a non-binary boundary in subnetting. We look at a CIDR chart for assistance in determining network size, and expand on our ability to calculate subnet hosts and ranges.



Lesson Description:

Classful networking and CIDR apply to IP assignments. FLSM and VLSM apply to how subnets are assigned within the infrastructure. In this lesson, we put together everything we've learned to construct an example network using both FLSM and its replacement, VLSM.

Final Steps

Conclusion and Review


Lesson Description:

Conclusion and final review of the course.

What's Next


Lesson Description:

Additional training to consider after completing this course.

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