Introduction
For devices to communicate over a network there needs to be some logical addressing scheme. Much in the same way that the post office uses addresses to uniquely identify each house networks use an IP address to uniquely identify each device on a network. There are two main IP address types IPv4 and IPv6 in this post we will be examining IPv4 addressing.
IPv4 Basics
The two main components of an IPv4 address are the IP address and the Network Mask. An IPv4 address uses a dotted-decimal notation and is composed of 4 decimal numbers ranging from 0 to 255. Each decimal in an IPv4 address is referred to as an octet. The IPv4 address uniquely identifies a device on a subnet or a sub-network and an IPv4 address might look like 10.234.1.88. Next, we look at what a Network Mask is.
A Network Mask or Subnet Mask is used in combination with an IPv4 address to determine what particular subnet that a device belongs to. The Network Mask also uses a dotted-decimal notation and an example of that is 255.0.0.0. When we combine these two addresses, we have a fully formed IPv4 address scheme. The network IP of a device could be 10.234.1.88 with a network mask of 255.0.0.0. Next, we look at how we separate IPv4 addresses into classes.
IPv4 Classes
IPv4 Addresses are separated into ranges known as classes:
| Class | Address Range of First Octet | Network Mask |
|---|---|---|
| Class A | 1 to 126 | 255.0.0.0 |
| Class B | 128 to 191 | 255.255.0.0 |
| Class C | 192 to 223 | 255.255.255.0 |
| Class D | 224 to 239 |
Decimal vs Binary Formats
Finally, let’s look at how we can represent an IPv4 address in another format known as binary. IPv4 addresses are 32 bits long with each octet of an address being comprised of 8 bits and each address can be represented in binary instead of decimals. The IP 10.234.1.88 can be represented as 00001010.11101010.00000001.01011000. Here you can see that an IP address contains 32 bits and representing an IP address this way can be useful in understanding how the network mask works. It is also common to see a string of 8 bits being separated by a space 0000 1010 to make it easier for us to see.
If we were to represent the network mask of 255.0.0.0 in binary it would look like this 11111111.00000000.00000000.00000000. When we review subnetting we will do a deeper discussion on why this is important. For now just understand that an IP address represented in the dotted-decimal form can be converted to a binary format as well. You are now familiar with the IPv4 address schemes but there is sooo much more to learn! Next, check out our post on subnetting coming soon!
Wrap Up!
That wraps up the basics of an IPv4 address schemes in posts coming soon we will discuss the structure of an IPv6 addressing scheme and subnetting! Stay tuned for more great content!