2.1 Understanding IP Schemes

Basics​

You probably already understand that when two computing devices need to find each other and transfer data beyond a single network, they use IP addresses. All of the devices on your network have a unique IP address. Most people who use the Internet have some experience with using IP addresses, but understanding them is critical to administering a network. 

You should know the following terms:

  • Host address
  • Network address
  • IPv4
  • IPv6
  • Dotted-decimal notation
  • Binary number system (base 2)
  • Octet
  • Hexadecimal number system (base 16)

An IP address has two pieces of information: the host address, also called the client address, and the network address, which might also be referred to as the server address. The host address identifies where on your network a device is connected.

IPv4 is the most common method to configure an IP address for a computing device; although, IPv4 is not limitless and as the number of Internet-enabled devices has grown exponentially network administrators should be aware they may have to eventually move to IPv6. 

An IPv4 address represents a 32-bit number in dotted-decimal notation that uses the binary (base 2) number system, because computers only understand and utilize binary code. The 32-bit number is presented as a series of four number sequences, each with eight characters (4 x 8 = 32), which are often referred to as octets. All of the characters are 0s or 1s, because those are the only two numbers used in the binary number system. So, an IP address in binary that a computer would read might look like:

11000000.10101000.11100101.00011001

While this is not a tutorial on numbering systems and how to convert between them, like converting binary (base 2) numbers to decimal (base 10) numbers or even hexadecimal (base 16), you can find many of those online if you want to learn more. It can be helpful to learn more about binary and hexadecimal numbers, however you can still recognize and use the numbers in IP addresses for basic networking tasks with a basic understanding.

An IPv4 address in decimal notation uses a series of four numbers that range between 0 and 255. These are also presented in dotted-decimal notation. These four numbers presented in decimal form are the equivalent of that same number represented in binary octets. When converting the previous binary stream of four octets, you get the following IPv4 address:

192.168.229.25

Many people would read this as, “one ninety-two dot one sixty-eight dot two twenty-nine dot twenty-five.” This is the decimal notation equivalent of the binary example first shared.

Some of the numbers in an IPv4 address identify the network address and some identify the host address. For example, if in the IPv4 address 10.0.0.53, the network is represented by the first two numbers 10.0, then all devices on that network have an IPv4 address that begins with 10.0. The other numbers in this example, 0.53, are unique to a device. No one else on the 10.0 network can have the same 0.53 at the end of their address.
 

Here are additional resources you may find useful:

Complete the following task or self-assessment:

Identify the IP addresses of several devices you work with while on your network over several days.  

  • What is the network address for your district?  If there are more than one, can you identify them?
  • Are the IP addresses fixed for the devices you checked (always the same, or do they change?  Why do you think that is?