When talking about the internet community, we can see how there are five address classes that were originally defined. Why have they been defined in the first place? These addresses and classes work in such a way that they accommodate all the networks needed. For example, TCP/IP supports class A, B, and C. These classes are assigned to the host. I will now guide you through all of the address classes of IP for your better understanding.
1.Class A. The addresses under this class are always assigned to those networks which have numerous numbers of hosts. When taking a look at the high-order bit in A, we can easily see that it is always zero. That is a default setting. The seven bits that follow are completing the first octet. That together makes a complete ID. There are 24 bits remaining and they always represent the host itself. What would be a conclusion? It is possible for 126 networks and also 16, 777, 214 hosts to be on the network.
2.Class B. These type of addresses are always assigned to so-called medium or large-sized networks. We talked about the zero binary in class A, but in B, it is different, with a default setting of 1 0. Then it has 14 other bits that create an ID of the network. The rest bits (16 of them), make it possible for the network to have 65, 534 hosts, while the available networks are literally countless, like 16, 384.
3.Class C. Opposite from class B, the addresses under a C class is used for small networks. The C class also has three high-order bits, which are set to 1 1 0. Then it has 21 bits that make the networks ID, and the last 8 which represent the host’s ID. Class C is allowing 2, 097, 152 networks with 254 hosts per one.
4.Class D. This type of IP addresses are made for IP multicast addresses. Class D has four high-order bits and they are set to a default level of 1 1 1 0. There are also some remaining bits that have a purpose to help the host to recognize them, if interested. I would like you to remember that this class is supported by Microsoft. Why did Microsoft choose class D? Because it allows the apps to have the multicast data and to send them to multicast-capable hosts, and all that on the internetwork.
5.Class E. This is the last class we are going to represent you. Hope that you have realized how classes decrease and increase at some points. This class is actually an experimental one most of the times reserved for some future use or purpose. Class E has high-order bits and they are set by 1 1 1 1.
There is one more thing I would like to mention. When combining the IP network with ID, or IP host and ID address, you will get an IP address.