What is the valid range of a Class A network address?

Let us know what an IP address is first, if you already know, skip this section.

IP (Internet Protocol):
It is one of the fundamental protocols inorder to have communications on the Internet. IP describes how the information is addressed, routed by networking devices. An IP address is a number identifying of a computer or another device on the Internet. A simple example could be mailing address.

There are 2 types of IP
1. IPv4 : 32 bit long, Ex: 35.244.11.196
2. IPv6 : 128 bit long, it is so much longer than IPv4

Example for IPv4 :

1. Dotted Decimal Notation

2. Hexadecimal Notation

CLASS ADDRESSING :

So, In IPv4 addressing, there are 5 classes to range IP Values : Class A, B, C, D and E.
The order of bits in the first octet determine the classes of IP address.
IPv4 address is divided into two parts:
1. Network ID
2. Host ID
The class can determine the bits used for network ID and host ID.
The number of total networks and hosts possible in that particular class can be calculated.
Only class A, B and C are commonly used. classes D and E are reserved classes, D for multicast groups and E for future purposes.

CLASS A :

IP address belonging to class A are assigned to the networks that contain a large number of hosts. Here, class A can support 16 million hosts on 127 networks.
Here, the network ID is 8 bits long and the host ID is 24 bits long.
IP addresses belonging to class A ranges from 1.x.x.x – 126.x.x.x
Default Subnet Mask: 255.x.x.x

Number Of Hosts and Networks:

Number of Hosts: (2^24)-2= 16,777,214 i.e 16 million hosts
Number of Networks: (2^7)-2=126 
Note: Reducing 2 because, 0.0.0.0 and 127.a.b.c are different addresses

>> The range of class A is 1.0.0.1 to 126.255.255.254

Other classes

Class B: 128.1.0.1 to 191.255.255.254
Class C: 192.0.1.1 to 223.255.254.254
Class D: 244.0.0.0 to 239.255.255.255
Class E: 240.0.0.0 to 254.255.255.254

My Personal Notes