IP address is the logical address in the network layer of the TCP/IP protocol. IP Address is the unique address assigned to each device on the network which facilitates the identification of each device on the network. There are two standard of IP address:
- IPv4 (IP version 4)
- IPv6 (IP version 6)
Let’s understand each of these in detail.
An IPv4 address is a 32-bit address that uniquely and universally defines the connection of a device (for example, a computer or a router) to the Internet.
IPv4 addresses are unique in the sense that each address defines one, and only one, connection to the Internet. Two devices on the Internet can never have the same address at the same time.
IPv4 uses 32-bit addresses, which means that the address space is 232 or 4,294,967,296 (more than 4 billion).
IPv4 addresses are represented in two notations:
- Binary notation:
In binary notation, the IPv4 address is displayed as 32 bits. For example binary notation of an address is:
10000001 00001011 00001011 11101111
- Dotted-Decimal notation:
In dotted-decimal notation, the IP address representation is more compact and easy to ready. It is written in decimal form with a decimal point (dot) separating the bytes. For example, dotted-decimal notation of above mentioned IP address is:
Initially IPv4 addresses were based on concept of classes. IPv4 addresses are divided into five classes:
- Class A:
This class includes IP addresses ranging from 1.x.x.x to 126.x.x.x. The IP address 127.x.x.x is reserved for reverse lookup. The default subnet mask for this class of IP address is 255.0.0.0.
- Class B:
This class includes IP addresses ranging from 128.0.x.x to 191.255.x.x. The default subnet mask for this class of IP address is 255.255.0.0.
- Class C:
This class includes IP addresses ranging from 192.0.0.x to 192.255.255.x. The default subnet mask for this class of IP address is 255.255.255.0.
- Class D:
This class includes IP addresses ranging from 184.108.40.206 to 220.127.116.11. Class D does not have subnet mask.
- Class E:
This class includes IP addresses ranging from 240.0.0.0 to 255.255.255.254. Class D too does not have subnet mask.
To overcome the problem of depletion of IP addresses for long time, IPv6 were introduced. An IPv6 address is a 128-bit address.
IPv6 has a much larger address space i.e. 2128 addresses are available. It is represented by 16-bit hexadecimal numbers represented by colon (:). For example, an IPv6 is represented by: