Internet Protocol IPv4

Internet Protocols 

The Internet Protocol (IP) is the principal communications protocol in the Internet Protocol Suite for relaying datagram across network boundaries. An Internet Protocol address (IP address) is a numerical label assigned to each device in a computer network that uses the Internet Protocol for communication. There exist two versions of IP addresses: IPv4 and IPv6. The IP provides unreliable, connectionless, best-effort delivery services, where as TCP provides reliable, efficient and cost effective end-to-end delivery of data.

IPv4 ADDRESSES

An IPv4 address is a 32-bit address that uniquely the connection of a device to the Internet. The address space (An address space is the total number of addresses used by the protocol) of IPv4 is 2^32or 4,294,967,296.

There are two notations to show an IPv4 address: binary notation and dotted decimal notation. In binary notation, the IPv4 address is displayed as 32 bits or simply a 4-byte address. To read easily IP address are usually written in decimal form with a decimal point separating the bytes.

For example:

Decimal representation 172.16.254.1

Corresponding binary representation  10101100.00010000.11111110.00000001

Classful addressing

In classful addressing, the address space is divided into five classes: A, B, C, D, and E.  We can find the class of an address, when given the address in binary notation or dotted-decimal notation. The following figure helps you to class of an IP address. If we have dotted-decimal notation then first part of the address is used to determine the class. If we have given address in binary form then first few bits can used to determine the class of the address. 

Classes and range of IP address

Some IP addresses are reserved for private use that can be used to setup networks without registration. Those are given below

10.0.0.0        to  10.255.255.255   total number 2^24

172.16.0.0    to  172.31.255.255   total number 2^20

192.168.0.0  to  192.168.255.255 total number 2^16

Some other important IP addresses are,

0.0.0.0           used to represent “this host”

0000-------hostID  a host on this network

11111111.1111111.11111111.11111111  Broadcast on this network

127.anything   Loopback (eg: 127.0.0.1)