Basics of IP address | TCP/IP layer

 The Internet Protocol is responsible for basic network connectivity. In TCP/IP the Internet Protocol or IP works with The Network Layer of TCP/IP model when mapped with TCP. In networking there has to be a physical location for sending the data and has to be physical location to receiving the data. For that every physical location have a unique network address. This address is called the IP address. IP address works just like postal address.


Structure of IP address: The IP address is a set of numbers separated by periods. There two versions of IP IPv4 and IPv6. In IPv4 an IP address is a 32-bit number, divided into two sections called network number and the host number. IP addresses are written in four fields, eight bits of it are separated by periods. Each field can be a number ranging from 0 to 255. This method of addressing is called dotted decimal notation.

An IP Address looks like:

Field1. Field2. Field3. Field4


Network Number and Host Number: The four fields of an IP address are clubbed into two sections, the network number and the host number. There are 5 types of classes in a Network. Among the 3 types are uses now. Depending on the type of network class the network number and host number field are allocated.

Network Class

Network Section of the IP Address

Host Section of the IP Address

Class A


Field2. Field3. Field4

Class B

Field1. Field2.


Class C

Field1. Field2. Field3




All hosts or network interfaces on the same network use the same network number. Each host or network interface on the same network must have a unique host number.


TCP (Transmission Control Protocol): TCP/IP consist of protocols, applications, and services. Protocols enable a server application to offer services, and the client application to use those services. The Internet is a large worldwide network of computers, which uses TCP/IP as the underlying communication protocol.


TCP/IP uses IP to deliver packets to upper layer applications and provide a reliable stream of data among computers on the network. Once the packets arrive at the correct IP address, TCP goes to work. TCP’s main work is error checking and make sure that right number of packets been received and in proper order. That’s why TCP guarantees that the data received by a computer on a TCP/IP network, is exactly the same data sent to it by another computer on the network.