What is TCP/IP Model and its Layers?

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What is TCP/IP Model?

TCP/IP is a (transmission control protocol/Internet protocol) which is created by DARPA agency (Defense Advanced Research Projects Agency) in 1970. After that, it is acknowledged as a standard protocol by ARPANET (Advanced Research Projects Agency Network) in 1983. This model is described as the computer network protocol that tells how computers should be connected to the internet.

In other words, we can say that the TCP/IP model is a model which is used as a communication protocol where it describes the connectivity of systems with the internet and tells how data can be transmitted from the system to the internet between the source and destination.

This model is very similar to OSI model but not that much because both these model have their own speciality. In this model there are four or five layer if we include Physical layer, we are mainly focuses on four layers let see:

Application Layer
Transport Layer
Internet layer
Network Access layer

Now , let discuss these layers one by one:

1) Network Access Layer

This layer is the lowest layer in this model and it is a combination of physical and data link layer (As we saw in our previous blog of OSI model). This layer contains the protocols that the computer used to deliver the data to the other computers which are connected to the network.

In other words, the network access layer defines how the data can be used to transmit to the network physically between the systems is known as “Network Access interface or link layer”.

2) Internet Layer

This the second lowest layer of the TCP/IP model and it is also known as network layer, this is because this layer is responsible for transferring the data over the network via IP or we can say address. It provides the packets to the network node and transmit it to the destination it is known as “Internet or network layer”.

In this layer there have some basic protocols are :

I.P – I.P is an “Internet Protocol” which is used to provide the data packet from one network to another network node or we can say one computer to another computer. It is known as IP.
ARP– ARP is an “Address Resolution Protocol”, it is used to find out the mac address of the computer system from its IP address. It is known as ARP.
I.C.M.P– ICMP is an “Internet Control Protocol”, it is an error reporting protocol that is used for handling the error over the network. It is known as ICMP.
RARP– RARP is a “Reverse Address Resolution Protocol” which is used to mapping the physical address into the IP address. It is known as RARP.
I.G.M.P– IGMP is an “Internet Group Management Protocol” which is used to allow several devices to share one IP address so that they all receive the same data. It is known as IGMP.

3) Transport Layer

The Transport layer just the application layer is the host-to-host layer. This layer is responsible for end to end communication and error free transmission. It is known as “Transport layer” of TCP/IP model.

There are mainly two important protocols are:

UDP– UDP is “User Datagram Protocol”, it is an unreliable protocol that provides a connectionless service that enhances the network throughout the host-to-host transport layer. It is mainly used for broadcasting the messages over the network.
TCP– TCP is a “Transmission Control Protocol”, It is a reliable protocol that is mainly used for end-to-end and error-free communication over the network. It is known as TCP.

4) Application Layer

This is the toppest layer of the TCP/IP model and this layer defined as Application, Presentation and session layer as per OSI model. It provide the services to the application software to run in a computer system so that user can interact with the system. It is known as “Application Layer”.

There are various protocols which are used in a application layer are :