TCP/IP Model.

By | July 23, 2009

TCP/IP Model :  This model is a description framework of internet protocols. It is also called as Internet protocol suite. This model is a later invention after the original model OSI model with 7 layers. TCP/IP contains 4 layers. It was developed by the defense ministry of United states in 1970. This model is also referred as Internet model or Dod model. TCP/IP is the short hand for Transmission Control Protocol and Internet Protocol.

Take a look at this diagram how the data is encapsulated at each layer. 300px-udp_encapsulationsvg

The TCP (Transmission Control Protocol )  operates at transport layer of the Internet protocol suite and provides the network devices with reliable and secured communication facilities. Applications of TCP include Email and file transfer.

IP (Internet Protocol) is a networking protocol used for communicating data over a packet-switched network. It operates on the Internet layer of the protocol suite and facilitates the delivery of datagrams based on the IP Address of the network hosts.

Indeed, TCP/IP protocol suite is the core of communication and computing over the Internet.

It gives set of guidelines to communicate over the network and also implements certain networking protocols to help computers communicate over the network. The model shows the end to end connectivity between the source and destination specifying how the data is formatted, addressed, transmitted and received to the destination.

Although this model is always compared with the OSI reference model , this model is descriptive and not a reference model as OSI is.


Layers in TCP/IP Model:

Application Layer: This layer works where the high level protocols reside. It defines how the host programs interface with the transport layer services to use the network efficiently. It defines the application protocols.

Transport Layer: This layer provides the communication management between the communicating computers. It is responsible to establish and take care of the sessions between the hosts.It is the most important layer and basically uses two protocols

TCP: Transmission Control Protocol – Connection oriented

UDP: User datagram Protocol – Connection less.

Internet Layer: This layer is responsible to encapsulate the data into the IP datagrams which contains the source and destination IP address information useful for routing. It performs the routing of the IP datagrams over the networks.

Link Layer/ network Interface Layer: This is the last layer of the model and it specifies the details how the data is actually and physically transmitted over the network. It includes the electrical specification of the data that is transmitted, how the bits are signaled by the hardware.