Saturday, 26 April 2014

DIFFERENCE BETWEEN OSI AND TCP IP

Difference between OSI and TCP IP Model
TCP/IP is a communication protocol that allows for connections of hosts to the internet. OSI, on the other hand, is a communication gateway between the network and the end users. TCP/IP refers to Transmission Control Protocol used in and by the applications on the internet. This protocol can borrow its roots from the Department of Defense, which developed it to allow different devices to be connected to the internet. OSI, on the other hand, refers to Open Systems Interconnection, a communication gateway developed by the International Organization for Standardization (ISO).

Just what differences are there among the two? First off is the model of implementation on which each is developed. TCP/IP comes from the implementation of the OSI model, which led innovation in the field. OSI, on the other hand, was developed as a reference model that could be employed online. The model upon which TCP/IP is developed, on the other hand, points toward a model that revolves around the internet. The model around which OSI was developed upon is a theoretical model and not the internet.

There are four levels or layers upon which TCP is developed. These layers include the Link Layer, the Internet Layer, Application Layer and the Transport Layer. The OSI gateway, on the other hand, is developed upon a seven-layer model. The seven layers include Physical Layer, DataLink Layer, Network Layer, Transport Layer, Session Layer, Presentation Layer and, last but not least, Application Layer.

When it comes to general reliability, TCP/IP is considered to be a more reliable option as opposed to OSI model. The OSI model is, in most cases, referred to as a reference tool, being the older of the two models. OSI is also known for its strict protocol and boundaries. This is not the case with TCP/IP. It allows for a loosening of the rules, provided the general guidelines are met. 

On the approach that the two implement, TCP/IP is seen to implement a horizontal approach while the OSI model is shown to implement a vertical approach. It is also important to note that TCP/IP combines the session layer and presentation too in the application layer. OSI, on the other side, seems to take a different approach to the presentation, having different session and presentation layers altogether.

It is also imperative to note the design followed when protocols were being designed. In TCP/IP, the protocols were first designed and then the model was developed. In OSI, the model development came first and then the protocol development came in second.

When it comes to the communications, TCP/IP supports only connectionless communication emanating from the network layer. OSI, on the other hand, seems to do quite well, supporting both connectionless and connection-oriented communication within the network layer. Last but not least is the protocol dependency of the two. TCP/IP is a protocol dependent model, whereas OSI is a protocol independent standard.

Summary
TCP refers to Transmission Control Protocol.
OSI refers to Open Systems Interconnection.
Model TCP/IP is developed on points toward a model the internet.
TCP/IP has 4 layers.
OSI has 7 layers.
TCP/IP more reliable than OSI
OSI has strict boundaries; TCP/IP does not have very strict boundaries.
TCP/IP follow a horizontal approach.
OSI follows a vertical approach.
In the application layer, TCP/IP uses both session and presentation layer.
OSI uses different session and presentation layers.
TCP/IP developed protocols then model.
OSI developed model then protocol.
TCP/IP offers support for connectionless communication within the network layer.
In the network layer, OSI supports both connectionless and connection-oriented communication.
TCP/IP is protocol dependent.
OSI is protocol independent.

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