OSI Model

Each day you go to websites at the click of a button, you surf the Internet, watch videos, play MMO games and do lots more just by sitting at home. When there is a technical problem, you do not have any connection and… bang! And your social life is gone (is it?!). Would you like to know what’s going on behind the scenes? How is your computer connected with the world… what is Internet… what is IP address… what the router is… what the hub is… what rj-45 cable are? Well these terms might not be strange to you. Lets embark in this new world. The world of Networking.

If you want to know what Network is check out my last post – Network Basics.
Lets start from the basics. You may have heard this many times, “The OSI Layer”… What is it?

OSI Layer

Well Open System Interconnect (OSI) is just a reference model used in any network and by network manufacturers. Suppose you have to build a house, you cannot just hire men and say “Hey put some bricks here, put some sand here… oh gosh I missed a window lets break it and re-build it”
What you need is a reference model which you will base your actions and components on. OSI layer is just a reference model used to communicate or build the foundation of a network. It is the model, the blueprint that will serve to allow communication between computers in a network.

A glance at the OSI layer.

ITCuties-OSI Model

ITCuties – OSI Model

Each one of the layers present have different function and I’ll be covering it in the incoming posts of the Networking series. For now, let’s summarize it.

Application When you need data, you interact with it.
Presentation Ensure data is received in useable format. Encryption is done here.
Session Providing with connection maintenance and responsible for ports.
Transport Break data for assigning sequence numbers. Error checking if errors are present in data received.
Network How will computers find you in the network. IP address are used here.
DataLink Responsible for flow control. MAC addresses are used here.
Physical Deals with raw signals. Cabling and hardware interaction.

Next I’ll be explaining the Physical Layer. Stay tuned!

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