<h2 style="margin: 0px 0px 14px; padding: 0px; border: 0px; line-height: 1.3em; vertical-align: baseline; word-wrap: break-word;"><span style="font-size: 17px; -webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">What is OSI model?</span></h2>
<p style="margin: 0px 0px 1em; padding: 0px; border: 0px; line-height: inherit; vertical-align: baseline;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">The OSI model (Open System Interconnection) model defines a computer networking framework to implement protocols in seven layers. A protocol in the networking terms is a kind of negotiation and rule in between two networking entities.</span></p>
<h2 style="margin: 0px 0px 14px; padding: 0px; border: 0px; line-height: 1.3em; vertical-align: baseline; word-wrap: break-word;"><span style="font-size: 17px; -webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Layers of OSI model:</span></h2>
<h3 style="margin: 0px 0px 14px; padding: 0px; border: 0px; font-weight: 400; line-height: 1.3em; vertical-align: baseline; word-wrap: break-word;"><span style="font-size: 17px; -webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Physical layer</span></h3>
<p style="margin: 0px 0px 1em; padding: 0px; border: 0px; line-height: inherit; vertical-align: baseline;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">The Physical layer is also called as the Layer 1. Here are the basic functionalities of the Physical layer:</span></p>
<ul style="margin: 0px 0px 15px 30px; padding: 0px; border: 0px; line-height: inherit; vertical-align: baseline; list-style: none;">
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Responsible for electrical signals, light signal, radio signals etc.</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Hardware layer of the OSI layer</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Devices like repeater, hub, cables, ethernet work on this layer</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Protocols like RS232, ATM, FDDI, Ethernet work on this layer</span></li>
</ul>
<div>
<h3 style="margin: 0px 0px 14px; padding: 0px; border: 0px; font-weight: 400; line-height: 1.3em; vertical-align: baseline; word-wrap: break-word;"><span style="font-size: 17px; -webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Data Link ;layer</span></h3>
<p style="margin: 0px 0px 1em; padding: 0px; border: 0px; line-height: inherit; vertical-align: baseline;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">The data link layer is also called as the Layer 2 of the OSI model. Here are the basic functionalities of the data link layer:</span></p>
<ul style="margin: 0px 0px 15px 30px; padding: 0px; border: 0px; line-height: inherit; vertical-align: baseline; list-style: none;">
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Responsible for encoding and decoding of the electrical signals into bits.</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Manages data errors from the ;</span><span style="font-family: 'Helvetica Neue Light', HelveticaNeue-Light, helvetica, arial, sans-serif; font-style: inherit; font-variant-caps: inherit; -webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">physical layer</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Convers electrical signals into frames</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">The data link layer is divided into two sub-layers</span>
<ul style="margin: 0px 0px 0px 30px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: none;">
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">The Media Access Control (MAC) layer</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Logical Link Control (LLC) layer.</span></li>
</ul>
</li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">The MAC sublayer controls how a computer on the network gains access to the data and permission to transmit it.</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">The LLC layer controls frame synchronization, flow control and error checking.</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">MAC address is a part of the layer 2.</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Devices like Switch work at this layer</span></li>
</ul>
<h3 style="margin: 0px 0px 14px; padding: 0px; border: 0px; font-weight: 400; line-height: 1.3em; vertical-align: baseline; word-wrap: break-word;"><span style="font-size: 17px; -webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Network Layer</span></h3>
<p style="margin: 0px 0px 1em; padding: 0px; border: 0px; line-height: inherit; vertical-align: baseline;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">The Network layer is also called as the layer 3 of the OSI model. ;Here are the basic functionalities of the network layer:</span></p>
<ul style="margin: 0px 0px 15px 30px; padding: 0px; border: 0px; line-height: inherit; vertical-align: baseline; list-style: none;">
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Switching and routing technologies work here</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Creates logical paths between two hosts across the world wide web called as virtual circuits</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Routes the data packet to destination</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Routing and forwarding of the data packets.</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Internetworking, error handling, congestion control and packet sequencing work at this layer</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Router works at layer three</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Different network protocols like TCP/ IP, IPX, AppleTalk work at this layer</span></li>
</ul>
<h3 style="margin: 0px 0px 14px; padding: 0px; border: 0px; font-weight: 400; line-height: 1.3em; vertical-align: baseline; word-wrap: break-word;"><span style="font-size: 17px; -webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Transport layer</span></h3>
<p style="margin: 0px 0px 1em; padding: 0px; border: 0px; line-height: inherit; vertical-align: baseline;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">The Transport  ;layer is also called as the layer 4 of the OSI model. ;Here are the basic functionalities of the Transport layer:</span></p>
<ul style="margin: 0px 0px 15px 30px; padding: 0px; border: 0px; line-height: inherit; vertical-align: baseline; list-style: none;">
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Responsible for the transparent transfer of data between end systems</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Responsible for end-to-end error recovery and flow control</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Responsible for complete data transfer.</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Protocols like SPX, TCP, UDP work here</span></li>
</ul>
<h3 style="margin: 0px 0px 14px; padding: 0px; border: 0px; font-weight: 400; line-height: 1.3em; vertical-align: baseline; word-wrap: break-word;"><span style="font-size: 17px; -webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Session layer</span></h3>
<p style="margin: 0px 0px 1em; padding: 0px; border: 0px; line-height: inherit; vertical-align: baseline;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">The Session  ;layer is also called as the layer 5 of the OSI model. ;Here are the basic functionalities of the Session layer:</span></p>
<ul style="margin: 0px 0px 15px 30px; padding: 0px; border: 0px; line-height: inherit; vertical-align: baseline; list-style: none;">
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Responsible for establishment, management and termination of connections between applications.</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">The session layer sets up, coordinates, and terminates conversations, exchanges, and dialogues between the applications at each end.</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">It deals with session and connection coordination.</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Protocols like NFS, NetBios names, RPC, SQL work at this layer.</span></li>
</ul>
<h3 style="margin: 0px 0px 14px; padding: 0px; border: 0px; font-weight: 400; line-height: 1.3em; vertical-align: baseline; word-wrap: break-word;"><span style="font-size: 17px; -webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Presentation ;layer:</span></h3>
<p style="margin: 0px 0px 1em; padding: 0px; border: 0px; line-height: inherit; vertical-align: baseline;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">The Presentation layer is also called as the layer 6 of the OSI model. ;Here are the basic functionalities of the presentation layer:</span></p>
<ul style="margin: 0px 0px 15px 30px; padding: 0px; border: 0px; line-height: inherit; vertical-align: baseline; list-style: none;">
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Responsible for data representation on your screen</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Encryption and decryption of the data</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Data semantics and syntax</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Layer 6 Presentation examples include encryption, ASCII, EBCDIC, TIFF, GIF, PICT, JPEG, MPEG, MIDI.</span></li>
</ul>
<h3 style="margin: 0px 0px 14px; padding: 0px; border: 0px; font-weight: 400; line-height: 1.3em; vertical-align: baseline; word-wrap: break-word;"><span style="font-size: 17px; -webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Application Layer:</span></h3>
<p style="margin: 0px 0px 1em; padding: 0px; border: 0px; line-height: inherit; vertical-align: baseline;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">The Application layer is also called as the layer 7 of the OSI model. ;Here are the basic functionalities of the Application layer:</span></p>
<ul style="margin: 0px 0px 15px 30px; padding: 0px; border: 0px; line-height: inherit; vertical-align: baseline; list-style: none;">
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Application layer supports application, apps, and end-user processes.</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Quality of service</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">This layer is responsible for application services for file transfers, e-mail, and other network software services.</span></li>
<li style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant-caps: inherit; line-height: inherit; vertical-align: baseline; list-style: square;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Protocols like Telnet, FTP, HTTP work on this layer.</span></li>
</ul>
<div><span style="-webkit-text-size-adjust: auto;">Credit. Fossbytes, IEEE, wekipedia ;</span></div>
</div>
<p></p>
<div style="clear: both;"><a href="https://lh3.googleusercontent.com/-1ht8gIj1TCA/VwEj_g-7WWI/AAAAAAAABWU/WvmC-ynseNo/s640/blogger-image-870833694.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://lh3.googleusercontent.com/-1ht8gIj1TCA/VwEj_g-7WWI/AAAAAAAABWU/WvmC-ynseNo/s640/blogger-image-870833694.jpg" /></a></div>

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