Essay Title: 

OSI Model and Network

March 29, 2016 | Author: | Posted in e-commerce, mathematics and economics

OSI Model and Network

Open System Interconnection or so called OSI is a model which describes a framework in networking for employing 7 layers of protocols . Each control is directed from one layer to its next layer , starting at the application layer in one station , and arranged to the base layer , above the control to the subsequently position and back up to the hierarchy

This OSI model serves as reference which is defined in seven layers to facilitate in illustrating the process of how applications run upon network capable devices which converse [banner_entry_middle]

with one another . The model is generic and applies to all network types , not just TCP / IP , and all media types , not just Ethernet

It should be noted , however , that most protocols in day-to-day use work on a slightly modified layer system . TCP / IP , for example , uses a 6-rather than a 7-layer model . Nevertheless , in to ease the exchange of ideas , even those who only ever use TCP / IP will refer to the 7-layer model when discussing networking principles with peers from a different networking background

An operational example of how the OSI model can be used to describe what happens when users browse a web page on a web site . This page that users are reading is stored on our website and users are most probably using a web browser to read this . We will use the OSI model to describe what happens when users click a link in a web page in the web browser and what happens as the web server receives processes and responds to the request . This example assumes that users are on a local area network and that users are using an Ethernet card to communicate with the network

OSI MODEL (Server-Client Webpage Activity

Layer 1 (Physical

Ethernet (CSMA /CD ) – The physical layer provides the means to transmit the web page request to the default gateway

Layer 2 (Data Link

Ethernet (LLC MAC ) – Once the request from the web browser has been created it is sent to the network card . Once it reaches the network card it must be converted into a message that is sent from the computer to the default gateway which will forward the message to the Internet . At the data link layer , the web request is inserted inside a network request to the default gateway

Layer 3 (Network

IP and ARP – Internet Protocol (IP ) is a network layer protocol that uses unique addresses for the web server and for the computer . To reach a web server on the Internet , IP protocol also allows the computer to figure out how to reach the Internet web server via the default gateway The computer creates a message addressed to the web server with the computer ‘s return IP address . The computer uses ARP to figure out the physical MAC address of the default gateway and then passes the data to the NETWORK layer

Layer 4 (Transport

TCP – To communicate with a web server the computer must open a… [banner_entry_footer]


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