OSI Model Layer Function

Best wishes guys ....

     OSI Model Layer Function - On this occasion I will share a bit of knowledge I have gained from the lessons I have received during lectures. This science is said to be the basis of current knowledge will learn about computer networks. I will share this time is about layers - layers of the OSI layers.

      Previous probably still there who do not know what the OSI. The OSI model is not a physical form but rather a guide for application developers in order to create and implement applications that can run on a network. In simple OSI is a picture of the part - and instrumental parts contained in the network, which is depicted in the form of layers.

      OSI consists of 7 layers (layer) were divided into two groups. The first group is the top 3 layers that define how applications - applications communicate with each other and how the application interacts with the user. The second group is the 4 bottom layer that defines how data is moved from one place to another. Here's a picture of the OSI layer:

 

      Now it's time we discuss each part one by one .....

1. Application Layer (Layer 7): Application Layer is the top layer of the OSI layers that exist. Application Layer is the place where the user or the user interacts with the computer. This layer is actually functioning when we need access to the network / network, for example, Internet Explorer, Google Chrome. Application Layer is also responsible for identifying and ensuring the existence of the intended communication partner and determining whether the intended communication resources reasonably available. In addition, the Application Layer also acts as an interface between the actual application program, wherein the application program is not included in the layer structure, with the following layers underneath. 
2. Presentation Layer (Layer 6): Presentation Layer is the second layer from the top of the OSI layer which is just below the Application Layer. Fungi of this layer as the name 'presentation' which presents data to the Application Layer and is responsible for the translation of data and formatting code (program). This layer is essentially a translator and perform coding and conversion functions. Successful data transfer technique is to adapt the data into a standard format before sent. Computer configured to receive a standard data format and then converted back to its original form to be read by the application in question. 
3. Session Layer (Layer 5): Session Layer is the third layer after the Presentation Layer. Session Layer is responsible for forming, managing, and then decides session - the session between layers - presentation layer. Session Layer also provides dialog control between devices or network point (node). Session Layer conclusion is essentially maintain the separation of data from one application to another application's data. 
4. Transport Layer (Layer 4): The Transport Layer is responsible for providing mechanisms for multiplexing (multiplexing is a technique to transmit or receive several different types of data at once, through the media network) method of the application - the application of upper - layer, create a session, and decides virtual circuit (connection between two hosts in a network through a three-way handshake mechanism). It also hides the detail - the detail of the information depends on the network, hiding it from the layers - the higher layer. 
5. Network Layer (Layer 3): Network Layer is the layer that serves to manage the addressing equipment, track the location of equipment in the network, and determine the best way to move data. This means that the Network layer must transport traffic between devices which is not locally connected. Router (One of the tools in the layer-3) ​​is set at the Network layer and provide the routing services within an internetwork. 
6. Data Link Layer (Layer 2): Data Link layer provides the physical transmission of the data and handles error notification, network topology, and flow control. This means that this layer will ensure that messages will be sent through the appropriate tool on the LAN using the hardware address (hardware address), and translate messages - messages from the Network layer into bits - bits to be transferred to the Physical Layer. Data Link layer also perform on the message or data format into fractions - fractions called a data frame, and adds a header consisting of the address of the destination and origin hard device. 
7. Physical Layer (Layer 1): Layer physical here to do two things: send and receive bits bits. Bit has only two values​​, namely 0 and 1 Physical Layer to communicate directly with various types of actual communication media. Various different types of media represent these bit values ​​in different ways. Physical Layer determines the physical, mechanical, procedural, and functional activate, maintain, and deactivate physical connections between systems. 

      Well it's the end of my sharing about the OSI Model Layer Functions. Hopefully what I share can be helpful for you. We are sorry if there are mistakes in this writing.

Thank you ....

GBU