Network Models

First to start Learning about Networking, we need to know about Network Models which are commonly used…

There are two commonly used Networking Models:

• OSI Model
• TCP/IP Model

let’s look each models in detail.

1. OSI MODEL:  

The Open Source Inter Connection Model consists of 7 layers in its Network Models.

• Physical Layer

        It is the last layer in the hierarchy when you send an request to a server. In this 7 layer model it deals with the network cables and cards we used. Physical layer starts its works when the network card in our system gets connected to the Ethernet frame and linked with an outer network.

        Whenever, the data or request reaches the physical layer it will be send to the network card to checkup  source and destination MAC address of the request and send it to the right destination over the internet. It also,  check the data frames to verify the data’s were arranged in sequence , before it send.

        When an response is received from the server Physical layer is the first layer to look over the data and it checks the frames to verify data sequence and MAC address. Then the data packet is given to the Data Link layer. It deals with

• Data-Link Layer

         This layer will add up the source and destination MAC address primarily to the IP packet received from the Network Layer . Then it will be send to Physical layer for further processing of the request.

         If a response is received by a Data-link layer it will wipe out the MAC address and sends the remaining IP Packet to the Network Layer. It deals with Physical or Machine addressing like MAC address.

• Network Layer

        In the Network Layer it will add an IP section with source and destination IP address to the TCP segment received from the Transport layer and send that request to the Data Link layer for further processing…

        If a response received from the last layer, Network Layer will check the source and destination IP address to verify that the received data is for the computer and it will took up the IP segment and send the remaining TCP segment to the Transport Layer. It deals with logical addressing like IP address.

• Transport Layer

       Transport layer will take the complete data and chops down them to smaller bytes and set some data sequence to assemble them in order and send the TCP segment to Network Layer…

        Transport layer will took the data from the response and reassemble them by using sequence number and provide the remaining chunk of data to Session Layer. It deals with assembling and disassembling data during exchange.

• Session Layer

       Session Layer is designed to maintain the connection between the server and client on a remote system. This layer keep tracking on every single session we made with the server and saves them as log files (temporary files) in our systems.

• Presentation Layer

Presentation Layer is designed to change the data format that a particular application supports. It also keep tracks on Port numbers each application will run on different ports, so that the data would be delivered to the right application.

• Application Layer

Application Layer is built in smarts that allow us to interface with a network. It deals with the API – Application Programming Interfaces.

2. TCP / IP MODEL :

The Transmission Control Protocol / Internet Protocol is an another model which is commonly used in networking and it consists of 4 layers.

• Network Interface Layer

This layer plays work of two layers such as Physical Layer and Data Link Layer from the OSI Model.

• Internet Layer

This layer plays the work of Network layer in OSI Model.

• Transport Layer

This layer works on similar of Transport layer in OSI Model.

• Application Layer

This layer acts the final 3 layer in OSI Model.

Hierarchy of the layer changes from bottom to top or top to bottom based on the way of data exchange. for example: If data need to be send from your side the hierarchy should be top to bottom and for receiving data the hierarchy should be bottom to top.

       

If some of the words aren’t understood to you we will made separate blog on that such as IP packets, Data Frames etc…..

Inform us if any changes need to be made to make it better understanding. Help Mutual!!!!.

Happy Hacking 🙂