OSI Model

 OSI (Open System Interconnection) =>

    Open system interconnection is designed by the ISO (International Standard Organization) .International Org for standardization. It is a logical concept that how the data flow in the network. It allows various type of hardware & network vendor to work together, in the form of protocol. It has seven layers & each layer & each layer having its own function in the network.

Physical (Layer 1)

This layer conveys the bit stream - electrical impulse, light or radio signal -- through the network at the electrical and mechanical level. It provides the hardware means of sending and receiving data on a carrier, including defining cables, cards and physical aspects. Fast Ethernet, RS232, and ATM are protocols with physical layer components.

Data Link (Layer 2)

At this layer, data packets are encoded and decoded into bits. It furnishes transmission protocol knowledge and management and handles errors in the physical layer, flow control and frame synchronization. The data link layer is divided into two sub layers: The Media Access Control (MAC) layer and the Logical Link Control (LLC) layer. The MAC sub layer controls how a computer on the network gains access to the data and permission to transmit it. The LLC layer controls frame synchronization, flow control and error checking.

Network (Layer 3)

This layer provides switching and routing technologies, creating logical paths, known as virtual circuits, for transmitting data from node to node. Routing and forwarding are functions of this layer, as well as addressing, internetworking, error handling, congestion control and packet sequencing

Transport (Layer 4)

This layer provides transparent transfer of data between end systems, or hosts, and is responsible for end-to-end error recovery and flow control. It ensures complete data transfer.

Session (Layer 5)

This layer establishes, manages and terminates connections between applications. The session layer sets up, coordinates, and terminates conversations, exchanges, and dialogues between the applications at each end. It deals with session and connection coordination.

Presentation (Layer 6)

This layer provides independence from differences in data representation (e.g., encryption) by translating from application to network format, and vice versa. The presentation layer works to transform data into the form that the application layer can accept. This layer formats and encrypts data to be sent across a network, providing freedom from compatibility problems. It is sometimes called the syntax layer.

Application (Layer 7)

This layer supports application and end-user processes. Communication partners are identified, quality of service is identified, user authentication and privacy are considered, and any constraints on data syntax are identified. Everything at this layer is application-specific. This layer provides application services for file transfers, e-mail, and other network software services. Telnet and FTP are applications that exist entirely in the application level. Tiered application architectures are part of this layer.

                                     

                                         Working Of OSI Layer's

 1>Application Layer => Provide graphical interface between user & computer.

 2>Presentation Layer => Responsible to present the data, encryption, decrypt & security on the folder .

 3>Session Layer        => To create managed terminate the session

 4>Transport Layer       => Carries the data from source to destination means transport the data in the network.

 5>Network Layer      => Choose first path first.

 6>Data Link Layer     => All the technologies, topologies, PPTP & media works on these

 7>Physical Layer        =>                        two layer

             

                                               IT CONTAINS

 * Application  , Presentation , Session Layer :- HTTP , HTTPS , DNS ,DHCP . FTP , POP3 , TELNET ,        SMT etc

* Transport Layer :- TCP/UTP

* Network Layer :- IP , ICMP , ARP , RARP

* Data Layer :-        LLT , PPTP , PPP

* Physical Layer :-   AS Above same

           

                                           Full Form's And There working

 > HTTP :-- Hyper Text Transfer (Protocal is used to brows a web server and pages works on the 80           no port )

> HTTPS :-- Hyper Text Transfer Protocal Secure (Its is use for web security purpose & works on 4043 port.

> FTP :-- File Transfer Protocol (It works on 20 & 21 no port . used to downlod and uplod files .

> POP 3 :-- Post Office Protocol no 3 (it works on port no 110 & used to access email on the clients site.

>TELNET :-- Telecommunication network (used to take remote control of the swith from the location.it works on 23 no port,

>TCP /UDP :-- Transmision Control Protocol ( works on 6 & 7 no port & used to carry the data from source to destination

> IP :-- Internet Protocol (IP address in binary codings )

> ICMP :--Internet Control Message Protocol (used in local networks and on the Internet, most typically, for network troubleshooting and problem location)

>ARP :--Address Resolution Protocol (used to convert an IP address into a physical address)

> RARP :-- Reverse Address Resolution Protocol

> 

>PPTP :-- Point to Point Transfer Protocol

> PPP :-- Point to Point Protocol

                                                                  Watch It In Hindi                                                                                                                             

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