PROTOCOLS SUBMITTED BY : SUDEEP C D ; BSc(CS) Ist Year Ist Sem. T h i s p r e s e n t a t i o n w i l l p r o b a b l y i n v o l v e a u d i e n c e d i s c u s s i o n, w h i c h w i l l c r e a t e a c t i o n i t e m s. U s e P o w e r P o i n t t o k e e p t r a c k o f t h e s e a c t i o n i t e m s d u r i n g y o u r p r e s e n t a t i o n I n S l i d e S h o w, c l i c k o n t h e r i g h t m o u s e b u t t o n S e l e c t “ M e e t i n g M i n d e r ” S e l e c t t h e “ A c t i o n I t e m s ” t a b T y p e i n a c t i o n i t e m s a s t h e y c o m e u p C l i c k O K t o d i s m i s s t h i s b o x T h i s w i l l a u t o m a t i c a l l y c r e a t e a n A c t i o n I t e m s l i d e a t t h e e n d o f y o u r p r e s e n t a t i o n w i t h y o u r p o i n t s e n t e r e d.

Protocols are set of rules to navigate through the computer. O S I Layers are layers which is divided into seven parts starting from physical layer to application layer which has no physical appearance. INTRODUCTION

Open system interconnection (O S I) The ISO (International Organization for Standardization) is a worldwide federation that promotes international standards. In the early 1980s, it began work on a set of protocols that would promote open networking environments that would let MultiFinder computer systems communicate with one another using internationally accepted communication protocols.

It eventually developed the OSI reference model. The OSI model defines a layered architecture and the protocols defined in each layer are responsible for: a. Communicating with the same protocol layer running in the opposite computer. b. Providing services to the layer above it (except for the top-level application layer).

The techniques of Layered Protocols were developed to meet the following goals as well: 1.To provide a logical decomposition of a complex network into smaller, more understandable parts (layers) 2.To provide standard interfaces between network functions, for example, standard interfaces between software program modules.

3.To provide for symmetry in functions performed at each node in the network. 4.To provide means to predict and control any changes made to network logic. 5.To provide a standard language to clarify communications between and among network designers, managers, vendors, and users when discussing network functions.

Layers included in OSI model are:

Physical Layer The lowest layer in the OSI model is called the Physical Layer. The functions within this layer are responsible for activating, maintaining, and deactivating a physical circuit between two nodes.

Data-link Layer The Data-link Layer is responsible for the transfer of data over the channel. It provides for the synchronization of data delimit the flow of bits from the physical layer. It also provides for the identify of the bits. It ensures that data arrives safely at the receiving node.

Network Layer The Network Layer specifies the interface of the user node into a packet- switched network, as well as the interface of two nodes with each other through a packet network. It also specifies network routing and the communications between networks (internetworking).

Transport Layer The Transport Layer provides the interface between the data communications network and the upper three layers.It also gives the user options in obtaining certain levels of quality (and cost) from the network itself (i.e. the network layer). This layer is designed to keep the user isolated form some of the physical and functional aspects of the packet network.

Session Layer The Session Layer serves as a user interface into the transport layer. The layer provides for an organized means to exchange data between users.

Presentation Layer The Presentation Layer provides the syntax of data in the model, that is, the representation of data. The layer consists of many tables of syntax, such as ASCII etc. The layer also provides for virtual terminal display and for services such as resolving the receipt of an electronic message from the application layer and negotiating with its layer a specific page image layout.

Application Layer The Application Layer is concerned with the support of an user application process. The layer contains service elements to support application processes such as job management, programming language send/receive, and business data exchange. The layer also supports the virtual terminal and virtual file concept.

PROTOCOLS Protocols are rules and procedures for communicating. When several computers are network, the rules and technical procedures governing their communication and interaction are called Protocols. Network communication protocols are defined within the context of a layered architecture, usually called a protocol stack. The OSI protocol stack is often used as a reference to define the different types of services that are required for systems to communicate.

The protocol stack defines how communication hardware and software interoperate at various level. Layering is a design approach that specifies different functions and services at levels in the protocol stack. A Protocol Stack is a combination of protocols. Each layer specifies a different protocol for handling a function or subsystem of the communication process.

Data being sent from one LAN to another along any of several available paths is routed. The protocols that support multipart LAN-to-LAN communications are known as Routable Protocols. As LAN technology matured, and the data communication needs of business expanded, LANs became components in larger data communication networks where LANs talked to each other. Because routable protocols can be used to tie several LANs together and create new wide-area environments, they are becoming increasingly important.

Protocols have several roles both at the sending computer and the receiving computer. At the sending computer, the protocol: I. Breaks the data into smaller sections, called packets. II. Adds addressing information to the packets so the destination computer on the network will know the data belongs to it. III. Prepares the data for actual transmission through the NIC (Network Interconnection Cable)

At the receiving computer, the protocol carries out the same series of steps in reverse order, such as: I. Takes data packets off the cable. II. Brings the data packets into the computer through the network. III. Strips the data packets of all of transmitting information added by the sending computer. IV. Copies the data from the packets to a buffer for reassembly. V. Passes the reassembled data to the application in a usable from.

Some examples of protocols that are commonly used in networking are: POP FTP HTTP TCP/IP SMTP IMAP MIME (Multiple purpose Internet Mail Extension protocol)

THE END OM NAMAH SHIVAYA. “The impossible gets possible if you have courage to withstand”