18200121001_PCC-CS-602.pptx 18200121001_PCC-CS-602.ppt18200121001_PCC-CS-602.ppt18200121001_PCC-CS-602.ppt
- 1. OSI MODEL Presented By Name : SOUMYAJIT BAGCHI Roll No : 18200121001 Paper Name : COMPUTER NETWORKING Paper Code : PCC-CS-602 Semester : 6TH Department : COMPUTER SCIENCE ENGINEERING Institute of Science & Technology CA1 Examination For Odd Semester-2023
- 2. TopicOutLine • Introduction OSI • OSI History • OSI Layers • Introduction TCP/IP • TCP/IP Layers 2
- 3. Introduction OSI • The Open System Interconnection Reference Model (OSI Reference Model or OSI Model) is an abstract description for layered communications and computer network protocol design. • It divides network architecture into seven layers which, from top to bottom, are the Application, Presentation, Session, Transport, Network, Data Link, and Physical Layers. It is therefore often referred to as the OSI Seven Layer Model. 3
- 4. OSI History • In 1978, the International Standars Organization (ISO) began to develop its OSI framework architecture. • OSI has two major components: an abstract model of networking, called the Basic Reference Model or seven-layer model, and a set of specific protocols. 4
- 5. Layers 5-7 relate to user applications. Layers 1-4 relate to communications technology. 7-Layer OSI Model Layer 7 Layer 6 Layer 5 Layer 4 Layer 3 Layer 2 Layer 1 Application Layer Presentation Layer Session Layer Transport Layer Network Layer Data Link Layer Physical Layer Communications subnet boundary
- 6. Layer1: Physical Layer • The major functions and services performed by the Physical Layer are: • Establishment and termination of a connection to a communication medium. • Participation in the process whereby the communication resources are effectively shared among multiple users. For example, flow control. • Modulation, or conversion between the representation of digital data in user equipment and the corresponding signals transmitted over a communications channel. These are signals operating over the physical cabling (such as copper and optical fiber) or over a radio link. 6
- 7. Layer 2: Data Link Layer • The Data Link Layer provides the functional and procedural means to transfer data between network entities and to detect and possibly correct errors that may occur in the Physical Layer. • Originally, this layer was intended for point-to-point and point-to- multipoint media, characteristic of wide area media in the telephone system. • The data link layer is divided into two sub-layers by IEEE. 7
- 8. • Manages addressing/routing of data within the subnet • Addresses messages and translates logical addresses and names into physical addresses. • Determines the route from the source to the destination computer • Manages traffic problems, such as switching, routing, and controlling the congestion of data packets. • Routing can be: • Based on static tables • determined at start of each session • Individually determined for each packet, reflecting the current network load. Layer 3: Network Layer
- 9. • Manages transmission packets • Repackages long messages when necessary into small packets for transmission • Reassembles packets in correct order to get the original message. • Handles error recognition and recovery. • Transport layer at receiving acknowledges packet delivery. • Resends missing packets Layer 4: Transport Layer
- 10. • Allows two applications on different computers to establish, use, and end a session. • e.g. file transfer, remote login • Establishes dialog control • Regulates which side transmits, plus when and how long it transmits. • Performs token management and synchronization. Layer 5: Session Layer
- 11. • Related to representation of transmitted data • Translates different data representations from the Application layer into uniform standard format • Providing services for secure efficient data transmission • e.g. data encryption, and data compression. Layer 6: Presentation Layer
- 12. • Level at which applications access network services. • Represents services that directly support software applications for file transfers, database access, and electronic mail etc. Layer 7: Application Layer
- 13. Introduction TCP/IP • The Internet Protocol Suite (commonly known as TCP/IP) is the set of communications protocols used for the Internet and other similar networks. • It is named from two of the most important protocols in it: • the Transmission Control Protocol (TCP) and • the Internet Protocol (IP), which were the first two networking protocols defined in this standard. 13
- 14. TCP/IP Layers OSI TCP/IP Application Layer Application Layer TELNET, FTP, SMTP, POP3, SNMP, NNTP, DNS,NIS, NFS, HTTP, ... Presentation Layer Session Layer Transport Layer Transport Layer TCP , UDP , ... Network Layer Internet Layer IP , ICMP, ARP, RARP, ... Data Link Layer Link Layer FDDI, Ethernet, ISDN, X.25,... Physical Layer 14
- 15. Reference