Osi model slides
- 1. Protocol Reference Model of OSI
- 2. Network History of OSI layer Introduction to the OSI layer How OSI was created and why 7 Layers : Conclusion Resources
- 3. 1. The need for standardization - many vendors, no interoperability - no common framework 2. ISO OSI (Open System Intercommunication) in 1984. 3. OSI Protocol Suite – unaccepted by vendors and users. (TCP won)
- 4. Purpose: Before OSI was created people created their Software/Hardware as they wanted it to be. There was not any compatibility. Now OSI is used as a rule set for all vendors to create their Software/Hardware by using the standards. framework tool
- 5. Open Systems Interconnection (OSI) Each layer support the layers above it and offers services to the layers below Each layer performs unique and specific task A layer only has knowledge of its neighbour layers only. A layer service is independent of the implementation.
- 6. Each layer contains a logical grouping of functions Each function receive an input(one or more) and produces an output Application------software,email(oulook) Presentation-----operating system Session---------crate session Transport--------how much info Network Layer----router operator Data link layer----switch data Physical layer-----eathernet
- 7. User Interface Data Formatting Est & Maint Connection TCP, UDP IP-Routers MAC-Switch Signals- Cables Data Segment Packet Frame Bits
- 8. Layer abstraction and the path of the message
- 9. OSI . Data Encapsulation a) PDU conception – each protocol on the diff. layer has its own format. b) Headers are added while a packet is going down the stack at each layer. c) Trailers are usually added on the second layer. Packet: Header(contains inf) Data area(user info) Trailer(techniques for error freee transmission)
- 10. Applications and Services run on it Functionality: + User interface Popular Protocols DNS (Domain Naming System) — Used to translate the name with IP address and vice versa. DHCP (Dynamic Host Configuration Protocol) — Used to assign IP address and DNS information automatically to host HTTP (Hypertext Transfer Protocol) — Used to browse web pages SMTP (Simple Mail Transfer Protocol) — Used to sends email NTP (Network Time Protocol) — Used to synchronizes clocks Protocol Data Unit (Data)
- 11. Functionality: + Data representation, prepare, encryption & decryption, adds extension files Popular Protocols: + Video (WMV, AVI…) + Bitmap(JPG,PNG…) + Audio (WAV, MP3, Protocol Data Unit (Data)
- 12. Session Functionality + Set up, monitor & terminate the connection session Popular Protocols: + SQL, NETBIOS names… PDU(Data)
- 13. Transport Functionality segmentation, connection management(UDP, TCP), Reliability Flow control (Ready/not ready signals,) Windowing(Sender host will wait for an acknowledgement signal), advertise window Multiplexing( allows diff users, using port address e.g server),congestion window Popular protocols TCP + UDP PDU Segment
- 14. Network Functionality + Path determination + Source & Destination logical addresses Popular protocols + IP( 32bit address) PDU (Packet/Datagram) Device (Router)
- 15. Data Link Functionality + Physical addressesIncludes 2 layers: + Upper layer: Logical Link Control (LLC) + Lower layer: Media Access Control (MAC) MAC( 48 bit long address) ARP,RARP,I.P,ICMP Popular protocols + LAN, + WAN (HDLC, PPP, …) PDU Frame Device Switch, Bridge
- 16. Physical Functionality Encodes and transmits data bits,+ Electric signals, + Radio signals Popular Protocols Ethernet PDU Bit (0, 1) Device Hub, Repeater…
- 17. The way people learn Networking A standard for software A standard for hardware Seven layers architecture Each layer independent on the others Similar to TCP/IP(TCP/IP explained) OSI is used as a model for developing network aware applications(Here I mean that people use its structure to model software)