1. FCN week 10 lThe need for standards lStandards organisations lOSI model lTCP/IP model Network Standards and Models

2. FCN week 10 Standards lProcesses or protocols that has been endorsed by the networking industry lRatified by a standards organization lDocumented agreements containing ltechnical specifications or other precise criteria that stipulate how a particular product or service should be designed or performed Slide 2

3. FCN week 10 Organisations responsible for standards lAmerican National Standards Institute (ANSI) lElectronics Industry Alliance (EIA) lInstitute of Electrical and Electronic Engineers (IEEE) lInternational Organization for Standardization (ISO) lInternational Telecommunication Union (ITU)

4. FCN week 10 IEEE Networking Specifications Slide 4

5. FCN week 10 The Seven Layer OSI Model lThe OSI model breaks the process of communication down into several layers Application Presentation Session Transport Network Data link Physical Slide 5 Different stages data must/may go through as it travels from one device to another At the top, the Application layer provides OS services for application software At the bottom, the Physical layer deals with wiring issues Nmemonics – Please do not throw sausage pizza away! All PC’s seem to network data poorly

6. FCN week 10 OSI model – Why bother? lReal-world network protocols don’t implement the OSI seven layer protocol stack model lBut nearly all network protocols are based on a simplified layered model lThe layered model helps us think about the many processes involved in communicating over networks lA good model provides support for thinking Slide 6

7. FCN week 10 OSI model – Why bother? lBenefits include l assists in protocol design l fosters competition l changes in one layer do not affect other layers l provides a common language Slide 7

8. FCN week 10 The Application Layer lProvides interface to the software enabling programs to use network devices lDefinition of the way that network services use the network lDefines how many services work, including lFile sharing, Network Printing, Message Services etc lE.g Application Program Interface (API) lRoutine that allows a program to interact with the operating system lBelongs to the Application layer of OSI Model lApplications lHTTP lEmail lEtc... Slide 8

9. FCN week 10 The Presentation Layer lThis layer “presents” data, which is to say it does some pre-processing, such as ldata compression lencryption lcharacter set conversion lTranslates between the application and the network Slide 9

10. FCN week 10 The Session Layer lA communications management layer lDefines how two computers synchronise, maintain and close a communication session lThis includes such things as lsecurity authentication lacknowledgement of data transfer lestablishing and relinquishing a connection identity Slide 10

11. FCN week 10 The Transport Layer lData packet management lEnsures that chunks of data have been transferred without error – does lots of error and flow control lTakes data and packs it into chunks or chops it up into chunks suitable for transmission lTakes chunks and unpacks them or combines them into data streams Slide 11

12. FCN week 10 The Network Layer lThis is Internet Protocol address layer for path selection around the network lRouting of packets uses IP addresses lNetwork Layer Address lResides at Network level of OSI Model lFollows hierarchical addressing scheme lCan be assigned through operating system software Slide 12

13. FCN week 10 The Data Link Layer lDecodes packets into what are called frames which contain lPhysical source and destination addressing ldata validity / error checking lThe network technology being used will influence how this layer works e.g. Ethernet, token ring ….. lTo accommodate shared access for multiple network nodes, the IEEE expanded the OSI Model by separating the Data Link layer into two sublayers lLogical Link Control (LLC) sublayer lMedia Access Control (MAC) sublayer Slide 13

14. FCN week 10 The Physical Layer lThis is the physical networking media layer which includes the cabling technology lDefines the transmission technique and the hardware definitions (connectors and so on) lNetworking may take place over copper cables, optical fibres, infra-red radiation, radio waves… and this variation should be transparent to the user Slide 14

15. FCN week 10 Communication Between Two Systems Slide 15

16. FCN week 10 TCP/IP lThe problem with the OSI model is a ‘concept’ not an actual implementation lTCP/IP is a set of protocols used.

17. FCN week 10 What is TCP/IP? lTCP/IP stands for Transport Control Protocol / Internet Protocol suite. lTCP/IP was created in 1983 to replace NCP. lTCP/IP can successfully switch packets from all shapes and sizes and varieties of networks. lTherfore TCP/IP has become the backbone of the Internet and its composite LANs and WANs, due to it's ability to switch packets from computer systems on any network to another network, regardless of network peculiarities, operating system differences and other packet differences Slide 17

18. FCN week 10 What is TCP/IP? lThe higher layer, Transmission Control Protocol, manages the assembling of a message or file into smaller packets that are transmitted over the Internet and received by a TCP layer that reassembles the packets into the original message.layerTransmission Control Protocolpacket l The lower layer, Internet Protocol, handles the address part of each packet so that it gets to the right destination.Internet Protocoladdress lEach gateway computer on the network checks this address to see where to forward the message.gateway Slide 18

19. FCN week 10 What is TCP/IP? lEven though some packets from the same message are routed differently than others, they'll be reassembled at the destination. lUses the client/server model of communication in which a computer user (a client) requests and is provided a service (such as sending a Web page) by another computer (a server) in the network.client/server lTCP/IP communication is primarily point-to-point, meaning each communication is from one point (or host computer) in the network to another point or host computer.host lTCP/IP and the higher-level applications that use it are collectively said to be "stateless" because each client request is considered a new request unrelated to any previous one Slide 19

20. FCN week 10 What is TCP/IP? lBeing stateless frees network paths so that everyone can use them continuously. lYou will be familiar application protocols that use TCP/IP to get to the Internet. l These include the World Wide Web's Hypertext Transfer Protocol (HTTP)HTTP l File Transfer Protocol (FTP)FTP lTelnet (Telnet) which lets you logon to remote computersTelnet l Simple Mail Transfer Protocol (SMTP).SMTP Slide 20

21. FCN week 10 OSI Model TCP/IP TCP/IP vs OSI Slide 21

22. FCN week 10 Layers with TCP/IP and OSI Model

23. FCN week 10 Slide 23 Conclusion We have discussed:- lOrganizations that set standards for networking lStandard “root concepts” of networking lLayered models of processes and layers in our conceptual model of networking lWhy protocols are required for interoperability lDetails of the seven layers of the OSI model