1. Communication Architecture and Network Protocol Layering Networks and Protocols Prepared by: TGK First Prepared on: Last Modified on: Quality checked by: Copyright 2009 Asia Pacific Institute of Information Technology

2. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 2 of 27 Topic & Structure of the lesson Introduction to Data Communication Model Data Communication Data Communication Networking Protocols and Protocol Architecture

3. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 3 of 27 Learning Outcomes At the end of this module, YOU should be able to: Explain the Networking details with the technology and architecture. Explain the communication protocols in Computer Networks.

4. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 4 of 27 Key Terms you must be able to use If you have mastered this topic, you should be able to use the following terms correctly in your assignments and exams: Networking Entity System Protocol Syntax Semantics PDU

5. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 5 of 27 Main Teaching Points Data Communications Model Networking Wide Area Networks Local Area Networks Protocols OSI Reference Model TCP/IP Protocol Suite

6. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 6 of 27 Source: generates data to be transmitted Transmitter: converts data into signals Transmission System: carries the signals Receiver: converts received signal into data Destination: takes incoming data Data Communications Model

7. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 7 of 27 Data Communications Reference Model Figure 1.1 Simplified Communication Model – William Stalling Data and Computer communication

8. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 8 of 27 Point to Point communication not practical Devices are too far apart Large set of devices would need impractical number of connections Solution is a communications network Networking

9. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 9 of 27 Figure 1.3 Simplified Network Model – William Stalling- Data and Computer communication Networking

10. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 10 of 27 Large geographical area Crossing public rights of way Rely in part on common carrier circuits Alternative technologies –Circuit switching –Packet switching –Frame relay –Asynchronous Transfer Mode (ATM) Wide Area Network

11. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 11 of 27 Smaller scope –Building or small campus Usually owned by same organization as attached devices Data rates much higher than WAN Usually broadcast systems Now some switched systems and ATM are being introduced Local Area Network

12. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 12 of 27 ENTITY - anything capable of sending or receiving info: –application program –file transfer package –e-mail package SYSTEM - a physically distinct object that contains one or more ENTITIES: –computer, terminals, remote sensors etc. Protocols

13. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 13 of 27 For two entities to successfully communicate, they must agree on: What is communicated? How is it communicated? When is it communicated? Must conform to some mutually acceptable set of conventions governing the exchange of data between the entities: PROTOCOLS Protocols

14. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 14 of 27 Key Elements of Protocols Syntax –Data formats, Signal levels Semantics –Control information, Error handling Timing –Speed matching, Sequencing Protocols

15. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 15 of 27 Task of communication is broken up into modules For example file transfer could use three modules –File transfer application –Communication service module –Network access module Protocol Architecture

16. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 16 of 27 Overview of Networking Simplified File Transfer Architecture Figure 1.6 Protocol in Simplified Architecture – William Stalling – D&C Communication Protocol Architecture

17. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 17 of 27 Addressing Requirements Two levels of addressing required Each computer needs unique network address Each application on a (multi-tasking) computer needs a unique address within the computer –The service access point or SAP Protocol Architecture

18. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 18 of 27 Protocol Data Unit (PDU) At each layer, protocols are used to communicate Control information is added to user data at each layer Transport layer may fragment user data Each fragment has a transport header added –Destination SAP –Sequence number –Error detection code This gives a transport protocol data unit Protocol Architecture

19. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 19 of 27 A layer model Each layer performs a subset of the required communication functions Each layer relies on the next lower layer to perform more primitive functions Each layer provides services to the next higher layer Changes in one layer should not require changes in other layers OSI Reference Model

20. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 20 of 27 Dominant commercial protocol architecture Specified and extensively used before OSI Developed by research funded US Department of Defense Used by the Internet TCP/IP Protocol Suite

21. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 21 of 27 TCP/IP Protocol Architecture Application Layer –Communication between processes or applications End to end or transport layer (TCP/UDP/…) –End to end transfer of data –May include reliability mechanism (TCP) –Hides detail of underlying network Internet Layer (IP) –Routing of data TCP/IP Protocol Suite

22. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 22 of 27 Network Layer –Logical interface between end system and network Physical Layer –Transmission medium –Signal rate and encoding TCP/IP Protocol Suite

23. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 23 of 27 Quick Review Question 1.List the major disadvantages with the layered approach to protocols. 2.Discuss the need or lack of need for a network layer(OSI layer 3) in a broadcast network.

24. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 24 of 27 Follow Up Assignment Presentation on Layered Model Approach (OSI or TCP/IP)

25. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 25 of 27 Summary of Main Teaching Points Data Communications Model Networking Wide Area Networks Local Area Networks Protocols Key Elements of Protocols Protocol Architecture Addressing Requirements Protocol Data Unit (PDU) OSI Reference Model TCP/IP Protocol Suite

26. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 26 of 27 Q & A Question and Answer Session

27. Networks and Protocols Communication Architecture and Network Protocol Layering Slide 27 of 27 Topic and Structure of next session  Network Hardware (I) Classification of Networks (PAN, LAN, MAN, and WAN) WAN technologies (Frame Relay, ISDN, and ATM) Next Session