1. EEC4113 Data Communication & Multimedia System Chapter 1: Introduction by Muhazam Mustapha, July 2010

2. Learning Outcome
By the end of this chapter, students are expected to have some surface overview of models, networking, protocol architecture & standards related to data communication

3. Chapter Content Communications model Data communication networking
Protocol architecture
OSI
TCP/IP
Standards

4. Communications Model

5. Data Communication Tasks
Fundamental purpose of communications system: Exchange of data between two parties
Communications model
Data communication networking
Protocol architecture
OSI
TCP/IP
Standards
Address
Routing
Recovery
Message formatting
Security
Network management

6. Data Communications Networking

7. Data Communication Networking
Point to point communication not usually practical
Devices are far apart
Large set of devices would need impractical number of connections
Solution is a communications network:
Wide Area Network (WAN)
Local Area Network (LAN)

8. Wide Area Network (WAN)
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)

9. WAN Technologies Circuit Switching Packet switching
Dedicated communications path established for the duration of the conversation
e.g. telephone network
Packet switching
Data sent out of sequence
Small chunks (packets) of data at a time
Packets passed from node to node between source and destination
Used for terminal-to-computer and computer-to-computer communications

10. WAN Technologies Frame Relay Asynchronous Transfer Mode (ATM)
Packet switching systems have large overheads to compensate errors
Modern systems are more reliable
Errors can be caught in end system
Most overhead for error control is stripped out
Asynchronous Transfer Mode (ATM)
Evolution of frame relay
Little overhead for error control
Fixed packet (called cell) length
Anything from 10Mbps to Gbps
Constant data rate using packet switching technique

11. Local Area Network (LAN)
Smaller scope
Single or a cluster of building
Usually owned by same organization
Data rates much higher than WAN

12. LAN Configurations Switched Wireless Switched Ethernet ATM LAN
May be single or multiple switches
ATM LAN
Fiber Channel
Wireless
Mobility
Ease of installation

13. Metropolitan Area Networks (MAN)
Middle ground between LAN and WAN
High speed
Cover larger area than LAN
City
Town
Private or public network

14. Networking Configuration
Client
Service Provider
Phone line, DSL
Internet
ATM Network
LAN
Ethernet switches
Local Servers

15. Standardized Protocol Architecture for Data Communications

16. Standardized Protocol Architecture
Required for devices to communicate
Vendors have more marketable products
Customers can insist on standards based equipment
Two standards
OSI Reference model
TCP/IP protocol suite
Also:
Internetwork Packet eXchange/Sequenced Packet eXchange (IPX/SPX)
NetBIOS Enhanced User Interface (NetBEUI)
AppleTalk
IBM Systems Network Architecture (SNA)

17. OSI

18. OSI Reference Model Open System Interconnection (OSI) reference model
Designed by International Organization for Standardization (ISO)
A seven-layer model
Never seriously implemented as a protocol stack
A theoretical model designed to show how a protocol stack should be implemented

19. OSI Reference Model Application Layer 7 Presentation Layer 6 Session
Transport
Layer 4
Network
Layer 3
Data Link
Layer 2
Physical
Layer 1

20. OSI Reference Model Application Layer 7 Presentation Layer 6
Basically communication softwares
Provide the human interface to the communication system
Session
Layer 5
Transport
Layer 4
Network
Layer 3
Data Link
Layer 2
Physical
Layer 1

21. OSI Reference Model Application Layer 7 Presentation Layer 6 Session
Standardizes data representation
Decouples application from data
Transport
Layer 4
Network
Layer 3
Data Link
Layer 2
Physical
Layer 1

22. OSI Reference Model Application Layer 7 Presentation Layer 6 Session
Transport
Layer 4
Sessions data structure
Creates, maintains, destroy sessions
Network security
Network
Layer 3
Data Link
Layer 2
Physical
Layer 1

23. OSI Reference Model Application Layer 7 Presentation Layer 6 Session
Transport
Layer 4
Network
Layer 3
Low Level Communication APIs
Creates, maintains, destroy connection to network devices
Routing technology
Data Link
Layer 2
Physical
Layer 1

24. OSI Reference Model Bit level manipulation
Communication hardware device driver
Error detection, recovery, transparent flow
Application
Layer 7
Presentation
Layer 6
Session
Layer 5
Transport
Layer 4
Network
Layer 3
Data Link
Layer 2
Physical
Layer 1

25. OSI Reference Model Communication hardwares: modems, network cards
Embedded machine code on the communication hardware
Conversion of data to signals: NRZ, Manchester coding
Application
Layer 7
Presentation
Layer 6
Session
Layer 5
Transport
Layer 4
Network
Layer 3
Data Link
Layer 2
Physical
Layer 1

26. OSI Reference Model Application Layer 7 Presentation Layer 6 Session
Actual connectors
Cables, optical fibers, telephone line
Transport
Layer 4
Network
Layer 3
Data Link
Layer 2
Physical
Layer 1

27. OSI Environment Application Application Presentation Presentation
Headers being attached at each layer
Headers being stripped off at each layer
Application
Application
Data
Data
Presentation
Presentation
Session
Session
Transport
Transport
Network
Network
Data Link
Data Link
Physical
Physical
Connectors, switchers

28. TCP/IP

29. TCP/IP Model Transmission Control Protocol / Internet Protocol
Result of protocol research & development conducted on the experimental packet-switched network, ARPANET, funded by Defense Advanced Research Projects Agency (DARPA)
Generally referred as the TCP/IP protocol suite
Consists of a large collection of protocols that have been issued as internet standards by the Internet Architecture Board (IAB)
Most widely used interoperable network protocol architecture

30. TCP/IP Model Application Layer 5 Transport Layer 4 Internet Layer 3
Network Access
Layer 2
Physical
Layer 1

31. OSI vs TCP/IP Application Application
Communication Softwares & Device Drivers
Presentation
Session
Transport
Transport
Internet
Communication Hardwares & Embedded Code
Network
Network Access
Data Link
Physical
Physical
Connectors

32. TCP/IP Layers Application Transport Communicating softwares Internet
Make use of many protocols available: FTP, HTTP, SMTP, POP, etc
Control data (standardized), data structure, and sessions
Internet
Network Access
Physical

33. TCP/IP Layers Application Transport Internet
Low Level Communication APIs
Creates, maintains, destroy connection to network devices
Application transparent communication
Device driver
Network Access
Physical

34. TCP/IP Layers Routing functions at communication hardware
Internet Protocol and IP address
Application
Transport
Internet
Network Access
Physical

35. TCP/IP Layers
Embedded Code on Communication hardwares: modems, network cards
Conversion of data to signals: NRZ, Manchester coding
Bit level manipulation
Error detection, recovery, transparent flow
Application
Transport
Internet
Network Access
Physical

36. TCP/IP Layers Application Actual connectors Transport
Cables, optical fibers, telephone line
Transport
Internet
Network Access
Physical

37. Operations of TCP/IP
For successful communication, two levels of addressing are needed
Each host on a subnetwork must have a unique global internet address: IP address
Each process with a host must have an address that is unique within the host to allow TCP to deliver data to proper process: ports

38. Operations of TCP/IP Application Application Transport Transport
Headers being attached at each layer except at physical layer
Headers being stripped off at each layer except at physical layer
Application
Application
Data
Data
Transport
Transport
Internet
Internet
Network Access
Network Access
Physical
Physical
Connectors, switchers