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

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

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

Communications Model

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

Data Communications Networking

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)

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)

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

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

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

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

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

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

Standardized Protocol Architecture for Data Communications

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)

OSI

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

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

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

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

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

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

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

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

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

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

TCP/IP

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

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

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

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

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

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

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

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

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

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