EEC4113 Data Communication & Multimedia System Chapter 1: Introduction by Muhazam Mustapha, September 2011

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 CO1

Data Communication Tasks Communications model Data communication networking Protocol architecture –OSI –TCP/IP Standards Address Routing Recovery Message formatting Security Network management Fundamental purpose of communications system: Exchange of data between two parties CO1

Data Communications Networking CO1

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) CO1

Wide Area Network (WAN) Large geographical area Crossing public rights of way Rely in part on common carrier circuits Used technologies –Circuit switching –Packet switching –Frame relay –Asynchronous Transfer Mode (ATM) CO1

WAN Technologies Circuit 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 CO1

WAN Technologies Frame Relay –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 CO1

Local Area Network (LAN) Smaller scope –Single or a cluster of building Usually owned by same organization Data rates much higher than WAN CO1

LAN Configurations Switched –Switched Ethernet May be single or multiple switches –ATM LAN –Fiber Channel Wireless –Mobility –Ease of installation CO1

Metropolitan Area Networks (MAN) Middle ground between LAN and WAN High speed Cover larger area than LAN –City –Town Private or public network CO1

Networking Configuration Client Service Provider Phone line, DSL Internet Client ATM Network LAN Ethernet switches Local Servers CO1

Standardized Protocol Architecture for Data Communications CO1

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) CO1

OSI CO1

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 CO1

OSI Reference Model ApplicationLayer 7 PresentationLayer 6 SessionLayer 5 TransportLayer 4 NetworkLayer 3 Data LinkLayer 2 PhysicalLayer 1 CO1

OSI Reference Model ApplicationLayer 7 PresentationLayer 6 SessionLayer 5 TransportLayer 4 NetworkLayer 3 Data LinkLayer 2 PhysicalLayer 1 -Basically communication softwares -Provide the human interface to the communication system CO1

OSI Reference Model ApplicationLayer 7 PresentationLayer 6 SessionLayer 5 TransportLayer 4 NetworkLayer 3 Data LinkLayer 2 PhysicalLayer 1 -Standardizes data representation -Decouples application from data CO1

OSI Reference Model ApplicationLayer 7 PresentationLayer 6 SessionLayer 5 TransportLayer 4 NetworkLayer 3 Data LinkLayer 2 PhysicalLayer 1 -Sessions data structure -Creates, maintains, destroy sessions -Network security CO1

OSI Reference Model ApplicationLayer 7 PresentationLayer 6 SessionLayer 5 TransportLayer 4 NetworkLayer 3 Data LinkLayer 2 PhysicalLayer 1 -Low Level Communication APIs -Creates, maintains, destroy connection to network devices -Routing technology CO1

OSI Reference Model ApplicationLayer 7 PresentationLayer 6 SessionLayer 5 TransportLayer 4 NetworkLayer 3 Data LinkLayer 2 PhysicalLayer 1 -Bit level manipulation -Communication hardware device driver -Error detection, recovery, transparent flow CO1

OSI Reference Model ApplicationLayer 7 PresentationLayer 6 SessionLayer 5 TransportLayer 4 NetworkLayer 3 Data LinkLayer 2 PhysicalLayer 1 -Communication hardwares: modems, network cards -Embedded machine code on the communication hardware -Conversion of data to signals: NRZ, Manchester coding CO1

OSI Reference Model ApplicationLayer 7 PresentationLayer 6 SessionLayer 5 TransportLayer 4 NetworkLayer 3 Data LinkLayer 2 PhysicalLayer 1 -Actual connectors -Cables, optical fibers, telephone line CO1

OSI Environment Application Presentation Session Transport Network Data Link Physical Application Presentation Session Transport Network Data Link Physical Headers being attached at each layer Headers being stripped off at each layer Data Connectors, switchers Data CO1

TCP/IP CO1

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 to 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 CO1

TCP/IP Model ApplicationLayer 5 TransportLayer 4 InternetLayer 3 Network AccessLayer 2 PhysicalLayer 1 CO1

OSI vs TCP/IP Application Presentation Session Transport Network Data Link Physical Application Transport Network Access Internet Physical Communication Softwares & Device Drivers Communication Hardwares & Embedded Code Connectors CO1

TCP/IP Layers Application Transport Internet Network Access Physical -Communicating softwares -Make use of many protocols available: FTP, HTTP, SMTP, POP, etc -Control data (standardized), data structure, and sessions CO1

TCP/IP Layers Application Transport Internet Network Access Physical -Low Level Communication APIs -Creates, maintains, destroy connection to network devices -Application transparent communication -Device driver CO1

TCP/IP Layers Application Transport Internet Network Access Physical -Routing functions at communication hardware -Internet Protocol and IP address CO1

TCP/IP Layers Application Transport Internet Network Access Physical -Embedded Code on Communication hardwares: modems, network cards -Conversion of data to signals: NRZ, Manchester coding -Bit level manipulation -Error detection, recovery, transparent flow CO1

TCP/IP Layers Application Transport Internet Network Access Physical -Actual connectors -Cables, optical fibers, telephone line CO1

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 CO1

Operations of TCP/IP Application Transport Network Access Internet Physical Application Transport Internet Physical Headers being attached at each layer except at physical layer Headers being stripped off at each layer except at physical layer Connectors, switchers Network Access Data CO1