Spring 2000John Kristoff1 Introduction Computer Networks

Spring 2000John Kristoff2 Motivation and Scope Computer networks and internets: an overview of concepts, terminology and technologies that form the basis for digital communication in private corporate networks the the global Internet.

Spring 2000John Kristoff3 Motivation for Networks zInformation Access zSharing of Resources zFacilitate Communications

Spring 2000John Kristoff4 What a Network Includes zTransmission hardware zSpecial-purpose hardware devices yinterconnect transmission media ycontrol transmission yrun protocol software zProtocol software yencodes and formats data ydetects and corrects problems

Spring 2000John Kristoff5 What a Network Does zProvides communication that is yReliable yFair yEfficient yFrom one application to another

Spring 2000John Kristoff6 What a Network Does [continued] zAutomatically detects and corrects yData corruption yData loss yDuplication yOut-of-order delivery zAutomatically finds optimal path from source to destination

Spring 2000John Kristoff7 Data Communication versus Networking zWith only two nodes, mostly EE issues. zWith more than two nodes, lot more issues!

Spring 2000John Kristoff8 Direction of Transmission Point to PointBroadcast

Spring 2000John Kristoff9 Network Topologies

Spring 2000John Kristoff10 Transmission Media zWireline yString yGarden Hose yCopper xTwisted Pair xCoax yOptical Fiber z Wireless ySound yLight and mirrors yInfrared yRF yMicrowave

Spring 2000John Kristoff11 Network Scope zLocal Area Network (LAN) zMetropolitan Area Network (MAN) zWide Area Network (WAN)

Spring 2000John Kristoff12 Data Transmission Serial Parallel

Spring 2000John Kristoff13 Multiplexing

Spring 2000John Kristoff14 Communication Modes zSimplex zHalf-duplex zFull-duplex

Spring 2000John Kristoff15 Connection-oriented versus Connectionless zConnection Setup zData Transfer zConnection Termination z Data Transfer

Spring 2000John Kristoff16 Circuit Switching versus Packet Switching zDedicated yfixed bandwidth yroute fixed at setup yidle capacity wasted ynetwork state z Best Effort yend-to-end control ymultiplexing technique yre-route capability ycongestion problems

Spring 2000John Kristoff17 Examples zPublic Switched Telephone Network zInternet zPostal Service zTrain zCar and highway system

Spring 2000John Kristoff18 Standards zHardware zSoftware zProtocols zAdvantages and Disadvantages zProprietary, De Facto, De Jure zStandards Bodies yIETF, IEEE, OSI, ANSI, ATM Forum, etc.

Spring 2000John Kristoff19 Protocols zRules, standards and etiquette zMetric System zEnglish zDinner party zMorse Code zTCP/IP zHTML

Spring 2000John Kristoff20 Layering

Spring 2000John Kristoff21 Headers, Data and Trailers

Spring 2000John Kristoff22 Encapsulation

Spring 2000John Kristoff23 ISO OSI Reference Model z7: Application Layer z6: Presentation Layer z5: Session Layer z4: Transport Layer z3: Network Layer z2: Data link Layer z1: Physical Layer

Spring 2000John Kristoff24 Interfaces and Services zPDUs zSDUs zSAPs zPeer communications zService Primitives zetc... read Tanenbaum and 1.3.5

Spring 2000John Kristoff25 TCP/IP Model z5: Application Layer z4: Transport Layer z3: Network Layer z2: Data link Layer z1: Physical Layer

Spring 2000John Kristoff26 OSI versus TCP/IP z“Rough consensus and running code” zSimplicity zTime to market zAvailability

Spring 2000John Kristoff27 Network Classification zPhysical medium: copper, fiber, wireless zScope: LAN, MAN, WAN zTopology: bus, star, ring, mesh zSwitching style: circuit, packet zApplication: voice, data, video zProtocol: IP, OSI, Ethernet, ATM zTransmission rate: 10Mb/s, Gigabit

Spring 2000John Kristoff28 Terms I (we) Often Use zFrames: think data link layer zPackets: think network layer zDatagrams: think IP zSegments: think TCP zCells: think ATM zLayer : refer to reference models

Spring 2000John Kristoff29 The End-to-End Argument z“End-to-End Arguments in System Design” yJ.H. Saltzer, D.P. Reed, and D.D. Clark yhttp://web.mit.edu/Saltzer/www/publications /