ECE544: Communication Networks-II, Spring 2010Today’s LectureClass StructureContact InformationCourse ReadingsCourse GradingStudent CommitmentsPrerequisitesCourse TopicsProjectsWhat is the problem?Application ConsiderationsSlide 13Reliable File TransferRemote LoginNetwork AudioNetwork VideoWebWhat is….Network StructureNetwork MetricsBandwidth versus LatencyDelay x Bandwidth ProductSlide 24Network FailuresStatistical Multiplexing GainBack in the old days..Then came TDM..Logical network viewPacket switching (Internet)Packet SwitchingCharacteristics of Packet SwitchingProtocolsProtocols (contd.)LayeringLayering CharacteristicsISO ArchitectureInternet ArchitectureLayering General IssuesExample: Transport layerExample: Network LayerInter-Process CommunicationIPC AbstractionsInterfacesSlide 45Slide 46Protocol MachineryMachinery (cont)Network ArchitectureConcept Example 1: Sensor NetsConcept Example 2: InfostationsDesigning a NetworkRequirements (contd.)Requirements AnalysisNetwork ComponentsSlide 56High-Level DesignHigh Level DesignToday’s HomeworkECE544: Communication Networks-II, Spring 2010D. RaychaudhuriLecture IIncludes teaching materials from L. Peterson & L. GovidanToday’s Lecture•Administrative matters•Course Overview–topics covered–design & prototyping projects•Introduction to networkingClass Structure•Friday 4:45-7:30pm•Lecture format–Slides, Board, …–Interactive•Two 80 min sessions–with a 10 min break in betweenContact Information•Instructor: Prof. D. Raychaudhuri–Email: [email protected]–Office Hours: by appt, WINLAB Tech Center or Core 501•TA: KC Huang–Email:[email protected]–Office hours: tbd•Class Resources–Web page: http://www.winlab.rutgers.edu/comnet2–Mailing list: [email protected]–Sign up for mailing list at: http://lists.winlab.rutgers.edu/listinfo/comnet2Course Readings•Textbook (required, to be used for ~60% material)–Peterson & Davie, “Computer Networks: A Systems Approach”, Morgan Kaufman, 3rd ed•Research papers in networking–to be distributed either online or in class–collection of classical and topical research•~10 papers and standards documents•required reading to supplement text book overviewCourse Grading•Class participation & homework: 5%–Brief in-class presentations–Assigned homework from textbook•Midterm (25%) and Final (35%)–Open book, 1 page of notes permitted; includes both descriptive and numerical problems•Design & Prototyping Assignments: 35%–network architecture paper 10%–protocol project & report 25%•No makeup exams, no extra credit workStudent Commitments•Keep up with your reading–read applicable text book chapter and distributed papers/RFC’s before and after each class•Sharpen your programming skills–study C/C++ & Unix programming as needed and work on simple programming exercises early in the semester•Work independently–no “collaboration” of any sort•Turn in assignments on time•Make sure assignments are gradable–follow project and program submission rulesPrerequisites•Curricular prerequisites–Computer Networks I or equivalent–General communications and computer architecture/OS background•Skills–C/C++ programming •significant programming project–use of design and analysis toolsCourse Topics•Introduction•Network Principles•Shared Media/MAC•Pkt switching (ATM)•IP Basics•IP Advanced•Mobility Protocols-- mid-term•Network security•Transport layer•Higher-layer protocols•Hardware issues•Case studies and research topics–Sensor networks–Vehicular networks–future Internet archProjects•Network architecture paper- top-down design- requirements- specifications- system analysis- report•Warm-up Projects- C/C++ programming exercises- Unix sockets, etc.- simple link protocols •Network software project- new routing protocol- software platform provided- student teams will write competing protocol specs - meetings to specify “standard”- group demo & inter-op demoWhat is the problem?Application Considerations•Application input to network–traffic data rate–traffic pattern (bursty or constant bit rate)–traffic target (multipoint or single destination, mobile or fixed)•Network service delivered to application–delay sensitivity–loss sensitivityChapter 1, Figure 7A Multimedia ApplicationReliable File Transfer•Loss sensitive•Not delay sensitive relative to round trip times•Point-to-point or multipoint•BurstyRemote Login•Loss sensitive•Delay sensitive –subject to interactive constraints–can tolerate up to several hundreds of milliseconds•Bursty•Point to pointNetwork Audio•Relatively low bandwidth–Digitized samples, packetized•Delay variance sensitive•Loss tolerant•Possibly multipoint, long duration sessions–natural limit to number of simultaneous sendersNetwork Video•High bandwidth•Compressed video, bursty•Loss tolerance function of compression•Delay tolerance a function of interactivity•Possibly multipoint•Larger number of simultaneous sourcesWeb•Transactional traffic–short requests, possibly large responses•Loss tolerant•Delay sensitive–human interactivity•Point-to-point (multipoint is asynchronous)What is….•Structure•Metrics•Failure modes•FunctionsNetwork StructureBackbonesRegionalsCampus LANsNetwork Metrics•Bandwidth–transmission capacity•Delay–queueing delay–propagation delay (limited by c)•Delay-Bandwidth product–important for control algorithmsBandwidth versus Latency•Relative importance–1-byte: 1ms vs 100ms dominates 1Mbps vs 100Mbps–25MB: 1Mbps vs 100Mbps dominates 1ms vs 100ms•Infinite bandwidth–RTT dominates•Throughput = TransferSize / TransferTime•TransferTime = RTT + 1/Bandwidth x TransferSize–1-MB file to 1-Gbps link as 1-KB packet to 1-Mbps linkDelay x Bandwidth Product•Amount of data “in flight” or “in the pipe”•Example: 100ms x 45Mbps = 560KBBandwidthDelayChapter 1, Figure 910,00050002000100050020010050201052110010RTT (ms)1-MB object, 1.5-Mbps link1-MB object, 10-Mbps link2-KB object, 1.5-Mbps link2-KB object, 10-Mbps link1-byte object, 1.5-Mbps link1-byte object, 10-Mbps linkPerceived latency (ms)Network Failures•Packet loss–queue overflows–line noise•Node or link failures•Routing transients or failuresStatistical Multiplexing Gain1 Mbps link; users require 0.1 Mbps when transmitting; users active only 10% of the time.•Circuit