CSE 5300: Advanced Computer NetworksCourse infoCourse GoalsWireless networksOther wireless networksCourse TopicsCourse mechanicsGradingPart 0: Networking ReviewWhat’s a network: “nuts and bolts” viewWhat’s a protocol?Slide 12A closer look at network structure:The network edge:Network edge: connection-oriented serviceNetwork edge: connectionless serviceThe Network CoreNetwork Core: Circuit SwitchingNetwork Core: Packet SwitchingAccess networks and physical mediaExample access net: home networkWe have seen “pieces” of networkInternet protocol stackLayering: logical communicationLayering: physical communicationInternet structure: network of networksSlide 27Slide 28Slide 291-1CSE 5300: Advanced Computer Networks Bing WangComputer Science & Engineering DepartmentFall 20081-2Course infoInstructor: Bing Wang, [email protected]Office: ITEB 367Lecture: 3:30-4:45pm, TuTh, E2 322Office hours: by appointment1-3Course GoalsWireless networks, basics & advanced topicsa second course: i.e., assumes a first coursedifference & synergy between wired & wireless networks foundational material: longer lifemix of theory and practice1-4Wireless networksWireless LAN, ad-hoc network, wireless mesh, sensor network Internet1-5Other wireless networksCellular networksUnderwater sensor networksVehicular ad-hoc worksDelay/disruption tolerant networksPocket switching networksTurtle networksZebra networksDiesel networks1-6Course Topicsphysical layer basicsMACroutingnetwork simulation, performance analysis network measurement/managementmobilitysecuritycommon themes: randomization, indirection, virtualization, scalability, optimization1-7Course mechanicsclass www site: www.engr.uconn.edu/~bing/cse5300textbook: nonepapers, all posted on www siteprereq: previous course in networkingsome knowledge of probability, optimization theory, algorithmsworkload:3 paper critics2 written homeworks1 programming assignment (on using ns-2)1 semester-long project1-8GradingPaper critics (10%)3 papersHomework (30%)Semester-long project (60%) Goal: hand-on experiences through a well-defined research problemTeam of 2 students Topic (your background, preference)•Fill in background surveyProposal (due 5th class)Midterm report/presentation (14th class)Final report/presentation (last class)1-9Part 0: Networking Review Goals: review key topics from intro networks courseequalize backgroundsidentify remedial work ease into courseOverview:overviewerror controlflow controlcongestion controlroutingLANsaddressingsynthesis:“a day in the life”control timescales1-10What’s a network: “nuts and bolts” viewnetwork edge: millions of end-system devices: pc’s workstations, serversPDA’s, phones, toastersrunning network appsnetwork core: routers, switches forwarding datapackets: packet switchingcalls: circuit switchingcommunication linksfiber, copper, radio, …local netcompanynetregional netrouterworkstationservermobileWeb-enabled toaster+weather forecasterhttp://dancing-man.com/robin/toasty/1-11What’s a protocol?a human protocol and a computer network protocol:HiHiGot thetime?2:00TCP connection req.TCP connectionreply.Get http://www.cse.uconn.edu/index.html<file>time1-12What’s a protocol?human protocols:“what’s the time?”“I have a question”introductions… specific msgs sent… specific actions taken when msgs received, or other eventsnetwork protocols:machines rather than humansall communication activity in Internet governed by protocolsprotocols define format, order of msgs sent and received among network entities, and actions taken on msg transmission, receipt1-13A closer look at network structure:network edge: applications and hostsnetwork core: routersnetwork of networksaccess networks, physical media: communication links1-14The network edge:end systems (hosts):run application programse.g., WWW, emailat “edge of network”client/server modelclient host requests, receives service from servere.g., WWW client (browser)/ server; email client/serverpeer-peer model: host interaction symmetrice.g.: Gnutella, KaZaA1-15Network edge: connection-oriented serviceGoal: data transfer between end systemshandshaking: setup (prepare for) data transfer ahead of timeHello, hello back human protocolset up “state” in two communicating hostsTCP - Transmission Control Protocol Internet’s connection-oriented serviceTCP service [RFC 793]reliable, in-order byte-stream data transferloss: acknowledgements and retransmissionsflow control: sender won’t overwhelm receivercongestion control: senders “slow down sending rate” when network congested1-16Network edge: connectionless serviceGoal: data transfer between end systemssame as before!UDP - User Datagram Protocol [RFC 768]: Internet’s connectionless serviceunreliable data transferno flow controlno congestion controlApp’s using TCP: HTTP (WWW), BitTorrent (file transfer), Telnet (remote login), SMTP (email)App’s using UDP:streaming media, teleconferencing, Internet telephony1-17The Network Coremesh of interconnected routersfundamental question: how is data transferred through net?circuit switching: dedicated circuit per call: telephone netpacket-switching: data sent thru net in discrete “chunks”1-18Network Core: Circuit SwitchingEnd-end resources reserved for “call”link bandwidth, switch capacitydedicated resources: no sharingcircuit-like (guaranteed) performancecall setup required1-19Network Core: Packet Switchingeach end-end data stream divided into packetsuser A, B packets share network resources each packet uses full link bandwidth resources used as needed, resource contention: aggregate resource demand can exceed amount availablecongestion: packets queue, wait for link usestore and forward: packets move one hop at a timetransmit over linkwait turn at next linkBandwidth division into “pieces”Dedicated allocationResource reservation1-20Access networks and physical mediaQ: How to connect end systems to edge router?residential access netsinstitutional access networks (school, company)mobile access networksKeep in mind: bandwidth (bits per second) of access network?shared or