Lecture 1 IntroductionToday’s LectureCourse StaffCourse GoalsCourse FormatRecitation SectionsWaiting ListAdministrative StuffGradingPolicy on CollaborationPolicy on Late Work and Regrading This WeekHistory of Computer NetworksEarly Communication over Long DistanceTelegraph: Communication Using ElectronsTelegraph EngineeringTelephonyTelephony MilestonesBack in the Old Days…Circuit SwitchingTelephony MilestonesTelephony MilestonesTelephony MilestonesSummaryData or Computer Networks1Lecture 1IntroductionHui ZhangSchool of Computer ScienceCarnegie Mellon University15-441 Networking, Fall 2007http://www.cs.cmu.edu/~srini/15-441/F07/2Today’s Lecturez Course outline and goals.z History and overview3Course Staffz Instructors» Hui Zhang– <[email protected]> , Wean Hall 7126» Srini Seshan– <[email protected]>, Wean Hall 8113zTeaching assistants:» Daniel Spangenberger [email protected]» Albert Sheu [email protected]» One more TA to confirm soon4Course Goalsz Become familiar with the principles and practice of computer networking» Protocols, resource sharing» Routing, transport protocols, naming, ...zLearn how to write networked applications:» An IRC server» A peer-to-peer file transfer programzGet some understanding about network internals in a hands on way.» You’ll implement a routing protocol for your IRC server» TCP-style congestion control5Course Formatz ~30 lectures» Cover the “principles and practice”» Readings are posted beforehandz4 homework assignmentsz Mid-term and final.z 3 programming projects.» How to use and build networks / networked applications» Application layer; include key ideas from kernel» Larger, open-ended group projects. Start early!6Recitation Sectionsz Key 441 objective» systems and distributed programmingz Different from what you’ve done before!» Low level ( C )» Often designed to run indefinitely. Handle all errors!» Must be secure» Interfaces specified by documented protocols» Concurrency involved (inter and intra-machine)» Must have good test methodszRecitations address this» “A system hackers’ view of software engineering”» Practical techniques designed to save you time & pain!7Waiting Listz Currently 58 people are enrolled, and 28 people are on the waiting list.z If you are enrolled and do not plan to take the course, please drop it within a reasonable amount of timez If you are on the waiting list» Please come to lectures for the time being» Please sign in for each lecture» We expect to sort out waiting list issue within the next couple of weeks8Administrative Stuffz Watch the course web page.» Handouts, readings, ..z Read courses bboards.» “Announce” for official announcements» “General” for questions/answersz Office hours posted on web page.z Course secretary» Barbara Grandillo, Wean Hall 8018z Office hours this week by email / appointment» Final office hours posted Thursdayz Books – have people gone to the bookstore? How many copies? Should be there…9Gradingz Roughly equal weight in projects and testing on course contents.z 45% projects» 10% for Project I, 15% for Project II, 20% for Project IIIz40% exams» 15% for Midterm, 25% for Final exam z15% for homeworksz You need to demonstrate competence in both projects and tests to pass the course. Don’t fail any component.10Policy on Collaborationz Working together is important.» Discuss course material in general terms» Work together on program debugging, ..zParts must be your own work» Homework, midterm, finalzProjects: Teams of two» Collaboration, group project skills» Both students should understand the entire projectzWeb page has details.11Policy on Late Work andRegradingz No assignments with a “short fuse”.» Homeworks: ~1 week» Projects: ~5 weekszLate work will receive a 10% penalty/day.» No penalty for a limited number of handins - see web page» No assignment can be more than 2 days latez Only exception is documented illness and family emergenciesz Start on time!» Every year some students discover that a 4 week project cannot be completed in a weekzRequests for regrading must be submitted in writing with course secretary within 2 weeks.» Regrading will be done by original grader12This Weekz Intro – what’s this all about?z Applications and Network programming review.z Course outline:» Low-level (physical, link, circuits, etc.) » Internet core concepts (addressing, routing, DNS)» Advanced topicszOn to the good stuff…13History of Computer Networksz Communicationz Telecommunication z Telecommunication networkz Computer networkz Convergence network14Early Communication over Long Distancez Between human beingsz Letter and messenger» Information carried by physical objects» Speed limited by transportation means: horse, bird, train, car» Bandwidth? distance? security? z Fire» Early optical communication » Speed of light » Bandwidth? distance? security?15Telegraph: Communication Using Electronsz Between human beingsz Major milestones:» 1827: Ohm’s Law» 1837: “workable” telegraph invented by Samuel Morse» 1838: demonstration over 10 miles at 10 w.p.m» 1844: Capitol Hill to Baltimore» 1851: Western Union founded» 1868: transatlantic cable laid» 1985: last telegraph circuit closed downz Other important dates» 1869: transcontinental railway» 1876: Alexander Bell invented telephone16Telegraph Engineeringz Technical issues» How to encode information? » How to feed/input information to the system? » How to output information? » How to improve the distance? » How to improve the speed?zCommon issues faced by all telecommunication systems17Telephonyz Interactive telecommunication between peoplez Analog voice vs. digital information» Transmitter/receiver continuously contact with eletronic circuit» Electric current varies with acoustic pressureAnalog/Continuous SignalDigital/Discrete Signal18Telephony Milestonesz 1876: Alaxendar Bell invented telephonez 1878: Public switches installed at New Haven and San Francisco, public switched telephone network is born– People can talk without being on the same wire !Without Switch With Switch19Back in the Old Days…20Circuit Switchingz Source first establishes a connection (circuit) to the destination» Each switch along the way stores info about connection (and possibly allocates resources)zSource sends the data over the circuit» No need to include the destination address with the data since the switches know the pathzThe connection is
View Full Document
Unlocking...