COS 461: Computer NetworksGoals for Today’s ClassWhat You Learn in This CourseStructure of the Course (1st Half)Structure of the Course (2nd Half)Learning the Material: PeopleLearning the Material: Mailing ListLearning the Material: BooksGrading and ScheduleProgramming AssignmentsFacilities for ProgrammingSlide 12Graduate Students: Two ChoicesPolicies: Write Your Own CodeOkay, so let’s get started… with a crash course in data networkingKey Concepts in NetworkingProtocols: Calendar ServiceOkay, So This is Getting TediousWell, Not Quite EnoughSpecifying the DetailsExample: HyperText Transfer ProtocolExample: IP PacketIP: Best-Effort Packet DeliveryExample: Transmission Control ProtocolProtocol StandardizationLayering: A Modular ApproachIP Suite: End Hosts vs. RoutersThe Internet Protocol SuiteLayer EncapsulationWhat if the Data Doesn’t Fit?Protocol DemultiplexingDemultiplexing: Port NumbersIs Layering Harmful?Resource Allocation: QueuesWhat if the Data gets Dropped?What if the Data is Out of Order?Resource Allocation: Congestion ControlTransmission Control ProtocolNaming: Domain Name System (DNS)Domain Name SystemDNS Resolver and Local DNS ServerConclusionsCOS 461: Computer NetworksSpring 2009 (MW 1:30-2:50 in CS 105)Mike FreedmanTeaching Assistants: Wyatt Lloyd and Jeff Terracehttp://www.cs.princeton.edu/courses/archive/spr09/cos461/1Goals for Today’s Class•COS 461 overview–Goals of the course–Structure of the course–Learning the material–Programming assignments–Course grading–Academic policies•Key concepts in data networking–Protocols–Layering–Resource allocation –Naming2What You Learn in This Course•Skill: network programming–Socket programming–Designing and implementing protocols•Knowledge: how the Internet works–IP protocol suite–Internet architecture–Applications (Web, DNS, P2P, …)•Insight: key concepts in networking–Protocols–Layering–Resource allocation–Naming3Structure of the Course (1st Half)•Start at the top–Sockets: how applications view the Internet–Protocols: essential elements of a protocol•Then study the “narrow waist” of IP–IP best-effort packet-delivery service–IP addressing and packet forwarding•And how to build on top of the narrow waist–Transport protocols (TCP, UDP)–Domain Name System (DNS)–Glue (ARP, DHCP, ICMP)–End-system security and privacy (NAT, firewalls)•Looking underneath IP–Link technologies (Ethernet)4Structure of the Course (2nd Half)•And how to get the traffic from here to there–Internet routing architecture (the “inter” in Internet)–Intradomain and interdomain routing protocols•Building applications–DNS and HTTP–Content-distribution networks–Peer-to-peer and distributed hash tables–P2P Applications: BitTorrent, etc.–Multimedia streaming•Other approaching to building networks–Delay /disruption tolerant networks–Multicast, anycast, …5Learning the Material: People•Lecture (Prof. Mike Freedman)–When: MW 1:30-2:50 in Computer Science 105–Slides available online at course Web site–Office hours (room 208) by appointment–Email: mfreed+cos461 at cs.princeton.edu•Teaching Assistants –Wyatt Lloyd•Office hours: Mon 3-4pm, Tue 4-5pm (CS 003)•E-mail: wlloyd+cos461 at cs.princeton.edu –Jeff Terrace•Office hours: Wed 3-4pm, Thu 1-2pm (CS 001B)•E-mail: jterrace+cos461 at cs.princeton.edu•Main email: cos461-staff at lists.cs.princeton.edu6Learning the Material: Mailing List•Mailing list–If you’re enrolled, you should be on it–E-mail: cos461 at lists.cs.princeton.edu–Sign up: https://lists.cs.princeton.edu/mailman/listinfo/cos461•Read often–Good place to ask questions–But do not post your code •Reply, too–Good place to answer questions (participation!)7Learning the Material: Books•Required textbook–Computer Networks: A Systems Approach (4th edition), by Peterson and Davie [Okay to use the 3rd edition]–Mostly covers the material in the first half of the class•Books on reserve–Networking text books•Computer Networking: A Top-Down Approach Featuring the Internet (3rd edition), by Kurose and Ross •Computer Networks (4th edition), by Tanenbaum–Network programming references•TCP/IP Illustrated, Volume 1: The Protocols, by Stevens•Unix Network Programming, Volume 1: The Sockets Networking API (3rd Edition), by Stevens, Fenner, & Rudolf•Online resources–E.g. on socket programming8Grading and Schedule•Assignments (10% each)–95% 3 hours, 75% two day late, 50% two days late–One free late day during semester•Two exams (40% total)–Midterm exam in week six (20%)–Final exam during exam period (20%)•Class participation (10%)–In lecture–On the listserv9Programming Assignments•Five assignments (with target due dates)–Introduction to sockets (Sun Feb 15)–HTTP proxy (Sun Mar 8)–IP router (Sun Apr 12)–Firewall (Sun Apr 26)–Reliable transport (Tue May 12) – no late accepted•Last three: Stanford Virtual Network System–Constructs virtual network topologies that integrate directly into physical networks–Traffic forwarded to your program, running in user space–http://yuba.stanford.edu/vns/10Facilities for Programming•Computer cluster in Friend Center 010–Friend Center 010 computers–Machines: labpc-XX.cs.princeton.edu for XX of 01 to 30–Why: common environment, and access to lab TAs•Accessing your account–If you are enrolled, you have a labpc account–Using your OIT login and password•Logging in to the machines remotely–SSH to portal.cs.princeton.edu, and then to FC 010–Need a CS account, if you don’t have one already–https://csguide.cs.princeton.edu/requests/account–Request a “class account”11Facilities for Programming•Other option: your own PC (not recommended)–Running GNU tools on Linux, or–Running GNU tools on Windows, or–Running a standard C development environment–Development environment not supported by TAs•Suggestion: test access this week–Logging in to the FC 010 cluster–Writing and running “Hello World” in C•Submitting assignments–Using Blackboard–More details coming soon!12Graduate Students: Two Choices•Pick one of two options–Do the five programming assignments–Or, first two assignments, plus research project•Research projects–Networking-related research problem–Must have a systems programming component–Write-up of project due on Dean’s Date–Talk to me about a project before
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