11EE 122: Introduction ToCommunication NetworksFall 2006 (MW 4-5:30 in Cory 247)Vern PaxsonTAs: Dilip Anthony Joseph and Sukun Kimhttp://inst.eecs.berkeley.edu/~ee122/Materials with thanks to Jennifer Rexford, Ion Stoica,and colleagues at Princeton and UC Berkeley2Goals for Today’s Class• EE 122 overview– Goals of the course– Structure of the course– Instructor & TAs– Prereqs & assignments– Course grading– Academic policies• What makes networking challenging– The fundamental issues we must grapple with to build aglobal Internet23What You Learn in This Course• Insight: key concepts in networking– Protocols– Layering– Resource allocation– Security– Naming• Knowledge: how the Internet works– Internet architecture– IP protocol suite– Applications (Web, e-mail, P2P, …)• Skill: network programming– Socket programming– Designing and implementing protocols4What This Course Is and Isn’t• EE122 comes in two flavors:– Spring offering: taught by EE faculty More emphasis on diverse link technologies, wireless & mobility,communication theory & simulation– Fall offering: taught by CS faculty More emphasis on Internet technology, applications, practice &empiricism / hands-on– Differences aren’t huge, though• My particular emphasis:– Today’s actual (messy) Internet Not yesterday’s, and not much about tomorrow’s– Security perspectives35Structure of the Course (1st Half)• Start at the top– Protocols: how to structure communication– Sockets: how applications view the Internet• 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)– Applications (Web, email, file transfer)• Looking underneath IP– Link technologies (Ethernet, bridges, switches)6Structure of the Course (2nd Half)• How to get the traffic from here to there …– Glue (ARP, DHCP, ICMP)– Routing (intradomain, interdomain)• … in a way that’s both efficient and stable– How much data to keep in flight (the window)– Without clogging the network (congestion)– With some assurance (quality of service) … or not• How to control network traffic …– Enforcing policy– Defending against attacks• … and scale it to potentially huge structures– Peer-to-peer & overlays47Instructor• Vern Paxson ([email protected])– Senior scientist at the International Computer ScienceInstitute and also the Lawrence Berkeley National Lab Research focuses on network security & network measurement– http://www.icir.org/vern/– Office hours W 2:30-3:30PM in 329 Soda And by appointment at ICSI• http://www.icsi.berkeley.edu/where.html• This week only by appointment– Phone: 666-2882 Email works much better!– Hearing impaired: please be ready to repeat questions &comments!8TAs• Dilip Anthony Joseph ([email protected])– Office hours F 11-12 in 311 Soda And by appointment– Section F 10-11 in 293 Cory• Sukun Kim ([email protected])– Office hours T 11-12 in 410 Soda And by appointment– Section T 10-11 in 400 Cory• Co-teach 3rd section– W 12-1 in 293 Cory59Interact!• Inevitably, you won’t understand something(s) …that’s my fault, but you need to help.• Come to office hours, request an appointment,communicate by e-mail– We are here to help, including general advice!– TAs first line for help with programming problems• Give us suggestions/complaints/feedback as earlyas you can• What’s your background? Tell us at– http://tinyurl.com/fbc7u10Course Materials• Textbooks– L. L. Peterson and B. Davie, Computer Networks: A SystemApproach, 3nd Edition, Morgan Kaufman, 2003. Note, we jump around in it a lot– W. R. Stevens, B. Fenner, A. M. Rudoff, Unix NetworkProgramming: The Sockets Networking API, Vol. 1, 3rd Ed.,Addison-Wesley, 2004.– Recommended & on reserve: W. R. Stevens, TCP/IP Illustrated, Volume 1: The Protocols, Addison-Wesley, 1993.• Web site: http://inst.eecs.berkeley.edu/~ee122/– Updated frequently, including lecture slides (generally in advance)• Mailing list: [email protected]– Sign up: http://mailman.icsi.berkeley.edu/mailman/listinfo/ee122611Class Workload• Four homeworks spread over the semester– Strict due dates (no slip days!)– Deadlines are generally 3:50PM prior to lecture• Three (mini-)projects– Simple “echo” server (socket programming)– Simple Web crawler– “Chat” tool 1st phase: design protocol 2nd phase: implement to reference protocol design– C (or C++) required– Deadlines 11PM• Exams– Midterm: Monday October 16– Final: Saturday Dec 16– Closed book, open crib sheet12Prerequisites• CS 61A, 61B– Programming, data structures, softwareengineering– Knowledge of C or C++• Math 53 or 54– In fact, we’ll be relatively light on math, thoughyour algebra should be very solid, you shouldknow basic probability, and you’ll need to becomfortable with thinking abstractly• Background material will not be covered inlecture. TAs will spend very little timereviewing material not specific to networking713Grading• Course graded to mean of B– Relatively easy to get a B, harder to get an A or a C≈ 10% A, 15% A-, 15% B+, 20% B, 15% B-, 15% C+, 10% C– A+ reserved for superstars (1 or 2 per class)– Mean can shift up for an excellent class20%Final exam20%Midterm exam40% (10+10+20)Projects20% (5% each)Homeworks14No Cheating• Cheating means not doing the assignment byyourself.• Fine to talk with other students about assignmentsoutside of class.• No copying, no Google, etc.• If you’re unsure, then ask.• We will do automated similarity detection onassignments.8155 Minute BreakQuestions Before We Proceed?16Networking: Actually Not Boring• How hard can it be??• You just string a wire (or other signaling path)between two computers …• … first one squirts bits down the link …• … and the second one slurps them up. Right?• Where does it get tricky?917Why Networking Is Challenging• Fundamental challenge: the speed of light• Question: how long does it take light to travel fromBerkeley to New York?• Answer:– Distance Berkeley → New York: 4,125 km (great circle)– Traveling 300,000 km/s: 13.75 msec18Fundamental Challenge: Speed of Light• Question: how long does it take an Internet“packet”
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