EE 122 Introduction To Communication Networks Fall 2006 MW 4 5 30 in Cory 247 Vern Paxson TAs Dilip Anthony Joseph and Sukun Kim http inst eecs berkeley edu ee122 Materials with thanks to Jennifer Rexford Ion Stoica and colleagues at Princeton and UC Berkeley 1 Goals 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 a global Internet 2 1 What 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 protocols 3 What 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 perspectives 4 2 Structure 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 5 Structure 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 overlays 6 3 Instructor Vern Paxson vern icsi berkeley edu Senior scientist at the International Computer Science Institute 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 7 TAs Dilip Anthony Joseph dilip eecs berkeley edu Office hours F 11 12 in 311 Soda And by appointment Section F 10 11 in 293 Cory Sukun Kim binetude eecs berkeley edu 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 Cory 8 4 Interact 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 early as you can What s your background Tell us at http tinyurl com fbc7u 9 Course Materials Textbooks L L Peterson and B Davie Computer Networks A System Approach 3nd Edition Morgan Kaufman 2003 Note we jump around in it a lot W R Stevens B Fenner A M Rudoff Unix Network Programming The Sockets Networking API Vol 1 3rd Ed Addison Wesley 2004 Recommended on reserve W R Stevens TCP IP Illustrated Volume 1 The Protocols AddisonWesley 1993 Web site http inst eecs berkeley edu ee122 Updated frequently including lecture slides generally in advance Mailing list ee122 icsi berkeley edu Sign up http mailman icsi berkeley edu mailman listinfo ee122 10 5 Class 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 sheet 11 Prerequisites CS 61A 61B Programming data structures software engineering Knowledge of C or C Math 53 or 54 In fact we ll be relatively light on math though your algebra should be very solid you should know basic probability and you ll need to be comfortable with thinking abstractly Background material will not be covered in lecture TAs will spend very little time reviewing material not specific to networking 12 6 Grading Homeworks 20 5 each Projects 40 10 10 20 Midterm exam 20 Final exam 20 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 class 13 No Cheating Cheating means not doing the assignment by yourself Fine to talk with other students about assignments outside of class No copying no Google etc If you re unsure then ask We will do automated similarity detection on assignments 14 7 5 Minute Break Questions Before We Proceed 15 Networking 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 16 8 Why Networking Is Challenging Fundamental challenge the speed of light Question how long does it take light to travel from Berkeley to New York Answer Distance Berkeley New York 4 125 km great circle Traveling 300 000 km s 13 75 msec 17 Fundamental Challenge Speed of Light Question how long does it take an Internet packet to travel from Berkeley to New York Answer For sure 13 75 msec Depends on The route the packet takes could be circuitous The propagation speed of the links the packet traverses E g in optical fiber light propagates at about 2 3 C The transmission rate bandwidth of the links bits sec and thus the size of the packet Number of hops traversed store and forward delay The competition for bandwidth the packet encounters congestion It may have to sit wait in router queues In practice this boils down to 40 msec 18 9 Fundamental Challenge Speed of Light Question how many cycles does your PC execute before it can possibly get a reply to a message it sent to a New York web
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