EECS 122 Introduction to Computer Networks Course Goals

EECS 122: Introduction to Computer Networks Course Goals and Overview Computer Science Division Department of Electrical Engineering and Computer Sciences University of California, Berkeley, CA 94720 -1776 Katz, Stoica F 04 1

Instructors § Instructors - Randy Katz (randy@cs. Berkeley. edu), Office Hours: Tu 1 -2 PM, W 11 -12 noon, and by appointment, 637 Soda Hall - Ion Stoica (istoica@cs. Berkeley. edu), Office Hours: M 5 -6 PM, W 4 -5 PM, 645 Soda Hall § Textbooks - L. L. Peterson and B. Davie, Computer Networks: A System Approach, 3 nd Edition, Morgan Kaufman, San Francisco, 2003. - W. R. Stevens, B. Fenner, A. M. Rudoff, Unix Network Programming: The Sockets Networking API, Vol. 1, 3 rd Ed. , Addison-Wesley, Boston, 2004. Katz, Stoica F 04 2

TAs § § § Byung-Gon Chun, bgchun@cs. Berkeley. edu Tu 4 -5 PM, room TBD Xuanming Dong, xuanming@eecs. Berkeley. edu Time and room TBD Ling Huang, hling@cs. Berkeley. edu Tu 2 -3 PM, room TBD Sonesh Surana, sonesh@cs. Berkeley. edu Time and room TBD For final office hour schedule, please see the web Katz, Stoica F 04 3

Overview § § Administrivia Overview and History of the Internet Katz, Stoica F 04 4

Administrivia § Course Web page: - http: //inst. eecs. berkeley. edu/~ee 122/ - Check often to get the latest information § Deadlines - HWs: due 10: 50 am on the indicated date (10 minutes before lecture) § § Exams are closed-book, with open crib sheet 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 as early as possible Katz, Stoica F 04 5

Course Goals § Learn the main architectural concepts and technological components of communication networks, with the Internet as the overarching example - Understand how the Internet works - And why the Internet is the way it is § Apply what you learned in three mini-class projects Katz, Stoica F 04 6

Class Workload § § NOTE: EE 122 is a 4 unit course starting this semester! Four homeworks spread over the semester - Strict deadlines and due dates (no slip days!) § Three (mini-)projects - 1 st and 3 rd are part of a larger project, which involves implementing a comprehensive network application • C (or C++) required - 2 nd is a simulation project § Two midterm exams - September 30 and November 4 § Final exam - December 16 - Note dates and plan your travel accordingly! Katz, Stoica F 04 7

Grading Homeworks Projects Midterm exams Final exam § 20% (5% each) 40% (10% + 20%) 20% (10% each) 20% Consultation on HWs is OK, but must hand in own work - Correlation between understanding HWs and doing well on exams § 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 (only 1 or 2 per class) Mean can shift up for an especially great class Katz, Stoica F 04 8

Overview § Ø Administrivia Overview and History of the Internet • See http: //www. isoc. org/internet/history/ for more details Katz, Stoica F 04 9

What is a Communication Network? (End-system Centric View) § Network offers one basic service: move information - Bird, fire, messenger, truck, telegraph, telephone, Internet … - Another example, transportation service: move objects • Horse, train, truck, airplane. . . § What distinguish different types of networks? - The services they provide § What distinguish the services? - Latency Bandwidth Loss rate Number of end systems Service interface (how to invoke the service? ) Others • Reliability, unicast vs. multicast, real-time. . . Katz, Stoica F 04 10

What is a Communication Network? (Infrastructure Centric View) § § Communication medium: electron, photon Network components: - Links – carry bits from one place to another (or maybe multiple places): fiber, copper, satellite, … - Interfaces – attach devices to links - Switches/routers – interconnect links: electronic/optic, crossbar/Banyan - Hosts – communication endpoints: workstations, PDAs, cell phones, toasters § Protocols – rules governing communication between nodes - TCP/IP, ATM, MPLS, SONET, Ethernet, X. 25 § Applications: Web browser, X Windows, FTP, . . . Katz, Stoica F 04 11

Network Components (Examples) Links Interfaces Fibers Ethernet card Switches/routers Large router Wireless card Coaxial Cable Telephone switch Katz, Stoica F 04 12

Types of Networks § Geographical distance - § Local Area Networks (LAN): Ethernet, Token ring, FDDI Metropolitan Area Networks (MAN): DQDB, SMDS Wide Area Networks (WAN): X. 25, ATM, frame relay Caveat: LAN, MAN, WAN may mean different things • Service, network technology, networks Information type - Data networks vs. telecommunication networks § Application type - Special purpose networks: airline reservation network, banking network, credit card network, telephony - General purpose network: Internet Katz, Stoica F 04 13

Types of Networks § Right to use - Private: enterprise networks - Public: telephony network, Internet § Ownership of protocols - Proprietary: SNA - Open: IP § Technologies - Terrestrial vs. satellite - Wired vs. wireless § Protocols - IP, Apple. Talk, SNA Katz, Stoica F 04 14

The Internet (cont’d) § § Global scale, general purpose, heterogeneoustechnologies, public, computer network Internet Protocol - Open standard: Internet Engineering Task Force (IETF) as standard body ( http: //www. ietf. org ) - Technical basis for other types of networks • Intranet: enterprise IP network § Developed by the research community Katz, Stoica F 04 15

Internet vs. Telephone Net § § Strengths - Intelligence at ends - Decentralized control - Operates over heterogeneous access technologies Weaknesses - No differential service - Variable performance delay - New functions difficult to add since end nodes must be upgraded - No trusted infrastructure § § Strengths - No end-point intelligence - Heterogeneous devices - Excellent voice performance Weaknesses - Achieves performance by overallocating resources - Difficult to add new services to “Intelligent Network” due to complex call model - Expensive approach for reliability Katz, Stoica F 04 16

History of the Internet § 68 -70’s: started as a research project, 56 kbps, initially 4 nodes (UCLA, UCSB, SRI, Utah) then < 100 computers - 2 September 2004/35 th Anniversary of the Internet - http: //www. cnn. com/2004/TECH/internet/08/29/internet. birthda y. ap/index. html § § § 80 -83: TCP/IP, DNS; ARPANET and MILNET split 85 -86: NSF builds NSFNET as backbone, links 6 Supercomputer centers, 1. 5 Mbps, 10, 000 computers 87 -90: link regional networks, NSI (NASA), ESNet (DOE), DARTnet, TWBNet (DARPA), 100, 000 computers 90 -92: NSFNET moves to 45 Mbps, 16 mid-level networks 94: NSF backbone dismantled, multiple private backbones; Introduction of Commercial Internet Today: backbones run at 10 Gbps, close to 200 millions computers in 150 countries Katz, Stoica F 04 17

The ARPANet SRI 940 UCSB IBM 360 IMPs Utah PDP 10 § UCLA Sigma 7 § BBN team that implemented the interface message processor Paul Baran - RAND Corp, early 1960 s - Communications networks that would survive a major enemy attack ARPANet: Research vehicle for “Resource Sharing Computer Networks” - 2 September 1969: UCLA first node on the ARPANet - December 1969: 4 nodes connected by phone lines Katz, Stoica F 04 18

ARPANet Evolves into Internet ARPANet SATNet PRNet 1965 TCP/IP 1975 Web Hosting Multiple ISPs Internet 2 Backbone Internet Exchanges NSFNet Deregulation & ISP Commercialization ASP AIP WWW 1985 1995 2005 Application Hosting ASP: Application Service Provider AIP: Application Infrastructure Provider (e-commerce tookit, etc. ) Katz, Stoica F 04 19

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Digex Backbone Qwest IP Backbone (Late 1999) GTE Internetworking Backbone Parallel Backbones Katz, Stoica F 04 23

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Growth of the Internet Number of Hosts on the Internet: Aug. 1981 213 Oct. 1984 1, 024 Dec. 1987 28, 174 Oct. 1990 313, 000 Oct. 1993 2, 056, 000 Apr. 1995 5, 706, 000 Jan. 1997 16, 146, 000 Jan. 1999 56, 218, 000 Jan. 2001 109, 374, 000 Jan. 2003 171, 638, 297 Jan. 2004 233, 101, 481 Data available at: http: //www. isc. org/ Estimated number of users: http: //www. internetworldstats. com/stats. htm Katz, Stoica F 04 25

Services Provided by the Internet § Shared access to computing resources - telnet (1970’s) § Shared access to data/files - FTP, NFS, AFS (1980’s) § Communication medium over which people interact - email (1980’s), on-line chat rooms, instant messaging (1990’s) - audio, video (1990’s) • replacing telephone network? § Medium for information dissemination - USENET (1980’s) - WWW (1990’s) • replacing newspaper, magazine? - Audio, video (late 90’s) • replacing radio, CD, TV? - File sharing (late 90’s) Katz, Stoica F 04 26

Internet Physical Infrastructure ISP § Residential Access - Modem - DSL - Cable modem - Satellite § Backbone Enterprise/ISP access, Backbone transmission - T 1/T 3, DS-1 DS-3 - OC-3 … OC-76 - ATM vs. SONET, vs. WDM ISP § Campus network - Ethernet, ATM § Internet Service Providers - access, regional, backbone - Point of Presence (POP) - Network Access Point (NAP) Katz, Stoica F 04 27

Network “Cloud” Katz, Stoica F 04 28

Regional Nets + Backbone Regional Net Backbone Regional Net LAN Katz, Stoica F 04 29

Backbones + NAPs + ISPs ISP ISP NAP Backbones Business ISP LAN ISP NAP Consumer ISP LAN Dial-up Katz, Stoica F 04 30

Core Networks + Access Networks DSL Always on Cable Head Ends @home Covad Cingular Cell LAN NAP Core Networks NAP ISP Satellite Fixed Wireless Sprint LAN AOL LAN Dial-up Katz, Stoica F 04 31

Computers Inside the Core DSL Always on Cable Head Ends @home Covad Cingular Cell LAN NAP ISP Satellite Fixed Wireless Sprint LAN AOL LAN Dial-up Katz, Stoica F 04 32

The Evolution of the Enterprise Late-1980 s Internal users Private Corporate Network Dedicated facilities/ computer centers Limited customer/ external access Dedicated applications/ 3 rd party DBMS E. g. , Oracle Katz, Stoica F 04 33

The Evolution of the Enterprise 1995 Internal users Private Corporate Network Dedicated facilities/ computer centers Limited customer/ external access Outsourced “Enterprise Resource Planning” Apps e. g. , People. Soft, BAAN Katz, Stoica F 04 34

The Evolution of the Enterprise 1997 Internal users Virtual Private Network ISP Mesh Outsourced Web Hosting Internet Dedicated Facility Outsourced ERP Apps External Customers Katz, Stoica F 04 35

The Evolution of the Enterprise 1997 Internal users P o r t a l Outsourced Web Hosting Search Caching Internet Ads Services EComm Virtual Private Network ISP Mesh Internet Dedicated Facility Outsourced ERP Apps External Customers Katz, Stoica F 04 36

The Evolution of the Enterprise 1999 3 rd Party Facilities Mgmt P o r t a l Outsourced Web Hosting Search Cache Ads EComm Internet Services Applications Service Provider ISP Mesh VPNs Content Delivery “Net” Caching + Media Servers Customers Katz, Stoica F 04 37

Services Within the Network: Content Distribution “Internet Grid” Parallel Network Backbones Internet Exchange Points Co-Location Scalable Servers Web Caches Katz, Stoica F 04 38

P 2 P Services in the Internet: Napster, Gnutella, Freenet, … Directory Service Register my copy Find me a copy . . . Madonna Like a Virgin Madonna Material Girl . . . Look here Grid computing: sharing resources/enabling collaboration Katz, Stoica F 04 39

Services Within the Network: Streaming Media Broadcasters Content Broadcast Network Content Distribution Through Multicast Overlay Network Load Balancing Thru Server Redirection; Edge Servers Inter-ISP Redirection Peering Redirection Fabric Content Broadcast Management Platform and Tools Clients Katz, Stoica F 04 40 Steve Mc. Canne

Summary § § Course administrative trivia Internet history and background Katz, Stoica F 04 41