CMPT 371 Data Communications and Networking Fall 2004

2 Outline  Course information r What is network? r A brief introduction to the Internet’s m past m present r Summary

3 Course Information r Instructor: m Jiangchuan (JC) LIU Room 10826, Applied Science Building m Tel: m Office Hours: TBD (Wed afternoon ?) m is the best way to communicate with me r TA(s) m Zhengbing Bian ( )

4 Course Information r Time & Venue m Wednesday 17:30-20:20pm m RC Brown 8100 r There will be one or two breaks

5 Course Information r Textbook m Computer Networking: A Top-Down Approach Featuring the Internet, by Kurose and Ross r Reference books m Computer Networks, 4/e by Andrew Tanenbaum m Data and Computer communications, 7th edition, William Stallings, Prentice Hall, 2003 m And more (see Web) r Resource m Home page

6 Course Information r Textbook m Computer Networking: A Top-Down Approach Featuring the Internet, by Kurose and Ross r Why using this book ? m New content – this is a fast-changing area m But more important, new structure and target Top-down Featuring the Internet

7 What Are the Goals Of This Course? r Understand how Internet works m Its philosophy m Its protocols and mechanisms r Learn network programming r Have fun! m Are you happy with no Internet access in your life ?

8 What Will We Cover? (Tentative schedule) r Introduction (1.5 – 2 weeks) m Internet architecture and design philosophy r Applications (2-3 weeks) m HTTP, , DNS r transport services (2-3 weeks) m reliability; congestion control; transport protocols: TCP/UDP r network services (2-3 weeks) m routing; network protocols: IP/IPv6 r link and physical layers (2-3 weeks) m multiple access; Ethernet, FDDI, hubs and bridges

9 What Do You Need To Do? r Your prerequisites m algorithms: e.g. shortest path algorithms m programming: C/C++, Java m basic concepts of operating systems r Your workload m reading assignment for every lecture m homework assignments 3 written assignments 2 programming projects m one mid-term exam, and one final exam

10 Grading (tentative) r Class participation r More important is what you learn than the grades Written Homework10% Programming work15% Mid-term exam30% Final exam45%

Questions?

12 Outline r Course information  What is network? r A brief introduction to the Internet’s m past m present r Summary

13 Q: What is Network? r Telephone network r Dialup r Local area network r Internet r Mobile phone r … Nodes -- Interconnected

14 Why Internet ? r The most successful network m Open m Heterogeneous m Simple network, complex end-terminals End-to-end argument r How about other networks? m Telephone m Mobile phone m Wireless LAN m Cable TV r IP convergence… r And, about the authors of the text book

15 Course Information r Textbook m Computer Networking: A Top-Down Approach Featuring the Internet, by Kurose and Ross r Reference books m Computer Networks, 4/e by Andrew Tanenbaum m Data and Computer communications, 7th edition, William Stallings, Prentice Hall, 2003

16 Motivation: Communication r Need some common interface to communicate  network protocol r A->B: Hi r B->A: Hi r A->B: What time is it ? r B->A: 1:00pm r What if no protocol… r Woi kx ioa nio ? r … r …

17 An Example: Simple Mail Transfer Protocol (SMTP) r Scenario m client: Outlook, TheBat, Netscap … m server: in Unix, Windows … r Messages from a client to a mail server m HELO m MAIL FROM: m RCPT TO: m DATA m QUIT r Messages from a mail server to a client m status code –1xx - Informative message –2xx - Command ok –3xx - Command ok so far, send the rest of it. –4xx - Command was correct, but couldn't be performed for some reason. –5xx - Command unimplemented, or incorrect, or a serious program error occurred. m mail body user mailbox outgoing message queue mail server user agent user agent user agent mail server user agent user agent mail server user agent SMTP POP3, IMAP SMTP

18 Internet Standardization Process r All standards of the Internet are published as RFC (Request for Comments) m but not all RFCs are Internet Standards ! but not all RFCs are Internet Standards ! m available: m Till this morning: RFC3099 r A typical (but not the only) way of standardization: m Internet draft m RFC m Proposed standard m Draft standard (requires 2 working implementations) m Internet standard (declared by Internet Architecture Board)

19 Internet Standardization Process r All standards of the Internet are published as RFC (Request for Comments) m but not all RFCs are Internet Standards ! but not all RFCs are Internet Standards ! m available: m Till now: RFC3866 r A typical (but not the only) way of standardization: m Internet draft m RFC m Proposed standard m Draft standard (requires 2 working implementations) m Internet standard (declared by Internet Architecture Board)

20 Outline r Course information r What is a network protocol?  A brief introduction to the Internet’s  past  present r Summary

21 A Brief History of the Internet r 1957 m USSR launches Sputnik, US formed Advanced Research Projects Agency (ARPA) as a response r 1968 m Bolt Beranek and Newman, Inc. (BBN) was awarded Packet Switch contract to build Interface Message Processors (IMPs) for ARPANET

22 r 1969 m ARPANET commissioned: 4 nodes, 50kbps A Brief History of the Internet

23 Initial Expansion of the ARPANET Dec. 1969March 1971July 1970 Apr Sep. 1972

24 Multiple Networks r 1974: Initial design of TCP to connect multiple networks r 1986: NSF builds NSFNET as backbone, links 6 supercomputer centers, 56 kbps; this allows an explosion of connections, especially from universities r 1987: 10,000 hosts r 1989: 100,000 hosts WELCOME by Leonard Kleinrock …

25 Web and Commercialization of the Internet r 1991: NSF lifts restrictions on the commercial use of the Net; World Wide Web released r 1992: 1 million hosts r Today: backbones run at 10Gbps, 100s millions computers in 150 countries r Internet history and Timeline m

26 Growth of the Internet in Terms of Number of Hosts Number of Hosts on the Internet: Aug Oct ,024 Dec ,174 Oct ,000 Jul ,776,000 Jul ,540,000 Jul ,047,000 Jul ,128,493

27 Backbone: National ISP Local/Regional ISP Local/Regional ISP Internet Physical Infrastructure r Residential Access m Modem m DSL m Cable modem r Access to ISP, Backbone transmission m T1/T3, OC-3, OC-12 m ATM, SONET, WDM r Internet Service Providers m Local/Regional/Natio nal m They exchange packets at Point of Presence (POP) r Campus network access m Ethernet m FDDI m Wireless

28 Local Access: ADSL r Asymmetrical Digital Subscriber Line (ADSL) r Telephone company’s solution to “last mile problem”

29 Local Access: Cable Modems r Fiber node: K homes r Distribution hub: 20K - 40 K homes r Regional headend: 200 K K homes

30 From AT&T web site. AT&T US Internet Backbone

31 Canadian 2G National Internet Backbone From

32 AT&T Global Backbone IP Network From

33 Web and Commercialization of the Internet

34 Killer applications - FTP

35 Killer applications -

36 Killer applications – WWW 1990-

37 Killer applications – P2P 2000-

38 Killer applications- what’s next ? r Media streaming (Internet TV) r E-commerce r Online game r…r…

39 Summary r Course information r Network: nodes -> interconnected r Protocol: format and the order of messages exchanged, as well as the actions taken r Internet: The past: m started as ARPANET: late 1960s m initial link bandwidth: 50 kbps m number of hosts: 4 r Internet: Current: m number of hosts: grows at an exponential speed July 2002 was about 162 millions m backbone speed: 10 Gbps

40 Practices r Log into a Unix machine (or Windows) r Read the manual of ping and traceroute, and try them on a machine 1. % /bin/ping 2. % /usr/sbin/traceroute  Look at the web sites of the routers you see through traceroute