1 / 39

Business Data Communications

Business Data Communications. 8/e, John Wiley & Sons 2004, FitzGerald and Dennis. Organization of the Textbook (FD). Part 1: Introduction (Ch1) Part 2: Fundamentals (Ch2-5) Part 3: Networking (Ch6-10) Part 4: Network management (Ch11-13) . Introduction to Data Communications. Topic 1.

asis
Télécharger la présentation

Business Data Communications

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Business Data Communications 8/e, John Wiley & Sons 2004, FitzGerald and Dennis

  2. Organization of the Textbook (FD) • Part 1: Introduction (Ch1) • Part 2: Fundamentals (Ch2-5) • Part 3: Networking (Ch6-10) • Part 4: Network management (Ch11-13)

  3. Introduction to Data Communications Topic 1

  4. Some Hot Topics in Data Communications • Email Spamming • 13 billion spam emails/day, $10 billion losses this year • Worm/virus attacks • W32/SirCam@MM (Mass Mailer Worm) Alert • Blaster worm • Hacking • Great Global Grid (GGG) • Web services • Wi-Fi • WiMAX

  5. Outlines • A brief history of data communications • Moore’s law • The Internet • Network concepts

  6. Data Communications Definitions: • Data Communications The movement of computer information from one point to another by means of electrical or optical transmission systems. (How about satellite system?) Such systems are often called data communications networks. • Telecommunications Includes the transmission of voice and video as well as data.

  7. A Brief History of Telecommunications • 1837 - Samuel Morse exhibited a working telegraph system. • 1843 - Alexander Bain patented a printing telegraph. • 1876 - Alexander Graham Bell, invented the first telephone. • 1880 - first pay telephone • 1915 - first transcontinental telephone service and first transatlantic voice connections. • 1947 - transistor invented in Bell Labs • 1951 - first direct long distance dialing • 1962 - first international satellite telephone call • 1968 - Carterfone court decision allowed non-Bell equipment to connect to Bell System Network • 1970 - permitted MCI to provide limited long distance service in competition to AT&T. • 1984 - deregulation of AT&T • 1980s - public service of digital networks • 1990s - cellular telephones commonplace

  8. Phases of Telecommunications Development • Telegraph & Telephone (19th century) • Satellite communications (1960s) • Digital communications (1980s) • Internet age (1990s) • Wireless communications (1990s) • 21st century? Trends: From wired to wireless, from analog to digital, from voice communicating to data communicating

  9. The Invention of Telephone • Who invented the telephone? • Alexander Graham Bell? • Elisha Gray's caveat, as it was filed in the United States Patent Office, February 14, 1876 • Elisha was a new immigrant, who did not have good English communication skills. The economic condition was too bad to have enough money to pay the patent fee.

  10. Semiconductor Industry – the foundation of IT • Vacuum tube – Early the 20th century (?) • Transistor (Transfer resistor), 1947 at Bell Lab invented by John Bardeen, Walter Brattain, and Willian Shockley (Physics Nobel prize winner in 1956) • Integrated circuit, invented by Jack Kilby, TI, in 1959 (Physics Nobel prize winner in 2000)

  11. Moore’s Law • When: 1965 • Who: Gordon Moore, co-founder of Intel. Dr. Moore was preparing a speech and made a memorable observation. When he started to graph data about the growth in memory chip performance, he realized there was a striking trend. • What: Each new chip contained roughly twice as much capacity as its predecessor, and each chip was released within 18-24 months of the previous chip. • An Analogy: If this trend were applicable to airline industry, the plane would cost $500, weigh a few pounds, travel around the world in 20 minutes.

  12. Analyses • Moore’s minimum cost • 1962 – 12 components/chip • 1965 – 50 components/chip • 1970 – 10% of the cost in 1965 per transistor • 1975 – 65,000 components/chip • The speed growth is faster than size reduction, because there has been a rapid increase in clock frequency. • Kuzweil (1999) pointed out that the doubling of processing power started earlier: • 1908 (Hollerith Tabulator) • 1911 (Monroe Calculator) • 1946 (ENIAC) • 1951 (Univac I) • 1959 (IBM 7090)

  13. CPU’s Capacity Growth 2000

  14. Internet, Intranet and Extranet • The Internet: a network of networks servicing the users worldwide • Intranet: an organization's private network that uses Internet technology • Extranet: The intranet that some of its functions are accessible to the organization's business partners

  15. The Internet • Three aspects of the Internet evolution • Capacity growth • Application and traffic growth • Internet policy change

  16. Internet Capacity ARPANET (1969): The Internet was started by the U.S. Department of Defense as a network of four computers. - 1974, 62 hosts - 1983, 1000 hosts - 1989, decommissioned NSFNET (1986): Built up by National Science Foundation with a 3-tier structure - 1987, 10,000 hosts in the Internet, 1000 in BITNET - 1988, upgraded to T1 (1.544 Mbps). - 1991, upgraded to T3 (45Mbps) - 1995, decommissioned vBNS (1995): 622Mbps in 1995 vBNS+ (now): 2.5 Gbps (or more)

  17. NSFNET By 1991, the NSFNET's backbone network service has been upgraded to T3 (45 Mbps) links

  18. Internet Policy and deregulations Originally, commercial traffic was forbidden on the Internet, because the major portions of these networks were funded by the various national governments and research organizations. In the early 1990s, commercial networks began connecting into these networks, opening it to commercial traffic.

  19. Today’s Internet Abilene vBNS CA*Net 3 Figure 9-11 Gigapops and high speed backbones of Internet 2/Abilene, vBNS, and CA*Net 3

  20. vBNS Components The vBNS is accessible to select application sites through four NAPs in New York, San Francisco, Chicago, and Washington, D.C. The vBNS is mainly composed of OC3 /T3

  21. NAP • Network access point (NAP) • The NAP is defined as a high-speed network or switch to which a number of routers can be connected for the purpose of traffic exchange. NAPs must operate at speeds of at least 100 Mbps and must be able to be upgraded as required by demand and usage. • The concept of the NAP is built on the FIX (Federal Internet eXchange) and the CIX (Commercial Internet eXchange), which are built around FDDI rings with attached Internet networks operating at speeds of up to 45 Mbps.

  22. Some vBNS Facts (2001) • Speed: 2.5 Gbps (OC-48) • Multi-protocol Label Switching (MPLS) • 0.001% Packet loss and 100% availability • both unicast and multicast • IPv6 enabled • Extends to Europe and Asia

  23. Abilene • Abilene is an advanced backbone network that supports the development and deployment of the new applications being developed within the Internet2 community. Abilene connects regional network aggregation points, called gigaPoPs, to support the work of Internet2 universities as they develop advanced Internet applications. Abilene complements other high-performance research networks.

  24. Internet Hosts Growth (Recent statistics) July 1999:56,218,000 Internet hosts January 2000: 68,862,283 Internet hosts July 2000: 86,509,613 Internet hosts January 2001: 113,873,000 Internet hosts (MIDS) Now: ?

  25. Internet Addresses Anyone with access to the Internet can communicate with any computer on the Internet. Addresses consist of two parts, the computer name and its domain. computer.domain Each domain has an addressing board that assigns addresses for its domain.

  26. Domain Names EDU COM GOV MIL ORG NET Country Codes CA (Canada) AU (Australia) UK (United Kingdom) DE (Germany) FR (France) CN (China) IN (India) MX (Mexico) Internet Domain Names

  27. Components of a Network • Server (or Host computer) Central computer in the network, storing data or software that can be accessed by the clients. • Client The input/output hardware device at the other end of a communications circuit. • Circuit The pathway through which the messages travel. • Peer-to-peer networks Do not need a server or host, but are designed to connect similar computers which share their data and software with each other.

  28. Components of a Network

  29. Types of Networks Networks can be classified in many different ways. One of the most common is by geographic scope: • Local Area Networks (LAN) • Backbone Networks (BNs) • Metropolitan Area Networks (MANs) • Wide Area Networks (WANs)

  30. Types of Networks

  31. Types of Networks • Local Area Networks (LAN) A group of microcomputers or other workstation devices located in the same general area and connected by a common circuit. Covers a clearly defined small area, such as within or between a few buildings, Support data rates of 10 to 100 million bits per second (Mbps).

  32. Types of Networks • Backbone Network (BN) A larger, central network connecting several LANs, other BNs, metropolitan area networks, and wide area networks. Typically span up to several miles. Support data rates from 64 Kbps to 45 Mbps.

  33. Types of Networks • Metropolitan Area Network (MAN) Connects LANs and BNs located in different areas to each other and to wide area networks. Typically span from 3 - 30 miles. Supports data rates of 100 to 1000 Mbps.

  34. Types of Networks • Wide Area Network (WAN) Connects BNs and MANs and are usually leased from inter-exchange carriers. Typically span hundreds or thousands of miles. Supports data rates of 28.8 Kbps to 2 Gbps.

  35. What is a Protocol? • A standard that allows entities (i.e. application programs) from different systems to communicate • Shared conventions for communicating information • Includes syntax, semantics, and timing

  36. Standardized Protocol Architectures • Vendors like standards because they make their products more marketable • Customers like standards because they enable products from different vendors to interoperate • Two protocol standards are well-known: • TCP/IP: widely implemented • OSI: less used, still useful for modeling/conceptualizing

  37. Internet Standards • Email related standards • IMAP, POP, X.400, SMTP, CMC, MIME, binhex, uuencode • Web related standards • http, CGI, html/xml/vrml/sgml • Internet directory standards • X.500, LDAP • Application standards • http, FTP, telnet, gopher, wais • Videoconferencing standards • H.320, H.323, Mpeg-1, Mpeg-2

  38. *Telecommunication Standards Organizations • International Telecommunications Union - Telecommunication Standardization Sector (ITU-TSS). Formerly called the Consultative Committee on International Telegraph and Telephone (CCITT) • International Organization for Standards (ISO). Member of the ITU, makes technical recommendations about data communications interfaces. • American National Standards Institute (ANSI) • Institute of Electrical and Electronics Engineers (IEEE) • Internet Engineering Task Force (IETF) • Electronic Industries Association (EIA) • National Institute of Standards and Technology (NIST) • National Exchange Carriers Association (NECA) • Corporation for Open Systems (COS) • Electronic Data Interchange -(EDI) of Electronic Data Interchange for Administration Commerce and Transport (EDIFACT).

  39. *Internet Engineering Task Force A protocol proposed by a vendor IETF working group study the proposal IETF issues a request for comment (RFC) IETF reviews the comments IETF proposes an improved RFC The RFC becomes a proposed standard The proposed standard becomes a draft standard if two or more vendors adopt it

More Related