Business Data Communications

1. Business Data Communications 7/e, John Wiley & Sons 2002, FitzGerald and Dennis 4/e, Prentice Hall 2001, William Stallings

2. Organization of the Textbook (FD) • Part 1: Introduction (Ch1) • Part 2: Fundamentals (Ch2-5) • Part 3: Networking (Ch6-9) • Part 4: Network management (Ch10-12) Chapter 11 will not be covered

3. Organization of the Textbook (WS) • Part 1: Requirements (Ch2-3) • Part 2: TCP/IP and The Internet (ch4-5) • Part 3: Data Communications (Ch6-10) • Part 4: Networking (Ch11-15) • Part 5: Applications (Ch16-17) • Part 6: Management Issues (Ch18-20)

4. Introduction to Data Communications Topic 1/Chapter 1

5. Discussion • Why is it important to study data communication? • What is the definition of data communication? • Do you know the following figures: • the fastest CPU available on the market • the highest bandwidth of the Internet backbone • the number of ISPs in the US • What is the trend of data communications?

6. 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)

7. 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.

8. 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)

9. CPU’s Capacity Growth 2000

10. Moore’s Law (Cont’d) • Moore's observation, now known as Moore's Law, described a trend that has continued and is still remarkably accurate. It is the basis for many planners' performance forecasts. In 26 years the number of transistors on a chip has increased more than 3,200 times, from 2,300 on the 4004 in 1971 to 7.5 million on the Pentium II processor. • Machrone’s Law:the machine you want always costs $5,000 • Rock’s Law: the cost of capital equipment to build semiconductors will double every four years

11. Questions from Moore’s Law • What are implications of Moore’s law to the information age? • Will Moore’s law hit the wall eventually? • What are its implications to recent economy downturn? • Any impact on data communication technologies? • How does it affect your career?

12. 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.

13. Data Communications • Another vision of information forms (VIViD): • Voice communications • Image communications • Video communications • Data communications (limited to text)

14. 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.

15. Components of a Network

16. 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)

17. Types of Networks

18. 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).

19. 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.

20. 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.

21. 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.

22. Network Model A method of describing and analyzing data communications networks, by breaking the entire set of communications functions into a series of layers, each of which can be defined separately. This allows vendors to develop software and hardware to provide the functions separately.

23. Open Systems Interconnection (OSI) • Developed by the International Organization for Standardization (ISO) in 1984 • The primary architectural model for intercomputer communications. • A conceptual model composed of seven layers, each specifying particular network functions. • Describes how information from a software application in one computer moves through a network medium to a software application in another computer.

24. ISO’s OSI Model OSI has 7 layers: • Application layer • Presentation layer • Session layer • Transport layer • Network layer • Data link layer • Physical layer

25. OSI Model F-D’s Model Internet Model OSI Model Application layer: http, telnet, snmp, smtp, nfs, ftp Application layer TCP, UDP Network layer IPv4, IPv6 Data Link layer Data Link Layer (HDLC) Physical layer Physical layer

26. OSI Model • Network layer • provides routing and related functions • Transport layer • implements reliable internetwork data transport services • Session layer • establishes, manages and terminates communication sessions between presentation layer entities • Presentation layer • provides a variety of coding and conversion functions • Application layer • closest to the end user

27. Sender Receiver Application Layer Application Layer HTTP Request HTTP Request Transport Layer Transport Layer TCP HTTP Request TCP HTTP Request Network Layer Network Layer IP TCP HTTP Request IP TCP HTTP Request Data Link Layer Data Link Layer Ethernet IP TCP HTTP Request Ethernet IP TCP HTTP Request Physical Layer Physical Layer

28. Telephone and Access Technologies One-car garage Speck of Dust Grain of Sand Pea Ping Pong Ball Basketball 1980 Modem 300 bps 1990 Modem 9600 bps 2000 Modem 56 Kbps 2000 DSL 1.5 Mbps 2003 Wireless 40 Mbps 2007 Wireless 10 Gbps LAN and Backbone Technologies Note to illustrator: please draw real pictures for these items and partial pictures for the garage, and skyscraper Beach Ball One-car garage Baseball Ping Pong Ball Sugar Cube 1980 128 Kbps 1990 1-4 Mbps 2000 Desktop 10 Mbps 2000 Backbone 100 Mbps 2005 Backbone 10 Gbps WAN and Internet Technologies 50 Story Skyscraper Bicycle Tire Football Ping Pong Ball Pea 1980 56 Kbps 1990 1.5 Mbps 2000 Typical 45 Mbps 2000 High Speed 622 Mbps 2005 High Speed 25 Tbps Figure 1-6 Relative capacities of telephone, LAN/BN and WAN/Internet Circuits

29. Before Next Class Meeting • Think of the following questions: • How do you define the Internet? • What are intranet and extranet? • What are the most popular Internet applications? • What is e-commerce? • How data communications play roles in e-commerce? • How do you explain current economic conditions?