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Business Data Communications

8/e, John Wiley & Sons 2004, FitzGerald and Dennis

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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)

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Introduction to Data Communications

Topic 1

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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

HackingGreat Global Grid (GGG)Web services Wi-FiWiMAX

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Outlines

A brief history of data communicationsMoore’s lawThe InternetNetwork concepts

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Data Communications

Definitions:Data CommunicationsThe 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.

TelecommunicationsIncludes the transmission of voice and video

as well as data.

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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 telephone1915 - first transcontinental telephone service and first transatlantic voice connections.1947 - transistor invented in Bell Labs1951 - first direct long distance dialing1962 - first international satellite telephone call1968 - Carterfone court decision allowed non-Bell equipment to connect to Bell System Network1970 - permitted MCI to provide limited long distance service in competition to AT&T.1984 - deregulation of AT&T1980s - public service of digital networks1990s - cellular telephones commonplace

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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

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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.

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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)

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Moore’s Law

When: 1965Who: 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.

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AnalysesMoore’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)

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CPU’s Capacity Growth

2000

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Internet, Intranet and Extranet

The Internet: a network of networks servicing the users worldwideIntranet: 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

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The Internet

Three aspects of the Internet evolution Capacity growth Application and traffic growth Internet policy change

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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 1995vBNS+ (now): 2.5 Gbps (or more)

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NSFNET

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

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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.

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

AbilenevBNSCA*Net 3

Today’s Internet

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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

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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.

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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

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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.

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Internet Hosts Growth

(Recent statistics)July 1999: 56,218,000 Internet hostsJanuary 2000: 68,862,283 Internet hostsJuly 2000: 86,509,613 Internet hostsJanuary 2001: 113,873,000 Internet hosts (MIDS)Now: ?

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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.domainEach domain has an addressing board

that assigns addresses for its domain.

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Internet Domain Names Domain Names

EDUCOMGOVMILORGNET

Country CodesCA (Canada)AU (Australia)UK (United Kingdom)DE (Germany)FR (France)CN (China)IN (India)MX (Mexico)

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Components of a NetworkServer (or Host computer)Central computer in the network, storing data or software

that can be accessed by the clients.

ClientThe input/output hardware device at the other end of a communications circuit.

CircuitThe pathway through which the messages travel.

Peer-to-peer networksDo not need a server or host, but are designed to connect

similar computers which share their data and software with each other.

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Components of a Network

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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)

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Types of Networks

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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).

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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.

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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.

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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.

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What is a Protocol?

A standard that allows entities (i.e. application programs) from different systems to communicateShared conventions for communicating informationIncludes syntax, semantics, and timing

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Standardized Protocol ArchitecturesVendors like standards because they make their products more marketableCustomers like standards because they enable products from different vendors to interoperateTwo protocol standards are well-known: TCP/IP: widely implemented OSI: less used, still useful for

modeling/conceptualizing

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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

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*Telecommunication Standards OrganizationsInternational 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).

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*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 proposed standard becomes a draft standard if two or more vendors adopt it

The RFC becomes a proposed standard