business data communications
DESCRIPTION
Business Data Communications. Course organization. Course WWW site. http://web.missioncollege.edu/drjrole http://roletech.esmartdesign.com http://www.redrival.com/roletech http://www.course.com. Organization of the Textbook. Introduction to Data Communications. - PowerPoint PPT PresentationTRANSCRIPT
1
Business Data Communications
2
Course organization
3
Course WWW site
http://web.missioncollege.edu/drjrole http://roletech.esmartdesign.com http://www.redrival.com/roletechhttp://www.course.com
4
Organization of the Textbook
5
Introduction to Data Communications
6
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
7
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.
8
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
9
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
10
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.
11
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)
12
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.
13
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)
14
CPU’s Capacity Growth
2000
15
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
16
The Internet
Three aspects of the Internet evolution Capacity growth Application and traffic growth Internet policy change
17
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)
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
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: ?
20
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.
21
Internet Domain Names Domain Names
EDUCOMGOVMILORGNET
Country CodesCA (Canada)AU (Australia)UK (United Kingdom)DE (Germany)FR (France)CN (China)IN (India)MX (Mexico)
22
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.
23
Components of a Network
24
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)
25
Types of Networks
26
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).
27
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.
28
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.
29
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.
30
*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).
31
*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