introduction to computer network1 introduction to computer networks university of ilam dr. mozafar...
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Introduction to Computer Network 3 Agenda To establish a base for future computer network work and study. Review networking technologies, protocols. Finally, prepare to perform some projects in computer networks which are essential in national development, designing and building switches, routers, etc.TRANSCRIPT
Introduction to Computer Network 1
Introduction to Computer Networks
University of IlamDr. Mozafar Bag-Mohammadi
Introduction to Computer Network 2
Outline Agenda Policy, Grading, reading materials, etc. Communication. Overview and history of the Internet
Introduction to Computer Network 3
Agenda To establish a base for future computer
network work and study. Review networking technologies, protocols. Finally, prepare to perform some projects in
computer networks which are essential in national development, designing and building switches, routers, etc.
Introduction to Computer Network 4
Course Materials Course Web page
visit regularly Textbook
مهندسی اینترنت، احسان ملکیان، انتشارات نص “Computer Networks, A system approach”. Peterson & Davie
3rd edition
Introduction to Computer Network 5
Prerequisition
General knowledge in Computer. Fluency in English, specially reading. C programming. Knowledge of UNIX (LINUX) system and
programming.
Introduction to Computer Network 6
Communication as need.
Base of community Collection of trees is not a community.
Transferring data, knowledge, experience among people Base of civilization.
Psycological need. Love, affection. Just talking. Releasing someone. Base of Culture.
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Primary Communication means
Language Conventions
Body Language, Meta language. Universal.
Problems: Limited in Time and space. We are struggling all the history to overcome
these limitation.
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Communication elements Producer, Sender
Speaker Consumer, Receiver
Listener They both do processing and have limitation Message- Talk Transfer media, like air
Substance Capacity Delay
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Type of communication One to one
Direct talk. One to many
Talks, conferencing Many to Many
Like mass media, newspaper. Domain of communication
Small, primary society Medium, more developed society. Large, more advance society.
Introduction to Computer Network 10
First Step- Writing One of the most important human being
invention. (Why?) Overcome the primary limitations.
Time: By writing it down. Space: Distributing more copies, library, post, etc.
Problems: Indirect Communication, Through paper. Slow in producing and consuming Need proficiency Encoding message
Introduction to Computer Network 11
Next Step- Mailing Distribute messages as fast as and as far as
possible. Overcome mostly space limitation, while widen
the domain of communication. Media- human being network system. Indirect communication. Encoded message Slow.
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New wave- Telegraph In 1837, Samuel B. Morse invented it. Text message is encoded by dot and dashed
(binary, digital system). Message switching, human coding for efficiency,
and hop by hop routing. Fast transmission, (Time limitation) Slow production (25-30 word/min) The daily Telegraph.
Introduction to Computer Network 13
Telephone In 1876, While working on multiplexing telegraph,
invented By A. Graham Bell. One to one, completely real time communication. No need to proficiency. Fast, (time limitation) Easy to use or produce data. Exponential growths, 1000 in 1877 to 50,000 in
1880
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Broadcast media Printing, newspapers,
Easy to reproduce the same data. Easy to distribute message. Slow in producing and contribution.
Radio Easy to distribute message. Fast in producing and contribution of message. Limited of type of message, only voice.
TV All like radio, but with richer data.
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Computer Network Fast in producing, processing, distributing and
consuming messages. No limitation in time and space. Support different type of communication.
Mass media, news group. One to many, mailing list. One to one, mail, chat, talk.
Support of different type of message, data Only problem, need proficiency.
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History of the Internet 70’s: started as a research project, 56 kbps, < 100
computers 80-83: ARPANET and MILNET split, 85-86: NSF builds NSFNET as backbone, links 6
Supercomputer centers, 1.5 Mbps, 10,000 computers 87-90: link regional networks, NSI (NASA), ESNet(DOE),
DARTnet, TWBNet (DARPA), 100,000 computers 90-92: NSFNET moves to 45 Mbps, 16 mid-level networks 94: NSF backbone dismantled, multiple private backbones Today: backbones run at 2.4 Gbps, 10s millions computers
in 150 countries
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Growth of the InternetNumber of Hosts on
the Internet:Aug. 1981 213Oct. 1984 1,024Dec. 1987 28,174 Oct. 1990 313,000 Oct. 1993 2,056,000Apr. 1995 5,706,000Jul. 1997 19,540,000Jul. 1999 59,249,900Jul. 2001 117,288,000
1101001000100001000001000000100000001000000001000000000
1981 1984 1987 1990 1993 1996 1999
Data available at: http://www.netsizer.com/
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Recent Growth (1991-2000)
Introduction to Computer Network 19
Services Provided by the Internet Shared access to computing resources
telnet (1970’s) Shared access to data/files
FTP, NFS, AFS (1980’s) Communication medium over which people interact
email (1980’s), on-line chat rooms, instant messaging (1990’s)
audio, video (1990’s) replacing telephone network?
A medium for information dissemination USENET (1980’s) WWW (1990’s)
replacing newspaper, magazine? audio, video (1990’s)
replacing radio, CD, TV?
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Today’s Vision Everything is digital: voice, video, music,
pictures, live events Everything is on-line: bank statement,
medical record, books, airline schedule, weather, highway traffic, toaster, refrigerator …
Everyone is connected: doctor, teacher, broker, mother, son, friends, enemies
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What is Next? Electronic commerce
virtual enterprise Internet entertainment
interactive sitcom World as a small village
community organized according to interests enhanced understanding among diverse groups
Electronic democracy little people can voice their opinions to the whole world little people can coordinate their actions bridge the gap between information haves and have-not’s
Electronic terrorism hacker can bring the whole world to its knee
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Industrial Players Telephone companies
own long-haul and access communication links, customers
Cable companies own access links
Wireless/Satellite companies alternative communication links
Utility companies: power, water, railway own right of way to lay down more wires
Medium companies own content
Internet Service Providers Equipment companies
switches/routers, chips, optics, computers Software companies
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Commercial Internet after 1994
NSF Network
Regional ISP
America On Line
IBM
BartnetCampus Network
Joe's CompanyStanford
Xerox Parc
Berkeley
NSF Network
Internet MCI
UUnet
SprintNet
Modem
IBM
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BackboneISP ISP
Internet Physical Infrastructure
Residential Access Modem DSL Cable
modem Satellite
Enterprise/ISP access, Backbone transmission T1/T3, DS-1 DS-3 OC-3, OC-12 ATM vs. SONET, vs.
WDM
Campus network Ethernet, ATM
Internet Service Providers access, regional, backbone Point of Presence (POP) Network Access Point (NAP)