CE80N Introduction to Networks & The Internet

CE80NCE80NIntroduction to NetworksIntroduction to Networks

&&The InternetThe Internet

Dr. Chane L. Fullmer

UCSC

Winter 2002

January 15, 2002 CE80N -- Winter 2002 -- Lecture #4

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New Session HoursNew Session Hours

Jack’s Lounge (1st floor BE)–Thursdays – 7:30 -> 8:30 PM

TA Office Hours–Tuesdays – 6:30 -> 7:30 PM

–Fridays – 1:00 -> 2:00 PM


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HomeworkHomework

Must be turned in during –– Class lecture– Session– TA Office Hour


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Today’s ReadingToday’s Reading

Chapter 8, Internet: The Early Years; Chapter 9, Two Decades of Incredible

Growth; Chapter 10, The Global Internet; Chapter 11, the Information


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The Early Years…The Early Years…

A Multitude of Local Area Network (LAN) technologies exist --– Combinations of :

• Speed, reliability, cost, platform, etc..

– Performance determines cost• High speed costs more

– Platform dependency of Network Interface Card (NIC)

– Not all technologies are available across all platforms, restricting interoperability among certain platforms


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The Early YearsThe Early Years

Many autonomous groups installing independent networks– Allowed them to control access,

policies, etc..– Resulted in a proliferation of LAN

technologies from various vendors.


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LAN technologies are basically incompatible– Electrically:

• Voltage, frequency, speed

– Protocol• Encoding

– Other LAN limitations• distance


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Wide Area Networks (WAN)– First WANs used dialup technology to

form a set of long-haul transmission lines

– Uses a dedicated machine at each local site to unify the transmission lines into a coordinated system


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A WAN differs from a disjoint set of transmission lines because of the inclusion of a special computer (Gateway) at each site that connects to the transmission lines and keeps communication independent of the computers that use the WAN


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WAN

G1

G2

G2 G3


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WANs are expensive to install and maintain– Leased transmission lines– Dedicated hardware

Again, many WAN and LAN technologies were developed, and incompatibilities continued to exist.

WANs are not compatible with LAN technology, and cannot directly interoperate.


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Many WANs and LANs were installed, but machines on the WANs could not access information on the LANs..– Remote access was separated from local

accessA single cohesive network was

desirable.


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US Department of Defense had a similar scenario – lots of autonomous networks that could not interoperate

The DoD funded network research in the early ’70s through (D)ARPA creating various network technologies, including a research WAN called ARPANET.


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ARPANET allowed researchers the opportunity to build a working test-bed for networking ideas.– Solved incompatibility issues– Solved interoperability issues– Created an internetwork of LANs and

the WANs The Internet is born


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ARPANETBackbone

UCLALAN

UCLALAN

MITLAN

MITLAN

UCBLAN

UCBLAN

DARPALAN

DARPALAN

G1

G2

G2 G3


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Internet Software– Internet Protocol (IP)

• Provides basic communication

– Transmission Control Protocol (TCP)• Provides services for applications to

communicate

– The “TCP/IP Internet Protocol Suite”• aka TCP/IP


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ARAPA placed the research and software into the public domain.– All information was freely available to any

person or vendor, allowing them to create devices or networks that would interoperate with the Internet technology.

– Improvements were documented and made publicly available.

– This philosophy is called an Open System


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Internet documentation– On-line and accessible from the Internet– Reports for improvements to the Internet were

initially a two step process• Request for comments (RFC) went out first• Internet Engineering Note came out with the

comments as the final report.

– Today the RFC remains as the definitive documentation for the Internet

• On-line at www.faqs.org/rfcs/– Also www.ietf.org/rfc.html


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The UNIX operating system – Built at Bell Labs in the early ’70s– UNIX given to universities to study– UC Berkeley team added LAN software

• Distributed to others via the Berkeley Software Distribution (BSD) and became known as BSD UNIX (The ancestor of today’s Free BSD)


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ARPA negotiated with UCB to add the TCP/IP suite to the BSD UNIX release.– Gave large number of universities access to

study networking, and deploy it in their departments.

1982 the US Military chose the Internet as its primary communication system.

1983 the ARPANET began running TCP/IP exclusively.


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Incredible growth from day one..– In 1982 ~200 machines were connected– By 1983 the number had doubled– With growth comes the problems..

• Static lists of machines need updated• Limited memory space …• Software updates..


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The Computer Science Network (CSNET)– Sponsored by NSF in early `80s

• Goal was to connect every Computer Scientist in the country over one network.

• CSNET was deployed using TCP/IP and the Internet• By mid 1980s most major university and research

labs were connected to the Internet• Graduate students began to investigate the details of

these new technologies, and include them in their research topics.

– Developed new applications– Extended the technology


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The IAB (Internet Activities Board)– Original controlling body to coordinate

TCP/IP research and Internet development.

• Chairman – Internet Architect• RFC Editor• Formed volunteer task forces to solve

problems– Task forces generated new RFCs


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The IETF (Internet Engineering Task Force)– Originally chartered for short-term

Internet development.– Now is responsible for most of the

Internet technical development• Working groups meet and create the RFCs

– Manet, ipsec, tcp…


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NSFNET– NSF recognized the importance of the

Internet to the scientific community.– Interconnected the supercomputer

centers around the US with a TCP/IP WAN

• Proved useful, but small• NSF looked for ways to improve the ARPA

Internet


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The NSFNET Backbone– 1988 WAN established as main

backbone of the Internet• MCI – long distance transmission lines• IBM – dedicated computers and software• MERIT – network operation


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The ANS Backbone (Advanced Networks and Services)– Consortium of MCI, IBM & MERIT

• Allowed the government to begin privatization of the Internet

– 1992 – WAN was built to serve as the Internet backbone

• ANSNET, 30 times NSFNET capacity


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Exponential growth …….

0

10000000

20000000

30000000

40000000

50000000

60000000

70000000

80000000

1983 1986 1989 1992 1995 1998 2001

ComputersConnected


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By 1999, the Internet was growing so fast that, on average, a computer was added to the Internet every second – and the rate continues to increase.

An interesting fact:– At any time from 1983 through 1999, approximately half the

growth of the Internet occurred in the previous 12 months…

So, after you have been “on” the Internet for only one year, you will have had more experience than half the other users….


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Growth – Good and Bad– Good for vendors– Bad for the IETF

• Predictions of imminent collapse– March 1993, Summer ’97

• Technology improvements have kept up with bandwidth and switching speeds required.


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The Hard limit – Address space– The IP protocol is limited to a number

contained in 4 bytes (32 bits)…

Byte 0Byte 1Byte 2Byte 3

•This limits the number of possibilities to 232 = 4,294,967,296

•There are solutions – IPv6, NAT


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Summary– The Internet began as an ARPA research

project.– The TCP/IP protocol software was developed

to make the Internet operational.– The Internet is an Open System, with the

technology freely available to all.– The Internet documentation is available on-line

in the form of reports known as RFCs.


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Summary (continued)– BSD UNIX distributed TCP/IP suite freely to

universities in the early 80s– 1982 US Military adopted TCP/IP as primary

communication standard– Exponential growth from its inception– IAB formed to coordinate development– IETF - major technical development body

• Working groups


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Summary (Continued)– 1988 – NSFNET Backbone– 1992 – Privatization (ANSNET)– Exponential growth from its inception

• Half of the users today have been there less than one year……

– IP Address 32 bit limitation


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GlossaryGlossaryGlossaryGlossary

ARPA– Abbreviation for Advanced Research Projects

Agency. Backbone Network

– Used to refer to a central network to which many routers connect.


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Internet– The collection of networks and routers

that use the TCP/IP protocol suite and function as a single, large network.

Open System– A non-proprietary technology or

system: any vendor can use the specifications of an open system to build products and services.


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RFC– Abbreviation for Request For Comments.

TCP/IP – Literally, the name of protocols that specify

how computers communicate on the Internet.


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TCP/IP Software– The name of the software that implements the

protocols. Wide Area Network (WAN)

– Any network technology that can span long geographic distances.


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GlossaryGlossary

ANSNET – A major Wide Area Network that formed part

of the Internet in the mid-1990s. Internet Architecture Board (IAB)

– Set policy and standards for TCP/IP and the connected Internet.

Internet Engineering Task Force (IETF) – Responsible for designing and testing new

technologies for TCP/IP and the Internet.


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GlossaryGlossary

Internet Protocol (IP) – Specification for the format of packets computers

use when they communicate across the Internet. National Science Foundation (NSF)

– A U.S. government agency that has funded the development of a WAN for the Internet and helped scientists connect to the Internet.


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GlossaryGlossary National Science Foundation NETwork

(NSFNET)– The Wide Area Network that forms the

backbone of the Internet in the United States.

Operating System – Complex software that manages the

computer, control I/O devices, and provides file storage on multi-user computers.


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GlossaryGlossary

Request For Comments (RFC)– Series of notes that contain the TCP/IP

protocol standards. Transmission Control Protocol (TCP)

– One of the two major TCP/IP protocols. TCP handles the difficult task of ensuring that all data arrives at the destination in the correct order.


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The Global The Global InternetInternet


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The Global InternetThe Global Internet

The Internet was originally sponsored by the US Government (through ARPA).– Efforts concentrated in the US– ARPA experimented with satellite

connections to test the Internet• Norway, England


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Email – the first “killer app”– Began with dialup networks

• UNIX – UUCP (Unix to Unix Copy)• BITNET, FIDONET

– Dialup software could be used from most locations in the world.

• Telephone systems interoperate globally– ITU (International Telecommunication Union)

standards


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European development– Research networks

• JANET (Joint Academic Network)• EARN (European Academic And Research

Network)

EBONE– 1991 – cooperative formed in Europe to

operate a WAN spanning Europe, and connecting to the US Internet


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Figure 10.2 The European Backbone


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1997 – All seven continents are reached by the Internet – including Antarctica.

1998 – Total Globalization is achieved:– Every populated country in the world

has Internet access.


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Infrastructure– New infrastructure makes new

industries possible• Shipping• Railroads• Interstate highway system• Airlines


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Communication Infrastructure– Messengers on foot/horseback– Postal mail system

• Universal delivery– Any individual can send a letter to any other

individual.– The scope of an infrastructure defines a closed

community that shares the benefits it offers.

– Telegraph system• Introduced high-speed delivery.


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Communication Infrastructure (cont)– The Telephone system

• Extended instantaneous communication to individual homes and offices, and allowing interactive conversations.

• Wireless (cell) phones extend instantaneous communication to the individual directly, wherever they may be.


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The Internet Infrastructure– Basic communications facilities are

general purpose• Almost any network application can use the

Internet

– Most of the services available were not invented when the Internet was conceived.

• Web browsers, Real Audio, email…


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Internet Infrastructure– The TCP/IP Suite is the key

• General purpose• Efficient• Flexible• Robust


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The Internet is a global information infrastructure.

Although it offers many services, the Internet’s chief advantage lies in the design of the TCP/IP software that has accommodated changes in computers, networks and services.

(And it has done so now, for 20+ years)


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Summary– Email was the first killer app.– EBONE brought Europe to the Internet– 1997 – Every continent is connected– 1998 – Every populated country is

connected– The Internet is the new infrastructure– TCP/IP is the key to how the Internet works.


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GlossaryGlossary

EBONE – (European backBONE) The Wide Area

Network facilities that interconnected many European countries to one another and to the Internet in the mid 1990s.

BITNET– (Because It’s Time NETwork) An early

network developed at City University of New York.


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GlossaryGlossary

ITU– Abbreviation for International Telecommunication

Union. PTT

– Abbreviation for Post, Telegraph, and Telephone.


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GlossaryGlossary

UUCP– (Unix to Unix Copy Program) Software developed

in the mid 1970s that allows one computer to copy files to or from another over a (usually dial-up) connection.


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GlossaryGlossary

Infrastructure– A service or facility that is fundamental to

society

Documents

CE80N Introduction to Networks & The Internet