Packet switching – the first generation

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History and present

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Packet switching – the first generation

• The end of 1950s

• Cold war at its peak; DoD (USA – department of defense) looks for command and control center that could survive nuclear attack

• During 1960s

• Contract with RAND corporation (still looking for a solution). Paul Baran develops a distributed and fault tolerant system as a basis for packet switching. AT&T thinks it is not feasible.

Structure of telephone systems

Baran’s distributed switching system

Source: Andrew S. Tanenbaum, „Computer Networks“, Fourth Edition, 2003

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ARPANET

• 1967

• Feasibility of packet switched networks

• Donald Davies (at NPL) independently developed packet switching system as a campus network. They referenced work from Paul Baran

• 1969

• (D)ARPA contracted consulting

company BBN to develop that kind of network and necessary software.

Graduate students from the University of Utah developed host software.

Result: ARPANET

Dec 1969 Jul 1970 Mar 1971

Apr 1972 Sep 1972

Development of ARPANET

Structure of packet switched subnet according to Clark

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ARPANET and NSFNET

• 1974

• First ARPANET protocol (Vinton Cerf and Robert Kahn)

• ARPA pushed usage of TCP/IP;

University of California Berkeley

integrated these protocols in Berkeley Unix

• Late 1970s – end of 1980s

• TCP/IP emerged in its nearly final form

• Associated standards were published in 1981

• Form the 1. January 1983 TCP/IP became the only approved part of ARPANET

NSF backbone 1988

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Commercialization of Internet

• During 1980s

• IP addresses becoming more expensive (scarce); development of hierarchical name structure – DNS – domain name system

• Further growth of network (universities, research labs, libraries,…); problems with overload;

NSF contract MERIT (consortium from Chicago) to continue operating the network; upgrade of backbone (56kbps ‐> 448kbps ‐>1.5Mbps)

• Merger of ARPANET and NSFNET followed by many other regional networks (Canada, Europe, Pacific)

• 1990

• First step of commercialization of internet NSFNET donated to nonprofit corporation ANS (Advanced Networks and Services – MERIT, MCI, IBM); further upgrade of the backbone 1.5 Mbps ‐> 45Mbps

• NSF ensures fair competition (through the agreements with PacBell, Ameritech, MSF and Sprint)

• 1995

• ANSNET sold to American Online. Real commercialization of IP services

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WWW

• During 1990s

• Development in other countries EuropaNET and EBONE (started at 2Mbps then upgraded to 34Mbps)

• Until early 1990s Internet was mainly used in academia.

• Everything changed with development of world wide web (WWW) – Tim Berners‐Lee (CERN physicist) and Mosaic Browser Marc Andersen (National Center for Supercomputer Applications in Urbana Illinois)

• Rise of Internet Service Providers – increased number of home computers on the internet (dial‐up service)

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Simplified overview of Internet today

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Wide area data networks – evolution

• 1970s

• X.25 system – connection‐oriented wide area data networks of the first generation. System was used for a decade.

• 1980s

• Frame relay system – mostly used for connections of LANs (even until today)

• 1990s

• Development of ATM (asynchronous transfer mode); the main aim was

transfer of speech, data, cable TV, telegraph using one type of data network.

ATM did not achieved awaited success but it is used for data transport of Internet traffic

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Local area networks

• Early 1970s

• Norman Abrahamson and colleagues from the university of Hawaii developed wireless (short range radio) ALOHANET. They were using computers from

neighboring islands to communicate with main computer in Honolulu

• 1976

• Using previous work from Abrahamson, Bob Metcalfe and David Boggs (Xerox PARC) developed the first LAN, called Ethernet, data rate of 2,94Mbps

• 1978

• Xerox Ethernet is standardized by DEC, Intel and Xerox (10 Mbps Ethernet)

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Local area networks

• 1978 onwards

• Bob Metcalfe founded company 3Com which sold over 100 Millions of Ethernet adapters

• Development of Ethernet (100 Mbps and 1000 Mbps, switching, cabling)

• Token bus and token ring were added

• Middle of 1990s

• Standardization of Ethernet compatible wireless communication network WiFi

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Standardization communities

Telecommunication

ITU International Telecommunication Union

International Standards

ISO International Standards Organization

IEEE Institute of Electrical and Electronics Engineering

Internet standards ISOC Internet Society

IAB Internet Architecture Board IRTF Internet Research Task Force IETF Internet Engineering Task Force

IEEE 802 Working‐Groups

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Overview and conclusion

• Definition of a network

• Scalability (hierarchical aggregation)

• Addressing, routing, forwarding

• Multiplexing

• Layering and protocols (separation of concerns)

• OSI model and Internet (TCP/IP) model

• Latency and bandwidth

• Standardization

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Literature

[PetersonDavie2007] Larry L. Peterson and Bruce S. Davie, „Computer Networks: A Systems Approach“, Edition 4, 2007.

1.2 Requirements

1.3 Network Architecture

1.4.1 Application Programming Interface (Sockets) 1.5 Performance

4.1.1 What is an Internetwork?

4.1.3 Global Addresses

4.1.4 Datagramm Forwarding in IP 4.3.1 Subnetting

4.3.2 Classless Routing (CIDR)

[Tanenbaum2003] Andrew S. Tanenbaum, „Computer Networks“, Fourth Edition, 2003.

1.5 Example Networks

1.6 Network Standardization