COMP429 Computer Network Software Lecture 01: History Jeff Wiegley, Ph.D. Computer Science
Revised: February 1, 2006
[Most of] you have never known a world without the Internet.
1 The beginning a What you perceive to be the “Internet” is a useful collection of applications built on top of networking protocols and technologies that have existed since before you were born. Today this infrastructure supplies a wealth of information and services:
• Weather report
• Encylopedias
• News
• Shopping
• Entertainment
• Research
• Communication aup until now
2 Networking needs The Internet is engineered to be implemented by a wide range of hardware. Individuals have different needs and resources. When deploying a network the following considerations are important:
• Cost
• Features
• Environmental conditions
Variations in needs causes heterogenous solutions and networks.
The Internet is specifically designed to allow such networks to interoperate.
3 A public solution • Open System Interconnection
• The Internet is composed of free technologies
• No company owns proprietary rights or patents to the protocols and specifications that define the Internet.
• All such protocols and Specifications are publicly available and free.
• Thus anyone can build an application or device that interoperates prefectly with the rest of the Internet.
4 Early Research • The US Government recognized the potential of networked systems many years ago.
• DARPA (a US Defense Research Agency) funded research on computer networking in the early 1970’s.
• This reasearch resulted in the TCP/IP Internet Protocol Suite.
• The resulting design of TCP/IP has proven to be robust and reliable – Significant changes haven’t been required for thirty years. – Supports 650 million end points currently.
5 Basic Communication Services: Network Protocols provide the specifications for providing basic communication.
• IP
• TCP
• UDP
• ICMP
• ARP
You can think of these as French, English, German, Cantonese, etc. They are a language but they don’t say anything by themselves.
6 Application protocols Application Protocols use these languages to arrange for communication of content. These includes protocols such as:
• HTTP (Web browser stuff)
• SMTP (email transport)
• FTP (file transfer)
• SSH (remote login)
7 Communication Catagories TCP/IP network communication is subdivided into two catagories:
1. Connectionless Packet Delivery Service (i.e. UDP) • Packets may be lost • Low overhead • Simplistic Design
2. Reliable Stream Transport Service (i.e. TCP) • Packets cannot be lost (without such an event being detected) • Higher overhead • Increased complexity.
8 TCP/IP Characteristics There are other types of networks. What makes TCP/IP unique? • Network Technology independence – Twisted Pair copper ethernet – Optical Fiber – Microwave transmission – 802.11a/b/g wireless • Universal Interconnection – Any two attached computers can communicate regardless of their manufacturer, operating system or hardware. • End-to-End acknowledgments – End points acknowledge each other rather than individual hops. • Application protocol Standards – Services that use TCP/IP, such as SMTP, HTTP, FTP or SSH, are also standardized and publicly available.
9 History • Defense Advanced Research Project Agency (DARPA) Began working toward Internet technology in the mid 1970’s.
• The network protocols took their current form around 1977-1979.
• DARPA used pioneered the use and design of packet switched technology on their military research network ARPANET using leased lines.
• Research was also done using radio and satellit communications.
• Researchers where attracted from many different institutions and companies.
10 Organization • DARPA held regular meetings to share information and ideas.
• This group was known as the Internet Research Group (IRG).
• By 1979 the IRG was so large that an informal committee was established to coordinate and guide their efforts.
• This committee was the Internet Control and Configuration Board (ICCB)
11 Early Architecture • The Internet became a global presence in 1980 when DARPA began converting machines on its research networks to the TCP/IP standard.
• ARPANET became the backbone of this global network.
• In 1983 The Office of the Secretary of Defense mandated that all computers connected to long haul networks use TCP/IP.
• ARPANET was also split into two networks. 1. One for continued research (ARPANET) 2. One for military communication. (MILNET)
12 Funding Expansion • DARPA funded UC berkeley and Unix to incorporate TCP/IP into their products.
• This funding allowed DARPA to quickly incorporate TCP/IP into 90% of the computer science departments at universities.
• Timing was significant since at this time most department were acquiring their second or third computers (main/mini-frames) and connecting them together on local area networks.
13 Berkeley Sockets Berkeley took it one step further.
a • sockets were added to BSD.
Sockets provided application programmers convenient and simple access to the TCP/IP protocols.
This became the de facto standard. aYou will get to know socket programming well this semester.
14 NSF Expansion The National Science Foundation (NSF) joined the effort in 1980
• Goal was to connect as many scientists as possible.
• The CSNET project was established to connect all computer scientists.
• In 1985 they began to establish network access centers around their six supercomputer centers.
• 1986: funded the expansion of a new wide area backbone known as the NSFNET backbone
• Seed money for regional networks was also available.
15 Explosive Growth Within seven years the Internet grew to span hundreds of individual networks throughout the United States and Europe.
• Nearly 20, 000 computers at universities, governments and corporate research laboratories.
• Size and use continued to grow much faster than anticipated.
a • 15% per month by 1987
• Many companies chose TCP/IP for their internal networks even if not connected to the global network.
a535% per year, welcome to compound interest
16 TCP/IP internet protocol suite: TCP/IP did not arise from a specific vendor or professional society.
Q: Who set the technical direction and decided what protocols became standard?
A: The Internet Architecture Board (IAB), formed in 1983 with the ICCB reorganization.
The IAB:
• Provided the focus and coordination for much of the TCP/IP research.
• Decided which protocols were requirements of the TCP/IP suite and set official policies.
17 Production • By mid-1989 the Internet had grown beyond research and into production facilities.
• Thousands of people depended on its use for daily business.
• Laboratory researchers could no longer expect instant acception and use of new ideas.
• The market place began to dominate the evolution of the Internet.
• IAB was reorganized into the Internet Research Task Force (IRTF).
• IAB was reconstituted from a wider audience.
18 IETF • Responsibility for protocol standards was passed to the Internet Engineering Task Force (IETF).
• The IETF is a large group.
• It has been divided into approximately 10 areas.
• Each area has its own manager.
• The chairman and area managers constitute the Internet Engineering Steering Group (IESG).
• These individuals are repsonsible for coordinating the efforts of the working groups.
19 Public Documentation No vendor owns the the TCP/IP technologies.
Q: Who, or where, are the protocols documented then?
A: On-line, free of charge.
Documentation appears in a series of text documents known as Request for Comments (RFCs). RFCs:
• Can be short or long.
• Can cover broad concepts or minute details.
• Can be either proposals or standards
20 RFC Creation • RFCs are now edited by the managers of the IETF and approved by the IESG as a whole.
• RFCs are numbered sequentially.
• Each new RFC is assigned a new number. later RFCs may obsolete earlier RFCs (2822 vs 822 for instance)
• http://www.ietf.org/
21 The future • The Intenet continues to evolve.
• Has moved from being central to decentralized managed.
• Needs to incorporate new concepts and needs. – Traffic patterns – VPNs – Security concerns – Commerce technologies – Social ideas ∗ Voting ∗ Sharing
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