Networking History

1. Networking History

2. History (1) • The networks we have today are the result of design decisions made years ago when the computing environment was very different • As these decisions became part of formal or de-facto standards they became harder to change • An understanding of current network design therefore benefits from some review of how we got here.... • In the 1940s the term “computer” referred to a person that operated a mechanical calculator!!! • These calculators became electronic and went through rapid technological change in the 1950s

3. History (2) • These hardware computers became binary-based rather than decimal-based, and generally took on an architecture recognizable today • By the 1960s a large organization might have a single, room-filling computer • The total number of computers in the world in the early 1960s was in the low thousands • Probably fewer in number (and less capable) than you would find today in the cars parked at a large sporting event • A very large organization might have more than one computer and consider “data communication” between them over phone lines

4. History (3) • Compiled languages made computers more usable • User access had the model: • Punch a deck of cards with a program (a “job”) • Submit the deck to the “operators” • Come back later to pick up your deck and the output • Correct errors in your deck and re-submit • “Time-sharing” was introduced during the 1960s • Users paid to “dial-up” these large centralized computers from a terminal using a phone and an “acoustic coupler” • Users interacted directly with the computer for the first time

5. History (4) • The invention of integrated circuits in 1958 meant that smaller computers were possible • By the latter half of the 1960s the minicomputer was making computers available to a larger community because of its lower cost • These were still large, immobile computers but they were only a few equipment racks in size • The microprocessor appeared in the early 1970s • The Intel 8086 appeared in 1978 • Over 35 years ago, yet backward compatibility in the instruction set is still maintained to some extent in today’s Intel chips

6. History (5) • Although other types preceded it, the IBM-PC of 1981 represents the beginning of the personal computer era for many people • 1981 also saw the Osborne 1, a “luggable” computer that was actually designed to be moved around • The late 1980s saw computers that would be comparable in form to today’s laptop computers • In parallel with this computer development thread there was also a network development thread

7. History (6) • By the early 1970s there were enough large computers at various organizations that networking them together was worth the effort • Many were educational institutions with ARPA contracts • ARPANET was created using Interface Message Processors (IMPS) interconnected with 56Kbit serial (phone) lines • The general purpose computer at a site was connected to the local IMP • The rack of equipment in an IMP was equivalent to today’s NIC (Network Interface Card)

8. History (7) • By the mid 1970s development of standardized higher-quality networking protocols and the availability of mini-computers allowed more computers to be interconnected • Universities began building networks local to their campuses as well as connecting to other universities • Note how the development of these protocols occurred when computers were still relatively small in number and did not move • i.e., before the large scale use of PCs, and laptops, and well before tablets and smartphones

9. History (8) • By the late 1970s the NSFNET had been started • This network used the TCP/IP protocol suite from the beginning • It interconnected a few dozen regional networks, which were growing rapidly • NSFNET was eventually connected to the original ARPANET • But the microprocessor-based small computers of the early 1980s were generally not networked together • Cassette tapes and floppy disks provided data transfer

10. History (9) • By the late 80s organizations were connecting their small computers with a variety of vendor-specific protocol suites • Netware, Appletalk, VINES • File sharing within an organization was the driving force • While the ARPANET and NSFNET had grown substantially they remained mostly a network for researchers using email, file transfer, remote login and news forums

11. History (10) • In the 90s the development of the Web and the browser finally gave individuals and organizations a reason to connect their computers to a larger network • As more documents were stored online there arose electronic catalogs for those documents • Documents were delivered by requesting a file download • A web page primarily added the concept of links between documents • Later e-commerce, on-line banking, etc. went beyond the original idea of document retrieval

12. History (11) • This led to a general migration to the TCP/IP protocol suite and to the highly interconnected computing environment we take for granted today • Organizations create private networks for their internal traffic (often using media they don’t own) • Across a security and administrative boundary the private network is connected to a larger public network

13. History (12) • Today cloud computing virtualizes an organization’s datacenter as a service (or platform, or infrastructure) available over the network • In some sense the pendulum has swung back toward the earlier remote computing model with the local device (which could be a mobile smartphone, or tablet, or netbook, or a desktop PC) providing access and a user interface