Transcript slides - My FIT (my.fit.edu)

Networking History
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
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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
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History (3)
• Compiled languages made computers more usable
• User access had the model:
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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
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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
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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
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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)
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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
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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
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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
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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
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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
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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
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