Transcript Ch 2 Internet Trends

Department of Engineering Science
ES465/CES 440, Intro. to Networking & Network Management
Internet Trends
http://www.sonoma.edu/users/k/kujoory
References
• “Computer Networks & Internet,” Douglas Comer, 6th ed, Pearson, 2014, Ch 2,
Textbook, 5th ed, slides by Lami Kaya ([email protected]) with some changes.
• “Computer Networks,” A. Tanenbaum, 5th ed., Prentice Hall, 2011, ISBN:
13:978013212695-3.
• “Computer & Communication Networks,” Nader F. Mir, 2nd ed, Prentice Hall, 2015, ISBN:
13: 9780133814743.
• “Data Communications Networking,” Behrouz A. Forouzan, 4th ed, Mc-Graw Hill, 2007
• “Data & Computer Communications,” W. Stallings, 7th ed., Prentice Hall, 2004.
• “Computer Networks: A Systems Approach," L. Peterson, B. Davie, 4th Ed., Morgan
Kaufmann 2007.
Ali Kujoory
5/31/2016
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Topics Covered
• 2.1 Introduction
• 2.2 Resource Sharing
• 2.3 Growth of the Internet
• 2.4 From Resource Sharing to Communication
• 2.5 From Text to Multimedia
• 2.6 Recent Trends
• 2.7 From Individual Computers to Cloud Computing
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2.1 Introduction
• This chapter describes:
– How data networking & the Internet have changed since their
inception
– A brief history of the Internet, highlighting the early motivations
– A shift in emphasis from sharing centralized facilities to fully
distributed information systems
• Later chapters in this part of the text describes:
– Specific Internet applications
– Communication paradigms available on the Internet
– The programming interface that Internet applications use to
communicate
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2.2 Resource Sharing
• Early computer networks were designed when computers
were large & expensive & the main motivation was
resource sharing
– Networks were devised to connect multiple users
• each with a screen & keyboard, to a large centralized computer
– Later networks allowed multiple users to share peripheral
devices
• early networks were designed to permit sharing of expensive,
centralized resources
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2.2 Resource Sharing
• 1960s - Dept of Defense for
Advanced Research
Projects Agency (DARPA or
ARPA) was interested in
finding ways to share
resources
– Researchers needed
powerful computers
• ARPA did the following to
achieve the visionary work:
– gathered some of the best
minds available
– focused them on computer
network research
– hired contractors to turn the
designs into a working
system: ARPANET
• but these computers were very
expensive, &
• ARPA budget was insufficient to
fund many computers
• The research turned out to
be revolutionary
– ARPA planned to
interconnect all computers
with a network &
• devised software that would allow
a researcher to use whichever
computer was best suited to
perform a given task
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2.3 Growth of the Internet
• In less than 30 years
– the Internet has grown from an early research prototype
connecting a handful of sites to a global communication system
– the rate of growth has been phenomenal
• Fig 2.1 illustrates the growth with a graph
– That uses a linear scale in which the y-axis represents values from
zero through 550 million
– Linear plots can be deceptive because they hide small details
• To understand the early growth rate
– Fig 2.2 shows the plot in log scale for the y-axis
– That Internet has had exponential growth for over 25 years
– Internet has been doubling in size every nine to fourteen months
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2.4 From Resource Sharing to Communication
• As it grew, the Internet
changed in two significant
ways:
– 1st, communication speeds
increased dramatically
– 2nd, new applications arose
that appealed to a broad
cross-section of society
– Internet is no longer
dominated by scientists &
engineers, scientific
applications, or access to
computational resources
Ali Kujoory
5/31/2016
• Two technological changes
fueled a shift away from
resource sharing to new
applications:
– Higher communication
speeds enabled
• applications to transfer large
volumes of data quickly
– The advent of powerful,
affordable, personal
computers provided
• the computational power
needed for complex
computation & graphical
displays, eliminating most of
the demand for shared
resources
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2.5 From Text to Multimedia
• One of the most obvious shifts has occurred in the data
being sent across the Internet
• Fig 2.3 illustrates one aspect of the shift
– That Internet communication initially involved textual data
– By 1990s, applications arose that allowed users to transfer images
easily
– By late 1990s, users began sending video clips & full-motion
videos
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2.5 From Text to Multimedia
• Fig 2.4 illustrates that a similar transition has occurred in audio
• Multimedia characterizes data that contains a combination of text,
graphics, audio, & video
• Much of the content on the Internet now consists of multimedia now
• Also, quality has improved as higher bandwidths have made it
possible to communicate high-resolution video & high-fidelity
audio
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2.6 Recent Trends
• New technologies & new applications continue to emerge
• Some of the most significant transitions have occurred as
traditional communication systems moved from analog to
digital, e.g.,
– Voice telephone network & cable television adopted Internet
technology
– Also, support for mobile users is accelerating
• Fig 2.5 lists some of the changes
• One of the most interesting aspects of the Internet arises
– from the way that Internet applications change even though the
underlying technology essentially remains the same
• Fig 2.6 lists types of applications that have emerged
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5/31/2016
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2.6 Recent Trends
Fig 2.5 Example of transitions in networking & the Internet
Fig 2.6 Examples of popular applications
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2.6 Recent Trends
• The availability of highquality teleconferencing
systems such as Cisco's
TelePresence, is
significant for businesses
– because such systems permit
meetings to occur with out
travel expense
• in many businesses travel
expenses have reduced
significantly
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• Some social networking
applications such as
– Facebook, 2nd, Life, YouTube
• Social network apps are
fascinating
– they have created new social
connections - sets of people
know each other only through
the Internet
– sociologists suggest that such
applications will enable more
people to find others with
shared interests & will foster
small social groups
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2.7 From Individual Computers to Cloud Computing
• Internet has brought in another
big change in digital world by
Cloud computing
• In early 2000, companies
realized that high-speed
Internet connections would
allow them to offer
– computing & data storage
services that can be much
cheaper for the user than if the
user implements on their own
• Companies started to become
cloud provider in their large
cloud data centers that
– contains many servers
(computers) & disks connected
to the Internet
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• So users including small
companies contracted cloud
services
• An individual with a smart
phone or a tablet can rent
storage in the cloud to keep
– music, pictures, videos & other
files to access from anywhere
& for back up &
– would not need to worry about
software, hardware, or
maintenance
• Cloud services are elastic
– a customer only pays for
resources actually used
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