The Four Forces of the Communications Revolution

1
The Four Forces of the Communications Revolution

• Internet Accessibility
• Bangkok 1999
• Charles Kuhlman
• New York University

2
Why is accessibility an issue?

• The digital and communications revolutions have
  made information pervasive
• Intellectual capital and the service industries
  as engines for growth
• Who can participate?

3
Paradigm Shifts

• The digital revolution
• New transmission modes
• Models of computation
• Circuit switching lt--gt packet switching

4
One The digital revolution

• War, computation and trajectories
• Mechanical computation
• Electrical
• Power of miniaturization and declining cost

5
Digital language

• Reality, analog reality, digital reality
• Bit representation
• Text, visual content, sound
• Infinite reproducibility
• Transmitability

6
Two New transmission modes

• 1700s semaphore signalling
• 1800s telegraph
• all copper
• 1900-1960 telephone
• copper, microwave, fiber
• 1960 All digital

7
All digital media

• Copper
• bandwidth related to gauge, distance and encoding
  scheme
• Radio
• Free air and coax
• bandwidth limited by power and spectrum
• Fiber
• laser and LED driven
• wave division multiplexing

8
Three Models of computation

• Mainframes
• Minicomputers
• Microcomputers
• Client/server
• Browser-thin client/central server

9
Communications and computers

• Terminals--low communication load
• Time-sharing--medium communication load
• Distributed computing--high communication load

10
From the desktop to the world

• LAN
• shared medium ethernet and token ring
• MAN
• metropolitan area network links LANS
• WAN
• wide area network

11
The computer is the network the network is the
computer

• Whether large or small, computers are almost
  never standalone devices.
• Networking is integral

12
Four Circuit switching and Packet switching

• Circuit switching clear permanent path 56/64
  kilobits wide
• Packet switching routed grouping of bits, no
  permanent path.

13
Circuit switching

• TDM Time division multiplexing
• ISDN
• SONET
• Class 5 switches and tandems

14
Packet switching and routing

• ATM -- Asynchronous transfer mode
• IP -- Internet protocol

15
Crossroads issues

• QOS Quality of service
• Switched circuits -- no issue
• ATM -- built-in, 10 overhead
• IP -- none yet. Does it matter?
• Convergence or replacement
• Use existing communications capital
• OR build new communications mode

16
New communications mode

• All IP, all the time
• All fiber, all the way
• All wave division

17
Accessibility challenges

• International organizations in catch-up mode
• Access --infrastructure inadequacy inequality
• Human physical differences
• Intellectual property
• Linguistic diversity
• Economic capacity