1'1 Data Communication

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Chapter 1
Introduction
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1.1 Data Communication
Components Data Representation Direction of
Data Flow
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Figure 1.1 Five components of data
communication
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Figure 1.2 Simplex
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Figure 1.3 Half-duplex
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Figure 1.4 Full-duplex
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1.2 Networks
Distributed Processing Network
Criteria Physical Structures Categories of
Networks
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Figure 1.5 Point-to-point connection
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Figure 1.6 Multipoint connection
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Figure 1.7 Categories of topology
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Figure 1.8 Fully connected mesh topology (for
five devices)
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Figure 1.9 Star topology
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Figure 1.10 Bus topology
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Figure 1.11 Ring topology
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Figure 1.12 Categories of networks
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Figure 1.13 LAN
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Figure 1.13 LAN (Continued)
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Figure 1.14 MAN
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Figure 1.15 WAN
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1.3 The Internet
A Brief History The Internet Today
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Internet

• Network Access Points (NAPs), where individual
  ISPs would interconnect, as suggested in the
  previous Fig. The NSF originally funded four such
  NAPs Chicago (operated by Ameritech), New York
  (really Pensauken, NJ, operated by Sprint), San
  Francisco (operated by Pacific Bell, now SBC),
  and Washington, D.C. (MAE-East, operated by MFS,
  now part of Worldcom).
• The very High Speed Backbone Network Service, a
  network interconnecting the NAPs and NSF-funded
  centers, operated by MCI. This network was
  installed in 1995 and operated at OC-3 (155.52
  Mbps) it was completely upgraded to OC-12
  (622.08 Mbps) in 1997.
• The Routing Arbiter, to ensure adequate routing
  protocols for the Internet.

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Internet
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Internet today
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Figure 1.16 Internet today
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1.4 Protocols and Standards
Protocols Standards Standards
Organizations Internet Standards