Telecommunications network model

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Telecommunications network model
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What can I do with Skype?

• Call someones computer.
• Talk to as many as 4 other people at a time with
  Conference calling.
• Call someones phone.
• Do file transfers.
• Instant Message while you talk.

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What do I need to use Skype?

• PC running Windows 2000 or XP
• 400 MHz processor
• 128 MB RAM
• 15 MB free disk space on your hard drive
• Sound Card, speakers and microphone
• Internet Connection (either dial-up minimum 33.6
  Kbps modem, or any broadband cable, DSL, etc.)

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Wide Area Network (WAN)

• Telecommunications network that covers a large
  geographic area

Source Courtesy of Cisco Systems Inc.
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Local Area Network (LAN)

• Connect computers within a limited physical area
  such as an office, classroom, or building

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VPN
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Client/Server Network
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Network Computing

• Networks are the central computing resource of
  the organization
• Thin clients network computers and other clients
  provide a browser-based user interface

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Peer-to-Peer Network
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Problem of The Last Mile

• Network providers use fiber optic to provide
  backbone
• But houses are connected to the backbone via
  twisted-pair
• Cannot get the benefit of the faster, better
  technology

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Wireless Web

• Connect portable communications devices to the
  Internet

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Network Topologies
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OSI TCP/IP Models
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Internet Telephony

• Using an Internet connection to pass voice data
  using IP
• Voice over IP (VoIP)
• Skips standard long-distance phone charges
• skype

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Bandwidth

• Bandwidth
• Frequency range of a telecommunications channel
• Determines transmission rate
• Classified in bits per second (bps)
• Transmission Rates
• Narrow-band low-speed
• Broadband high-speed

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Switching Alternatives

• Circuit Switching
• Switch opens a circuit to establish a link
  between a sender and receiver
• it remains open until the communication session
  is completed
• Packet Switching
• Break messages into groups called packets
• Transmit packets separately