Data Link Control Protocols

• ISDN - Integrated Services Digital Network
  • Circuit switched telephone network.
  • Uses Copper Wires of the telephone system.
  • Can deliver two connections at once.
  • 128 kbit/s.
  • It seems that it is not as popular as it once was.
  • It is a data link layer protocol
• DSL - Digital Subscriber Loop (Line)
  • Send voice at 4khz, Data at 25khz
  • Much higher data rates than ISDN
• Cable Internet
  • This is tougher to find information on.
  • My modem uses HFC (Hybird fiber coax)
  • It appears to be a two way system
  • The entire system uses frequency division multiplexing (see page 245)
  • I am a downstream system.
    • My connection is a modulated signal between 50MHz and 1000MHz.
  • Coax Cable is an upstream system.
    • My uplink is a modulated signal between 5MHz and 65Mhz.
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  • This is a shared network, many others are using this at the same time.
  • The cable modem tftps configuration file
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  • It will supply DHCP addresses, as well as Network Address Translation.