Why do we need STP in an ethernet?

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  • 9 years ago
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    You need STP, or Spanning Tree Protocol, to prevent logical switching loops in a physically redundant, switched topology. For example, if you had three switches connected together in a triangle, you would need a mechanism of blocking one of those links to prevent a frame from going through all three switches for all eternity, while at the same time you want all three links to physically exist for redundancy (if one link fails, the switches can all still reach each other).

  • Anonymous
    9 years ago

    I'm assuming you mean Shielded Twisted Pair, as in the type of wire.

    Shielded Twisted Pair wire serves two purposes:

    1) Reduces electrical interference from its own wires (this is what the twisting is for)

    2) Reduces electrical interference from other wires / devices in the area (this is what the shielding is for)

    Generally, as the speed of the data you transmit increases the voltage range decreases.

    For instance, 10Mbps ethernet networks generally use +2 and -2 volts, while 1000Mbps networks use 1, .5, -.5 and -1 volts. The lower the signaling and line voltages are, the more susceptible to interference the line becomes.

    Sources:

    http://en.wikipedia.org/wiki/Twisted_pair

    http://en.wikipedia.org/wiki/Ethernet_over_twisted...

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