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Time delay for Persistant HTTP

  1. Oct 26, 2013 #1


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    Hello all. I am trying to understand number 2c of this pdf:

    I have tried solving it on my own but I got the wrong answer. I am starting to get irritated.

    How I solved the problem:
    Time for DNS to supply client with IP: RTT1 + ... + RTTn
    Time for client to have initial handshake: RTT0
    Time for client to receive all message: RTT0

    Total time = RTT1 + ... + RTTn + RTT0 + RTT0 = RTT1 + ... + RTTn + (2 * RTT0)

    According to the answer I am missing a RTT0. I have no idea where that extra RTT0 comes from. May someone please help me out?
  2. jcsd
  3. Oct 26, 2013 #2


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    I think I realize why now. Is it because, first you have to request the base HTML file, and it is until this file is received at the client that the client can go on and ask about the objects contained in that HTML file? Hence, two different RTTs will occur.

    Can someone confirm this?
  4. Oct 30, 2013 #3


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    Seems right to me.
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