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2._Many networks have the following case: the data link layer handles transmission errors by requesting damaged frames to be retransmitted. If the probability of a frame's being damaged is p, what is the mean number of transmissions required to send a fr RRS feed

  • Question

  • 1.      Many networks have the following case: the data link layer handles transmission errors by requesting damaged frames to be retransmitted.  If the probability of a frame's being damaged is p, what is the mean number of transmissions required to send a frame if acknowledgements are never lost?

    Monday, November 9, 2009 3:37 PM

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  • Greetings Nana,

    Here is a solution to your question,

    The probability Pk, of a frame requiring exactly k transmissions is the probability of the first k - 1 attempts failing, pk-1, times the probability of the k-th transmission succeeding,(1 - p). The mean number of transmission is then just

                           

                    kPk =  ∑ k(1-p)pk-1    =  1 / (1-p)

                   k=1    k=1

     

    You can find more information about, how to handle transmission errors here http://research.microsoft.com/en-us/um/people/costa/cn_slides/cn_03-handout.pdf.

    Note: I would like to inform you that, this forum is for Windows Server 2008 Application compatibility and certification issues.

    Hope the above information should help.

    Regards,
    Harish

    Wednesday, November 11, 2009 4:18 PM