Consider two hosts, one is located on the west coast of the US and the other is

Question

Consider two hosts, one is located on the west coast of the US and the other is located on the east coast. The speed-of- light Round-Trip propagation Time (RTT) between these two hosts is 20 ms (millisecond). Suppose that they are connected by a channel with the transmission rate, R, of 1Gbps (10A9 bits per second). These two hosts run a pipelined/sliding-window protocol where the size of a packet is 1200 bytes (1 byte - 8 bits), including both header fields and data. How big would the window size at least have to be for the channel utilization to be greater than 70%? You may round up the answer to the closest integer.(Step-by-Step) Justifications:

Explanation / Answer

Here Given

         Round trip time RTT=20 ms

         Bandwidth=109bits/sec

         Size of the packet =1200*8 bits=960 bits

         Here given effieciency is greater than 70%

        Formula for calculating efficiency of Sliding window protocol =N/1+2a

         where a=Propagation Delay/Transmision delay

      Propagation Delay=RTT/2=20/2=10 ms

       Transmision delay=Length of packet/Bandwidth=96000/109=96*10-6seconds

         Effieciency>=70%

        N/1+2a=70/100

      N=0.7(1+2a)

      a=10*10-3/96*10-6=10-2/96*10-6=10000/96=104.16

     N=0.7(1+2*104.16)=0.7(1+208.32)=0.7*209.32=146.52=146

   N=146

Size of window is 146

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