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We can also use the same pictures to get the starting and ending times also. In essence, the calculation for the total number of bytes is the final Ack minus the initial Seq.
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Since the Len=0 when the Seq=1 at the initiation of the session (see the first picture), we can see that the bytes transferred is 152991 – 1, which is 152990 Bytes. To find the amount of data transferred, we look at the Ack when the payload is Len=0, and, in this scenario, the Ack is equal to 152991 in Bytes. This is the clue that its the last packet in the transfer. The final Ack from the server includes Ack=152991 and note that is also has a zero payload with Len=0. Below, we see that with packet 81, we begin the file upload. The first packet in the file transfer is where the Seq=1 *and* we have len>0.
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When using Wireshark, to find the Bytes transferred look at the sequence and acknowledgement fields (when using IPv4). The network throughput calculation is simply:
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