scp to transfer files from one host to another over the Internet. Assuming that the transfer speed is 2Mb/s, it takes around 1.5 seconds to send 3Mb size between 2 hosts. However, if the file's size is 1Mb, it takes 0.75 second instead of 0.5, i.e. the transfer speed is lower.
Why does this happen? Moreover, is there a way to calculate or predict the time to transfer small file?