Networking theory question can someone please explain to me in a little more detail the three packets that are being sent?: The ability to piggy-back acknowledgements is an even more important efficiency consideration for terminal servers. If you use Telnet with remote echoing and don't do piggy-backing, sending a single character packet results into two packets being sent back (the echo and the acknowledgment) which in return generates a responding acknowledgement. Four packets. If you can do piggy-backing, you can get the number of packets per character down to three (slow typist) or even two (fast typist).