What is the difference between an echo and ACK packet?

Discussion in 'OT Technology' started by debosteebo, Oct 15, 2003.

  1. debosteebo

    debosteebo New Member

    Apr 8, 2002
    Likes Received:
    south central la palma
    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).
    Last edited: Oct 15, 2003
  2. crotchfruit

    crotchfruit Guest

    echo is the term for displaying what the client typed.

    local echo = telnet client just displays character on the screen
    remote echo = telnet server sends the character back to the client as "normal text"

    acknowledgement packets are not visible to the user. they are packets acknowledging that data has arrived.

    so if there's remote echo, then there are four packets:

    1. client sends data to server
    2. server acks data
    3. server sends echo character
    4. client acks echo character

    by piggybacking acknowledgements, i believe they are referring to, for example, sending packets 2+3 together... and then even sending packet 4 of one round with packet 1 of the next (if the typer has typed another char during this time.).. reducing the number of "data sends" from 4 down to 3 or 2.
  3. Joe_Cool

    Joe_Cool Moderator

    Jun 30, 2003
    Likes Received:
    crotchfruit beat me to it. ^^What he said.

    Ever get users complaining that their tteellnneett tteerrmmiinnaallss llookkeedd lliikkee tthhiiss?? because they turned on local echo?

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