Network impact of TCP-option keep alive

Author: (Marvel)

Hi all,

does anyone know or has an assumption about the additional network traffic generated by the "keep alive" (USYS$TCP_PARAMS ka) option?

  • WAN connections from sites having 256 kBit/s to 12 MBit/s and 10-200 clients
  • around 1000 clients are connected to the central site

Is there a possibility to adjust the interval of the keep alive checks?


Thank you




  1. Hello Thomas,

    Possibly the article in

    can answer some of your questions. Even if this article refers to Version 7, it could possibly also be valid for newer versions.




    Author: gypsilon (
  2. Hi Wolgang,

    happy new year and thanks for replying!

    I already stumbled upon this article some months ago but as I understand it mainly adresses this topic related to the implementation on OS/390 - obviously it doesn´t.

    One open questions still then:

    "This interval must be configurable and must default to no less than 2 hours."
    For Uniface I only the find the option to set keep alive on or off (USYS$TCP_PARAMS ka).What is the default in UF 8.4 and is there a way to configure the probe interval on Windows?

    Other topics will be addressed by myself when doing some tests.


    Thank you

    Author: Marvel (
  3. Dear Thomas,

    The configuration of the TCP Keep-Alive Messages is done on Operating System level. In Uniface you can only configure if the TCP path should use keep-alive or not.

    The default of the Keep-Alive Timeout is usally 2 hours and the following Microsoft Knowledge Base Article describes how to tweak the different keep-alive settings (on Windows):

    And here are some additional information regarding the TCP Keep-Alive Messagesfrom the MSDN Library:

    For other Operating Systems (like for example UNIX/Linux) please check the corresponding topic in the OS documentation - or "simply" search on the WWW "library".

    Hope this helps.

    With kind regards,

    *** Usual disclaimer ***


    Author: diseli (