Call Delay gets worse and worse with length of call.

Discussion in '3CX Phone System - General' started by Ralph, Aug 15, 2007.

  1. Ralph

    Ralph Member

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    Good afternoon,

    I am having a rather odd problem with delay.

    Calls start out ok with a delay of less then 1/2 second.
    The delay begins getting worse and worse as the call continues till after 5 minutes of conversation you have a 6 second delay and after 10 minutes of conversation you have an 11 second delay. The delay is both directions.

    It goes like this:

    Start of call: Caller1<---less than 1/2 second delay--->Caller2
    5 minutes later: Caller1<---6 second delay--->Caller2
    10 minutes later: Caller2<---11 second delay--->Caller2

    Needless to say this is a major problem for us. Really hasn't been an issue until now most likely because we just switched to VoIP and hadn't made any lengthy calls until now.

    I have implemented QOS and it hasn't seemed to make any difference.

    Logs from one of the calls are below:

    Any help is greatly appreciated.

    Thanks again
     
  2. Ralph

    Ralph Member

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    Wierder still

    I have done a bit of testing.

    If I establish a call and then have the call remain active for several minutes with normal or little traffic the delay gets progressively worse.

    If I establish a call and then put it on hold with music on hold playing the delay does not get any worse when I resume it several minutes later.

    I also noticed that on a couple occassions when a call that has had no traffic had conversation resume the delay got progressively better with increased voice traffic.

    Does 3CX put calls into hibernation or lower their priority somehow if there is very little or no voice traffic? If so how do I disable this feature?

    Do VoIP providers do this?

    Thanks again
     
  3. RobLloyd

    RobLloyd Member

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    Do your phones have silence suppression turned on? Some of them can tell when they hear nothing do not push out any data packets to help keep the calls static free (or something to that effect). Maybe that's what's happening and the delay is caused by it turning on and off.

    Does this happen with all your phones and a softphone?

    Just my .02 worth.....
     
  4. SY

    SY Well-Known Member
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    It is like a "theory of relativity" - time is different for different (VoIP) systems :) .

    Currently MediaServer don't like system where time is faster then on PBX host. (in theory of relativity has speed less than 3CX PBX :) . Next version will be more tolerant even in this case because we investigate relativity more careful :) ).

    Do you run PBX on stand alone host or use Virtual Machine?
     
  5. Ralph

    Ralph Member

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    Problem solved !!! and then some !!!

    Good morning,

    I have been doing some more testing and harassment of tech support at a variety of our providers :lol:

    I was going through the 3CX management console for the millionth time when I read the following under "Edit VoIP Provider":

    It then occurred to me that we have no need to resolve firewall or transfer issues since we use a static public IP and that the delay we were experiencing might be due to additional steps or spooling on the PBX as it delivers audio in addition to everything else.

    So I unchecked the "PBX delivers audio" option for all our lines and voila our call quality jumped 100% (no static at all) and delay completely disappeared :D

    I have been testing this on a variety of calls ranging in length from 20 - 70 minutes so far and the excellent call quality and absence of delay are consistent.

    Take care,
     
  6. SY

    SY Well-Known Member
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    Re: Problem solved !!! and then some !!!

    Good evening :)
    Yes it is a case! As far as your have good environment, could you please help me to perform some tests ? ;)

    Thanks
     
  7. Ralph

    Ralph Member

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    Hi Sy

    Good afternoon Sy,

    I am running 3CX (Free Edition) on a Stand Alone, Windows Server 2003 virtual server. The Virtual Server has 1 Gig of RAM allocated to it and a 40 Gig virtual hard drive.

    It also has its own static public IP.

    So far calls up to 1hour and 30 minutes in length have been fine since implementing the fix above.
     
  8. Ralph

    Ralph Member

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    3 Hours and all is well

    Well I finished a 3 hour conference call (Tech Support) :roll:

    The system worked great, no static, no delay.

    So far so good :D
     
  9. liberars

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    Re: Problem solved !!! and then some !!!

    I have had same problem, and resolved with the same method. Best regards
     
  10. liberars

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    Can 3cx PBX interacted with external scripts

    Hi,
    I' m Developer,
    I would have the necessity to execute script on call in.
    Currently I make this from my client voip (start exe application on DTMF tone, record call in, etc.)
    In the future can 3cx PBX interacted with external scripts?

    Best regard

    Gianfranco
     
  11. SY

    SY Well-Known Member
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    So... Do you use VMWare or (other)"virtual machine" software to start PBX or not?

    Thanks :)
     
  12. liberars

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    Hi, I not use VMware.
    My configuration is:
    PIV 3000
    2Gb ram
    Hd SATA
    PBX run on the other HD.

    I've Test PBX also on the
    PIII 1000
    512 Mb ram
    HD 40 IDE

    Same problem, resolved in the same way.

    Regards

    Gianfranco
     
  13. liberars

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    S.O. XP pro
     
  14. SY

    SY Well-Known Member
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    Please specify maximum delay you reached and for what time.

    Thanks
     
  15. liberars

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    - call in

    - first minute of conversation no delay

    - Between first and second minute of conversation 2 or 3 second of delay

    - After the third minute of conversation the delay it remains stable 5 or 7 second

    Without the flag the delay less than 1 second

    P.S.
    The test has been made a lot accurately more times
    The delay is in in and out
     
  16. SY

    SY Well-Known Member
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    Gianfranco,

    Thanks a lot for your information.
    We are investigating reasons of this situation.

    Anybody has a comments?

    Thanks
     
  17. liberars

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    Hi, SY
    You can explain me exactly what makes the flag PBX delivers audio?

    Regards
    Gianfranco
     
  18. SY

    SY Well-Known Member
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    RTP proxy
     
  19. liberars

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    It seems strange that the audio is succeeded to feel
     
  20. liberars

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    Hi, I am making of the tests the PBX.
    I have noticed that if a client is closed without to carry out the logoff, the call remains hung and remains like bottom of the called new.
    Is normal?

    Regards
    Gianfranco
     

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