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Thread: UDP or TCP?

  1. #1
    150+ Forum Groupie HondaCop's Avatar
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    UDP or TCP?

    Which protocol do you recommend to use? My cockpit setup is made up of 4 clients and 1 server (5 PCs in total), all connected via a 10/100 LAN. All PCs are also connected to each other via Synergy, which allows me to control all clients from my server PC, so obviously, Synergy is also using up network bandwidth.

    Synergy works via TCP.

    Right now, I have SA configured for UDP. I have noticed that every now and then, all clients lose connections to one another. I don't know if it's Synergy causing the problem or SimAvionics.

    What you guys recommend? Should I use TCP for SimAvionics aswell? I have a feeling that the culprit might be Synergy, trying to hog up all network bandwidth.
    Regards,

    Efrain "E" Ruiz (HondaCop)
    LiveDISPATCH @ http://www.livedispatch.org

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    75+ Posting Member MartinK's Avatar
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    Re: UDP or TCP?

    Hi Efrain,

    The answer is more or less already in your question.

    UDP is short for User Datagram Protocol. From a protocolstack point of view it sits at the same level as TCP but compared to TCP it is a lot less reliable because it's missing things like handshaking and verification.

    In more popular words: a datagram means I'll throw the data over the fence and I don't give a monkeys if it ever arrives and/or is understood by the receivers.

    To some extend this can be seen as an advantage since this makes the protocol faster then TCP but he! you win some, you loose some.

    Some vendors of add-on software use UDP but build in their own verification methods. As long as they do this in a more clever way then TCP they have a double edged sword (speed from UDP + reliability like TCP).

    From what you are saying in your message it sounds like SA is losing data while running via a UDP Protocol. This could indeed be caused by a high utilisation of the available bandwith by some other application.

    I have no experience with Synergy but my recommendation would be to (if possible in your config) switch it off (observe the leds on your LAN switch to make sure it's really off) and then try SA again still running over UDP.
    Is SA still loosing data over UDP then reconfigure it to use TCP. I still find it hard to believe that a single application can fill up a 100 Mbps LAN but then again I've seen some more black snow in my professional life.....

    Hope this helps.

    Cheers,

    Martin
    2.6 GHz Intel Core 2 Duo E7200 3 GB Mem ATI HD 3650
    Vista/FS9.1/PMDG747/UTEurope/MEGAX Frankfurt/Cloud9 EHAM

    Flying is easy: move the stick forward - houses get bigger. Pull the stick back - houses get smaller again

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    500+ This must be a daytime job ian@737ng.co.uk's Avatar
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    Re: UDP or TCP?

    hello HC.....
    two things close to home here.
    first i had installed synergy on my network because with 5 PC's all those mice ( or is it mouse's) and keyboards, i reckoned it would be a good option.
    i ended up taking it out and putting back the hardware because using it gave me network issues. with synergy, i kept loosing connections. without it, everything ran smoothly.
    so i tend to agree with martin on this one.
    secondly, martin's description of UDP is perfect TCP may be old hat, but at least it doesn't speak without first being introduced and then only if it is the intended 'target'.
    i would agree that possibly synergy is using too much of the resources.
    for my money, take out synergy (you can always put it back) and move SA to TCP.
    bet you a beer it makes a difference.
    good luck chap.... rgds ... ian
    Mr. Ian. P. Sissons is hereby recognised as an Honorary Flight Sim Captain following his passing in February 2016. This is in recognition for his commitment to Flight Simulation.

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  4. #4
    150+ Forum Groupie HondaCop's Avatar
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    Re: UDP or TCP?

    Ok, lets say that Synergy is indeed the culprit, due to bandwidth hogging. What other alternative do I have, besides having my room look like a bowl of spaghetti with 5 pairs of keyboards and mice?

    Seeing that Synergy is still in alpha or beta stage and it's been like that since 2006, I would say that there must be other good alternatives besides it, with better performance.
    Regards,

    Efrain "E" Ruiz (HondaCop)
    LiveDISPATCH @ http://www.livedispatch.org

  5. #5
    75+ Posting Member MartinK's Avatar
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    Re: UDP or TCP?

    Hi Efrain,

    There is one (hardware) alternative which is a KVM switch. Don't know if they will switch up to 5 PC's but i't's worth investigating.

    On the software front, Synergy is not the only product out there that provides remote control facilities.

    A search through Google gave me a load of alternatives, even freeware.

    Happy googling.....

    Cheers,

    Martin
    2.6 GHz Intel Core 2 Duo E7200 3 GB Mem ATI HD 3650
    Vista/FS9.1/PMDG747/UTEurope/MEGAX Frankfurt/Cloud9 EHAM

    Flying is easy: move the stick forward - houses get bigger. Pull the stick back - houses get smaller again