Sync issues: connection, engine or module problem?

Hi there, playing the very awesome Twilight Struggle module (latest vassal+module versions) via the VASSAL server, we started to see sync issues where the GUI between one player and the next was different. We checked the user guide (RTFM? amazing… we complied) and understood the sync concept.

Problem was:

  • we only detected sync loss by a parallel conversation in skype,
  • there was no evidence that the connection to the server had failed (but can’t rule out a brief drop out in our connections),
  • recovery using ‘syncronize’ worked two times in six (after a failed sync, we’d variously restart vassal, rejoin the game, reload the “master” from a save game, reboot our boxen etc) showing something like “sending game state…” - but this would appear several times over a few minutes where the total .vasv file is 60kB.

So my questions:

  • for sync loss, what are the ordered list of most usual suspect: perhaps “connection, actual server, module, engine”?

  • assuming a connection to the server (or peer to peer), shouldn’t it be possible to implement and display sync loss detection?

  • how can we support the cause by collecting logging data to help debug this - and should it be vectored into the vassalengine world or into the module support forums?

  • if a connection to the vassal server is a likely problem, is adopting peer to peer a better bet?

Bit of a vassal n00b, have done the basic search for similar issues in the forum, happy to be directed to a thread explaining all this if I’ve failed in my search. :slight_smile:

Hi Matt,

The other possibility is that there is something wrong with the TS module itself (which seems unlikely given what you’re describing). Just so we can rule that out, can you describe what it is that you saw?

There was a very old version of the TS module where this could happen, but I don’t even think that early version was widely released.

  • M.

On 2011-03-15, at 1:28 AM, zschub mattb@classforge.com wrote:

Hi there, playing the very awesome Twilight Struggle module (latest
vassal+module versions) via the VASSAL server, we started to see sync
issues where the GUI between one player and the next was different. We
checked the user guide (RTFM? amazing… we complied) and understood the
sync concept.

Problem was:

  • we only detected sync loss by a parallel conversation in skype,
  • there was no evidence that the connection to the server had failed
    (but can’t rule out a brief drop out in our connections),
  • recovery using ‘syncronize’ worked two times in six (after a failed
    sync, we’d variously restart vassal, rejoin the game, reload the
    “master” from a save game, reboot our boxen etc) showing something like
    “sending game state…” - but this would appear several times over a few
    minutes where the total .vasv file is 60kB.

So my questions:

  • for sync loss, what are the ordered list of most usual suspect:
    perhaps “connection, actual server, module, engine”?

  • assuming a connection to the server (or peer to peer), shouldn’t it be
    possible to implement and display sync loss detection?

  • how can we support the cause by collecting logging data to help debug
    this - and should it be vectored into the vassalengine world or into the
    module support forums?

  • if a connection to the vassal server is a likely problem, is adopting
    peer to peer a better bet?

Bit of a vassal n00b, have done the basic search for similar issues in
the forum, happy to be directed to a thread explaining all this if I’ve
failed in my search. :slight_smile:


Read this topic online here:
https://forum.vassalengine.org/t/sync-issues-connection-engine-or-module-problem/3749/1


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US played SALT event and cycled the turn clock.
Russian played next card.
US player didn’t see this card play face up on the map as he should have (of?).
Russian player cycled the turn clock.
Still no sign of any change from the US point of view and we had lost sync.

That sounds like the server could no longer see one of the computers. It
could be that someone’s connexion kept dropping. If he had an intermittent
connexion, the sync likely would have failed as well.

Does that sound likely?

  • M.

On 15 March 2011 09:57, zschub mattb@classforge.com wrote:

US played SALT event and cycled the turn clock.
Russian played next card.
US player didn’t see this card play face up on the map as he should have
(of?).
Russian player cycled the turn clock.
Still no sign of any change from the US point of view and we had lost
sync.

It is certainly possible. Perhaps you or some other could suggest:

  • assuming a connection to the server (or peer to peer), wouldn’t it be possible to implement and display to the user sync loss detection (within the vassalengine client and server code) through a heatbeat + CRC of gamestate - or some similar and widely used mechanism ?

  • how can we support the cause by collecting debug log data when running with a suspected problem? is there perhaps a command line switch to feed the JRE?

Cheers,

matt

Hi there!

I would love to play all these games with you. The only one I have played before, is Twilight Struggle, but I actually bought POG, but havent tried it yet, and also, Labyrinth is on the way.

I can play live, or PBEM, doesnt matter!

I’ve had the same issues with Path of Glory this week. To make matters worse the module window takes a long time to show any changes in rooms although if I refresh the server status it shows the correct data. My opponents see my dice rolls but I don’t see theirs.

I upgraded to 3.1.18 from 17 but it had no effect and the module hasn’t changed from 7.2. I can only assume I have connection issues although I certainly can’t detect any, everything works just fine except the POG module…

Regards,

Julian