Possible solution to COOP "lag" or desync

His upload speed is max 40kb/sec... if the game requires more than that they might as well remove the COOP campaign as many connections around the world still offer less!

Here in Australia the fastest upload connection available to normal customers is 118kb/sec.... this is the connection I have and ARMA2 was using 140+kb/sec .... so there is definitely a problem! The game should not try to use this much bandwidth after the initial handshake and data sync.

The desync issues does not "settle down".... it continues and is not fixable, there is no workaround we could find. Pings are low.

The desync occurred in campaign mission Razor Two, which does not have many AI going at it... and its more evident in Manhattan which has more AI. The desync occurs at the very start when there is no fighting and only a few AI in the base.

The Host is on a 4ghz Dual Core, cant really get faster than that without going i7.... its WAY above recommended specs :)

Yapa

With all due respect, 40k upload is seriously low and if anything else on the network is using any connectivity online it's clearly going to get a lot lower than that.

However, having said that you're now confusing me. You have poor upload speeds yet pings are low? I assume you mean the pings are good? How good?

To put some perspective in place, I host Arma2 on a 3.16ghz C2D with 2GB of system RAM and aside from initial connects/game starting up there are no ping or desync problems whatsoever. Now, i'm on a 20mb down/750k up cable connection so system spec is clearly not the problem.

It's going to be down to a combination of mission content and network connectivity i'm afraid. If I have a lesser spec server running on a better spec network, it's clearly not a server spec problem (in your case).

Pings are less than 40ms, about 36 to 38ms.

Your connection is very good, is this a consumer based connection or business grade? Here in Australia the fastest connections are ADSL2+ based with uploads capped at 1mbit/second.

Does your server host campaign or other MP mode? Hosting a warfare game results in no lag... its the campaign in COOP.

Guys the lag bursts appear even on the LAN(as a local game, not internet), doesn't matter which you use it seems. It seems the host computer is not prioritizing the networking thread enough and the AI processing or some kind of campaign only script just snuffs it out. I don't know but I bet it has something to do with their scheduling. I have 2 gigabit computers connected over cat 5 in the same room, still get the lagging occasionally. It is exactly how you describe, the non-host computer everything freezes and people walk in place. Then it jumps back eventually.

Prehaps it is possible to use the mp bandwidth settings in the profile\arma.cfg file. I bet it works.

MaxMsgSend=1024; //(512)

MinErrorToSend=0.0025; //(11 for linux box)

MaxSizeGuaranteed=1024; //(512)

MaxSizeNonguaranteed=1400; //(384)

MinBandwidth=10240000;

MaxBandwidth=20480000;

It is clearly not a connection problem. I've been experincing the extreme desynch on a 10-megabit connection. Also: The desynch seen in the campaign (especially Manhattan) isn't possible to create in normal MP mode. There are locality problems in that mission that cannot be explained with simple lag/desynch.

Example: If I play as a host I can sometimes see my squad buddies acting as if they were regular AI bots (following my lead and obeying orders). But since my squad buddies are actually human players they have a totally different experience on their machines. They cannot see firefights that we're involved with together (on my computer). One person may see himself sitting in a vehicle and driving idly along the road while the other clients see him running around outside the vehicle etc. If this was a question of simple desynch the misplaced character would eventually snap back to his/her correct position. Causing the jerky lag movement correction seen in many online games. But in the ArmA2 campaign this continues for hours. It's as if the client and host were playing two different missions and not the same one.

It seems as if this problem isn't on the top of the developer's priority list right now. I suppose that means that the MP campaign will thus remain what it was to begin with: A good idea - and nothing else.