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VR network grinds to a halt after 25mins

Last response: in Networking
September 28, 2010 1:01:09 PM

Hello. We have 3 PCs on a LAN running a 3D game simulation with Virtual Reality 6DoF tracking data being sent across the network, moving VR entities around in the game.

After 20 minutes, the frame rate begins to drop, which is more noticable when activitiy is greater (aircraft baking, gun being fired with ground strikes kicking up).

After 25-28 minutes, the game freezes completely.

If you yank any of the ethernet cables, the simulation unfreezes and continues as normal, full frame rate. Plug the cable back in - within a few seconds, it completely freezes again.

Restarting the game mission frees everything up again, and works as normal for another 25mins.

We have tried the following:

* used WLAN instead. This sped up the freeze to the 12 minute mark.
* ran a different mission with only 2 PCs and less entities. This took over 60 minutes to begin slowing/freezing.
* replaced router, cables - no change.
* note that we have updated NIC & graphics drivers.

Any suggestions would be greatly appreciated.

The PCs are all Toshiba A500/02J latops running Windows 7 32bit. The NICs are Realtek PCIe GBE Family Connectors.

Thank you for your time.
September 28, 2010 5:42:34 PM

Excessive chatter. Your router may not be handling it nicely. Have you tried adding a switch in after the router and all computers connecting to the switch? (Not the switch in the router though)

What protocols do you have installed on the NICs?
September 29, 2010 9:13:12 AM

The 3 notebooks are connected to a 1gb Switch. Apologies, I misstated - there is no router.

Installed protocols:

Link-layer Topology Discovery Mapper I/O Driver
Link-layer Topology Discovery Responder
September 29, 2010 8:44:37 PM

Whatever computer is hosting the VR, I would run some performance counters against it or keep an eye on the performance of the network. The game sounds somewhat intensive.

Does the computer meet the specs required to host the VR? Generally, a single computer hosts the game and the other computers download little and upload litte to the host. This keeps traffic at a minimum and each computer hosts the environment, only taking a small delta change of user input.

With that, how does it run on a single computer? Add in another computer. Keep an eye on the network connection and see when it starts the fail. It could be waiting for an ACK from the other computers.

If you can, try setting your NICs to 1000/Full to maximize use of the network.