Network Issue

[Andrew Dixon 1073376]

I have an issue with slow response and constant disconnections with vPilot on a networked setup. What I have discovered is the network activity runs at 100% in spikes on the client machine. When this occurs vPilot is very very slow and the connection continually disconnects. At this time wideclient will not connect to FSX. I know this as my 2 computers are connected to the router via a switch and the activity can be observed by the activity lights. Same scenario FSInn and IVAP2 work flawlessly with NO disconnections. This indicates that simconnect is configured correctly as well as the fact that FSInn and IVAP have been working on this setup for years.

What seems to fix this issue is if I pull the Ethernet connection from the client computer and plug it back in the switch into a different socket. It doesn't matter which one just as long as it is disconnected and reconnected. The network activity drops, the lag disappears and wideclient connects straight away. If I shut down fsx and restart fsx again I have the same issue.

For me this is an issue that can be replicated time and time again.

Until this is fixed and the stuttering which I also suffer from, I cannot use this software.

Any advice would be appreciated.

Thanks

Andrew

[Ross Carlson]

Very odd ... especially the fact that moving the plug fixes it. Almost seems like something in your switch is doing some throttling on the packets, and its internal counters get reset when you move to a new port. That's mostly a guess, though.

[Andrew Dixon 1073376]

Very odd ... especially the fact that moving the plug fixes it. Almost seems like something in your switch is doing some throttling on the packets, and its internal counters get reset when you move to a new port. That's mostly a guess, though.

Hi Ross,

I can replicate this time and time again and to ensure this was not hardware related I have reinstalled the network adaptor and changed the switch with the same result. Only occurs with this software. I would be interested to know why the network activity is jumping up and down to 100% usage and when this occurs the problems exist.

To be thorough I have completed flights with FSInn and IVAP with no issues so this indicates a software rather than hardware cause. ASN works via a client as well.

Any ideas, I really want to give this a go.

Andrew

[Ross Carlson]

I'm not sure, but I don't think FSInn and IVAP are pure SimConnect clients ... I believe they still use a module running within FSX to do the actual repositioning of aircraft, even when the UI is running on a separate machine. Not 100% sure about that, though.

 

vPilot sends two packets to FSX via SimConnect for every aircraft, for every simulation frame. So if you have 20 aircraft in the session and your frame rate is 30 FPS, then there will be 1200 packets sent per second. One of those packets updates the aircraft position, and the other requests the ground altitude at the aircraft's current position. (That is used to implement an algorithm that makes sure aircraft are not floating or sunk below the ground when the other pilot is using different scenery with slightly different ground elevation.)

 

When FSX receives the ground altitude request, it will reply with a packet, bringing the total number of packets sent or received per second to 1800. Whether or not this is the reason for the 100% network usage spike you're seeing, I can't say. These packets are very small, so it seems unlikely that they are maxing out your network bandwidth, which I [Mod - Happy Thoughts]ume is at least 100 Mb/s.

 

It's also worth noting that none of the networking stuff is handled by the vPilot code. vPilot simply makes calls to the local SimConnect library, and it is up to that library (written by Microsoft) to handle the networking side of things. vPilot does not know or care that you are connecting to the sim over a network.

 

So, I'm not sure that there is anything I can do to help users that have networking problems, since that code is external to vPilot. It may just be the case that the way vPilot is written (with realtime aircraft position updates every sim frame) is never going to work smoothly when you introduce network latency into the mix.

 

That being said, other users have said that aircraft move smoothly when running vPilot on a networked machine.