Occasional problems joining co-op [Solved]

[Charon]

I've been running co-op successfully for several weeks now, so my port forwarding and such all works.

 

However, I keep running into a frustrating problem where players will get stuck while trying to join. No error message... just a black screen or stuck at 'downloading' until I stop the server and retry. In all cases I myself am able to join immediately. I've always been able to get the missions to work *eventually*, so I know it's not a problem with the .msnbin or the .list files.

 

I'm hosting using dserver. This is not a separate install, rather I'm running both dserver and the game binary at the same time. I'm also always deleting the .mission file before I start the server, so that it serves the .msnbin file instead and we all get faster load times.

 

I've also been updating the .sds file with a script (using sed to replace the mission name), and for a time I thought that might be related, but I encountered this problem today even after updating the SDS file the proper way, using dserver.

 

I thought at one time that this might be due to clients caching the .list file on a per-server basis and so requesting the wrong files, and that I could avoid this by changing the server name each time I started it. But today people struggled to join even with a brand new server name.

 

Sometimes it starts working for them after they restart their game clients.

 

Possibly unrelated, but I've also found that it is common for one or two players to get disconnected in the first 5s or so after joining. When this happens we finish mission, restart the server, and try again.

 

Has anyone else encountered this? Do you have suggestions for troubleshooting steps I could take? Are there perhaps logs I should enable?

Edited October 5, 2023 by Charon

[Charon]

Okay, after spending some quality time with wireshark, I think I've got this sorted out.

 

What seems to be happening is that my ISP (Spectrum, boo hiss) is throttling about 10-20% of upstream TCP traffic down to dial-up speeds. This never happens to downstream connections and this doesn't happen all the time, and their speed test of course shows everything as working great. But as soon as my outbound TCP traffic leaves the local area, there's a chance it gets throttled, and once a  connection gets throttled, it seems to stay throttled.

 

This also manifests as non-spectrum internet speed tests showing an upload speed of only about 50kbps roughtly 10-20% of the time.

 

In game, we see this as players sometimes getting the mission files at 50kpbs or less, and eventually the download times out (or we give up).

 

This seems like such a weird and nonsensical sort of throttling that I don't think this is a policy decision; I suspect their network is just broken somehow (but don't they have monitoring?...). In any case, I wasn't able to get their support to acknowledge a problem.

 

Rather than spend hours on the phone arguing with them, my workaround when I'm hosting is to run all my traffic through a VPN. The server is located here in LA to minimize latency, and it's using OpenVPN+UDP. I'm using AirVPN, since they've got servers here and allow you to forward multiple ports. This gets me off of Spectrum's crappy network ASAP and seemed to work very well. The latency wasn't noticeable in our first outing with this setup.

 

I better solution may be for me to just run my own OpenVPN server, which would be a little cheaper  and let me do without encryption, for better performance. Or maybe I should just get a VPN router to offload all that stuff from the CPU. Or both.

 

----

 

The issue with players getting disconnected after joining I think was separate. I think that was because I'd been too aggressive with the mission start timer. Raising that from 5s to 10s appears to have solved the problem.