Lag on LAN server

[douzeju]

I've set up a LAN server for young relatives and we're trying to play all together.
The server is run on a computer on Linux Mint, and it's really fine, except one of the computers we use has HUGE lag (network latency). I'm talking about 5 to 20 seconds of lag, with highs and lows.
This i could totally understand if everyone was suffering from the same lag, but it's only happening on that specific computer. EDIT: i've tested with several devices and it appears the lag appears for additional players who join a 2 player server (made up of the host and 1 player) whatever their device is.

Any idea of what could cause this problem ? and if we can alleviate it somehow ?
Or ways to pinpoint what's causing this lag ?

[douzeju]

On another note, having a section in the Luanti wiki dedicated to setting up a LAN server would really help ! I could understand some stuff on my own, but a plain step by step would've been easier.
I could help draft an article for the wiki to get the ball rolling if that's possible.

[Linuxdirk]

Setting up a LAN server or a server reachable from the Internet does not differ.

Is the LAN wired or wireless. If it is wireless, do you use a repeater?

[douzeju]

No, it's clearly different ? The wiki says you must download/install/setup stuff all over the place, but instead i only had to share the internal IP address of the device with which i set up the server from within the Luanti client.
Specifically, of all hte information available here (https://docs.luanti.org/for-server-hosts/setup/) only the internal IP address and the port-forwarding was really useful, but never explicitly telling the user where to put that information and what was its purpose.
Unless i'm missing something ? English is not my native language and i may be a bit blind sometimes.

It's wireless and no, we don't use a repeater. To be clear, we're using & smartphone to share an internet connection as a Wifi hotspot, then use 2 other smartphones and 2 laptops to play, one of which also serves as the Luanti server.

[Linuxdirk]

No, it's clearly different ?

It is technically the same. There is no difference in how a LAN server works in relation to how a server works that is accessible from the Internet. In the end you’re running the Luanti binary and giving it a configuration and world to serve.

To be clear, we're using & smartphone to share an internet connection as a Wifi hotspot, then use 2 other smartphones and 2 laptops to play, one of which also serves as the Luanti server.

Any more secrets you forget to mention in your first post? 🤣

Can you try using wired network with a router instead of some weird smartphone hotspot Internet bridging?

Is the device with huge lag somehow using the smartphone’s mobile data?

[douzeju]

It is technically the same. There is no difference in how a LAN server works in relation to how a server works that is accessible from the Internet. In the end you’re running the Luanti binary and giving it a configuration and world to serve.

Yes i know, but really there lots of extra steps that aren't necessarily needed in that wiki, or it's not explained why you need to go through all of them, so i still think a section dedicated to LAN servers should be added.

Can you try using wired network with a router instead of some weird smartphone hotspot Internet bridging?
Is the device with huge lag somehow using the smartphone’s mobile data?

Indeed, all the devices we tried to play with were linked to that smartphone's hotspot. We don't have a router at home so we just made with what we had... now in hindsight this was an interesting idea but might actually have been the problem.
In support of that suggestion, this morning we were somewhere where we could borrow a wifi router's connection, and we did try on that router (still wireless) and with 4 or more devices there was almost no lag. So yeah, this was probably due to us using the wifi hotpsot.
To my defense i really didn't know a wifi hotspot would have a lesser capacity than a regular wifi router - it sounds logical now that i know it.

Thanks Linuxdirk !

Was there a way i could have guessed where the problem came from ? like idk, in-game commands or logs i could read to understand what was going on and causing the lag ?