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Bandwidth issues.


Omicron

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So, last time I posted, I described how my (private, friends-only) server has crazy bandwidth draw when people play with Redpower frames... and how deactivating the frame-controlled moving castle gate dropped bandwidth usage for players in the area by over 90%.

Turns out I was wrong. It's not the frames that are having problems. It's the timers that were controlling the frame motors. Anywhere a timer runs, even on relatively slow settings (once per second or slower), bandwidth usage absolutely explodes.

In my area I play with items from Buildcraft, Industrialcraft and Railcraft. There are engines running, pipes pumping liquids, automated carts rolling along and macerators macerating, you know, as they do. Bandwidth usage for my IP is between 5 and 10 kB/s.

My friend uses a lot of Redpower. He has a water generator supplied by buckets via Redpower machinery, controlled by a timer. He has that frame-based moving castle gate, controlled by a multitude of timers (I think it's 4 or 6, I forget). He has a sorting system, again controlled by timers (one or two). With all timers off, his bandwidth usage is comparable to mine. The water generator isn't so bad, by itself.

However, activate the frame timers or the sorting system in addition (much less both at once!), and everything goes to all heck. He'll have bandwidth draws of upwards of 60 kB/s on average, with spikes going far higher the moment the timers fire. It's easy to see if the sorting system is on a 1-per-2-seconds timer speed - the bandwidth graph shows a sharp spike to 120-130 kB/s (ca. my connection's maximum) exactly every 2 seconds, while in between it's more like 30 kB/s. When he has both systems running, or sets the timers on one system too fast, he can't even stay connected. The server boots him with "disconnect.overflow" errors. The same will happen even with the timers set to very slow, if another player decides to visit him. Also, other players will have latency of around 1000ms even if not anywhere near, because the bandwidth is maxed out.

This is really bumming all of us out, since it's basically impossible for him to build what he wants to build, it's impossible for others to play lag-free, and I kind of feel guilty for offering "crappy" service to everyone. Is this really normal and to be expected? I am more than a little surprised that it should be impossible to host Tekkit for even one single player on a 1 MBit upstream, when in the past I've had 8-10 players on a vanilla server without the slightest hitch. That can't be right... can it?

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You'll find timers use surprisingly little bandwidth, its the redalloy wire. Insulated, uninsulated, jacketed - it makes almost no difference. Bundled I believe uses slightly less, but I've not done much testing. Using vanilla redstone dust or having timers directly adjacent to the frame/machine with no wire in between uses the least bandwidth. A rather large factory on my server went from 5mbit/s per player to ~0.5mbit/s by removing all redalloy wire on timer outputs. It only uses bandwidth when it changes state, so slow timers, or signals from buttons/levers are fine to run over redalloy, just nothing that changes state fast.

Hope this helps!

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