Steam bypassing ISP speed cap?!

[On_Point]

Hi guys, I recently upgraded to an "unlimited data" package with my ISP. Unfortunately, they severely cap the speed on unlimited data packages, which means you can't download much anyway.
I'm using a 4G router connected to my pc with ethernet, which gave me 40mbps or more, and now I'm getting 4mbps.
Now the speed appears the same on speedtest.net, on torrents, on uplay, downloading from websites etc
But somehow Steam seems to be getting around this cap. I'm getting full speed when downloading from Steam.
Does anyone know how Steam is able to do this? And is it possible to replicate that everywhere?

 

[Janus67]

I assume it's the ports that it uses aren't capped by the isp.

 

[On_Point]

I assume it's the ports that it uses aren't capped by the isp.

Any idea what ports steam uses for downloading? And is there anyway to get other applications to use them?
I tried changing my port to 80 and 443 while using torrents, and it made no difference.
What's even more confusing is, that they limit bandwidth for torrents, Netflix, telegram etc to 1mbps, but using a VPN gets around that.
But the VPN doesn't do anything for the overall cap, but steam somehow does it.

 

[Niku-Sama]

To log into Steam and download content:

• HTTP (TCP remote port 80) and HTTPS (443)
• UDP remote port 27015-27050.
• TCP remote port 27015-27050.

My guess is its using multiple data streams over multiple ports for the same files. it sounds like your ISP or maybe just your router is limiting each connection to places individually?
what are you paying for in terms of speed?

 

[EarthDog]

Depends on where you're DLing from I'd guess... Steam always lets my service (Gig) max out. I don't recall offhand if UPlay, Origin, Ubi do offhand...........

 

[On_Point]

My guess is its using multiple data streams over multiple ports for the same files. it sounds like your ISP or maybe just your router is limiting each connection to places individually?
what are you paying for in terms of speed?

I'm paying like $20 for this package. But having unlimited data capped at 4mbps is not great. Especially because when I had limited data (about 200gb a month) there was no cap on the speed.
I could get the maximum speed available on the 4G network. (this speed changes depending on the network load at that time)

Post magically merged: Mar 22, 2023

Depends on where you're DLing from I'd guess... Steam always lets my service (Gig) max out. I don't recall offhand if UPlay, Origin, Ubi do offhand...........

It's definitely can't be the download location. My package speed is capped at 4mbps, but Steam is bypassing it and giving me the maximum speed the ISP can provide lol
And as I mentioned, it's only on Steam. All other places I download from is speed capped.

 

[FoldingAddict]

I'm not a network engineer but I was intrigued by why you might be experiencing this so I loaded up Wireshark to see what packets looked like while downloading from Steam vs. downloading from Nvidia for example.



From the two images, top being downloading from Steam and bottom downloading a driver from Nvidia on Edge. The big difference I see is Steam is connected to and pulling large amounts of data from three different servers at once, those 162.254.193.13/162.254.193.36/162.254.193.39 addresses. Downloading from Nvidia is connecting to a single server at a single address. The only way I can think of to create more connections to download from a website is using a download manager. I haven't used one personally since the 56k days, but I remember back then the program would open multiple connections to the same server to "boost" download speeds. Whether that actually did anything on a 56k modem I have no idea.

Anyway, it might be something that's worth a test. If the way around this throttle is to have multiple connections to multiple servers, rather than just multiple connections to the same server, you're screwed.

 

[On_Point]

I'm not a network engineer but I was intrigued by why you might be experiencing this so I loaded up Wireshark to see what packets looked like while downloading from Steam vs. downloading from Nvidia for example.

View attachment 361266View attachment 361267

From the two images, top being downloading from Steam and bottom downloading a driver from Nvidia on Edge. The big difference I see is Steam is connected to and pulling large amounts of data from three different servers at once, those 162.254.193.13/162.254.193.36/162.254.193.39 addresses. Downloading from Nvidia is connecting to a single server at a single address. The only way I can think of to create more connections to download from a website is using a download manager. I haven't used one personally since the 56k days, but I remember back then the program would open multiple connections to the same server to "boost" download speeds. Whether that actually did anything on a 56k modem I have no idea.

Anyway, it might be something that's worth a test. If the way around this throttle is to have multiple connections to multiple servers, rather than just multiple connections to the same server, you're screwed.

Thanks for doing this, this is actually very interesting. I think Steam is getting around this by connecting to multiple connections to multiple servers because even on speedtest.net the max speed I get is around 4mbps. And that's only connecting to one server. I just tried using JDowloader to download a file using multiple connections, and the speed is still capped. But what's confusing is how torrents are also capped. Doesn't torrents use multiple connections to multiple peers?
And as I said before, they actually throttle torrents, which they state in the package. So my normal speed is 4mbps, but torrents can only get like 1mbps. VPN gets around that throttle, but not the actual speed limit for my package.

 

[FoldingAddict]

I'm not really sure how you would tell or find out without asking the right person at the ISP. Maybe they throttle certain types of traffic? Maybe Steam is lying to you somehow? I really don't know. You're right though it wouldn't make sense for torrents to be speed capped if the key to success here is just multiple connections to different servers to get the same file downloaded. What network throughput does task manager show while you're downloading from Steam?

 

[Niku-Sama]

i cant imagine unlimited data at 4 mbit a second being a thing unless you get X amount of data at high speed and then it throttles. that might be something to ask them too

 

[stompah]

Maybe Steam uses your ISP for some business and in their contract (or as a courtesy) they do not cap those downloads?

 

[EarthDog]

I'm not really sure how you would tell or find out without asking the right person at the ISP. Maybe they throttle certain types of traffic? Maybe Steam is lying to you somehow? I really don't know. You're right though it wouldn't make sense for torrents to be speed capped if the key to success here is just multiple connections to different servers to get the same file downloaded. What network throughput does task manager show while you're downloading from Steam?

I wonder if the torrent app 'pulls' the multiple streams together under one ip/port? It would be interesting to see his torrent app with Wireshark.

 

[On_Point]

I'm not really sure how you would tell or find out without asking the right person at the ISP. Maybe they throttle certain types of traffic? Maybe Steam is lying to you somehow? I really don't know. You're right though it wouldn't make sense for torrents to be speed capped if the key to success here is just multiple connections to different servers to get the same file downloaded. What network throughput does task manager show while you're downloading from Steam?

I don't think Steam is lying because I downloaded a game, which would not download that fast if it was 4mbit.

i cant imagine unlimited data at 4 mbit a second being a thing unless you get X amount of data at high speed and then it throttles. that might be something to ask them too

I have the middle plan...4Mbps Rs.5777 Postpaid package.

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I wonder if the torrent app 'pulls' the multiple streams together under one ip/port? It would be interesting to see his torrent app with Wireshark.

I do have Wireshark, but I'm not really sure what I should be looking for. Do you want me to put up a small video?