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AT&T Wireless traffic shaping apparently making some websites unusable

adriano.fyi

111–120 of 305 posts

Re: AT&T Wireless traffic shaping apparently making some websites unusable

#111
Taking a quick 5 minute look at the packet capture attached to the post, it looks to me like this is likely traffic shaping. While it's always difficult to be 100% sure from just the client side capture, the capture looks relatively clean of errors, and the amount of data in flight doesn't appear to even approach the advertised window. We're getting some merging of segments likely from a segment offload, but I doubt that's throwing off the results.

So there's a good chance there's a shaper letting through about 320kbit/s as it's relatively even throughout the capture.

Re: AT&T Wireless traffic shaping apparently making some websites unusable

#112
post #89

Earlier quoted context omitted.

> Said the other way around: fast.com is great to see actual throughput from Netflix as opposed to some fake throughout from a dedicated speed test site for the exact same reason. Yup. This is pretty much the reason Netflix created fast.com. They wanted a speed test service that couldn’t be gamed by ISPs. Many ISPs will prioritise traffic to know speed test services (like Ookla’s speedtest.net), making their services…

Couldn't ISPs just sniff the SNI hostname to differentiate fast.com vs actual Netflix video streaming?

You can think of the requests to fast.com as just loading the speed test control scripts and user interface. The actual speed test loads files from the same servers (with the same SNI hostname) used by actual Netflix video streaming. It wouldn't surprise me at all if the fast.com speed test loads real streaming video segments from these servers, the only difference being that it doesn't have the decryption key for these videos.

Re: AT&T Wireless traffic shaping apparently making some websites unusable

#113
post #55

Earlier quoted context omitted.

I think the era of traffic shaping as you describe it is no longer. Most connections are encrypted these days, a good thing. But that also means, me as an ISP in the middle, I only see the layer 4 packet. So I know where a packet is coming from and where it's going (and ttl and some other not really helpful data for this purpose.) I don't even know the port. So I'm left with doing (dumb) traffic shaping by destinatio…

So I had this conversation with one of the traffic shaping vendors many years ago. At the time when encryption still wasn't that common, they didn't sound too worried about the shift to all encrypted connections. Their product was already starting to use a behavioral analysis to shape the traffic most of their customers were interested in. So to detect bittorrent, they'd build a profile about how many bit torrent cli…

This is great insight. Thank you for that.

I imagine lots of people are or have spent lots of money and time trying to figure out the type of data or connection from patterns as you say.

A more nuanced and correct statement would have been to say that it's much harder to do than it used to be, when you could just look at the mime-type or similar to figure out what to throttle.

Re: AT&T Wireless traffic shaping apparently making some websites unusable

#115
post #66

Earlier quoted context omitted.

I used Google Fi for a while, and while I'd love to use them as a primary carrier again, I can't until they choose to support add-on SIMs for watches. As a Google Fi and YoutubeTV customer, I cannot wait until I no longer have to give AT&T any money at all.

The only thing with Fi is that it is T-Mobile, and you'll always be in a lower priority block of customers compared to people paying for T-Mobile directly, which mean you'll see slower traffic in congested areas at peak times (including e.g. during rush hour traffic).

Thats not true, Google Fi has the same priority as postpaid T-Mobile. This is something MVNOs negotiate in their contracts with carriers, not something thats true across the board.

Discount MVNOs increase their margins by buying wholesale deprioritized data while Google Fi has negotiated the no deprioritization.

Re: AT&T Wireless traffic shaping apparently making some websites unusable

#116
post #38

When I had AT&T VDSL they had weak peering. Some traffic that should have gone across town would routinely get routed several states away before coming back to town, because they hadn't peered with the local exchanges. Some traffic was ok. When I switched to an ISP with local peering, ping times between my home and my server downtown dropped to a few milliseconds. It's like being on my LAN. If this is still an issue…

Yep. I'm still on AT&T's ADSL (what used to be known as Uverse) and routinely get routed through Chicago rather than Detroit (I live 30 mi north) for major services like Cloudflare. Of the two choices I have for ISP, AT&T or Comcast, only AT&T has such poor routing. AT&T Fiber apparently has better peering but their supposed expansion hasn't happened in my area yet.

Re: AT&T Wireless traffic shaping apparently making some websites unusable

#117
post #83
post #51

Earlier quoted context omitted.

I never thought about this much, but what's interesting is that there's a missed opportunity for collaboration here. I think most ISPs throttle known streaming sites (netflix, youtube, etc.) by default for mobile plans. Some even advertise it [1]. And really what the ISPs have noticed is that if you throttle the throughput, the streaming services will switch to a lower quality stream (e.g. 720 or even 480 instead of…

> The two could have just worked together on a solution. We do...? Google Global Cache [0] and Netflix Open Connect [1] are both the result of ISP partnerships wherein we deploy cache nodes in the ISP's datacenter to reduce network load and improve our users' viewing experience. Whether a specific ISP chooses to partner with us or not (and the breadth of their deployment) depends on their willingness to sign the rele…

I didn't know about that. That's cool.

Re: AT&T Wireless traffic shaping apparently making some websites unusable

#118
post #55

Earlier quoted context omitted.

I think the era of traffic shaping as you describe it is no longer. Most connections are encrypted these days, a good thing. But that also means, me as an ISP in the middle, I only see the layer 4 packet. So I know where a packet is coming from and where it's going (and ttl and some other not really helpful data for this purpose.) I don't even know the port. So I'm left with doing (dumb) traffic shaping by destinatio…

Wait, why wouldn't they know the port? I'm not aware of any cases where the TCP header itself is encrypted.

99% of consumer traffic is on 443 these days (citation needed)

Re: AT&T Wireless traffic shaping apparently making some websites unusable

#119
post #96

Remember how 5G was supposed to support "the metaverse"?[1] I've been working on a high performance metaverse client. All Rust, all multi-threaded. Designed to max out a gamer PC. Supports Second Life and Open Simulator. Second Life had a reputation for being sluggish. Fixing that. I'm pulling content from the servers at 200Mb/s, sustained. 400Mb/s in tests, but don't need to go that fast. The servers (AWS front-ende…

Unlimited is a term of art that means "limited".

Re: AT&T Wireless traffic shaping apparently making some websites unusable

#120

Earlier quoted context omitted.

> Said the other way around: fast.com is great to see actual throughput from Netflix as opposed to some fake throughout from a dedicated speed test site for the exact same reason. Yup. This is pretty much the reason Netflix created fast.com. They wanted a speed test service that couldn’t be gamed by ISPs. Many ISPs will prioritise traffic to know speed test services (like Ookla’s speedtest.net), making their services…

Now that my ISP bundles Netflix subscription into their internet plans, access to netflix and fast.com now practically saturate the fiber link, while before it was outright blocked. Hooray for no net neutrality I guess. Another fun part: when netflix IPs was blocked by this ISP, it's pretty much impossible to use netflix because the only way to get around the block was to use VPN, but netflix itself blocks VPN access…

> Now that my ISP bundles Netflix subscription into their internet plans, access to netflix and fast.com now practically saturate the fiber link

They may have an ISP-local netflix cache, from Netflix themselves not some home-grown hack, so they can achieve that with some reliability without it costing as much as it otherwise would for bandwidth peering.

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