As a result of investigation because mobile carriers restricted access to specific websites



Optimizing communication performance, reducing latency (delay), and securing bandwidth by controlling traffic (communication volume) and delaying packets is called '

traffic shaping '. Due to this traffic shaping, some websites are not available on AT & T 's network, software engineer Adriano Caloiaro points out.

AT&T Wireless traffic shaping apparently making some websites unusable - Adriano Caloiaro
https://adriano.fyi/post/2023/2023-04-16-att-traffic-shaping-makes-websites-unusable/



For Mr. Caloiaro, who lives in a camper, mobile carriers such as AT & T and Verizon are said to be major network sources. Mr. Caloiaro seems to be using AT & T's business plan, but in AT & T Premier of business account management UI, it is displayed as 'Wireless Broadband Ultra for Router or Hotspt (sic)', and some such as strava.com website points out that the connection is unusually slow.

The AT & T business plan used by Mr. Caloiaro is a plan that allows you to use the network unlimitedly up to '50 GB', and you can use the network unlimitedly although the speed will decrease after reaching the upper limit. In addition, it seems that the monthly usage limit of 50 GB was not reached.

``I knew from experience that the network speed would be throttled when using fast.com , a network speed test service on AT & T's network. I used a network speed test service that doesn't happen.' He said that he used the following Linode services for the speed test.

Linode Speedtest
http://speedtest.fremont.linode.com/



The speed test results were 21 Mbps downstream, 4.5 Mbps upstream, and a delay of 130 ms. But that doesn't explain why strava.com takes 2 minutes to load.

So, when I opened Firefox's network tab, it turned out that it took several seconds to load dozens of cloudfront.com resources. In other words, it became clear that the problem that was slowing down the connection to a particular website was related to Cloudfront.



Mr. Caloiaro uses a mobile router

RV55 CAT-12 LTE-A that supports dual SIM, and he seems to have used it by inserting AT & T's SIM and Verizon's SIM. So when I used my Verizon SIM card to access strava.com, the Network tab did not show any Cloudfront resources. In other words, it became clear that the problem was still in AT & T's network.

In addition, Mr. Caloiaro used AT & T's business plan SIM card on the iPhone, so he enabled Internet sharing on this iPhone and conducted an experiment to use the PC with tethering. Then, the result of the speed test is 23 Mbps downstream and 3 Mbps upstream, which is a very good result.

In other words, you can access any website without problems with a SIM card for mobile networks, but with a SIM card for mobile routers (SIM dedicated to data communication), access to some websites is restricted. It became clear that there was

From the above analysis, Caloiaro said that the problem was the effect of traffic shaping. Since traffic shaping can be avoided by using a VPN, the image below is the result of the experiment. Download speed with VPN enabled is around 2MB/s.



However, if you disable the VPN, you should see that the download speed drops to around 30 KB / s at once.



``At the time of writing this article, it is unknown what caused such a significant slowdown,'' Caloiaro said. What is there is that AT & T is doing extreme traffic shaping on some plans, which has made some websites almost unusable.

Mr. Caloiaro reported this issue on AT & T's business forum as `` very aggressive AT & T traffic shaping '', but the post on this forum is private at the time of writing. Mr. Caloiaro says, ``I didn't make it private,'' and reports that for some reason the post was treated as hidden and although the URL itself remained, it became impossible to check the post.

·bonus
In addition, Mr. Caloiaro commented, ``I knew from my experience that the network speed was throttled when using fast.com, a network speed test service on AT & T's network.It is a mystery why this happens.'' But that's because AT&T's network restricts IP addresses for video streaming services.

Since fast.com is a Netflix service and the two use the same IP address, AT & T is a network speed test whether the data transferred when accessing fast.com is video (data from Netflix) You can't tell whether the data is intended or not, which slows down your connection speed.

in Mobile, Posted by logu_ii