Interesting cellular networking.

I was having a bit of a stumper with my mom's phone that ended up giving me some interesting insight into cellular networking and how carriers are routing traffic.

The phone in was dealing with would get 4g LTE service but eventually drop big name sites: anything from Google (including services), facebook, yelp, etc.. I did notice that sometimes partial functionality was there: facebook would work, but sends would fail. The phone always had some connectivity to less used sites and it was fast. Changing APN settings would give me full service--perhaps minutes, perhaps 12 hours.

It turned out to be due to bands the phone was capable of using. The phone was a Tmobile LG G5 using ATT towers thru a straight talk sim.

You may say "duh", but there was very little difference between AT&T and T-Mobile versions of the G5. It was also very odd only some sites were being refused, and that the phone reported 4G LTE Connection. Setting the phone to wcdma only (3G....which it reported as 4G without LTE) would cause everything to work properly, albeit more slowly. There are only two frequencies that the Tmobile phone didn't have that the att version did: 29 and 30, which are "overflow" or "downlink only" bands that weren't in all markets when the g5 was produced.

This leads me to believe that cellular carriers are choosing to route certain traffic to certain bands ("hey, people use Facebook and Google services a lot, let's send that traffic using band 30 because we don't use it much")