How does Win 10 know mobile hot spot is metered?

[michail71]

I had to use my mobile hotspot feature on my Lumia 1520 and I went to check the WiFi setting in Windows 10 to mark it metered. However, it was metered by default.

How does Windows 10 know this connection is metered?

 

[pankaj981]

May be it just checks the ISP (in this case the carrier) and assumes its a metered connection? It may also identify it from the access point (this case the phone).

 

[michail71]

I thought of those as possibilities, phone appears in the SSID. But I wasn't sure if there were any kinds of header info that occur from an AP to the client that might indicate that.

Another possibility is MS knows it's my phone and does a Microsoft account WiFi Sense sharing thing?

I just thought it was kind of neat that it worked and became curious.