Past discussions:  bug 452985 ,  bug 439173 ,  bug 446621 

shill has two per-service prioritization properties: Priority and PriorityWithinTechnology.  Currently it sets Priority to 1 if "Prefer this network" is checked, and 0 otherwise[0].  This means that if a user checks "Prefer this network" for (say) his home wifi, the home wifi service will have a higher sort order than ethernet and VPNs.  This often comes as a surprise to the user.

Chrome does not currently translate or use the PriorityWithinTechnology property.

Based on reading old bugs, I think this is the behavior we want:

 - Checking "Prefer this network" on a wifi service will set PriorityWithinTechnology=10, to rank this wifi SSID above other known wifi SSIDs.  It should not cause the wifi service to be preferred above ethernet or VPN services.

 - Checking "Always prefer cellular" on a cellular service will set Priority=10, to rank this cell service above all wifi and ethernet services.

 - VPN services should have Priority=50, because we always want them on the top of the stack.  If a VPN gets pushed down into second place, it won't encrypt any traffic.

 - Existing configurations should be upgraded in-place to reflect the new behavior.

(Exact priority numbers subject to change.)

WDYT?


[0] https://cs.chromium.org/chromium/src/chrome/browser/resources/settings/internet_page/internet_detail_page.js?rcl=474b839d898bfe57343d755b0e3af8fd5b246f36&l=278