[rakoo]

> Why would X x Y idle connections (X: TCP connections per app, Y: applictions) prevent your radio from sleeping?

In the worst case, if the pings aren't sent at the same moment and all applications have a timeout set to, let's say, 30 minutes, your phone will send a ping every 30/(X*Y) minutes. I don't know what the usual X and Y would be, but if they're high enough your radio will always be up (check out these slides, 23 in particular: https://www.igvita.com/slides/2013/io-radio-performance.pdf)

And that's only counting idle applications. If you have one that periodically polls a server, it gets even worse.

[Flowdalic]

Course, you shouldn't poll and if those mechanisms aren't coordinated, then you you will suffer. But that's why Android provides the AlarmManager API and I would expect other mobile platforms to provide something similar.