> For example, a disproportionate number of IM (XMPP, etc.) clients for, say, Android, appear to rely on a central server operated by the software maker, with s

> For example, a disproportionate number of IM (XMPP, etc.) clients for, say, Android, appear to rely on a central server operated by the software maker, with some proprietary protocol between the client and that server, rather than simply implementing the protocol directly. Of note is that old Nokia devices used to allow this (i.e. arbitrary TCP connections including long-lived instant messaging ones) and they reached longer battery lives than any Android device I ever had. They traditionally claim that you just can't have multiple long-lived TCP connections due to the keepalives keeping the radio powered on constantly, as well as the reconnect traffic (due to e.g. roaming) being significant. However, both things are fixed by coealescing all keepalives. Probably this doesn't scale to thousands of connections, but it does definitely scale to a couple tens.