BlackBerry cracked push like this years ago, though it wasn't open. The phones used to connect over the carrier's network to a private APN (over VPN or leased l

BlackBerry cracked push like this years ago, though it wasn't open. The phones used to connect over the carrier's network to a private APN (over VPN or leased line with to the carrier), so they always knew your BlackBerry's IP address. If you were out of range they'd do the whole storing it all up and when your device came back into coverage they'd send it all down. No hanging connections, the device was directly exposed into the BlackBerry network.