Mac and PC cloud sync and mobile push

Bonjour, you have new messages

Once updates arrive at the cloud, either from MobileMe sync or from entries made directly in MobileMe web apps, the cloud pushes those updates down to any registered iPhones or iPod touches connected to the account. On Mac OS X Tiger or Leopard, Apple also triggers push updates from the cloud that should show up immediately in Address Book and iCal, or “generally within a minute” according to Apple's site.

Updates made on the Mac desktop are not immediately pushed up to the cloud unless you manually initiate a sync (or wait for the system to trigger an update sync itself). However, updates are pushed down to Leopard desktop apps, typically within around ten to fifteen seconds of making changes from the web or on the iPhone. Updates pushed to the mobile are similarly fast.

This unique desktop push feature uses the same Wide-Area Bonjour mechanism used by MobileMe's Back to My Mac for remote file and screen sharing. For this to work, the Mac desktop must first be securely registered into Apple's Dynamic DNS server by simply turning BTMM on (which happens when you install the MobileMe update, if it's not already on). This then allows the MobileMe cloud servers to target updates to the machine as required without the desktop system needing to initiate the transactions. BTMM also automatically configures an encrypted, point to point IPSec connection to secure transactions over the Internet.

Other push messaging alternatives either use an expensive mobile network to keep track of mobile devices (as RIM's BlackBerry service does), or require a team of administrators to configure and maintain a Local Area Network supplying DNS and directory services (as Exchange Server does). Exchange can not remotely update desktop client machines unless they connect to the corporate network over a VPN or dialup networking link themselves. Thanks to the automatic Wide-Area Bonjour configuration of MobileMe's BTMM, none of that is needed.

MobileMe on Windows

Apple's BTMM push updating service does not update Windows desktop apps, which must sync on a regular interval to be kept up to date with the cloud. Rather than using Microsoft's own desktop ActiveSync in Windows XP (not to be confused with Exchange Server's unrelated push messaging component of the same name), or its successor in Windows Vista, the “Windows Mobile Device Center,” Apple brought over its own sync technology, bundled within iTunes.

This is not new to MobileMe; iTunes for Windows has long provided iPod, iPhone, and .Mac data sync with Outlook on the PC. This fact didn't prevent conspiracy theorists from complaining that iTunes 7.7 was “sneaking MobileMe onto Windows” after discovering optional new sync options in the latest version of iTunes.

During the iTunes install, Apple includes a MobileMe Control Panel that behaves identically with its Mac OS X counterpart, although on Windows there is no support for syncing anything apart from calendar, contacts, and bookmarks with the MobileMe cloud (below). Again, on Windows, there is currently no support for Back to My Mac or push updates, only sync.