Does Profile Manager for iOS Need to be Accessible over the Internet? We're replacing our BlackBerry handsets with iPhones, and we'll be using OS X's Profile Manager for MDM deployment and management.

I've done some exploratory research and I'm happy with the general principles, but I'm wondering if the MDM server needs to be publicly accessible for remote management of iPhones, or is the functionality exposed via the carrier?
The MDM server does need to be available by the device, but Profile Manager itself does not. In other words, the ability to access the Profile Manager doesn't need to be present on the device, providing the literal MDM server is accessible.