GMS Specifics
SMS-Point to Point service is defined in GMS recommendation
03.40 and GMS 03.41 defines the SMS-Cell Broadcast which allows advertising and public information to be broadcast to all mobile users in a specified geographical area. Messages are sent to an SMS Center which provides the store-and-forward mechanism. If not able to send the message immediately, it attempts to send messages later.
Some SMS Centers will try the transmission only once. Both Mobile Terminated (sent to a mobile handset) and Mobile Originated (sent from a mobile handset) operations are supported. Currently message delivery is done on a “best effort” basis which means there are no guarantees that a message will actually arrive at its destination.