Short Message Service (idea)

Here's how an SMS message travels through the GSM network. The description is slightly simplified and doesn't go into technical details.

1. The GSM handset sends the message to the SMS Center (SMSC), which stores the message for delivery
2. The SMSC send an acknowledgement about the received message to the sender
3. The SMSC tries to send the message to the receiving handset until the message times out
4. When the receiving handset has received the message, it sends an acknowledgement to the SMSC, which deletes the message

       1. --->      3. --->
Sender         SMSC         Receiver
       2. <---      4. <---