CPA MMS - how does it work?

The figure below illustrates how CPA MMS works: 
 
Telenor provides an access to the CPA gateway on the Internet by TCP/IP. All applications and content databases must reside on the content provider side. Telenor provides an implementation API that the content providers must use to access the CPA platform. This API is used to send messages to and from the CPA platform and the content provider.

The CPA platform works as follows:

1. The customer send MMS messages to the MMS Central, using a large account (e.g. 1999) to identify to which content provider the message should be sent.
2. The MMS Central server routes the messages to the CPA platform as shown in the figure.
3. The CPA platform checks that the customer is allowed to send/receive content.
4. The CPA platform checks that the customer has the necessary funds for this transaction.
5. A content provider's system connects to the CPA Platform through the Internet (TCP/IP), and is responsible for staying connected.
6. The CPA platform sends the messages transparently through to the appropriate content provider.
7. The content provider is responsible for the content of the services and for processing the messages.
8. If the incoming MMS messages require a response from the content provider, the content provider sends the response back to the CPA Platform. These messages must include the price of the content service, the customer's account, etc.
9. The CPA Platform will then send a request to the invoice system to bill the customer for the message before the message is sent to the customer.
10. If the message by any reasons cannot be sent to the customer, the billing of the customer is recalled.
11. The messages are sent via the MMS Central to the customer.
12. The revenue from each of the messages is split between the content provider and Telenor.