SDP vs. IMS (April 11, 2008)

While browsing through some telecom-related blogs, I can see that there’s a fair amount of authors still believing that the age of SDPs, or service delivery platforms (what you could call any JAIN SLEE-based application server, for example), is just a transition phase before operators will roll out IMS. Unbelievable.

These two architectures are so deeply interweaved into each other, and so widely misunderstood, that one could give several answers to the question Is IMS architecture a successor to SDPs architecture? without being false even once. Like this:

• Yes; when IMS will be rolled out, SDP will become unnecessary. IMS will require IP-based infrastructure as well as support from the device manufacturers; when both will be in place, a new way will be invented to develop services and deliver them over SIP inside IMS
• No; IMS does not offer anything new in services delivery in comparison with SDP. IMS will serve as an infrastructure convergence point, unifying all communications inside the operator’s network. SDP should by its definition include the network abstraction layer. With IMS and its pure SIP infrastructure this layer becomes not necessary any more, whereas all other parts of SDP could be reused
• The question is meaningless; they already working together. Operators have to demonstrate new services to the customers. Too many of these services require at least IMS-like network — think of parallel ringing. The shift is happening smoothly, platforms coexist.

My opinion is a combination of three. Operators still could not invent a reliable profit stream from pure services, and SDPs is a good place for operators to get service development experience. Here I am talking not only about JAIN SLEE approach to SDP, but about all others, like BT’s Connected Services Sandbox based on Microsoft CSF. These are good lessons to learn, and they all could be applied to IMS — without any conflict of interests between architectures.