5.4. SIP Programming Interfaces

In order to ease the development of SIP applications, programmers typically use Application Programming Interfaces (APIs) that encapsulate specific aspects of the SIP functionality so programmers can concentrate on the application service logic.

There are many ways to categorize the interfaces used for SIP programming. For instance, a first classification might split them into proprietary versus standard ones. SIP vendors may decide to expose the SIP functionality in their product by defining their own API that can be used only within the vendor’s platform. On the other hand, a number of standardization bodies have defined a number of standard APIs for SIP-application development. The standard approach helps boost innovation and cost reduction by addressing a much larger community of developers as compared with the proprietary approach.