One important aspect of OpenSIPS is that it does not handle media or RTP. Therefore, even for simple services such as playing an announcement you will have to rely on an external media server. The most common media server in use with OpenSIPS is Asterisk. Recently, Freeswitch™ and Yate™ are gaining traction to offer media services such as conference, voicemail, announcements, IVR, and so on. In this chapter, we will learn about parallel and serial forking and how to integrate OpenSIPS with a media server. We've chosen Asterisk because of its popularity and simplicity.
By the end of this chapter, we will be able to: