Chapter 8. Vovida SIP Stack
Now that you’ve had the user guide tour about how SIP works, let’s go a little deeper into the architecture and talk about the classes, modules, and threads that we implemented into our SIP stack.
Throughout this chapter, when we refer to a certain protocol stack, we’re referring to Vovida’s implementation of the standard that governs that stack.
If you don’t have a background in software development, you may find the remainder of this book’s content difficult to digest. You could help yourself by brushing up on the Unified Modeling Language (http://www.rational.com/uml/index.jsp), object-oriented design, C++, and data structure and theory, which, unfortunately, require a few years of schooling to understand.
Figure 8-1 shows how the major components of the SIP stack work together and with other protocol stacks.
Figure 8-1. SIP stack components
These processes are defined as follows:
Builds messages, either as brand-new requests or as reconstructions of received responses.
Encodes and decodes messages.
- SDP stack
Encodes, decodes, and alters Session Description Protocol (SDP) bodies.
- SIP transceiver
Includes five components, listed next. An intelligent structure, it matches requests with responses, and responses with acknowledgments.
- Transceiver: TX
Transmits messages over a transport layer -independent interface.
- Transceiver: ...