Chapter 2. The SIP Express Router

We discussed in the last chapter the big picture of a VoIP provider. Usually a VoIP provider is composed of several components. These components can reside in the same machine or be spread over several machines depending on your dimensioning. One of these components is the SIP proxy server, in our case the server running the OpenSER software. As the name implies, what best describes the SER is a SIP Router. It is able to manipulate the SIP headers and route packets at extremely high speeds. Third-party modules give SER extreme flexibility to play roles for which it was not originally intended, such as NAT traversal, IMS, Load Balancing, and other functionalities. In this chapter we will show you the possibilities and the architecture of the SIP Express Router.

By the end of this chapter you will be able to: