System Engineering for IMS Networks

Chapter 9

Implementing IMS Functional Elements

The specifications of the IMS have focused on defining the architecture, the functional elements within it, and their interaction. The standards do not mandate or dictate a particular implementation to realize these functional elements. One route, which initial implementers have taken, is to successfully reuse existing network assets and evolve them to conform to the IMS reference architecture. For instance, SIP servers have been leveraged for session control and the HLR subscriber function was enhanced to support the HSS features. We will, however, focus on engineering these solutions from commonly followed paradigms and trends.

9.1 The Network Itself

To start with, let’s understand the foundation ...