ABSTRACT
This chapter explains how the standards are defined and the interaction between them, through several layers of network, each governed by suitable protocols. It describes the various contributions to IMS from the collaborating standards organizations and consortia around the globe and their respective areas of activity. Each of the main contributors to IMS — namely, the 3GPP (Third-Generation Partnership Project), TISPAN (Telecommunications and Internet Services and Protocols for Advanced Networks), IETF (Internet Engineering Task Force), and OMA (Open Mobile Alliance) — are described here, along with their architectures and main concepts.
