Migration of Enterprise VoIP/SIP Solutions towards IMS

Voice-over-IP (VoIP) solutions are now widely spread and accepted by end-users. For an enterprise customer it is increasingly difficult to choose one of the numerous VoIP solutions which are available today. What options exist for an enterprise VOIP/session initiation protocol (SIP) solution to migrate from today's solutions towards interoperability with future IP Multimedia Subsystem (IMS) solutions, and what would motivate such an upgrade? We visualize four such solutions and position them along a possible migration roadmap. A common VoIP/SIP/IMS research platform is necessary as a test-bed for establishing an environment for development of future "All IP" products and services.