Everyone agrees that it is imperative to find the best way to bridge networks so that applications can flow seamlessly across all delivery platforms. People must be able to use the same applications on any device in their home, in transit, and in the office. The IP Multimedia Subsystem (IMS), which has been in development for several years, is a prime candidate for creating such a world.
Network World suggests that IMS seems to be a terrific idea, but agrees with the general consensus that it is emerging slowly. In the best of scenarios, it should be noted, combining worlds that were not created with such combinations in mind is slow work. The piece says there has been insufficient multivendor interoperability testing of the Session Initiation Protocol (SIP), a key element of IMS. A second problem is that not enough bridges (or "hooks") exist between IMS and carriers' operational support systems (OSSs). Finally, tension between wireless and wireline carriers is seen as chilling quick development. The writers report progress: Executives contacted for the report suggested that advances have been made in testing and interoperability on voice and voice-related elements of IMS.
This short post at Smacktooth provides a good definition of IMS, which it calls a framework for delivering IP content to mobile users. Its roots are as a means of expanding mobile delivery beyond Global System for Mobile communication (GSM). As such, it has been updated by several organizations to cover wireless local-area networks (WLANs), Code Division Multiple Access (CDMA) and fixed line services. Conceptually, the key is that IMS seeks to separate the access network from the service layer and thus creates a way to deliver any application to any platform.
IMS may be entering the do or die phase. Last week, ABI Research released a Research Brief that says network operators will begin rolling out all-IP networks during the next two years. This will enable IMS to be deployed, allowing quick creation of new applications and streamlined operations. The unstated assumption is that various methods will compete to fill this role. If IMS can't work through its complexities, other approaches will be used.
iTNews does a good job of discussing IMS from the telephone industry's point of view. The telcos come from a tradition where it takes a long period of time and a tremendous investment to develop an application. Today, however, the world is moving to IP and entrepreneurial organizations (Facebook is mentioned) are creating platforms in which application creation is so simple that even those with no computer skills can get in the game.
This, needless to say, is a tremendous challenge to the telcos. All is not lost for them, however, because they still have tremendous resources, customer relationships and brand names. The piece says the telcos are working to meet the challenge, and one way could be to leverage strengths in supporting IMS applications in such a way that they would be attractive partners to those writing the applications.
Anyone who wants to understand IMS and where it fits in must be prepared to deal with a high level of complexity. WirelessMoves, for instance, describes how IMS interrelates with another set of standards, known as Telecommunications and Internet Converged Services and Protocols for Advanced Networking (TISPAN), which is a set of standards from the European Standards Institute (ETSI). Essentially, IMS focuses on mobility. TISPAN is an attempt to create a broader confederacy of protocols that include non SIP-based IP services and the legacy public switched telephone network (PSTN). The bulk of the post describes TISPAN and how it attempts to bridge the different types of network infrastructures.
IMS is a complex undertaking. It holds great promise because it implies a deep and flexible marriage of different networks and simplicity for end users. The future is calling and it seems 2008 will be a critical year that could determine the fate of IMS.