Ever since the Third-Generation Partnership Program (3GPP) extended its roadmap for mobile services into the future during the late 1990s, the term "IMS" (IP multimedia subsystem) has been a major part of the service lexicon. Given the view that convergence on IP and convergence between fixed and mobile services are inevitable, and that content is the way of the future, it's hard to see how something called the "IP Multimedia Subsystem" could lose.
But for all the IMS hype of just a few years ago, IMS has suffered some momentum setbacks. IMS was supposed to be all about new mobile applications. Now some are questioning whether it will ever really be deployed at all.
IMS is an architecture that brings mobile calling, roaming and billing practices to multimedia services. The basic approach of IMS is that the user's handset may be connected to an IP network anywhere-even a wireline network instead of a mobile network-but the services provided to that user are controlled by the network operator that "owns" the user and the user's service contract. This is how mobile voice services have worked, and everyone knows that mobile voice has taken off, so the assertion that IMS could stimulate multimedia applications seems at least plausible.
The IMS approach to applications is pretty straightforward. Applications are registered with the cellular operator. By pressing some keys or buttons, the user can activate those applications no matter what network they happen to be on. The applications' security and quality, billing and performance, are all controlled by the operator that owns the customer's cellular plan.
Did the industry bypass IMS?
The good news is that it's a secure path to services beyond voice. The bad news is that we may be there already, without the benefit of IMS. The process of making IMS a standard has taken years, and along the way the market has moved to its own tempo, developing most of the things IMS was to offer but in an "over-the-top" form rather than an IMS-and-operator-controlled form.
What are the applications beyond mobile voice? Video, downloading music, software as a service (SaaS), social sites, navigation...there are many choices. Whatever one you pick, we already have it on the Internet, and we don't have it on IMS much anywhere in the world.
The primary web threat to IMS is the interactive web page technology set that we usually call "Web 2.0." With more and more websites creating rich experiences for users, mobile operators are finding their networks turned into plumbing again, commodity pipes that deliver content. Users already know where to go for content, and it's not to IMS-created resources. Even if mobile operators deploy IMS-based applications, will they be competing with applications the users have come to rely on? If so, it's pretty clear that IMS would have an uphill fight. IMS's desire to cover all the service bases and all the operator mobile and FMC needs may have delayed its completion to the point where it simply ran out of runway. The faster-moving over-the-web players have already staked their claim."
Some IMS vendors and operators are fighting back with features like fixed-mobile convergence that lets users switch voice and multimedia experiences between their 3G networks and home WiFi or hotspots. Some vendors are working on blending navigation and GPS features from phones with local search and local retail applications to create specialised mobile services. These new applications might be made available through IMS fast enough to help establish IMS as a concept.
Even if there are opportunities left for IMS to build on, there are also trends working against it. The Federal Communications Commission (FCC) set aside some spectrum from its latest auction for "open" wireless, which would presumably limit how much IMS could be used to funnel users into operator-owned applications. In Europe and some areas of Asia, regulators are looking more carefully at how mobile operators price their offerings, charge for roaming and control experiences. IMS's rigid relationship control may look a bit too rigid to suspicious regulators.
Video challenges IMS
The ascendancy of video has created its own challenge for IMS. Video applications on mobile devices have had spotty success worldwide. In the US, most video is consumed in the youth segment of the market, a segment where ad-sponsored services are also most popular. IMS was really designed for services that are directly charged. In Europe and Asia, where many people sit on public transportation for long periods, mobile video has broader appeal. But video bandwidth consumption there has operators concerned about network capacity, and thus about spiralling costs.
IMS faces challenges that may have solutions, but the question is whether IMS can apply those solutions in time. For the last two decades, the service provider standards space has consistently lagged the market, resulting in standards that have been only marginally relevant to service consumers or network operators. The fate of IMS may now depend on a few of its proponents, equipment vendors quietly looking at IMS not as a monolithic strategy but as a set of service tools that can be applied together or separately, and thus be used to support today's web-enabled applications.
Some call the IMS conception of services an "IMS-plus" approach because IMS leads the deployment, followed by IMS-enabled applications. The winning strategy for IMS-perhaps the only winning strategy-may be "plus-IMS," where applications are proven out in the traditional web way and are then enhanced by application of IMS security, operational stability and performance control.
At this point, IMS 2.0 might be a better name.