Over the past several months, I have detected a palpable sense of momentum on IMS. Operators are making specific IMS plans, and questions from audiences are far more focused, pertaining to service and deployment issues, not just technology. While the move to IMS should be viewed as a long-term retooling effort, this increased specificity will help develop a more balanced and business-friendly set of deployment and service strategies.

Operator announcements indicate the range of plans. T-Mobile North America recently announced a UMA service targeting its wireless consumers. At the same time, early trial results are trickling in from service providers that have implemented IMS and all-IP networks. These results appear to support significant cost reduction objectives in a consolidated wireline/wireless environment. BT, for example, has shared some interesting insights on its 21CN next-gen network experiences and how the company was able to achieve resulting cost reductions. As one might expect, an enabling architecture like IMS can have significant organizational implications that must be anticipated and resolved to support successful deployment.

However, there are at least two areas that are still relatively poorly developed but extremely critical to the broader success of IMS: service delivery platforms and the availability of devices and handsets. Both these areas are central elements in offering rich new services that create tangible value to users in the form of lower costs or a richer communications experience.

Somewhat ironically, there has been considerably less focus in the device area as a whole. Some of the critical questions here include applications, operating systems, architectural frameworks, Java specifications and support for third-party developers. Although specific designs clearly will be determined by operators and vendors, here is a quick overview of some of these items:

• Hardware: Performance and multi-tasking requirements for IMS applications will make battery life and processor performance crucial issues.

• Software: Support is needed for complex new protocol functions, multi-tasking and building blocks, such as presence and address book functions. In addition, open application programming interfaces are required to enable applications development, and handset application software support must be provided as dictated by operators and handset vendors.

• Interoperability and compatibility: Functionality with other protocols, such as non-IMS session initiation protocol or UMA, needs consideration.

• Cost: IMS handsets will have a natural tendency to be in the high-priced range, but solutions that can offer at least a basic set of IMS enablers to the largest group will be important in subscriber adoption.

This isn't a detailed set of requirements for IMS handsets, but the list is illustrative of some of the issues to be considered.

One of the big issues is the need to support legacy services together with the introduction of new IMS-based services. There is general agreement on the long-term goal — rapid, flexible service creation and delivery capabilities that can directly affect revenue by enabling a killer service portfolio if not a killer app. The more direct challenge lies in getting started on that road without creating yet another (in this case, IMS-based) silo. A holistic approach that develops a customer-based view and incorporates the entire product life cycle — including devices, marketing channels and customer care — could help provide more accurate plans in service rollout while planning for organizational change. In addition, handset functionality will need to be linked appropriately to network-based service enablers.

We can expect to see progress on these items as some of the announced operator IMS deployments begin to make their mark within the next year or so. (I include FMC and UMA in this category because the learning from those deployments will be useful to operators). As service realization efforts increase, the focus will shift to customer needs and services, a direction that can only help bring IMS-enabled services closer to reality.

PK Prasanna is IMS/Convergence Lead for inCode, a global wireless business and technology consulting firm. For more information, e-mail pprasanna@incodewireless.com