Key Trends Driving the Evolution of IMS

By Arun Bhikshesvaran      

I n a recent service provider survey conducted by Frost & Sullivan, the complexity of IMS was frequently mentioned as one of the factors curtailing growth within the market. Undeniably, the IMS designs (whether from ETSI ( News - Alert) or 3GPP) intrinsically present a couple of major problems. The first one is that the cost associated with deploying a full-blown IMS offering is seen as a risk, given the uncertainty about the uptake in services that the solution can provide. The other issue is that many operators remain skeptical about the scalability of the IMS platform, given its complexity. The scalability fears are further increased when some vendors offer migration paths to IMS via software upgrades to their installed base of softswitches, adding call control functions, for instance. The IMS real-time communications architecture was designed to fit in an overall services architecture that answer these requirements and, thus, provide the effective foundation for meeting and driving consumer demand. The capabilities of IMS have proven to be in step with the trends driving the telecommunications industry forward — such as cost reduction, fixed-mobile integration leveraging multiple access networks and providing integrated service for combined devices; in addition IMS facilitates increasing sophistication of communication services to meet demand for networked and interactive multimedia applications. IMS is positioned to be the important real-time component of the service-architecture of choice as service providers evolve their business models and move from vertical service and access technology to a layered and horizontal structure for combining multiple network assets under a common service.

Early IMS trials of innovative multimedia and communications services show that the ability to evolve dynamically is key in the ever-changing world of telecommunications. Companies are now leveraging the heavy lifting that has gone into IMS over almost a decade, and now take their value-added communications offerings to new levels. The IMS standard, itself of course continuously evolving, is formally stewarded and coordinated by 3GPP, with effective harmonization and cooperation with multiple standardization bodies. 3GPP is growing and is processing enhancements to the current standards. Several key trends that are burning at the forefront of IMS have emerged or evolved for 2007 and beyond.

A-IMS
Advances to IMS (A-IMS), a North American initiative put forward by a consortium led by Verizon (News - Alert) Wireless, continues to receive attention. The aim of A-IMS is to suggest enhancements to the existing 3GPP and 3GPP2 industry group specifications in order to make them more open to meet the overall service architecture requirements of carriers. Some of the issues championed by A-IMS have already been considered and addressed in standards group and some of the issues are more related to how to operate and run the network and services, and hence not really candidates for standardization.

3GPP IMS is commercially available today and is continuously being enhanced with new releases based on a roadmap. Suggested additions are incorporated once evaluated and agreed upon by the active standards participants. The harmonization work performed by 3GPP has resulted in the industry being relatively aligned on using the same 3GPP IMS as the basis, with specific additions on top of 3GPP IMS provided by several standardization groups such as 3GPP2, ETSI (News - Alert) /TISPAN and more. As with all standards, the IMS-related specifications will continuously evolve and improvements to the initial specification from 3GPP R5 already have been made.

TISPAN Multimedia Telephony
Standardization of a set of globally interoperable multimedia telephony services is currently being finalized in the industry standards bodies ETSI/TISPAN and 3GPP. Multimedia telephony combines the quality, interoperability, reliability, efficiency, regulatory and supplementary services of traditional telephony with rich, flexible media capabilities from Internet community-based services.
The objective is to provide the communications industry with the tools to build a multimedia communications network, for fixed and mobile devices, based on converged VoIP and globally interoperable. Beyond this baseline there is plenty of room for individual service provider differentiation, service packaging (bundling), and service management.

Built on IMS, multimedia telephony is access agnostic and can run over a variety of access networks. The interest in “VoIP for cellular” is increasing among operators. It offers a number of opportunities including higher ARPU through richer community communication, lower OPEX (News - Alert) by offering all mobile services from one common platform, as well as fixed/mobile converged service platforms, subscriptions and devices. Interoperability tests are beginning this year.

IMS Security
Protecting operators’ valuable assets is the main purpose of security functions. Protection needs to be complemented with functionality for attack detection, response to attacks and recovery after a successful security breach.
The complexity of ensuring reliable network security is viewed as one of the single most critical barriers to the successful implementation of converged IP networks. Companies like Ericsson (News - Alert) are continuously evolving their security solutions in order to keep up with new market opportunities, applications, business models and technologies.

The main security threats to consider are many, including denial of service (i.e. intruding flood attacks that prevent authorized access to the system resource), intrusion (unauthorized access), impersonation (both by users and the network), interception and disclosure. The decomposed and standardized nature of IMS have made it possible for specialized and value-added suppliers of security solutions to get involved in the development of IMS security solutions and service management of all mobile and wireline systems, and to secure the IMS based networks from user terminals all the way thru to service layer and network applications servers. This end-to-end approach of IMS best-of-breed security solutions is an effective safeguard of the network, users, and enables networks to offer secure and reliable multimedia communications, e-commerce, content experiences and more.

IMS QoS Control
Regardless of network capabilities and high reliability, the end-user experience is a fundamental factor for mass-market adoption of new IMS-based services. The perceived quality of experience by the user is extremely important for operators to achieve customer loyalty and maintain the competitive edge.

As services become more numerous, varied and complex, and terminals become more powerful, architectures for applying policies for service discovery, as well as for control of network resources for delivering services with guaranteed quality, are being consolidated in the IMS standards. Most operators are interested in architectures that apply policies to network resource control based on policy decision/enforcement points (defined by various standardization bodies)

IMS Standardization
IMS is defined as an open and standardized architecture for mobile and fixed services. One of the main characteristics of IMS is that it allows faster deployment of new services because it is based on a standardized architecture. Open interfaces and standard protocols provide flexibility for selecting “best-of-breed” components and enable operators to avoid getting locked into proprietary vendor solutions.

Ericsson is one of the main drivers of 3GPP, as well as the GSM Association SIP Trials, a series of initiatives focused on defining and implementing the architecture, enablers and services that are needed to successfully transition from the circuit-switched world to the IP world, with inter-carrier interoperability to foster industry growth. The aim is that open inter-working solutions for IP based services will be developed, establishing a high-quality inter-working environment that coexists with the variety of other solutions developed by the market. Examples here are the SIP and IMS inter-working trials programs with video share trials.

As the industry moves closer to a standardized, global IMS architecture, there is little doubt that new and complex issues will continue to emerge. It is important for players across the IMS ecosystem — vendors, application developers, and carriers alike —
to continue their cooperation in solving these issues and enabling the services that meet consumer demand.

Arun Bhikshesvaran is Vice President and General Manager of Strategy & Market Development within the North American Market Unit of Ericsson Inc. He has more than 14 years of experience in the wireless communications industry, serving a variety of roles including systems solutions and integration, field engineering, R&D and global product marketing.