Forward looking service providers know that the IP Multimedia Subsystem standard (IMS) is the best way to standardize the delivery of services – everything from telephony and messaging to video, text and pictures – for fixed, mobile and cable customers in a single user experience. According to Frost & Sullivan, IMS networks will serve half a billion users worldwide by 2010. Yet despite the promise IMS holds for service providers, networks will not switch to an all-IP infrastructure overnight. For this reason, service providers must understand what’s needed to allow applications to function in today’s traditional TDM networks, while opening a seamless transition to SIP and the coming IMS environment.

While IP-based networks hold tremendous promise, immediate transition from traditional to IMS networks can be difficult and costly. That’s why a carefully planned evolution, which takes into consideration not only future opportunities but also current needs, is critical. Described in this article are the top five criteria for a successful evolution to IMS.

1. Sustain existing applications to maintain current income and to open future long-term revenue streams.

Most carriers still depend on architectures which leverage TDM or SS7 technologies to deliver crucial services and applications, and many of those organizations are planning careful migrations towards IP, the introduction of SIP elements, and an eventual move to some form of IMS infrastructure. In the real world, most service providers will live and operate in this transitional mode for some time to come. No matter what architecture is being leveraged, if the transition to IMS is eminent then it’s important to remember that the ability to seamlessly transition applications is critical to maintaining current income and to opening future long-term revenue streams.

What most service providers need is a migration strategy that incorporates a bridge between their traditional networks and the coming IMS environment—a bridge that allows them to extend the useful life of their legacy infrastructure and preserve their current applications, while opening a clear pathway to the new service capabilities of the IMS future.

The ideal bridge solution has a flexible platform approach that allows service providers to deliver very basic capabilities like network announcements on their existing infrastructures, while at the same time positioning their networks to deliver video, multimedia, location and the other highly advanced IMS capabilities of tomorrow.

2. In terms of architecture: Use what you have to get where you want to go and don’t forget to leverage SOA for a smoother transition to IMS.

When selecting a vendor for your transition to IMS, you’ll need to work with a company that has established a migration strategy to effectively and efficiently move from your current architecture to an IMS architecture. To realize the full benefits of IMS integration, you’ll want to optimize the value of your current infrastructure, while evolving the architecture in a step-by-step modular approach. You need to be thinking in terms of incorporating IP capabilities to bridge the applications gap between traditional and IMS networks.

An applications bridge that supports multiple interfaces – including SIP, SIGTRAN and SS7 –will work with any network, and allow service providers to seamlessly transition applications from SS7 to SIP to IMS networks, or to simultaneously support multiple technologies as their networks evolve. This powerful interoperability also allows service providers to deliver a consistent level of access and services, even when consumers roam between older TDM networks and more advanced IMS infrastructures.

When you’re talking to vendors, they should be showing you how you can leverage a Service Oriented Architecture (SOA) in a multi-layer network environment to introduce new services quickly and easily. SOA came from the requirements for faster application development in the World Wide Web. It can enable telecom businesses to respond with agility to changes in customer preferences or market demand.

With this architecture, the applications are abstracted from the infrastructure layer and service providers can invest in the services their customers want and need today, then leverage this flexible approach to evolve their applications to an IMS network.

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