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One of the most prominent trends in telecom today is the general shift towards IP-based next generation networks, widely anticipated to culminate in the widespread rollout of IP multimedia subsystem (IMS) networks. <‾xml:namespace prefix = o ns = 'urn:schemas-microsoft-com:office:office' />

IMS rollout is the only logical conclusion of the current trend, as it answers key demands from both consumers and service providers. Many consumers are looking for a wider offering of content and services, more flexibility in where and how they access these services, and yet still expect to achieve this with the same QoS as on their home network.

Service providers can use IMS networks to answer these consumer demands and to deliver these services with greater efficiency over a converged IP network.

More importantly, providers can reshape their image entirely, moving beyond the role of a "bit-pipe" provider to become a high-value "one-stop-shop" provider for communications and services and media content.

However, service providers must keep in mind that in some respects, IMS rollout may be more delicate than that of other new services. In the early stages, there can often be pressure to rush to develop their provisioning and billing technology, just to be the first to offer a new service and gain an early market presence, with service assurance left as a priority for later stages.

In some cases in the past, this may have been sufficient, but this strategy could result in a major setback for IMS adoption. For example, when consumers first began using their home internet connections to log in to a free VoIP service, the service quality was unreliable, and that was understandable. However, with IMS, the QoS itself is part of what subscribers will be paying for. Service assurance must be a strategic consideration of any IMS rollout, just like provisioning and billing.

The challenge of providing IMS service assurance is a bit different from that of legacy networks, in that these solutions must not only be adapted to the IMS network architecture, but also to the IMS market.

For example, providers will have to satisfy a stricter demand for QoS from their IMS subscribers.

If service providers plan to leverage IMS for a higher-value business model in which they provide - and charge for - various services and content rather than just the connection, subscribers will expect them to take full responsibility for any deficiency in the quality in which these are delivered.

To address this demand, there should be closer integration between fault management and performance management systems in any service assurance solution for IMS.

Under most legacy networks, many operators run fault management systems with a narrow network view, ensuring that each piece functioned individually and often producing unreliable but satisfactory QoS as a side effect.

Old "stovepipe" network structures were simple enough that this strategy could be successful, but IMS networks will have more complex architecture and traffic patterns.

This trend is beginning to appear among converging IP network operators, and for IMS network management, this will be a basic requirement. Regardless of network structure, collaboration between fault and performance systems is a necessary step to providing the verifiable service quality expected by IMS subscribers.

A unified mediation layer will emerge as an important enabler of IMS management. In this network structure, there will be more data resources available to leverage for service assurance, and a unified mediation is the best way to properly utilize these resources.

Taking this a step further, IMS providers will need tools to enable a proactive and customer-centric service assurance strategy. These should include sophisticated fault management and a service-impact analysis.

A true proactive approach should entail identifying faults and preventing service degradation before the user experience is even affected. The right fault management systems can contribute to a proactive QoS strategy through rapid root-cause analysis, which can identify a fault's root-cause before the corresponding alarm is triggered.

Due to the high bandwidth demands of many IMS services, combined with increased nomadic network use, systems that monitor and analyze traffic trends to predict network congestion will also play an important role.

With these two tools in place, a service impact analysis can map the effects forward to identify the affected users and services, allowing the operator to take corrective action or bandwidth adjustments to maintain optimal user experience.

The <‾xml:namespace prefix = st1 ns = 'urn:schemas-microsoft-com:office:smarttags' />OSS industry's specialized, "best of breed" service assurance solution vendors are already looking ahead and developing solutions for IMS. Many of the specific tools and strategies that make up this solution - FM and PM integration, traffic analysis to predict congestion, service-impact analysis - are already in deployment over some of the more advanced networks.

For a successful IMS rollout, service providers simply need to make a strategic decision to make QoS and user experience a top priority from the beginning, and find the OSS providers that are prepared to make it happen.

Duby Yoely is VP of solutions engineering at TTI Telecom