Migrating Towards Convergence

By Nathan Franzmeier

Session Border Control, Next-Gen Networks, Service Providers: The service provider industry is
facing unparalleled change which is
breaking down the traditional barriers between carriers. Fixed-line voice is being “squeezed” by broadband VOIP, mobile and IP, while mobile’s popularity continues to grow at the expense of fixedline telecom services.Many users have switched at least some of their fixed-line use to mobile. Even cable companies are invading traditional telecom territory with VoIP. Industry analysts Frost & Sullivan expect that, by 2009, there will be nearly 20 million VoIP subscribers in the United States alone.

Meanwhile, increasing operating expenses are eroding margins and overall growth. Network and network development costs are also chipping away at margins and service providers are under pressure to reduce their network related expenses while simultaneously maintaining margins.

While some markets still have opportunities to grow in the mobile space, voice usage, the double-digit revenue growth and healthy profit margins once enjoyed have been lost to market saturation and intensifying competition.Mobile operators are also being challenged by VoIP. Fixed-line service providers increasingly offer VoIP, enabling them to compete more effectively on price while simultaneously offering new features such as seamless roaming, and WiFi (News - Alert) and WiMax access. These “fixed services” potentially threaten mobile voice revenues including high margin revenues such as international roaming.

This increased competition, price pressure, slowed growth and increased churn is forcing service providers to look beyond commodity-priced voice and data services to boost usage and maintain subscriber interest These trends are driving service providers towards a goal of service delivery anytime, anywhere, over any network. The IP Multimedia Subsystem (News - Alert) , (IMS) architecture and convergence has received a lot of attention as the primary vehicle for achieving these ideals.

However, the technology behind the trend towards convergence is very complex. To make it all work, one vendors equipment must connect to another vendors equipment, protocols from one network must be translated to another using a different protocol, services that already exist must be duplicated in a new network, services that didn’t exist in an old network need to be added. Services are being accessed from networks for which they were not designed.

It all started very simply with the connection of two phones through some copper wires. Later came electromechanical switches, digital switches, common channel signaling, the IN network, softswitches, session controllers, media gateways and then IP. Then the networks started their move towards convergence. . .With every advance in technology, new vendors and new protocols have been introduced and with those whole new industries have been created to address the continuing need to make the resulting networks work while simultaneously making it easy and cost effective to operate and deliver the desired services. With each new advance there has been a corresponding need to manage the migration between the old and the new.

In order to maximize their existing investments, service providers who are migrating towards NGN and IMS architectures need to continue to be able to access their existing services and to use them in new and different ways. In a typical NGN network today, access to the service network is provided either directly via SS7 or over SIGTRAN. The conversion of the various high level protocols, WIN, CAP, etc., is left up to various stack vendors who are then incorporated into different proprietary implementations for service access from the pool of softswitch vendors. This is the predominant method for providing services such as LNP and CNAM in current NGN networks. In the IMS architecture, the same services need to be accessible via SIP. In addition to SS7 based protocols, there may be other services that must be accessed using other industry methodologies; which may also require conversion to SIP. Fulfilling the role of the IMS SCIM and SSF, solutions such as the Stratus CSB (Converged Service Broker) have been developed to address the need to not only provide an IMS compliant access method to legacy IN services and other new services via SIP, but to also allow these services to be recombined in different ways to increase margins, decrease churn or drive profits. Some vendors such as Stratus, have solutions that operate under a unified environment — ours is called ENTICE (Emerging Network Telecommunication Infrastructure Environment). This enables solutions to be created that combine the functions of SBC (Session Border Controller) for example and the CSB to allow access and control over the control, media and service plane streams and therefore provide a wide variety of new and interesting services. This enables services that are provided by one network to be utilized in another. Similarly services provided by one vendor can be combined with services provided by another vendor. Finally, completely new services can be created using the SLEE associated with these products.

One example of service combination is as follows: A mobile service provider, providing prepaid service using an SCP to provide the authentication and billing services, decides to add color ringback service. The color ringback service is provided by one vendor and the prepaid service is provided by another. The issue in the past has been that the two could not easily be combined.

Each service required a CAP-oriented call flow which could not be mixed.With the advent of devices such as ours, it is now possible to combine the services so that color ringback can be utilized for both those subscribers making calls directly and those making calls indirectly using prepaid service. The combined service creates a new feature for the prepaid subscriber independent of the original service vendor. This new feature is could be considered a “sticky” service designed to decrease churn by providing a competitive feature not available elsewhere. Other times there may be a desire to utilize a service in a network for which it was not originally designed. An example of this would be if the same carrier wished to for example deploy VoIP over WiFi or WiMax to supplement his mobile network and wished for the same services to be available in those networks. Again, the solutions coming into the market can be used to access the IN services (color ringback and prepaid) and convert the CAP messaging to SIP while also providing brokering between the two applications. Stratus’ CSB solution is shown in Figure 1.

These solutions allow telecom providers and their subscribers to maximize their investments in legacy,VoIP, and 3GPP/3GPP2 networks. In these environments, the solution enables legacy, next-generation MGC, and 3G CSCF network elements to invoke multiple services for the same call and allows services on different platforms and networks to be applied to the same call. This opens the door to simplified subscriber experiences, improved retention rates, and new revenue-generating, IMS-capable services. It extends the life of the existing network infrastructure and provides an important step in the migration towards the vision of network and service convergence.

The industry has been changing rapidly since the inception of the Internet, but solution providers are keeping pace and responding to needs within the network.

Nathan Franzmeier is Vice President, Emergent Network Solutions, Stratus Technologies. For more information, visit the company online at www.stratus.com.