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Enabling Applications in an IMS World
by Jose Deras, Vice President, Sales Engineering
7/30/2007
IMS and rapid application deployment are vital to communication service provider's future success. Being a vast and powerful architecture, IMS brings a fair amount of complexity and cost. The transition to an IMS network in today's cost constrained environment is challenging, so most implementations are currently being phased in over long periods of time. Replacing non-IMS applications to comply with an IP structure remains a long term goal; however, if there's no additional revenue to be generated, replacement becomes a financial decision. Unfortunately, IMS does not adequately allow legacy applications access to IMS elements directly; the net effect being that major IMS expansions are delayed pending positive business cases. As a result, service providers are looking to maintain and reuse existing revenue producing applications and infrastructure in creative ways to maximize their existing customer base and revenues.
Compounding the problem, the service provider's converging network tends to create a lack of cross network-to-network feature transparency and impedes rapid and flawless application delivery, as new applications must be repeatedly stove-piped into the evolving underlying networks. New applications delivered today must ensure seamless application behavior across multiple networks and be ready to migrate to IMS as it rolls out.
Migrating to IMS Gradually
Today's current application development options include re-writing the applications to add appropriate signaling or call control into the application, or utilizing additional and costly general purpose equipment such as soft switches, signaling gateways and media gateways that provide the necessary rich call control and signaling required for network connectivity. These paths only compound the non-reusable "stove piping" deployment model, create numerous management and cost challenges, and do not keep up with the ongoing network evolution. Overall, these solutions simply do not address the evolving networks impact on applications. The question then becomes how to migrate to new IMS-based services while allowing the current applications to integrate with the new architecture. The IMS framework expects new SIP-based Application Servers to replace existing TDM and legacy applications. It is this required migration that presents a unique opportunity for solutions that manage to bridge the gap between the feature-rich, tried and true "legacy" applications and the IP core of IMS.
The answer is deploying a purpose built network layer solution that provides network connectivity between current and new applications as well as existing and next-generation network elements.
Today's networks require a purpose built network element that is deployed independently from the network and applications while still keeping pace with the ever evolving network to ensure feature transparency. A new network element, called an Application Session Controller or ASC, enables legacy applications to function in an IMS world and enables feature transparency across the entire subscriber population. As subscribers are migrated from one network to the next generation network, their experience remains constant.
In order to accomplish this, the ASC emulates and translates function calls that would normally be answered by IN-enabled devices (those speaking INAP, MAP, WIN, etc.) by presenting appropriate IMS-based calls. This new functionality is called an IN Service Capability Server, or IN-SCS. The net effect is that legacy applications are able to work within the IMS network without the need to modify or rewrite them. The applications interact with the abstracted network using their current APIs, including CCXML/VXML, SIP 3PCC, Web Services and Parlay/X. Other proprietary APIs may also be supported via dedicated API connectors allowing re-purposing of applications without extensive and time consuming re-coding. Those applications continue to utilize network protocols they were originally designed to utilize so there's no requirement to rewrite and retest and ultimately redeploy existing applications.
The ASC also allows the service operator to incorporate legacy applications into their composite application offerings, essentially allowing the mash up of applications hosted on new and old platforms. The ability of the ASC to mediate and chain call flows allows the creation of new composite applications that bring greater subscriber value and encourage up-take of new services, bringing additional revenue.
Sitting Between the Network Clouds
The ASC then becomes an essential component of the service operator's IMS migration strategy. By sitting "between the network clouds", the Application Session Controller provides a unique view of all the networks to the application developer and enables the service operator to migrate to IMS while retaining current revenue (ARPU) generating applications.
As subscribers are migrated from one network to the next generation network, their experience (revenue generating subscriptions) remains constant. The ASC accomplishes this by eliminating the network silos created by discrete network solutions used in the past, as well as those silos created when IMS is installed in mixed environments with legacy applications. This results in dramatic CAPEX and OPEX savings.
In an IMS deployment, the ASC can also deliver capabilities of the IM-SSF, SCIM, and OSA-SCS, in addition to the aforementioned IN-SCS capability. It's important to note that while the ASC provides all of the functions under one product, by and large the focus remains application deployment and delivery across all networks.
It will take several more years for the IMS vision to become fully realized. IMS are being installed today alongside existing networks, and as such, there's a need to allow the existing revenue generation applications of today to service new IMS subscribers. At the same time, new IMS applications should be made available with as much feature transparency as possible to existing subscribers. Those service providers that successfully transition to the IP world of IMS, without losing revenue in the process, will ensure a continued returned on their investment.
About the Author
Jose Deras is Vice President, Sales Engineering at AppTrigger, where he handles technical sales engagements. Prior to AppTrigger he was VP Sales Engineering for Siemens Communications, responsible for the global technical sales and support for the broadband equipment segment. At Siemens (which acquired startup Efficient Networks), Jose also held positions of VP Product Line Management and Director of Technical Marketing and Business Development. Prior to Efficient Networks, Jose held several roles in sales and sales engineering at Compaq Computer and Networth Inc., a startup in Dallas, TX that Compaq acquired in 1995.
About AppTrigger
AppTrigger is dynamically changing the telecom application delivery marketplace by empowering its customers to insulate their revenue-producing applications from the challenges of the ever evolving fixed-line, mobile, and IP networks. AppTrigger's Ignite™ Application Session Controller provides a purpose built unique combination of media, signaling, call control, and a family of APIs for multi-network, converged application deployments. In an environment of ongoing network evolution, AppTrigger delivers time to market advantages, reduces application deployment costs, and provides feature transparency across disparate networks.
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