Tekelec sets a practical IMS migration | October 5, 2007

The magic of IMS is that it will give the end-user a converged service experience over any type of access medium. However, the reality is getting to IMS for the service provider is an evolutionary process.

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Incumbent service providers have to balance the needs of their current network and service sets with what IMS can bring. With its TekCore Session Manager and related products, Tekelec is giving service providers an evolutionary path that makes the most out of the current network while preparing them to get to IMS on their own terms. In an exclusive interview, Telecommunications Magazine Executive Editor Sean Buckley talks to Dan Bantukul, director of product management at Tekelec about how it is helping the service provider to make their migration to IMS.

Telecommunications: Tekelec has a long heritage in the traditional and next-gen signaling worlds, and the company’s core contribution to the service provider’s IMS transition is the TekCore Session Manager. What are the components of this product set and how does it fit into the IMS evolution?

"We believe that by managing the services that’s exposed to the subscriber properly we can hide the complexity of switching from one network technology to the other technology from the subscriber itself."
Dan Bantukul, director of product management for Tekelec on minimizing the effect on subscribers as service providers migrate to IMS

Bantukul: That’s a good question, Sean. Basically, the Tekelec view is that IMS is not going to happen overnight and there’s going to be coexistence between the existing network technology and the new IMS overlay network. We came up with the concept called the session manager that can provide session management functions either within the NGN network that we have today or at the CSCF in IMS.

The components of it is if you want to basically bring the NGN network to line up with the IMS architecture, you can start by deploying the session manager in the SIP Signaling Router (SSR). The SSR basically implements session management in the NGN, and when you’re ready to upgrade that to IMS then the SSR can be software upgraded and become a CSCF (Call Session Control Function) in the IMS network. Therefore, basically we provide a very seamless evolution of the session management from what you have today to the IMS architecture of the future.

Telecommunications: Even though there are a number of advantages for carriers in moving to a next-gen and IMS architecture, the other issue at hand is minimizing the impact the transition has on the subscriber base. How can service providers maintain that balance?

Bantukul: We believe that a customer switching a technology should be transparent to a subscriber. A subscriber should not have to worry about, okay, what technology he is on at at this point in time. Let’s take take the example of dual mode services. The subscriber should not care whether he’s being served by the pre-IMS NGN network, GSM network or the IMS network itself. We believe that by managing the services that’s exposed to the subscriber properly we can hide the complexity of switching from one network technology to the other technology from the subscriber itself.

This is the part where the SCIM (Service Capability Interaction Management) function comes into play. By using the SCIM function, we can basically provide the legacy services of the new network architecture or be able to offer the new services on the legacy network architecture by basically managing service interaction at the SCIM layer between the legacy services and the next-gen services.

Telecommunications: Of course with any new technology element, there’s going to be different approaches of where something like the SCIM ( would reside in the network. What are those approaches and how Tekelec responds to those needs?

Bantukul: We believe the SCIM is going to require processing power because it does provide spatial functionality. It also has to understand its own protocol, especially if you want to do service interaction between the legacy IN type of service and the new services based on SIP. The SCIM has to really interact with the IN services or IMAP (Internet Message Access Protocol) and with the new SIP-based service framework, so it’s going to take quite a bit of horsepower.

We believe that the SCIM should be a standalone type of product that will allow them to scale independently from the CSCF or the session manager. In other words, the CSCF or the session manager makes a decision when and when not apply enhanced services to a basic session set up. Once that decision is made then the SCIM takes over to do service interaction. That way the CSCF can handle session management in the most cost efficient way. Once the CSCF decides that this particular session needs special treatment from the SCIM then the SCIM can take over and implement that service interaction to implement that special service. The bottom line is that we believe the SCIM should be an independent element within the network where the CSCF makes a decision to pass the call to the SCIM.

Telecommunications: As we all know, deploying an IMS network requires multiple moving parts to deliver services. In response to that, Tekelec has developed the Open IMS Alliance, which includes partners such as HP, BEA Systems and third-party software vendors. How important is it for a service provider to have a program like that and what does it do for them and their migration to IMS?

Bantukul: The importance of an alliance like Open IMS alliance is that we provide — I hate to use the term turnkey because I would rather use the term tested/integrated — solution. Obviously, Open IMS brings the best-of-breed into a solution where Tekelec provides unified signaling control that provides very efficient signaling management across multiple network technologies, while HP brings to us the unified subscriber profile that can unify the subscriber identity across multiple network technologies whether it is SS7, the NGN or the IMS network subscriber identity. BEA brings in a very flexible application framework that allows you to implement services.

Now, the beauty about this alliance is that each member can take advantage of each other’s strengths. Take an example like BEA. An operator might build an application on top of the BEA infrastructure and then that application can take advantage of the unified subscriber from HP, so that the application can be delivered to any type of subscriber whether it’s SS7, NGN or IMS. From the implementation standpoint, Tekelec provides you with signaling control that actually has implemented those services into those technologies. The alliance gives the operators an advantage of a solution that has been tested, that provides a level of differentiation and be able to combine a lot of these services and be able to expose those services to core network technology. Hence, you basically allow the operator to have a very smooth transition from the existing network technology to the future IMS network technology.