Tekelec Brings Tomorrow’s Network to Today’s Operators

By Richard "Zippy" Grigonis
Tekelec (www.tekelec.com) is a visionary company that has devised ingenious technologies enabling today’s network operators to offer new, revenue-generating multimedia services while leveraging their existing infrastructure.

Dan Bantukul, Tekelec’s Product Marketing Director for Next-gen Solutions, says, “In talking to operators about future technologies, we find they gravitate toward IMS as the technology of choice for evolving the core network into the next-gen space. However, IMS deployments are appearing slowly, for various reasons. Even so, next-gen traffic continues to rise, and many operators are concentrating their efforts into Next-Generation Networks (NGN), or what we call the pre-IMS SIP (Session Initiation Protocol (News - Alert) ) network. Operators are laying fiber to the curb to deliver next-gen services. International and national voice-over-IP (VoIP) traffic is up. WiMax is being deployed, and wireless long-term evolution (LTE (News - Alert) ) is being planned for. Many access technologies are coming online, but the core network is not quite ready for it, because IMS is being delayed.”

So how will the core network handle all of this traffic? “The NGN hasn’t been constructed the way you’d normally put a network together. It’s voice-centric, handles VoIP, and is built from many disparate softswitches that connect point-to-point – creating a virtual mesh network,” says Bantukul. “It’s difficult to evolve a network like that into one that can support multi-media services, such as IPTV (News - Alert) . If IMS doesn’t come into full play for a while, then operators must figure out how they can handle multi-media service delivery, and how they can grow their NGN in the meantime – without resorting to the creation of discrete vertical solutions within the network.”

“The NGN needs help from an architectural standpoint,” continues Bantukul, “and that’s why many operators come to us in search of solutions. They want to understand how to make their network more media independent rather than voice-centric. They have questions about scalability. It’s expensive to scale a network, and it’s very difficult to maintain the network when it grows beyond a certain size. Networks may have many point solutions deployed, especially those dealing with media, such as VoIP, messaging, and instant messaging, and none of these point solutions interoperate. Operators want to evolve their NGN so they can address their immediate business requirements today and at the same time align their network to where they want it to evolve to in the future, which is IMS. They want the benefits of IMS today, without all of the associated, up-front costs.”

“As it happens,” says Bantukul, “at Tekelec, we can achieve this by doing one quite simple thing – implementing a control layer on top of the next-gen network with our TekCore Session Manager (see sidebar). By ‘control layer’ I mean a SIP session-management or proxy layer on top of the NGN access layer. If you look at the RFC 3261 document describing the SIP architecture, it introduces the idea of a proxy to facilitate connectivity and routing as well as the service invocation.”

Today the NGN architecture is based on softswitches doing point-to-point SIP-based connections with each other, which is how the media flows. By overlaying a control layer, we can provide connectivity from the SIP signaling standpoint, and more importantly, utilize SIP in the way SIP signaling should be used, separating signaling and media so the network can be media independent instead of voice-centric.

By deploying SIP proxies on top of the NGN network, you set up a SIP signaling framework so that two SIP endpoints can talk to each other. Then, the media can be negotiated independently between the endpoints, which is essentially the same concept IMS brings to the table.

“Every IMS architecture slide out there depicts separate, horizontal layers for access, signaling and session control, and applications. We’re making this a reality with the SIP signaling framework. This approach allows operators to leverage their existing VoIP-only NGN to also support the deployment of multi-media services,” says Bantukul.

So what is the impact of this architectural change? Tekelec’s Ben Campbell, Principal Engineer, says, “Really, this isn’t an architectural change. What we’re doing is going back to SIP fundamentals, rather than using more proprietary media-path elements, which don’t play well in the basic SIP architecture. There are various extensions of SIP, and they all have a purpose. For example, SIMPLE (Session Initiation Protocol for Instant Messaging and Presence Leveraging Extensions) is used in applications involving presence. The important thing is to build out the network in such a way so that when these extensions of SIP arrive in the network, they can be introduced with no problems. For example, right now it’s very difficult to implement SIMPLE on some NGNs. Existing NGNs include SBCs and softswitches, which get in the way of these extensions, and proxies don’t. There’s another benefit of using a SIP proxy. It can act as a single point for SIP interoperability between proprietary variants of SIP used by the various softswitches.

There are also ancillary protocols that use a more open or standards-based approach to traverse firewalls and network address translation (NAT), such as STUN (Simple Traversal of UDP (News - Alert) through NATs) and TURN (Traversal Using Relay NAT). The conventional approach to NAT traversal and other media-path issues is a proprietary one using SBCs, which can cause architectural problems. The more open approach (TURN) makes it easier to deploy new service and new media types.”

Campbell continues: “So what we’re talking about is implementing a framework on top of the NGN so that the NGN can grow, be media-independent and more easily evolve into an IMS network in the future.”

“Even though IMS is progressing slowly,” Bantukul concludes, “NGN traffic is increasing on an architecture that can’t support the growth of the next-gen services operators want to deploy now. Our vision is to overlay a SIP control layer, a proxy layer, on the next-gen network so operators can leverage their existing NGN infrastructure investment to support the future services needed to answer today’s business needs. That way, operators can deploy exciting new services now – without all the initial IMS costs, while laying the groundwork for their eventual migration to IMS in its entirety.”

Richard “Zippy” Grigonis is Executive Editor of TMC’s (News - Alert) IP Communications Group.

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