Demand on the increase for end-to-end session management

Telecommunications Americas, July-August, 2004

As service providers carry more and more telephone calls via voice-over-IP (VoIP), they are finding a need for session management that goes beyond the network edges and into the network's core. At the same time, there must also be control at the edges to traverse firewalls and Network Address Translation devices [NATs] that, while they have meaning and purpose in data networks, are serious obstacles to the delivery of IP voice services.

But that's only the surface need that session controllers fulfill because VoIP is, after all, just the beginning of a multimedia applications experience that will transform traditional phone networks into pipelines that simultaneously carry voice, video and data traffic between carriers, to enterprise users and ultimately to consumers themselves.

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Despite the way they appear for the end user, these services are still packetized data that must optimally traverse the networks. Since each packet, or service, has its own peculiar characteristics, a service provider must understand the inherent elements of the data and take steps to prioritize or de-prioritize packets for a successful end-user experience.

"You need session controllers for all the layer 5 routing, management and control aspects of voice-over-IP, as opposed to simple layer 3 packet forwarding," explains Raj Sharma, president of NexTone Communications, a company strategically placed in the center of the session controller space.

NexTone is focused on providing end-to-end session management solutions that cover all the internal network needs, such as traffic management and edge interconnections between IP networks. NexTone session controllers utilize the unique suite of FlexControl technologies, including FlexPeer, FlexRoute and FlexPolicy, to address the complexities of signaling interoperability and media processing at network peering points. FlexPeer resolves incompatibilities between VoIP devices by adapting session signaling while providing control to route, process and manipulate session media. FlexRoute enables carriers to develop very granular and highly programmable facilities to govern the routing of real-time traffic over their IP networks while FlexPolicy ensures that carriers can manage and control session traffic.

For NexTone, session controllers are multidimensional problem solvers that go far beyond the normal session border control aspects of security, call admission control and signaling interoperability that most vendors provide. Using FlexControl technology, NexTone delivers a rich set of solutions that includes routing traffic as it enters and leaves the network while managing traffic within the network for quality and packet prioritization.

NexTone's solution goes beyond traditional layer 3 routers because it uses session information based on the types of sessions traversing the networks or the end points to determine how traffic is actually managed.

"Routers offer best-effort service," says Sharma. "Before service providers set up a voice call, they want to make sure the call can be completed and if so, to choose the best, most profitable route."

NexTone makes that happen through several key steps, "things like least-cost routing and route hunting to find the best route for a particular call," says Sharma. "NexTone is very different than competitors who are narrowly focused on one dimension of this problem, which is the border."

FlexPeer

The agility to adapt the network is especially important now as the peering points and network-to-network connections move from TDM, or traditional circuit-based equipment, to IP. ITXC, a global carrier's carrier, already exchanges over 30% of its traffic directly over VoIP interfaces with its peer carriers, using this lower-cost and much more flexible approach than traditional TDM interfaces. It's a trend occurring across the entire carrier space.

To make VoIP connections between evolving networks simple and seamless--and therefore a less costly and time-consuming process--ITXC uses FlexPeer technology.

"We must have a clean and crisp boundary between our network and the other network so we can pass traffic, maintain quality and maintain call detail records," says John Landau, ITXC's Executive Vice President of Product Management. "Many networks are starting to install VoIP backbones and once they have a VoIP backbone between their different points of presence, you can talk to them using VoIP directly."

Starting its existence as a VoIP carrier seven years ago, ITXC is capitalizing on the IP revolution that is beginning to overtake some of the entrenched voice carriers.

"All the early adoption of voice-over-IP happened because of this huge requirement for carriers to interconnect with each other using IP and it is the foundation for the business and the space," Sharma says.

Later pieces of technology, he says, were developed to enhance the IP experience while helping providers get more from their networks. NexTone gained incomparable expertise from supporting high volume production traffic among and within a very broad range of disparate VoIP networks. Many NexTone product enhancements were learned through extensive customer deployments rather than experience in a lab environment.