Introducing the “Applications Session Controller”

In case you haven’t noticed, the types of network elements used in IP Communications have proliferated in recent years. New network functions inevitably lead to new technologies and a new crop of new acronyms and initialisms. The first and most noticeable of these was the SBC (Session Border Controller), that jack-of-all-trades device that sits between the calling and called parties in a VoIP call, processing signaling and/or media streams involved in setting up, conducting, and tearing down these calls or “sessions”. (Back in 2003, Jeff Pulver briefly tried popularizing the term “voice router” which had been applied to SBCs, but that didn’t seem to catch on.)

Then came IMS (IP Multimedia Subsystem) and all sorts of new network elements appeared - though some of these “new” devices had the same basic functionality as existing network elements, and simply had new names. For example, the HSS (Home Subscriber Server) or UPSF (User Profile Server Function), the main user database and authentication center used in IMS, is similar to a wireless network’s HLR (Home Location Register) and AUC (Authentication Center). And the IMS network’s P-CSCF (Proxy-Call Session Control Function) is a SIP proxy server that’s essentially a Session Border Controller.

Now, however, AppTrigger (www.apptrigger.com), a Richardson, Texas-based company, has announced the development of a new class of network element: the Applications Session Controller (ASC).

Patrick FitzGerald, Vice President of Marketing at AppTrigger, says: “The Applications Session Controller resides between the applications service node and the core of the network, where it provides interworking from network-to-network and enables an applications package to traverse the multitude of networks to ensure that the service subscriber has access to the same applications features on the wireless side as he or she would on the wireline side.”

“We’re arguing from a network perspective that, fundamentally, a new piece of equipment is needed by a service provider,” says FitzGerald. “The ASC, situated between the applications and network core, provides ongoing network connectivity for all of the different applications that the provider offers on its networks. The ASC scales extremely well, and we’re able to deal with a variety of APIs so that we can interwork with the majority of applications currently deployed by service providers.”

FitzGerald drills down: “We feel strongly that this new category of network element is needed because, first, the network is always evolving and service providers are always optimizing their current network to take advantage of new technologies and new bandwidths. And, in turn, every time that they do that, the constant evolution of leveraging new technology impacts applications that are currently deployed on their networks, or it impacts the current application deployment model. We want to help the service provider by isolating the applications and removing them from the constant evolution of the network.”

“This also ties into IMS,” says FitzGerald. “I’d argue that our technology serves as a very good transition, if you will, in taking old traditional IN [Intelligent Network] applications and bridging them into the upcoming IMS network.”

All-in-all, it looks as if the ASC will be a welcome addition to both networks and Scrabble games the world over. IT

Richard Grigonis is Executive Editor of TMC’s IP Communications Group.

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