Sexy technology sells. Though it might be hard to imagine something with the name IP multimedia subsystem architecture as a sexy technology, somehow the allure of IMS has captured the imagination of not just the wireless industry but the telecom industry at large. The promise of the converged network, a single communications system and the fluid blending of applications that were once isolated from one another have lent themselves to the technology's appeal.

Although carriers are taking their first steps toward IMS, the full impact of the technology won't be seen for years. There will be a Wi-Fi/cellular device here and perhaps a fancy video calling application there, but that amazing leap forward in the way we communicate will be elusive to the end user in the near future. The changes will start happening in the core of the network, focusing on what is a distinctly un-sexy technology that promises capex and opex savings, that streamlines network operations and improves call efficiency — all innovations to which customers will be oblivious but to which carriers are paying close attention. It may not be sexiest element of IMS, but it will be one of the first deployed: the mobile softswitch.

While mobile operators are looking at softswitching as an evolutionary step toward IMS, the biggest driver for the technology is in its ability to handle the growing demands of the current-generation network. Massive subscriber growth coupled with ever falling revenue per voice-minute is forcing them to re-evaluate the architectures of their core networks. Most operators aren't overhauling their networks entirely, but many have capped spending on legacy mobile switching centers (MSCs) and are pouring their continuing core capex into next-generation platforms.

“I'm focused on near-term planning right now,” said Bill Maybery, executive director of MSC planning for Cingular, “Network planning is heavily driven by the efficiency gains we can achieve now. The softswitch architecture is much cheaper and generally drives down the cost per port. My view is if it's got call servers and media gateways and it saves me money, I'm all for it.”

And those savings are quantifiable. Carriers and vendors claim softswitching and next-generation distributed architectures can drive down costs per port between 20% and 30%. Softswitching also relates directly to physical plant costs. According to mobile media gateway maker Tekelec, an MSC serving a large market or region can occupy 2000 to 3000 square feet, requiring appropriate power and cooling facilities as well as staff. By centralizing the softswitch and installing a gateway in place of that MSC in the same market, you need 100 square feet and only a fraction of facilities costs, said Payam Maveddat, Tekelec assistant vice president of product management.

“Carriers are not just putting their growth into this new architecture, they're actively looking at replacing their legacy architectures,” Maveddat said.