The hype storm spinning around IP multimedia subsystem (IMS) reached a frenzied force earlier this year, and if you believed everything you heard, it seemed that technologies based on IMS would see real-world rollouts in cable systems almost instantaneously. But virtually all sizeable moves forward in cable engineering are evolutionary, not revolutionary.

IMS has been hailed as the answer for removing barricades between wireline and wireless by offering a single enhanced services architecture to deliver any service to your subs no matter how they connect -- when roaming, or from their home networks. The IMS architecture uses a VoIP implementation based on a 3rd Generation Partnership Project implementation of SIP, and runs over standard IP.

IMS Isn't Instant

"There was a perception that there'd be a flash cut to IMS," Elaine Smiles, director of cable marketing at Nortel, says. "One day you're not IMS, one day you are."

Of course, that's not how it is, she adds. We have indeed already seen major MSOs feeling out IMS technologies in '06, but a lot of that work won't go to market trials with real subs until 2007. Longer term, Smiles foresees around five years to "mass market."

Despite the time it will take, Smiles is quick to underline that MSOs are definitely committed to the potentials of IMS. At a recent Nortel conference, several cable ops in attendance said they were on the same page in terms of their true buy-in to making IMS work smoothly in their nets.

What IMS Really Is

Dave Spear, EVP, strategy and market development at Cedar Point Communications, puts it simply: IMS is a new, SIP-based, infrastructure built for wireless networks. It has added a routed control plane for messaging and signaling between elements, networks and end points. "Basically, a bunch of SIP-based proxies called CSCFs make up the core," Spear explains.

IMS will access application servers, as applicable, to deliver the service requested. "Application servers are like today's softswitches," Spear explains.

"It is all about mobility," he continues. "IMS is essential for portability of services across all devices. So if you don't have plans for mobility, IMS is unnecessary and added overhead."

Of course, many cable ops do have plans to parlay their triple-play into the quad-play by adding wireless, so the potential return on investment is not in question. The question is the true timeframe that IMS can happen, Spear stresses.

He says we shouldn't expect to see the first real IMS services rolling out in cable networks for a while. Interops and certification based on the developing CableLabs PacketCable Release 2 (formerly called PacketCable 2.0) integrating IMS won't happen until 2007. So, products based on that release probably wouldn't see a cable network with real subscribers until late 2007 or early 2008, he predicts.

Back in April, CableLabs issued a series of specs as part of PacketCable that were developed in alignment with the IMS architecture developed by the 3GPP. Using widely accepted standards-based protocols, such as the IETF's SIP, these specs offer ops a flexible way to deploy network capabilities as required by their specific service offerings, while maintaining interoperability across a variety of devices from multiple suppliers.

That CableLabs announcement flamed the fires already swirling around IMS. But it's important to note that combining PacketCable with IMS isn't a simple task, Andy Randall, VP of marketing at MetaSwitch says. The 3GPP IMS standard was originally designed for the cell phone business, and it needs significant tweaks to work well in an HFC net.

"But IMS may well be the technology defined by the wireless companies, popularized by telephony and deployed by the cable companies," Randall says.

He points out that while telcos have hyped IMS, they're not as nimble as cable. Randall sees MSOs moving on it much more quickly than the competition.

Nortel's Smiles concurs with that idea: "We expect cable ops to be among the first [to deploy IMS]. There's more of a convergence opportunity for cable."

Cable's Evolutionary Moves

Mike Clement, director of market management at Siemens Communications sees deployments happening in cable in the second half of 2007 with major rollouts in '08.

"It is true that standards are still evolving, but we have been working with [3GPP] IMS standards from the start and have developed IMS products from the ground up to support this architecture," Clement says. "We are currently in Release 5.0 of our IMS solutions and have more than 40 trials and 10 deployments worldwide."

Of course, those include many different types of service providers. One of those Siemens IMS demonstrations was with Time Warner Cable, which showed an integrated fixed mobile solution for voice. and displayed how additional multimedia services can be integrated using the same IMS architecture.

In Part 2 of this special report, we'll take a closer look at TWC's IMS explorations, as well as discuss cable ops' needs to ensure that capital equipment deployed today will meet their needs as they migrate in a steady, measured way to an IMS platform. Part 2 is set to arrive in your email box on Dec. 5.