News regarding IP Multimedia Subsystem (IMS) technology often comes in batches, driven partly by the cycle of IMS Forum ‘Plugfests.’

The group held its seventh such event June 1-9 at the University of New Hampshire Interoperability Lab (UNH IOL) in Durham, N.H. The eighth is slated for Oct 5-9.

Related news about session initiation protocol (SIP), which sits in the middle of an IMS architecture, also tends to be niche. There are numerous systems integrators, for instance, who are working out real-world interoperability among SIP-based VoIP components and features.

As for deployments, news has tilted internationally of late.

In February, Kabel Deutchland (KDG) began rolling out a Homebox, an IP-based voice and data gateway with built-in SIP client that leaned upon Camiant’s policy control server for transitioning customers over from legacy sevices. Throughout July, session border controller (SBC) provider Acme Packet announced both network interconnect and residential IMS applications deployed with providers in Sweden, Germany and Bolivia.

Business and cost structures

That said, both technologies are playing quiet roles within the North American MSO community.

The noisier of the two is SIP. Over the past year, applications geared toward business services have figured in articles written by engineers from Cox Communications and Atlantic Broadband. (Click here for “SIP Trunking for Cable,” from April 2009, and here for “Case Study: SIP Business Voice,” July 2008.)

Business voice is a logical first place for SIP applications.

“From a business perspective, it’s a natural place to do it,” Franklyn Athias, Comcast senior vice president, IP communications and services, said in an interview earlier this summer. “A lot of the PBXs support SIP.”

The successive rounds of interoperability events might lead one to suspect (as did Hamlet of his mother) that IMS Forum “doth protest too much.” As far as the SIP piece of the puzzle goes, at any rate, Athias put it in this context:

“Not all SIP is SIP. There’s a lot of interop. But it usually takes only a couple of weeks. Some of the things that need to be changed are really minor.”

There remains that crucial link between the two technologies. “IMS is the lead service engine for people talking about doing anything for SIP,” he said. It’s a complicated engine that MSOs have been tinkering with for years.

Athias said that Comcast was investigating then proprietary implementations of IMS as early as 2001, and has kept at it over the years. “We (Comcast) and Time Warner and Cox were the drivers for making IMS the baseline for what PacketCable 2.0 is today.”

Granted, PacketCable 2.0 has been baked and sitting on the shelf for several years. What may drive action toward IMS sooner than later is a new emphasis on the business case, namely: what Athias said was the “huge difference” in infrastructure costs between softswitch and IMS components.

Compared with a more niche PacketCable 1.5 softswitch universe, IMS infrastructure players are large players “competing for not a lot of pies.” The large supply and limited demand translates into attractive prices.

It also helps that IPTV is no longer a taboo topic. “We’re watching the OpenIPTV Forum,” Athias said. “One of the benefits of IMS is that it’s not just a voice application.”

Indeed, as Athias—and no doubt any competitive service provider—understands, IMS is a “last-mile agnostic” platform, wherein television becomes a matter of “kicking off a video session.”

—Jonathan Tombes

The Daily



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