The truth about IMS

Publicly, both Mark Wegleitner, senior vice president of technology for Verizon, and Chris Rice, executive vice president of shared services for AT&T, used a NXTcomm08 keynote panel to describe IMS as “a journey, not a destination,” saying elements of IMS are appearing in their networks today, but there is much more to come. Both men stressed the ongoing importance of IMS, however, in enabling them to open their networks to third-party developers so that services can be developed and deployed much more quickly while providing a seamless experience.

“Is IMS necessary for convergence? No,” said Pieter Poll, chief technology officer for Qwest Communications, on the same panel. “But it gives you a lot of benefits in terms of standardization. Today within Qwest, Web 2.0 services and IMS are co-existing, and we need them to be complementary because if you can get seamless support of Web 2.0, there is a great tide of content to be delivered.”

Jim Hansen, senior vice president for network services for Embarq, agrees with a more gradual IMS deployment.

“There are things being done today within Embarq that would qualify as being part of IMS,” Hansen said. “We get so hopped up on having to buy a big IMS system, and that's not the way it's happening. But that doesn't mean nothing is getting done. We won't go out and buy a platform now, but we will build it over time, based on the piece parts we are using today, including a lot of things we are already doing around fixed/mobile convergence.”

“People who think IMS is coming in a year have no understanding of how telecom works. We're on a 15-, 20-year trajectory with IMS deployments,” said Steve French, senior product marketing manager for Tekelec.

Tekelec is having success with a stepping-stone approach, working with carriers to deploy its SIP Session Router platform, which creates a routing consolidation point in session initiation protocol networks without forcing carriers to fully go to IMS. Such evolutionary steps to IMS are becoming popular. NEC is in its first field trial with a Latin American carrier using its “light IMS” platform, which does away with the centralized IMS home subscriber server database — something that seems to be an overall IMS deployment trend — and uses more readily available IETF-based SIP servers rather than 3GPP/IMS SIP servers, said Nick Satomi, vice president of business development for NEC.

The need to play nicely with already deployed gear comes into play strongly in the wireless realm — where IMS began. Even if wireless operators deploy IMS in the core, the availability of IMS clients is few and far between. An IMS-capable handset requires several protocols, including IPSec to secure the communications channel, SIP to handle signaling and call setup and teardown, and VCC for voice call continuity and network handoff. “I think IMS will be a standard on the handset someday, but someday is not tomorrow,” said Rick Pitz, senior product and business development manager for vendor Certicom.