Much of the discussion at the 2005 VoIP: Telephony conference — produced by Telephony and Wireless Review and held in Chicago on June 6 — focused on the IP multimedia subsystem architecture and its current and future role in the evolution of voice-over-IP technology. While some panelists disagreed on the potential of IMS, they were unanimous in their belief that VoIP eventually will dominate the telecom landscape in both the residential and enterprise markets.

Keynote speaker Fred Lax, CEO of Tekelec, characterized IMS as a complex architecture that is a work in progress, and said no vendor currently has a complete IMS solution. He also said IMS has been over-hyped and has “received a pass on a lot of important issues that aren't going away.”

“IMS isn't a magic bullet, but it holds enormous promise,” Lax said. “Some solutions are ready now, and five years from now it will be a done deal. Service providers need to create evolution plans to make sure they're around when that happens.”

Phil Holmes, chief technical officer of BT Exact, said in a later breakout session that a lot of people are still feeling their way on IMS, but disagreed that the technology has been over-hyped. “IMS is a relatively mature technology, but the applications aren't as mature,” he said.

Roger Heinz, vice president of Lucent Technologies' convergence solutions group, agreed that IMS-based applications represent a tipping point.

“The key for both vendors and service providers will be whether we can deliver applications that end users want,” he said. “That will determine whether IMS will be successful.”

While there is demand for VoIP services from both enterprise and residential customers, vendors and service providers don't know specifically what their customers want right now, said Von McConnell, director of IMS development for Sprint.

“There are a lot of golden nuggets out there, but there also have been a lot of hyped technologies that never went anywhere,” he said. A firm grasp of customer needs also would help service providers determine which applications truly require IMS, McConnell said.

“Some things don't make sense to be IMS, but no business case exists to determine that,” he said.

Heinz agreed. “People forget that IMS was developed for simple applications,” he said.

While panelists debated the relative merits of IMS, they seemed in complete agreement with the notion that VoIP eventually will transplant TDM as the technology platform of choice among telecom service providers. However, a plethora of network and operational hurdles must be cleared at both the service provider and customer levels before that happens.

It also probably won't happen as fast as many people think, according to Mark Kaish, vice president of next-generation services for BellSouth, who also delivered a keynote address during the conference.

“The world is going to change, and VoIP is going to be a part of it, but it's not happening as fast as the hype,” Kaish said.

A hindering factor is that potential VoIP customers often take a “if it isn't broken, don't fix it” approach to technology upgrades. “They recognize VoIP is the future, but they're not in any hurry,” Kaish said.

Another hindrance is cost, which can range from $600 to $1000 to upgrade a station in the enterprise to IP, Kaish said. “This is a very tough business case unless you can prove productivity gains will result,” he said.

In addition, it's often difficult to merge voice and data staffs within an enterprise, most companies lack the security expertise to support VoIP, and quality of service and bandwidth concerns persist, Kaish said.

Troubleshooting also is far less effective in a VoIP network than it is in a TDM network, said Mark Pugerude, senior vice president of marketing and business development for Broadwing Communications and another keynoter.

“There are lots of tools in TDM networks to fix problems, but not so in IP,” he said. “Typically, you would triage to find problems, but you can't do that in VoIP because there aren't enough tools.”

Nevertheless, VoIP currently is thriving in greenfield network builds where such deployments recently exceeded TDM deployments for the first time at BellSouth, Kaish said.

VoIP also is being watched carefully by the public-safety communications sector, specifically at the nation's public-safety answering points (PSAPs), which handle emergency 911 calls. Bill McMurray, president of the National Emergency Number Association (NENA), which represents emergency call centers across the country, told conference attendees that the recent FCC order requiring VoIP providers to offer the same enhanced 911 services made available by wireline and wireless carriers likely would lead to technologies that improve the performance of both PSAPs and first responders in the field. PSAPs are eager to leverage the advantages of an IP-backbone infrastructure, which would make possible a plethora of advanced applications.

“Therein lies our pathway to our future network design,” he said. “The solutions you develop for the nomadic consumer will present needed solutions for a myriad of other problems.”

McMurray added that PSAPs and VoIP vendors could learn a lot from each other and urged vendors to begin a dialogue with NENA. He said PSAPs need an intensive training program regarding IP-related issues and that NENA wants to train the telecom industry on what PSAPs need in terms of IP-based capabilities to facilitate the development of PSAP-friendly systems.

“We need to learn from you, and you need to learn from us,” he said.