With the FCC’s order mandating Enhanced 911 (E-911) compliance for VoIP providers looming, many firms won’t be able to comply completely with the order by the Nov. 28 deadline, according to several participants at an Internet telephony industry conference recently in Boston.

At one session in which the issue was discussed, a consensus developed that all VoIP providers won’t be able to comply.

The chief stumbling block centers on “nomadic VoIP,” a reference to the movement of Internet telephoning between different locations.

At the same time, Vonage, the largest provider of paid VoIP in the U.S., said it had reached an agreement with Level 3 Communications to provide the E-911 nomadic service. In addition to the deal with Vonage, Level 3 has announced agreements to supply its Level 3 E-911 Direct service to Earthlink.

Charles J. Meyers, Level 3 Group vice president of marketing, said in an interview that Level 3 had anticipated the problem two years ago and began working to have E-911 service available. The firm currently covers 67 percent of the nation with the service and expects to reach the 70 percent mark soon.

“We made the investment up front,” said Meyers. “(Users) must reregister and if they do we can provide nomadic capacity.” To utilize the service, users must “provision” or register or reregister their device location. If the location is supported by a local PSAT ( public safety answering points) users will be so informed.

Meyers said the service will improve over time, for instance as GPS capabilities are enhanced. “Over time it will be more automated,” he said.

Vonage is employing Level 3’s interconnection infrastructure into hundreds of routers across the country as it begins the deployment in the fourth quarter. “Vonage is running hard and fast to met the FCC’s 120-day deadline to turn up E-911 service throughout our footprint,” said Vonage senior vice president of architecture Martin Hakim Din in a statement “Physical connectivity is the first critical piece of infrastructure we need to build to get our calls to the selective routers.”

Level 3 also announced it is providing VoIP E-911 services to EarthLink. Another E-911 provider is Global Crossing, which is offering the service in 40 urban markets in the U.S. In keeping with FCC regulations, the nomadic VoIP service utilizes Automatic Number Identification (ANI) and Automatic Location Identification (ALI) features when emergency calls are connected with PSAPs.

Key infrastructure is also delivered by mission-critical wireless communications providers. TeleCommunication Systems (TCS) provides crucial routing and location services to Level 3. Another provider of the mission-critical infrastructure is Intrado.

Informal discussions at VON sessions revealed a consensus that many VoIP providers won’t be able to comply entirely with the Nov.28 FCC mandate. Some participants noted that in some locations master street address guides don’t exactly match postal addresses, presenting a potential problem. Number portability, in which a user can carry a phone number out of a home region, is another issue confronting the providers of E911.

Monica Marics vice president of product development at Intrado, told a session on VoIP at the VoIP conference, that Intrado was “confident” of its technology meeting the Nov. 28 deadline. She also said other wireless technologies – like Blackberry e-mail – will likely be required to face the E-911 challenge in the future.