VoIP's Big 'Brain' Gets Its First Test


Cable Television Laboratories Inc. has literally flipped the Internet-protocol switch, opening the first official testing round for the future brains of cable's voice-over-IP networks.

Amidst a slew of devices in the cable consortium's current certification wave 25 are two PacketCable 1.0 hopefuls from a brand-new category: call-management server. Commonly referred to as softswitches, CMSs are an IP voice system's nerve center, handling all of the call functions of a standard class-5 circuit switch.

Therefore, many consider gaining PacketCable CMS qualification to be a key in convincing MSOs that the technology is ready for deployment.

"The softswitch is really the key element to voice-over-IP," said Glenn Russell, director of CableLabs's PacketCable initiative. While the first multimedia terminal adapters and cable-modem termination systems gained PacketCable approval in the last round of testing, "this is something new. The softswitch is the brains of the network that controls both the CMTS and the MTA, so it is a big step."

In the last CableLabs certification wave, several providers took part in a CMS practice testing round. But by the time Certification Wave 25 began, there were just two CMS systems submitted, by Syndeo Corp. and Cisco Systems Inc.

A CMS from Cedar Point Communications Inc. is also going through a practice test, and eight or nine other CMS units are being prepared for future rounds of certification, Russell said.

Syndeo founder and CTO Ted Griggs is encouraged that testing has begun, even if it's with a small class.

Proof positive

"In talking to the operators, the qualifications are extremely important before voice gets deployed," he said. "This is sort of externalized proof that people are ready with standards for interoperability."

While the testing wave will evaluate CMS functions, it will not include media gateway controllers, which serve as the link between IP networks and the public switched-telephone network. Instead, gateways will be added to tests in certification wave 26.

This presents something of a quandary for Syndeo, because its soft switch contains the CMS and gateway elements.

"That's where it is not clear yet, what the operators are going to say about what they really want to see completely qualified," Griggs said. "Will CMS qualification be acceptable if you have a media gateway controller in it?"

At least one cable operator with plans for major voice deployments said it would. Delaying gateway tests is not a big deal, said Comcast Corp. senior vice president of new media Steve Craddock, given that it's far more important to meld the CMS function into the existing Data Over Cable Service Interface Specification network.

"With VoIP, the thing that you really need to go to the field with is to make sure that your switch — or the telephone solution that you use — will work with a DOCSIS network," said Craddock, who also is one of the original PacketCable authors.

Gateways "are very well known and manageable. Now, we want to optimize them for cable, but I can live with those today," he said. "The thing I really need to be able to go do this stuff in the field on a trial or otherwise, is for it to work on the access side."

Comcast trial underway

Indeed, Comcast is already busy with a VoIP trial in Philadelphia, testing several combinations of gear, including CMS units from Syneo and Cedar Point.

Comcast is also interested in the next-generation multimedia IP services that a PacketCable system can bring, but the MSO is not in a big hurry, Craddock stressed.

"PacketCable and VoIP is likely to be a nice service at some point. It's one of those things where there is not a gold rush to run out there and do it," he said. "We've got time, and we want to make sure we get it right the first time so we don't have to deal with half-baked solutions."

Back at CableLabs, the start of CMS testing has brought voice-over IP full circle, according to Russell.

"It's the fact that voice-over-IP started with the idea of the soft switch, and from that evolved a whole architecture for voice-over-IP — PacketCable," he said. "Now it is a major milestone that we are able to qualify that component, which is one of the more complex pieces of telecom-networking equipment that anyone will ever see."