PacketCable Tests Firm Up Cable's IP-Telephony Link


This week's Supercomm may focus on the telcos' advances in the realm of Internet protocol and voice services, but there's no moss growing on cable-industry efforts, either.

Though the first two testing waves of Cable Television Laboratories Inc.'s PacketCable initiative may not have produced certified devices, the project has dialed into next-generation IP services nevertheless, according to its director.

"I think sometimes because we haven't made a certification or award yet, or nobody has passed all of the tests, people might say, 'Well, nothing has happened yet,' but that's a wrong way to look at it," said PacketCable director Glenn Russell. "I think there has been an incredible amount of progress."

The PacketCable project builds on Data Over Cable Service Interface Specification 1.1 and is an effort to add the framework to control and direct the myriad of next-generation devices envisioned for future cable networks, including IP voice and multimedia applications. So far, the initiative has been busy with a series of interoperability events to test how the fledgling specifications bear out with real equipment.


The first few interoperability events have focused mostly on local-access devices such as cable modems and associated media terminal adapters (MTAs) for voice products, as well as the call-management server, the media gateway and the cable-modem termination system, Russell said.

Still yet to make it to the testing block are the devices found deeper in the network, including the next-generation GR303 gateways and terminals that translate IP traffic into switched signals to link into standard class-5 switches.

It's a matter of choosing priorities, and the initiative has its hands full with devices closer to the subscriber, Russell said.

"We haven't set a timetable when to test these IPDTs, IP digital terminals, which is the box that goes between the MTA and the class-5 switch," Russell said. "We are considering bringing some of those [GR303s] in, and really it is just a function of there are so many components already."

And at least lately, the number of electronics providers coming into the PacketCable project has gone up, Russell noted. That's possibly due in part to the growing cable-telephony market.

This year, 28 vendors have brought various components in for interoperability testing.

"You have some new vendors who may have overlooked cable in the past that are coming to the industry, and bringing products that they might have planned in other spaces, and recognizing that, 'Hey, this is pretty close to what the cable solution is,' and so they are bringing their equipment here," he said. "Some of them are from other areas of the voice-over-IP industry, or the CLEC (competitive local-exchange carrier)/telco space. Some of them are brand new."

The level of sophistication is also increasing, as vendors offer different combinations of IP functions. Predictably, MTAs are in fashion, as vendors look to combine IP data and voice functions.

"We've got probably more than a dozen that have been here – it's mostly the cable-modem vendors who have looked at our MTA specs and added the telephony functionality to the cable modem," Russell noted. "That's where we have seen the most development be furthest along."


The next big thing may be the call-management servers and soft switches, which are only now beginning to surface in product form.

"That is still the critical component of the architecture," Russell said. "We've seen some great progress there, but that's still the heart of voice-over-IP.

"So that is where the most opportunity is. There has been some great work done there, but the industry will really take off based on the results in that area."