New DOCSIS Spec Writes Integration Law

Think of it as sort of a DOCSIS preservation project for the diversifying cable ecosystem.The latest addition to the Data Over Cable Service Interface Specification family, embedded DOCSIS, is aimed at preserving its older siblings as cable-modem technology migrates from computers to other devices in a broadband household.

It also could lessen cable operators' headaches as their systems expand to oversee an increasing number of consumer devices.

Embedded DOCSIS is in the final draft stages at Cable Television Laboratories Inc. When the specification is completed in 2003, it will for the first time provide guidelines for building DOCSIS cable modems into non-computer devices, ranging from digital set-tops to media gateways to more exotic future devices such as the oft-threatened Internet-enabled refrigerator.


The eDOCSIS project was born about nine months ago at CableLabs, prompted by an increasing flow of products submitted for DOCSIS certification that went beyond stand-alone modems — including media terminal adapters for voice, set-top boxes and media gateway devices.

The problem was, there were no guidelines to do so, according to YAS Broadband Ventures LLC chief architect and CableLabs consultant Doug Jones.

"One supplier would throw it in one way, another supplier would throw it in another way, and a third supplier would do it a third way," he said. "And the trouble was from an operations standpoint, the cable operator was not maintaining the DOCSIS cable modem management views."

In particular, CableLabs found evidence some vendors were subtly bypassing certain modem configuration elements, giving packets delivered to and from the modem more priority than authorized by the cable operator, Jones said.

"So we just wrote in the rules that your product has to respond to these certain filters and QOS settings," he said. "We want to be sure the operator configuration is always there and affects all of the packets that go onto the cable network."


Among other things, eDOCSIS will define how the modem interacts with a device, while at the same time separating its functions so cable operators can still provision and monitor it. The guidelines apply whether that integration is in systems or directly on silicon.

"In a sense eDOCSIS doesn't really change DOCSIS cable modem protocol — it changes how it is slapped into the box," Jones said. "If you've got a modem, you expect it to look like a modem and quack like a modem and have all the same management visibility as a modem."

But while it has been on a fast track, the specification is still in draft stages. CableLabs recently readied eDOCSIS for the first wave of certification, and it is working to produce enough information to provide preliminary tests for devices coming in during Wave 25, set to begin in Jan 15.

The goal is to have the specification finalized in early 2003, with interoperability testing in Wave 26 in late spring and start the first formal certification testing in Wave 27 in September.

"But we will have enough information in everybody's hands and our own people, so that if somebody wants to show up in Wave 25, they are not violating eDOCSIS," CableLabs senior executive consultant Rouzbeh Yassini said.


Given the crop of multimedia devices now on vendor drawing boards, speed was crucial in developing the eDOCSIS guidelines.

"The good news is we caught this earlier this year when we were doing preliminary work with the PacketCable MTAs and residential home gateways," Jones said. "These products are not certified yet — they are not deployed yet. But we've caught these issues with DOCSIS modems, and the eDOCSIS effort is to clarify stuff and get it straightened out before those particular products hit the market."

It also paves the way for future products ranging far beyond just computers.

For chip giant Broadcom Corp., which provides much of the silicon used in cable devices, the new specification will help drive development of cheaper products with a wider consumer reach.

In particular, separating the DOCSIS functions from the device will lead to speedier product development.

"It's one thing to certify a modem; it's another thing to certify a $10,000 refrigerator," said Rich Nelson, Broadcom's director of marketing for broadband communications products. "If you are going to get to a really low cost device, can it go through certification waves at CableLabs for each model of toaster oven it is embedded in?"

While DOCSIS-enabled refrigerators might be far-fetched, Nelson said there are real near term applications possible in home automation devices and web cameras.

"I think there are business models there. Does the cable industry want necessarily all of the applications to be crashing instantaneously available tomorrow? Probably not," Nelson said. "But why not be aggressive? Why not set up a specification to be able to embed these? You've got a clear application that needs standardization already in set-top boxes — why not take it to a process where if somebody comes up with a business model and they can integrate it to a chip and at a cost point that makes sense to a consumer? Then a service comes out of it that makes sense to a consumer, it's great that the cable industry can have that set up so they can take advantage of it."

As for Broadcom, it is looking at the product lines to decide where it makes sense to apply the embryonic eDOCSIS guidelines. "We've already announced products that we are embedding DOCSIS modems inside of — set-top box chipsets, for example," Nelson said.


Given the potentially expanding DOCSIS device universe, rules for embedding modem function may indeed make life easier for device manufacturers, according to Michael Harris, president of cable analysis firm Kinetic Strategies Inc.

"There have been many folks that have essentially put routing or home networking code into the memory of a DOCSIS modem. Now the issue becomes, every time you change any of that code, even in the router piece, you have to get the modem recertified," he said. "The other option is, if you had an embedded DOCSIS module that was certified, you wouldn't need to get it recertified if you changed the router code."

Ultimately, it all depends on how much the cable industry really wants to see DOCSIS functions migrate into other devices, he noted.

"There has been kind of this DOCSIS inside mantra, which actually think a great thing and the industry should be all for it — you want as many devices connected to your pipe as possible," Harris said. "But that can be a little terrifying for a legacy monopoly mindset."