Modem-Interop Tests March On

Author:
Updated:
Original:

A total of 18 data vendors will congregate at Cable
Television Laboratories Inc. this week for the third round of interoperability testing,
although official "certification stamps" are not likely to be issued.

The tests are important for the industry because cable
operators want standardized cable modems to be available by Christmas -- if not earlier --
and manufacturers want to turn 18 months of research and development into sales.

But the first batch of DOCSIS-compliant (Data Over Cable
Service/Interoperability Specification) stickers aren't likely to emerge until
mid-August, according to senior MSO executives involved in the certification process.

Senior executives on the MSO, vendor and chip sides last
week expressed confidence in lead vendor Broadcom Corp., even as reports about delays
spread through the broadband community.

One maker of cable-modem-headend gear, who asked to remain
nameless, did say that shipments originally earmarked for May had slipped to July and,
now, to November. The vendor refused to point fingers, saying that the delays were not
because of any internal problems.

Postponements and lateness are par for the course in
delivering interoperable chip sets. Last year, the cable community was confident that
certification stickers would be a done deal by this month.

At a panel session at the Society of Cable
Telecommunications Engineers' Cable-Tec Expo in Denver earlier this month, however,
cable's lead technologists remained confident that retail shelves will be stacked
with certified, standardized cable modems in time for the Christmas buying season.

Last week, Broadcom executives appeared bewildered at
rumors of flaws in one of their six cable-modem-related chips, surmising that the rumors
may be rooted more in "feature creep" than in silicon software bugs.

That's because Broadcom plans to push key
"data-fragmentation" parameters into the chips that it will supply to
cable-modem-headend and client-device vendors, while complying with version 1.0 of the
DOCSIS standard.

The addition of data fragmentation is important for MSOs
that want to begin offering services like IP (Internet-protocol) voice, where chunks of
bandwidth are guaranteed, and not divvied up among cable-modem users on a first-come,
first-served basis.

"The confusion, I think, is that we put a lot of
features into the [headend] chip to facilitate compliance testing," said Henry
Nicholas, president of Broadcom, referring to a new board that Broadcom will bring to the
DOCSIS testing incubator this week.

"It turns out that if you have DOCSIS 1.0-compliant
headend equipment, it's not super easy to test the 1.0 subscriber unit, so we decided
to put some features in the chip to facilitate testing."

As for any major problems, Nicholas emphatically said there
were none. "Everything is just fine -- everything that's cited on our data
sheets is valid and working," he insisted.

Executives with Cisco Systems Inc., Motorola Inc., Bay
Networks Inc. and 3Com Corp. -- all of which make cable-modem-headend gear -- were not
available for comment or did not return phone queries at press time.

Several MSO engineers -- some of whom sit on the DOCSIS
"certification board," which will decide whether and when to issue compliance
stickers to cable-modem vendors -- also said they were unaware of any chip flaws, major or
otherwise.

"If there was a major flaw, we'd know it by
now," said one MSO engineer, speaking on background and referring to the two rounds
of interoperability tests that have already been completed.

One MSO executive, also speaking on condition of anonymity,
did say that even rumors of a chip bug raise the danger of becoming too dependent on a
single chip supplier, like Broadcom.

Although other silicon suppliers, like Stanford Telecom and
Libit Signal Processing, are developing chips for cable-modem equipment, the wide majority
of vendors making modems and associated headend gear use Broadcom's silicon.

"This is not something that the industry is unfamiliar
with -- the concept of becoming too locked in to one supplier," the executive said.
"The only difference is that now, it's showing up at the root level -- the
silicon level -- and not at the general hardware level."

Bob Cruickshank, vice president of Internet data for
CableLabs, also said he was unaware of any chip defects.

"I'm still really confident about November
deliveries," he said.

Each month throughout the summer, CableLabs will host
interoperability tests, called "waves," Cruickshank said, adding, "We have
work to do, but we're on track."

He described the DOCSIS "ATP," or
"Acceptance Test Plan," as "the current full-court press." That
effort, co-developed by CableLabs and vendors, is a common set of procedures to audit
interoperability progress.

Related