A hard-wrought consensus on specifications for delivery of
packet-telecommunications services over cable networks has opened the way for MSOs to
begin offering telephony in Internet-protocol mode as soon as mid-2000.
Cable Television Laboratories Inc.'s PacketCable group has
completed and issued for industry review specifications on 13 protocols tied to a
network-centric architectural approach to call signaling that is fast gaining ascendancy
in the IP-voice world at large.
The group thus postponed until the next phase of
specification development an approach to setting up calls and provisioning features that
AT&T Corp. engineers considered essential to meeting their standards for delivering
first-class telecommunications services to homes and businesses.
"What it comes down to is that all of the members now
agree that NCS [Network-Centric Call Signaling] is the best approach to early deployment
of packet telephony," said Dave Bukovinsky, director of the PacketCable process at
CableLabs was preparing an announcement at press time that
was said to include a statement of support for NCS from AT&T, which had originally
sought to make a new call-control agent associated with what it calls "Distributed
Open Signaling Architecture" its baseline criterion for equipment supporting IP
This past spring, AT&T sources hinted that the
time-to-market delays that might be incurred by holding out for DOSA-based systems were
swaying the company to think about an "interim" approach based on NCS.
Apparently, the time-to-market argument proved persuasive.
AT&T officials declined to comment in detail on their
new thinking about packet-voice architecture. But a spokesman said the company remained
committed to meeting its original quality standards.
"Everything I'm hearing says pretty clearly that we
have to be at that level of quality, and that the service we offer has to be made
available to our customers as a first-line service," AT&T Broadband &
Internet Services spokesman Mark Siegel said.
AT&T will also insist that IP-voice systems be able to
coexist with the circuit-switched-based systems that are currently deployed, Siegel said,
adding, "We don't want to have to retrofit systems to make them compatible with what
we deploy later."
AT&T is sure to do a significant amount of testing
through 2000, but it doesn't expect equipment to be available for commercial rollouts of
IP-based voice services until sometime in the first quarter of 2001, Siegel said.
Other MSOs, though, are considering earlier time frames.
Those include those that intend to use IP systems to support first-line residential
services, as well as those using the technology to jump into the hot second- and
multiple-line sales arena.
General Instrument Corp. -- which is developing
house-mounted devices known as "BTIs" (broadband-telephony interfaces) to
support the delivery of first-line and multiline services -- is discussing both types of
strategies with MSOs, according to director of marketing for IP telephony Glenn Altchek.
"We're likely to see several other customers becoming
more aggressive [than AT&T] in bringing services to market on this platform,"
Altchek said. Announcements from some of these customers could come within a matter of
weeks, he added.
So far, the MSO most vocally backing early IP-voice
services is Canada's Le Groupe Vidéotron Ltée. Vidéotron hoped to launch services
commercially in portions of its 2.3 million-household Quebec territory by year's end. But
it will take at least until spring to complete the prelaunch testing, said Patricia Leduc,
financial analyst for the MSO.
"In late fall, we'll connect about 2,000 residences to
test the scalability of the system, and then go to commercial launch, probably in the
spring," she said.
Vidéotron -- which is still weighing what level of
compression to use to meet voice-quality requirements while maximizing bandwidth
efficiency -- will confront the issue of scalability when it moves to the 2,000-home
trial, Leduc noted. "We'll have something to talk about in a couple of months,"
Vidéotron suppliers Cisco Systems Inc. and Telcordia
Technologies Inc. are supplying hardware and software in an architecture that closely
mirrors the one endorsed by PacketCable. It relies on the Multimedia Gateway Control
Protocol developed by the two companies with input from Level 3 Communications Inc. and
The PacketCable resolution of NCS specs allows Telcordia
and its partners to begin refining MGCP to bring their systems into compatibility with the
cable standard, noted Scott Davidson, executive director for voice-over-IP product
development at Telcordia.
But Davidson said Vidéotron and other customers could
begin deploying MGCP-based systems now and remain confident that they can be made
compatible with NCS architecture later via software patches.
"Getting beyond supplier agreements to a standard is
important. But we've been working closely with PacketCable as we developed MGCP, so we
only have very minor adjustments to make to bring it into conformity with NCS,"
Davidson said. "The important thing is that when it comes to adding, say, a set-top
box that uses NCS, our customers will be able to make the adjustments without having to
upgrade the whole system."
Davidson said MSOs would find that they can put the
platform or its proprietary precursor to work sooner than mid-2001 without compromising on
first-line service quality. "In reality, we're a lot closer than a year-and-a-half
away," he commented.
While MGCP-based products have been designed to meet the
phone industry's "five-nines" (99.999 percent) reliability standard, suppliers
were reluctant to guarantee that standard in the context of adaptation to NCS until the
PacketCable specs were completed and interoperability testing could begin.
Now the vendors can proceed, which helps MSOs that want to
introduce IP telephony next year, Davidson said.