5/98 tele.com. Cable Tinkers With IP Voice
Circuit-switched telephony was a no-go for
cable providers. Will VoIP finally turn the
trick?
teledotcom.com
By Carl Weinschenk
Carl Weinschenk is executive technology editor at
tele.com. His Internet address is
cweinsch@teledotcom.com.
Cable operators in the United States have long been teased by
an elusive pot of voice services gold at the end of the rainbow.
Providers were smart enough not to kid themselves about the
real value of that pot, and public posturings aside, their
involvement in circuit-switched telephony never gained all that
much momentum.
Lots of "couldn'ts" put telephony out of cable providers' reach.
Operators couldn't deal with the requirement that the public
switched network deliver lifeline services, like maintaining
power during electricity blackouts. They couldn't do the billing.
The biggest "couldn't"? They couldn't expect to capture too
much market share from incumbents that had a superior
reputation for reliability. So while U.S. cable operators made
some notable headway in the telephony business in their
operations in the United Kingdom, telephony was pretty much
a nonstarter in the States, except for some bypass services
aimed at commercial users.
IP telephony is changing all that, at least for now. Cable providers see voice over IP (VoIP) service as a way to break into the local telecom market without shouldering the heavy regulatory responsibilities and technical complexity of the public circuit-switched network, although the regulation of
VoIP could take some or even all of those advantages away.
But just as with cable's previous initiatives into the voice
business, things aren't as clear-cut as they seem. Despite the
interest of cable operators such as Cox Communications Inc.
(Atlanta) and Comcast Corp. (Philadelphia)--which expects to
run field trials early next year--no one's offering commercial
service yet. "There are a lot more questions than answers,"
says Mario Vecchi, chief technical officer for Road Runner,
the high-speed modem service of Time Warner Cable
(Stamford, Conn.). Among those questions:
* What exactly will cable VoIP service look like? Will it
simply be the voice component of a multimedia package? Will
it be robust enough to become a primary-line service, where
most people feel the real money is, or will cable providers be
content offering a cheap alternative for second- and third-line
service (see "Second Nature")?
* Will cable operators band together to offer end-to-end
VoIP long-distance networks, or will they take their
established track and develop their services independently?
* Is it necessary to focus on one or two VoIP disciplines to
make the business plan work across the industry?
* Will any regulation of VoIP ultimately squelch all these
efforts?
This is the season to ask those questions. "There has been
tremendous interest in this particular solution since last fall,"
says Jane Zeletes, vice president of marketing for Hybrid
Networks Inc. (Cupertino, Calif.), a cable and wireless
modem vendor. "We're aware of many medium to large
operators that are very interested in VoIP, domestically and
internationally." Zeletes says that Hybrid is talking to about 30
cable companies in the United States about either
circuit-switched or VoIP telephony.
TWO-WAY STREETS
As part of the general upgrade move to hybrid fiber-coaxial
infrastructure, the cable industry set baseline standards for
bidirectional high-speed data. Those standards are embodied
in Multimedia Cable Network System (MCNS), developed
by industry consortium Cable Television Laboratories Inc.
(CableLabs, Louisville, Colo.). The next piece of the
technology and deployment puzzle for VoIP and other
advanced services is to establish standards beyond MCNS
that will allow the lower latency and guaranteed levels of
service necessary for telephony. This effort, called
PacketCable, will pave the way for telephony and advanced
multimedia applications.
Voice will be an ancillary part of these services, as with audio
feeds for the videoconference services that cable providers
hope to deliver. Cable operators and the VoIP equipment
vendors that hope to do business with them will use the basic
and extended standards set during the previous two stages.
The industry is racing to set standards both for standalone
VoIP and as the audio element of the advanced packages.
"We set a spec in record time," says Steven Craddock, vice
president of new media development for Comcast and a key
player in the PacketCable efforts. Working products will be at
the Western Cable Television Show in Anaheim, Calif., in
December, and field trials will start early next year, Craddock
says.
The key question is how far the industry will go to position
VoIP as a primary-line service. This is far more complex,
demanding--and lucrative. "When you look at the initial plan,
you have to italicize the word 'initial,' " says Michael Harris,
president of Kinetic Strategies Inc. (Phoenix), which publishes
a cable industry newsletter. "It's not fully fleshed out what the
capability of the plant is."
The technical issues to the creation of a robust platform
capable of primary-line and advanced services are
considerable. Key to VoIP primary-line services are robust
quality of service (QoS) standards. The inclusion of
proprietary QoS features in cable modems coming onto the
market probably means that standards will happen sooner
rather than later. CableLabs' approach is to avoid reinventing
the wheel. It tweaks and standardizes the best proprietary
system available and develops technology only if nothing exists
in the marketplace.
Typically, CableLabs creates specifications by combining and
tweaking what it considers the best elements of techniques
already in the marketplace. It will not lack for candidates on
the QoS front. Phasecom Inc. (Cupertino, Calif.) recently
added bandwidth allocation to its SpeedDemon modems,
Motorola Multimedia Group (Arlington Heights, Ill.) says it
has gear with latencies below 40 milliseconds, and Hybrid
offers a channel-sharing algorithm in its modems. At least one
vendor--Com21 Inc. (Milpitas, Calif.)--has QoS functions
because it uses ATM transport.
The organization also is looking into arranging a marriage
between Internet QoS standards such as resource reservation
protocol (RSVP) and cable QoS. "The completion of MCNS
standards with QoS extensions enables cable operators for the
first time to begin exploring deployment of HFC [hybrid
fiber/coax] local loop bypass solutions," says Paul Bosco,
general manager of the cable products and solutions group of
Cisco Systems Inc. (San Jose, Calif.). Guaranteeing QoS may
be the most important task the industry faces. The solutions
that vendors are bringing to market, coupled with CableLabs'
efforts, suggest that the answers could come relatively quickly.
"For the last two months, CableLabs has had a fast-track
effort to get QoS injected into the standard," says David
Waks, president of System Dynamics Inc. (Morris Plains,
N.J.), a firm that consults with cable operators on advanced
services. "That shows how critical this issue is seen."
There are other issues, however, including packetizing dual
tone multifrequency (DTMF) push-button tones and
developing protocols for call initiation, call setup, and the
extension of PBX and Centrex features. Management and
billing issues must be confronted. Gatekeepers--software
devices akin to advanced intelligent network service control
points that act as the link to the H.323 multimedia protocol
and house call control features--must be perfected.
PacketCable is working on a device called a multimedia
terminal adapter (MTA). In twisted-pair VoIP networks, calls
generally enter and leave the customer premises in analog
format. Digitization, compression, and packetization are done
in the network, generally at the gateway device. In cable's
HFC world, the IP network extends to the premises. This
means that the digitizing, compressing, and packetizing of
voice information must be handled by equipment housed at the
end points.
In some scenarios, the PC can provide some of the
functionality--such as its sound card--but this generally adds
too much delay for voice traffic. In the main, the job will be
done by the MTA. These devices will serve as the interface
between the telephone (via an RJ-11 jack) and the Ethernet
system trafficking the data in the home (via an RJ-45 jack).
They will contain an IP stack, a processor, memory, echo
cancellation, and digital signal processors. They will also have
a toggle that will automatically shift operations to the public
switched telephone network if the HFC network goes down,
Craddock says.
The industry must figure out how to deploy MTA circuitry to
the widest group of potential customers. A standalone
MTA--with its own power supply and housing--may be too
expensive. If so, VoIP may be limited to households in which
other services, such as compressed digital video or high-speed
data, allow deployment of a device in which common functions
are shared. Such a scenario would consign the potential VoIP
market to a subset of a subset--targets would be cable
subscribers (it is unlikely that many people who are not cable
subscribers would use cable-based VoIP) who take the other
service or services with which MTA circuitry could share
some processing and powering capabilities. This does not
seem like the best way to get into a new business to many
cable executives. Instead, MTAs costing $200 or less must be
developed, says Jeff Turner, associate director of strategy for
MediaOne (Englewood, Colo.), a cable company.
POWER STRUGGLE
The other vexing issue is power, which is the key to lifeline
service. Today's circuit-switched telephones are powered by
the networks, so they work even if the home's power goes
down. Cable operators must match this to be considered a
primary-line alternative. Right now, only about 4 watts of
power can be sent down the aluminum member of the coaxial
cable entering subscriber homes or businesses. Primary-line
telephony and an OpenCable box would draw 8 to 12 watts.
Since second-line services don't have always-available
mandates, they can be home powered. Finding ways to drive
consumer premises equipment through coaxial cables is a
challenge the industry must face.
If that challenge can be met, the possibility of end-to-end
cable-anchored IP long-distance networks becomes feasible.
In such a scenario, cable operators would be able to offer a
unique set of services. A possible scenario is that calls
between subscribers on the same cable system are free.
Long-distance calls to people who are not subscribers or
aren't served by operators belonging to the consortium (or
another VoIP long-distance consortium with which it peers) go
through a gateway to the public circuit-switched network.
Finally, calls from one operator's participating subscriber to
another would stay within the network. "There's a lot of
interest," Turner says. "It's the Holy Grail for us because you
avoid access fees on both ends."
Cable companies are exploring partnerships with IP voice
startups as well. Tom Evslin, chairman and CEO of IP
telephony provider ITXC Corp. (North Brunswick, N.J.),
says several cable operators have approached his company to
ask about possible deals. "I wouldn't be surprised if there
weren't trials in 1998, but I would be extraordinarily surprised
if there were any significant revenue impact," says Evslin, who
won't divulge the cable companies that have approached
ITXC. "I anticipate commercial service in 1999." Amy Reiber,
the manager of product marketing for The Williams
Companies (Tulsa, Okla.), says teaming with cable operators
on end-to-end IP long-distance networks is an interesting idea
but that no substantive conversations are ongoing. Some
operators are interested in letting the long-distance carrier
handle per-minute billing issues, which have always stumped
cable operators, Evslin says. Local services, he says, will likely
be either free or charged at a flat rate.
Cable providers have always seen telephony as a natural
evolution of their business. It has been retarded by the
industry's inertia, as well as tricky technical and thorny
regulatory issues surrounding primary-line telephony. VoIP
may well be a way around the biggest problems. Indeed, there
appears to be no single issue that will keep operators from
harnessing VoIP. "I don't see any showstopper," says
Craddock. "I don't think we're going to fall on our swords. It's
just a matter of making it work."
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