News on Aware Splitterless demo (long)
Thanks to Pat Mudge for this. I basically just cut and pasted it from the Amati thread. There is tons of general info and a bunch that is specific to Alcatel, but since they are one of the major ADSL players you probably should read it anyway.
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Aware demonstrated its new DSL Lite for editors and analysts last week
at their Bedford headquarters
<<<
What is meant by splitterless?
The original ADSL standard, T1.413 incorporates a POTS Splitter in both the remote
terminal and the central office. The splitter is designed to separate the voice band from
the DSL spectrum. The idea is to protect both signals from interfering with one
another. The issue of where the POTS Splitter belongs in both locations has been
widely debated and is yet satisfactorily resolved. In most cases the Splitter is a
separate physical device that requires a skilled technician to install.
DSL-Lite eliminates the need for a POTS Splitter, hence the term splitterless. It is
designed to be implemented on a modem chipset with a PC. PCs that today provide
32Kbps and maybe 56Kbps will be capable of hundreds of kilobits using DSL Lite.
At a home a PC user simply plugs the DSL Lite Modem into the phone jack. This
simplification will enable rapid mass deployment of DSL technology. The removal of
the splitter removes the requirement of a "truck roll" by the service provider to install
the device. This greatly facilitates mass deployment.
Will I need new wiring in my home?
No, DSL-Lite has been designed to work with existing home wiring. It is important to
note that this environment is as widely variable as the local loop itself. Here, the
topology is largely random with different gauge wires, flat pairs etc. Also, every phone
jack in the home represents a bridged tap.
What's a bridged tap?
A bridged tap is an unterminated wire pair that sits in parallel to the main wire pair. In
the local loop they appear when the local phone company "taps' off an existing pair to
provision a new service to a new subscriber. Typically, they do not remove the
un-used cable segment and a bridged tap is created.
In the home, every unused phone jack represents a bridged tap.
Bridged taps create an impairment to the transmission system. The signal traverses
down the un-terminated cable and reflects back to the main pair affecting the main
signal. The reflection can severely affect the primary signal.
What data rates are supported?
For CSA type loops payload data rates of over 1.5 Mbps downstream and over 384
kbps upstream are supported with the splitterless configuration. For longer loops the
system achieves payload rates of over 512 kbps downstream and 128 Kbps
upstream. For those requiring symmetrical rates DSL-lite can support 384 Kbps
symmetric over the 18,000 foot loops. All these data rates are supported
simultaneously with voice band services such as POTS, fax, and modems.
Why DMT?
Discrete MultiTone modulation is the technology used in T1.413 for full rate ADSL. It
has proven over and over again that it is extremely robust in the local loop
environment. By using Aware's DMT technology in the DSL lite application
interoperability with full rate is easily achievable.
Why is interoperability with full rateT1.413 important?
Local exchange carriers must deploy access equipment in thousands of Central Offices
and Digital Loop carrier systems. With the major LECs having over 10 million local
loops, the equipment they select for deployment must be technically robust and
available from multiple vendors. Thus, standards play an important role. T1.413
compliant central office and outside loop equipment is coming on the market from
numerous vendors including many of the large established vendors. The DMT
technology that Aware is proposing for DSL lite is such that it can be made to talk to
standard compliant ADSL T1.413. In the event that DSL Lite was not interoperable
with T1.413 the LEC would be faced with deploying two systems or perhaps none at
all, preferring to wait for the standards to settle.
Recently, a large industry consortium presented their support of DMT for Splitterless
DSL at the T1E1.4 standards body.
Can I make a Phone call while using the DSL-Lite modem? Fax? Voice band modem
call?
Yes, DSL-Lite enables simultaneous use of the voice band for all voice band services.
How does it compare to ISDN?
ISDN is a switched service that is transported through the PSTN. It supports data
rates of 64K and 128K. DSL-Lite is primarily targeted at IP data services. IP/PPP is
transported over the loop in ATM cells or other frame based packets such as FUNI or
HDLC like frames. Once it reaches the CO or DLC cabinet the data is transported to
the ISP via the LECs ATM interoffice WAN. Thus the data never reaches the PSTN
freeing up ports on the voice switches.
What does "always on" mean?
Current dial-up services require the user to "make a call" to the ISP. The connection is
only active during the duration of the call. DSL-Lite enables the connection to be
always on in a fashion similar to a LAN. When you get to the office you turn on your
computer and stay on the LAN all day. DSL-Lite will be similar in that once you
connect to the network you can remain on for as long as you'd like. Thus, you'll be
able to receive an EMAIL when it arrives. No longer will you have to dial-in just to
download your email. Additionally, advances in push technology can leveraged to
create new exciting applications.>>>>
alcatel.com.
<<<
Paris, December 2, 1997 -- Alcatel has taken a further step in its continuing effort to
improve the ease of use and ease of installation of ADSL.
It has demonstrated a high-speed ADSL service that does not need a POTS splitter to
be installed in the subscriber's home. The "splitterless" ADSL service is offered over
the existing Alcatel DSLAM and ADSL modem.
This further extends the range of services that can be offered with the Alcatel DSLAM
to include a rate-adaptive splitterless ADSL-Lite service in addition to the full rate
ADSL service. Moreover, the demonstration confirms that splitterless ADSL with
simultaneous POTS services can be interoperable with DMT standard-compliant
(T1.413) equipment.
Alcatel is active in contributing to the different standardisation bodies currently working
on a "Lite" version of ADSL and ensuring that ADSL-Lite modems will be able to
interwork with existing standard-compliant DSLAMs. Operators and service providers
therefore have choice in offering a wide range of services to subscribers connected to a
single type of ADSL DSLAM. This can range from several hundreds of kilobits to
multiple megabits, with or without POTS splitters at the subscriber site. ADSL
subscribers can be offered service upgrades with an optional installation of a POTS
splitter to maximise performance.
Alcatel aims at commercially offering support for ADSL-Lite on its third-generation
ADSL DSLAM. The highly-programmable, rate- adaptive DMT chipset currently
used in the Alcatel ADSL equipment already offers the flexibility needed to implement
this solution.
This new development for splitterless ADSL represents a further move by Alcatel to
ensure mass-market availability of high-speed Internet access based on a single,
standardised ADSL technology.
Recently, Alcatel has announced other ADSL products improving ADSL's ease of use,
such as the ADSL PC-NIC card with Plug 'n Play support (shown at Interop '97,
Atlanta) and the ADSL modem with USB interface (shown at Comdex '97, Las
Vegas).
This solution offers operators a range of variants, including versions with and without
splitters to allow them to extend their service offerings taking into account commercial,
regulatory and installed base parameters. In addition, several variants of POTS splitters
are available to maximise ADSL performance, as part of easy-to-install solutions.
Alcatel's main customers for ADSL technology are Singapore Telecom, the American
operators Ameritech, BellSouth, Pacific Bell and SouthWestern Bell, Telia in Sweden,
British Telecom and, more recently, Bell Canada, Belgacom, Telefonica in Spain and
France Telecom. Pilot projects have also been ordered by Korea, Japan and
Denmark. Today Alcatel holds over 30% of world market, making it the world leader
in ADSL technology.
>>>
As I understand it, the T1/E1 committee is considering adding a Lite solution to the
standard. The head of the ITUI committee is from COMS and they --- COMS ---
want to use a separate standard and have agreed to make it backwards compatible
with the ANSI standard. Compatibility is the big issue. TI/ADI/AMTX/ALA are all
working towards this. TI/ Alcatel is a slam-dunk --- the others are close.
ADSL vendors met with PC leaders in December and chose DMT as the accepted
standard. Their goal is to reach the Christmas '98 market with announcements possibly
as early as February.
Q: Will modems be software upgradeable, whether free-standing or installed in box?
A: Yes, if based on DSPs.
Q: Will telcos install standard ADSL so customers can upgrade to higher speeds as
wanted or needed?
A: Yes, this is likely.
Q: Are there regulatory issues involved with the FCC?
A: One said, no, one said, yes, one said he'd ask his experts and get back with me.
Q: Who would stand to lose?
A: ISDN and HDSL.
Q: Who will gain?
A: DMT players with Lite solutions. Retail modem makers: COMS, of course, though
no one knows whether they'll use ADI or TI for chips. Both are rumored to be in talks.
Q: Does WSTL have a Lite product?
A: I don't know. Anyone???
Q: Strategy behind decision?
A: If computer makers include in boxes, telcos will be forced to upgrade COs. If 2 or
3 PC makers begin, the others will scramble to find OEMs.
Q: Will there be market for stand-alone modems?
A: Yes.
I haven't drawn any profound conclusions other than it appears the PC and telco
industries are cooperating, They agree they don't want a split standard, nor do they
want to confuse the market. My Siemens contact made this clear as did the others. The
decision to push a Lite solution doesn't change telcos thinking on standard ADSL ---
they'll most likely install it from the git-go --- and in the meantime not have to worry
about provisioning the customer premise. Jim Bender said success actually could lead
to a "nightmare scenario" if telcos had to do both ends.
So now I guess we wait for the PC makers to announce "DSL for Christmas," and
load up on COMS and ??? in the meantime. I don't own any, but I think the time has
come. . .
Incidentally, besides ALA and AWRE and TI, who else has a splitterless solution? I'm
too tired to search the different news archives.
Also, we seldom talk about Siemens, but don't be fooled. They're hand-in-glove with
TI. And as for Cisco, I wouldn't be surprised if they're in the middle of this somehow,
somewhere. |
