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VoxTechnologies
Enterprise Networks
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What are you waiting for?
Digital subscriber line (DSL) technology is fast. Once users experience DSL
speeds, they do not want to go back to dialup access. It's that simple.
DSL achieves broadband speeds over ordinary phone lines. With DSL, home and
business users can access high-bandwidth information on demand, with improved
opportunities to experience streaming video, online gaming, multimedia
applications, and telecommuting. DSL is "always-on". Unlike a dialup
connection, there is no logging on and off or waiting for a dial tone. With DSL,
the connection is always there - ready to use. In addition, DSL doesn't tie up
the user's phone line.
DSL bandwidth is dedicated. Unlike cable Internet access, with DSL there's no
danger that a user's connection speed will slow down as more users log on.
DSL is reliable and secure. Because DSL provides a dedicated connection over
existing phone lines, it has none of the security risks associated with shared
bandwidth solutions like cable.
How does DSL work?
DSL solves the bottleneck problem associated with delivering network services
over phone lines. When a computer receives information from the Internet over a
phone line the telephone company filters information that arrives as digital
data and converts it into analog for telephone lines, requiring the computer's
modem to change the data back into digital form. A DSL transmission is digital.
It does not need this conversion. This allows phone lines to carry more
bandwidth for transmitting data.
Typically, individual DSL connections provide from 1.544 Megabits per second
(Mb/s) to 512 Kilobits per second (Kb/s) downstream and about 128 Kb/s upstream.
A DSL line can carry both data and voice signals and the data signal is
continuously connected.
As a service provider, are you serious about providing your users - both
residential and business - with fast, reliable and affordable network access?
DSL technology allows providers to offer service bundles that include voice,
Internet, and local area network (LAN) services, all using existing phone lines.
DSL installations in homes and businesses began in 1998 and are continuing at
a greatly increased pace throughout the U.S. and around the world.
Telecommunications companies, such as Alcatel, are meeting the demands of home
and business users for high-speed access to the Internet and corporate networks
with wide spread deployment of DSL technology.
According to
DSL Forum: Virtually every major telephone company in Europe, the US, Canada
and around Asia Pacific has announced commercial DSL rollouts and there is more
news every week. Throughout these regions, most companies and individuals in
major metropolitan areas will have access to the service soon if they don't
already.
According
to TeleChoice, 38-million homes will be capable of receiving DSL service in
2000, demonstrating that the industry is committed to deploying and expanding
DSL availability around the world. Because DSL uses the telephone wires that
already connect millions of residential and business consumers, a DSL buildout
only requires small, incremental investments that providers can strategically
deploy. This greatly reduces the risk associated with large capital outlays.
Alcatel offers a cost-effective, flexible architecture that easily scales to
meet the demands of a mass market DSL services rollout. Alcatel takes an
end-to-end systems approach to DSL with proven solutions. Alcatel DSL solutions
allow for the introduction of new network services with a competitive edge -
exactly what service providers are looking to offer.
Types of DSL
There are different variations of DSL, including Asymmetric DSL (ADSL),
Symmetric DSL (SDSL), Integrated services digital network (ISDN) DSL (IDSL),
High bit rate DSL (HDSL-2), Very high bit rate DSL (VDSL), and G.Lite (also
known as DSL-Lite, splitterless ADSL, or universal ADSL). ADSL, the most common
form of DSL, devotes most bandwidth to the downstream direction, sending data to
the user. Typically, ADSL generates downstream speeds of up to 8 Mb/s and
upstream speeds of up to 640 Kb/s.
Learn more about:
Applications of DSL
The Internet is changing the way we work, the way we relax, and the way we
live. More than just the World Wide Web, the Internet provides access to a whole
range of data and multimedia services. Many new applications are available and
more are becoming available everyday. Users are beginning to enjoy more graphics
and audio intensive applications over the Internet, and a whole new world of
interactive three-dimensional applications awaits that can't be realized with
today's slower access technologies.
Access is the biggest problem facing Internet users today. The growing demand
for access has produced bottlenecks and traffic jams. ADSL
high-speed Internet access breaks through the bottlenecks giving users quick,
reliable access to high-bandwidth content.
ADSL is the most cost-effective solution for offering new applications to the
mass market using the existing copper network infrastructure. Providers can
offer ADSL applications as a portfolio of service levels or classes similar to
an airline distinguishes classes of seating, such as first class, business, or
economy. There is hundreds of educational, residential, business, and government
applications served effectively by ADSL technology.
Here are a few examples:
Voice over DSL
Voice over digital subscriber line (VoDSL) is a new DSL technology that
delivers voice services over DSL using Asymmetric DSL (ADSL) or SHDSL (Symmetric
High Bit Rate DSL) to integrate voice with data services. VoDSL gives service
providers the ability to offer residential, and small- and medium-sized business
users, high speed data and multiple voice channels over a single telephone line.
By offering voice on the same DSL technology as data services, VoDSL offers
providers new revenue opportunities they can easily and cost effectively deploy
using their existing DSL infrastructure.
Alcatel believes it is possible to provide VoDSL at only a slightly higher
price than current integrated services digital network (ISDN) offerings. At this
price, Alcatel expects demand to be high as providers can offer users
simultaneous voice lines with higher bandwidth data access than ISDN.
Video on Demand
Video on Demand allows you to access any video program that you are
interested in watching, whenever you want to watch it. Watch a new first run
movie or view your favorite movie classic. You could take a video tour of your
dream home, go online and play the latest video game, or take a virtual visit to
a vacation spot and see if it is the right one for you. With Video on Demand
using ADSL technology, you can do all this and more over your existing phone
line and still place and receive telephone calls at the same time.
Video Conferencing
Video conferencing provides a tool to improve meetings, telecommuting,
training, or services for businesses with multiple sites or between businesses,
through offering face-to-face communications. Businesses that operate
multinationally can benefit from video conferencing wherever the physical
location.
Telecommuting
With telecommuting, employees can work at home and have all the access
capabilities that are available when they work in the office. As a telecommuter,
an employee can access a virtual local area network (LAN) with other
telecommuters, access application servers, share files with co-workers, and
browse and retrieve faxes that arrive at the central corporate fax server.
Telecommuters can receive e-mail and have the bandwidth available to retrieve
messages from a voice mail server.
Tele Medicine
Tele Medicine is an Internet-based application that enables users to access
information stored on a server database via a Web browser. This service, which
simulates a medical record database, allows users to retrieve and view patient
information, diagnostics, prescription, and graphical data such as x-rays. With
Tele Medicine, doctors can provide better care for their patients. A doctor
could get a patient's most recent records, quickly, from a hospital or other
health care facilities; the system could transmit a patient's medical images to
a specialist for consultation while the patient's doctor is consulting the
specialist; or, a hospital could retrieve a patient's medical history in an
emergency.
Telelearning
Telelearning, or interactive education, promises to revolutionize educational
opportunities for children and adults. High speed Internet technology offers
schools fast and cost-effective access to the Information Superhighway. Schools
can connect to and from the Internet, other schools, community colleges, and
universities, local and national libraries, teachers and students homes, and
district offices. Telelearning services can include in-school interactive
learning programs, in-home supplemental educational materials for students,
"Edutainment" programs geared to pre-school age children that
incorporate interactive learning elements or simple learning games, adult
training and education courses on demand, and virtual classrooms.
Interactive Network Games
Interactive Network Game applications support interactive and multi-player
computer games across an IP-based network. After subscribing to this service,
users can select a game from a menu. The service then launches the selected game
from a remote drive. Interactive Network Games cover the spectrum of computer
games from multi-player car racing to Java-based action games. The games range
in size from under 2 MB to over 2 GB for animation and video intensive games.
Broadcast Audio & TV
Broadcast Audio & TV captures and distributes "live" TV or
audio streams across an IP-based network, demonstrating the "live"
broadcasting capabilities of ADSL high speed Internet. With ADSL technology, an
audio or video stream captures only a part of the available bandwidth so users
can continue to "surf" the Internet while listening to CD-quality
music or watching a "live" TV broadcast.
Online Shopping
Online Shopping applications cover a wide range of products that businesses
can sell over the Internet. These applications could include:
- A CD store where users could listen to high quality CD clips taken from
the latest CDs before making a purchase
- A fashion store where retailers sell clothing items, making use of Virtual
Reality (VR) clips to turn models 360 degrees enabling users to see the
clothing from the front, side, and rear. Added interactivity could help
users visualize what an item will look like on them before they purchase the
item.
- A video store where users could view high quality video clips taken from
videotape, DVD, or Laser Disc before making a purchase
ADSL
Asymmetric digital subscriber line (ADSL) is the most widely deployed form of
DSL technology. Most homes and small businesses currently using DSL technology
use ADSL.
ADSL is a technology for transmitting digital information at a high bandwidth
on existing phone lines to homes and businesses. Unlike regular dialup phone
service, ADSL provides a continuously available, "always on"
connection. ADSL simultaneously accommodates analog (voice) information and
digital (data) information on the same line. Specifically designed to exploit
the one-way nature of most multimedia communication in which large amounts of
information flow to the user, ADSL is asymmetric - which means that it uses most
of the bandwidth available to transmit information downstream to the user and
only a small part to receive information from the user. Typically, ADSL
generates downstream speeds of up to 8 Megabits per second (Mb/s) - 125 times
faster than traditional 56.6 Kilobits per second (Kb/s) analog modems - and
generates upstream speeds of up to 640 Kb/s.
Unlike cable technology, ADSL provides dedicated bandwidth so its speed and
capacity are unaffected by how many homes or businesses are using the service at
the same time. The precise speed of your ADSL connection depends to some extent
on how far you are from the central office (CO) of the company providing your
ADSL service. However, depending on your location, there is a flavor of DSL for
you.
SDSL
Symmetric digital subscriber line (SDSL), also know as single line DSL, is a
technology that delivers a symmetric link to data networks for residential and
business users. Using existing telephone lines, SDSL extension technology can
transport multiple services, such as private line, digital voice transmission,
Internet protocol (IP), or frame relay. Because SDSL is symmetric, its maximum
data rate is the same both upstream and downstream. Typically, SDSL generates
speeds of 2.3 Megabits per second (Mb/s) upstream and downstream.
Specifically designed with the small- and medium-sized businesses in mind,
SDSL has faster upstream capabilities than asymmetric DSL (ADSL), making it more
suitable for 'push and pull' communication services, such as web hosting or
teleconferencing.
IDSL
Integrated services digital network (ISDN) digital subscriber line (IDSL) is
a variation of DSL technology that allows users to employ existing ISDN card
technology for data-only use.
Specifically designed for those homes and businesses located too far from a
telephone company's central office (CO) to subscribe to the more commonly used
asymmetric DSL (ADSL) technology, IDSL transmits digital data from users at
speeds up to 144 Kilobits per second (Kb/s) on existing telephone lines.
IDSL technology uses digital (rather than analog or voice) transmission to
bypass the phone company's CO equipment that handles analog signals. IDSL uses
ISDN transmission coding to bundle together ISDN service and voice all on one
circuit.
While ISDN passes through the phone company's CO voice network, IDSL bypasses
the voice network by plugging into a special router at the phone company end.
Unlike ISDN service, which requires call setup and may involve per-call fees,
IDSL is a dedicated service, typically billed at a flat rate with no usage
charges.
HDSL-2
High bit rate digital subscriber line (HDSL-2) is a newer version of DSL
technology, also known as high-speed DSL.
HDSL-2 is a symmetric technology intended to replace T1/E1 lines and older
generation HDSL technology. Telephone companies widely used the older HDSL,
which uses two pairs of copper wires, to provide T1 service. HDSL-2 transports
data at rates of up to 1.5 Megabits per second (Mb/s) over a single pair of
copper wires at distances of up to 12,000 feet (3,650 m).
Specifically developed to serve as a standard by which different vendors'
equipment could interoperate, HDSL-2 does not hinder other services. HDSL-2
supports voice, data, video using asynchronous transfer mode (ATM), private-line
T1 service, and frame relay. An even more recent development in HDSL technology
is G.SHDSL, a multiple-rate version promoted by the International
Telecommunication Union (ITU). G.SHDSL is a standards-based version of
symmetrical rate adaptive DSL that can accommodate line rates from 384 kb/s to
2.3 Mb/s off a single line card.
VDSL
Very high bit rate digital subscriber line (VDSL) is one of the hottest areas
of DSL development. VDSL technology transmits high speed data over existing
telephone lines with the promise of lightning fast transfer speeds.
VDSL offers fast data rates over relatively short distances - the shorter the
distance, the faster the connection rate. In trials, VDSL has produced speeds
between 51 and 55 Megabits per second (Mb/s) over lines of up to 1,000 feet (300
m).
As the final length of cable to a home or business, VDSL connects to
neighborhood optical network units (ONUs), which connect to the telephone
company's central office (CO) main fiber network backbone. This architecture
allows VDSL users to access the maximum bandwidth available through ordinary
phone lines.
The increased bandwidth offered with VDSL technology will result in the
delivery of a new wave of services, including interactive TV, video on demand,
and high definition TV.
Get more information on Alcatel's
VDSL solution.
G.Lite
G.Lite (also known as DSL-Lite, splitterless ADSL and universal ADSL) is
similar to ADSL, offering lower speeds without the need for POTS splitters at
the customer premises. The benefits of simple installation and a lower cost of
implementation are considered to offset the potential drawback of reduced speed,
which is limited to 1.5 Mb/s downstream and 384 kb/s upstream.
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