How does ADSL broadband internet work and what are the key protocols used

Hi! Thanks for the question.

The following articles can give you a better understanding of how ADSL
works. The last two articles meanwhile talk about its protocols and
standards.

?Asymmetric Digital Subscriber Line?
http://en.wikipedia.org/wiki/ADSL 

?How DSL Works? by Curt Franklin (mostly covers the ADSL concept)
http://computer.howstuffworks.com/dsl.htm/printable 

?How ADSL Works?
http://www.multithread.co.uk/adsl/howitworks.php 

?What is ADSL?? by Bradley Salzwedel 
http://www.intoweb.co.za/articles-adsl.html 

?ADSL Protocol Stack?
http://www2.rad.com/networks/2005/modems/ADSLprst.htm 

?ADSL Standards?
http://www2.rad.com/networks/2005/modems/adslstan.htm 


Search terms used:  
how adsl works 
list protocols

I hope these links would help you in your research. Before rating this
answer, please ask for a clarification if you have a question or if
you would need further information.
                                                          
                              
Regards,                              
Easterangel-ga                              
Google Answers Researcher

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Request for Answer Clarification by aw378-ga on 25 Oct 2005 00:41 PDT

Thanks for prompt response, however, I wasn't looking just for a list
of links to do the research myself as I don't have the time. I am
willing to pay $20 for a summation of how ADSL broadband works and the
key protocols used.

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Clarification of Answer by easterangel-ga on 25 Oct 2005 01:08 PDT

Hi!

Most users use the ADSL variety when they get DSL service. In ADSL,
the frequencies are divided since services assume that users download
a lot more stuff than they usually upload or send to other web
servers. In this case, the service will look faster since most of the
time you are just surfing or downloading email or files.

ADSL or any type of DSL service makes use of your telphone wires. Your
phone wires can actually hold more data and this is what ADSL likes to
exploit. One way bis to divide the signal into three bands, The voice
signals are in the  0 to 4 KHz (kilohertz) band, the uploading part is
in the 25 and 160 KHz while downloads are made at 240 KHz. Disruptions
for signals are minimized this way. tHis is the CAP way. The DMT
method meanwhile separates signals in 247 different 4khz lines and
finds the best channel for the signal.

This short passage from Howstuffworks provides a good explanation of
basic DSL connection for the home.

"ADSL uses two pieces of equipment, one on the customer end and one at
the Internet service provider, telephone company or other provider of
DSL services. At the customer's location there is a DSL transceiver,
which may also provide other services. The DSL service provider has a
DSL Access Multiplexer (DSLAM) to receive customer connections."

Source:
http://computer.howstuffworks.com/dsl.htm/printable

The protocols used are the following:

ATMALL5
VCMuxed
LLC/SNAP
MAC, PPPoA, PPoE
IP
http://www2.rad.com/networks/2005/modems/ADSLprst.htm

I hope this helps.

Thanks!

Felt initial response was poor, subsequent clarification fair. First
experience of Google answers, not sure if my expectations were too
high, but expected more. However, researcher was prompt and curteous
in responses.