[ale] OT: nakes DSL

[Christopher Woodfield]

IIRC, the main differences between SDSL and ADSL have very little to do 
with the actual underlying technologies, and more to do with marketing 
and pricing:

1. SDSL is ordered on a dedicated, "conditioned" loop (bridge taps 
removed, etc), which will result in a stabler signal with higher 
potential sync speeds, whereas ADSL has historically been only 
available on a loop that also provides dialtone, and is not 
conditioned. These are not technical requirements, but results in 
better loop pricing for ADSL in order to differentiate the two services 
and justify the increased cost of SDSL.

2. SDSL's upstream speed is the same as its download speed, again, to 
appeal to office users and allow more competitive pricing for home 
users who don't need upload. My understanding, IIRC, is that the two 
speeds are not identical, but very close, riding carrier frequencies 
that are as close as possible without interfering (correct me if I'm 
wrong here)...

3. SDSL IP is typically routed to the customer's CPE via static routes 
in CIDR blocks, as opposed to single IPs within a /24 being bridged 
among multiple customer DSL lines for ADSL.

4. SDSL customers typically get "business-class" customer support as 
opposed to "consumer-level" support - priority call queueing, routing 
to higher-level CSR reps as opposed to contractors in Bangalore reading 
from scripts, etc. Sometimes SDSL even comes with an SLA.

If there are actual protocol/modulation-related technological 
differences between the two, I'd like to know what they are, but so far 
I haven't heard of any.

-C

On Jul 11, 2004, at 11:07 PM, James P. Kinney III wrote:

> On Sun, 2004-07-11 at 22:48, Dow Hurst wrote:
>
>> I am wondering if the more expensive SDSL plans aren't worth it in the
>> long run for home offices.
>> Dow
>
> SDSL is a rock solid technology. It is more of a "dedicated pipe" back
> to the switching station than ADSL can ever be. It is similar to a T1
> line but with no voice capabilities. In fact,it goes on it's own line
> and can't share with voice.
>
> At one time I had dual access. ADSL with bellsouth and SDSL with
> Earthlink. In a 1.5 year stretch, the SDSL never faultered while the
> ADSL was decent but did go out (i.e. lost sync) several times.
>
> -- 
> James P. Kinney III          \Changing the mobile computing world/
> CEO & Director of Engineering \          one Linux user         /
> Local Net Solutions,LLC        \           at a time.          /
> 770-493-8244                    \.___________________________./
> http://www.localnetsolutions.com
>
> GPG ID: 829C6CA7 James P. Kinney III (M.S. Physics)
> <jkinney at localnetsolutions.com>
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