Re: OpenBSD as SDSL router replacement?

[Jens Ropers <ropers_(_at_)_ropersonline_(_dot_)_com>]

On 11 Feb 2005, at 09:32, Siegbert Marschall wrote:

> ACK.
> Even the ITU is confused by now... ;)
> But in the beginning it was Single, Asymmetrich wasn't invented yet
> and it was all symmetric anyway, the new thing was that this thing 
> could
> work with only a single line, eg. pait of wires.
>
> Bye, Siggi.
>
>
> 7.4.3          SHDSL - Single pair high-speed DSL (ITU-T G.991.2)[4]
>
> Single pair high-speed DSL (SHDSL) is defined in a recent ITU
> Recommendation (ITU-T G.991.2)[5] for symmetric, high-speed DSL. SHDSL
> connections are best suited for servers (web, FTP, file) and other
> business uses such as video conferencing that require high speeds in 
> both
> directions. SHDSL uses a copper pair to send and receive data through 
> two
> bands, which allow for speeds up to 2.3 Mbit/s in both directions. By
> including a second copper pair, SHDSL speeds can reach 4.6 Mbit/s in 
> each
> direction. These speeds are possible over a 3 km range with data rates
> attenuating for longer distances. The two SHDSL bands send data over 
> the
> low frequencies to extend the reach of the loop, making it impossible 
> for
> SHDSL to carry a voice channel (POTS or ISDN) like ADSL.[6]  This lack 
> of
> voice capability imposes significant installation costs in the local
> loopa cost that is passed on to the consumer through higher 
> subscription
> costs. Therefore, SHDSL is more suitable as a replacement for 
> traditional
> leased lines for business (businesses can usually absorb higher
> subscription rates than private users) rather than for the consumer
> market.
>
> In some parts of Europe, SHDSL is referred to simply as SDSL, not to be
> confused with a different standard of the same name used in North 
> America,
> which is described below.
> 7.4.4          Symmetrical DSL (SDSL)
>
> SDSL is a proprietary standard mainly used in North America, but which
> even there is losing popularity to SHDSL. SDSL offers equivalent 
> traffic
> flow in each direction but, like SHDSL, it cannot share the line with
> analogue signals, thus posing significant installation/modification 
> costs
> in the local loop. SDSL is best suited to sites that require 
> significant
> upload speeds such as web/FTP servers and business applications. The
> capacity of SDSL is adjusted according to signal quality and speeds and
> distance combinations ranging from 160 kbit/s over 7 km to 1.5 Mbit/s 
> over
> 3 km are offered. Higher speeds are possible by combining multiple 
> twisted
> pair wires.

Thanks again. :)

Wherever there is ambiguity, it's of course best to know both 
definitions and be aware of the ambiguity -- rather than 
knowing/insisting on just one definition.
Thanks all. I'm glad we got to the bottom of it.

Thanks and regards,
ropers

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