SDSL v ADSL?

bigpaddy2004

Can someone whom has sdsl please tell me a 1 thing.
First of all I have a 5meg down / 512 up adsl connection from Magnet. Whilst doing a download it rarely ever reaches 300kBit/s. Doing a speedtest on speedtest.ie it is only around 2.5 meg down all the time and less sometimes.
Now question is, if I were to get a 8 meg down / 1 meg up sdsl line, and seen as it is different technology would I expect to see my download speeds at around 800kBit/s? Also it would be uncontented unlike the adsl line?

Foxwood

The first S in SDSL stands for Symmetric - that means that it has the same speed in both directions. A 8 meg down / 1 meg up line is, by definition Asymmetrical, as in ADSL.

Magnet claims to have little or no contention on their network. So if you're only getting 2.5 meg downloads on a 5Mbps ine it's more likely to be crappy copper, and poor synching than contention. Even ADSL2+ technology can't push a 5Mbps signal down 10 miles of copper.

watty

SDSL is the SAME technology as ADSL. Just proportions the upload and download differntly.

Unless you are hosting your own servers, SDSL has no advantage and is disadvantagious, as whatever the upload gains is subtracted from download.

If you only host a web & FTP sharing server only you can even get ADSL the opposite way round.


I suspect the OP is thinking of ADSL2. It is Magnet LLU rather than eircom bitstream reselling, becasuse it is supposed to be more than 3M, so it probabily already is ADSL2. It is an 8M equipment but limited to 2.5 by copper.

bigpaddy2004

The guy whom I was speaking with in Magnet said they do not use the "regular" cards in the exchange which Eircon uses to provide dsl down a line which can only go 4.5km. They said they use their own ones which can go up to 8km? Is this Bull?

Boston

watty wrote:

SDSL is the SAME technology as ADSL.

Thats not true at all at all at all. SDSL Uses the frequency spectrum of you line in a different manner to ADSL, thus requiring specalised equipment at the transmitter and reciever. Some companies offer Symetric ADSL, and claim it to be SDSL, it isn't. I've no idea as to what magnet provide.

bigpaddy2004, there is no reason why magnet wouldn't be able to provide longer range with better equipment.

watty

Yes I meant it just uses the spectrum differently. But you can get DSLAMs and Modems that do both. The same box may not always do it, but it is the same technology. Just a different configuration. Since he is on Magnet LLU, he is already using the "better equipment".

rardagh

Hi,

Magnet uses ADSL2+ for it's own unbundled services.

The following link gives a solid technical description of the differences between ADSL/ADSL2/ADSL2+. Our ADSL2+ network is multimodel and will adapt to the best mode for a particular copper environment.

http://www.dslforum.org/learndsl/pdf/ADSL2_wp.pdf

It is correct to say that we could support Annex M of the ADSL standard which would allow for symmetric services up to a maximum, 1Meg. However, Magnet have invested in g.ShDSL.bis technologies which can provide a far higher level of symmetric service over a copper pair. SDSL and ADSL are different technologies, that they both use copper as the medium for the signal is the main similarity.

All of these technologies are subject to physics, and the signal carried on the copper can be impeded by distance attenuation, copper corrosion, multiple bridges etc.

ShDSL type services, can be viewed as similar to leased lines, eircom use HDSL (which is a precursor technology to ShDSL) to deliver their leased lines. It is a powerful technology that especially helps business support telephony, VPNs, Conferencing, off-site back up etc.

Best,

Rory

Foxwood

bigpaddy2004 wrote:

The guy whom I was speaking with in Magnet said they do not use the "regular" cards in the exchange which Eircon uses to provide dsl down a line which can only go 4.5km. They said they use their own ones which can go up to 8km? Is this Bull?

No, it's not bull. Magnet (and Smart) are the only companies offering DSL that do not use eircoms "cards" in the exchange, but instead install their own, better hardware (at very considerabe expense).


(BT have their own hardware in some exchanges, but there hasn't been any indication that any of it has been upgraded since it was installed 3 or 4 years ago, and they were badly burned by the experience).