ADSL - how long before...

[mushroom]

How long do you think it will be before upload speeds will match download speeds?

[Chenks]

SDSL does it already... it'll cost ya though.

[LSG501]

adsl (Asymmetric digital subscriber line) never will have matching up and down speeds - its part of the differention between it and sdsl plus how we keep the prices (still relatively expensive compared with a lot of countries!!) cheaper.

[mushroom]

Yeah but when will SDSL replace ADSL then?

[nicky munchkin]

A couple of thousand years knowing BT. They still need to upgrade all the exchanges and replace wire still around from 100 years ago, the same wire everyone is pushing broadband down. If we british ever have any real hope of getting a fast and better service that is.

Cable is the way to go, if it is ever made available to everyone. And Virgin would need to pump billions into it.

[LSG501]

we (those of us with only bt adsl as an option) will all be using wimax or 4G mobile networks before you get sdsl out of bt in this country

[Tom]

Originally Posted by nicky munchkin

A couple of thousand years knowing BT. They still need to upgrade all the exchanges and replace wire still around from 100 years ago, the same wire everyone is pushing broadband down. If we british ever have any real hope of getting a fast and better service that is.

Cable is the way to go, if it is ever made available to everyone. And Virgin would need to pump billions into it.

Two things;

1) 21CN, Google it. It's the beginning of BT's step towards FTTC w/VDSL & FTTP.

2) Cable will never be the future so long as there's only one, uncontested ISP at the head of it.

Mushroom: ADSL is just that; Asymmetric. The idea is that the average user doesn't need as much upload as they do download. Unfortunatly it seems to have been taken out of context in recent years: the ISPs see it as a blessing in revenue.

You need to look up how ADSL works, in dirty electronics-level detail. You'll probably answer your own questions then.

We can already have up to 3Mbit upstreams curtosy of the ADSL2+ Annex M extensions, but as far as it goes in the UK, only Be actually offer this (and it's capped to ~2.5Mbit) until BT's 21CN WBC products begin to filter down to the non-LLU ISPs. There's Entanet and Andrews & Arnold on the list for this AFAIK, but it's still not symmetrical..

However, going back to the point about dirty electronics, think of it this way: you only have a finite amount of bandwidth (in Hz) that can be used on the line. Too high, and the attenuation over distance is just too unrealistic.

With ADSL/ADSL2+ it's broken down like this:

- Low frequencies for your telephone conversations
- Some higher frequencies (about 20-25%) for your upstream
- The majority of the higher frequencies are used for your downstream frequencies

Note that in the case of ADSL2+ and Annex M, the frequency range used for the upstream is deducted from that available to the downstream, so you will see a reduction in downstream speed when this is enabled.

On an SDSL line, the phone line isn't needed (it's targeted purely at business users) so those frequencies are sacrificed as extra upstream bandwidth. The bandwidth from low-high is divided (fairly, as far as I can remember) evenly between upstream and downstream; hence the 'symmetric' nomenclature.

In a perfect world.. There'd be enough bandwidth realistically available for a symmetrical 24Mbit down and up 'SDSL' connection, but that's just not the case; you do have to make some sacrifices, and as I've said already: it's finite.

We can do clever things with better cabling (twisted pair) and shorter distances (max. 100m, for instance) but none of this is what's laying in the ground. BT are currently upgrading their entire core network (Google '21CN' or checkout the info on samknows.com) so that in the future (and not just parts of Milton Keynes) they can start laying FTTC like NTL/Telewest have done before them.

For now, if you want a decent upstream. Get an ADSL2+ connection from Be, and ask them to enable 'upload plus'.

[anthonylei]

never.... unless it is a business connection... but it cost...

i remembered looking for a couple years back.... never looked again due to the price

[dogbref]

Had something come through from Virgin the other day saying they were testing 50 mbit lines, and their fastest currently available being 20 or 24 mbit ( cant remember which)

[Tom]

Originally Posted by dogbref

Had something come through from Virgin the other day saying they were testing 50 mbit lines, and their fastest currently available being 20 or 24 mbit ( cant remember which)

Sadly their, even though their infrastructure can (they claim) support up to 100Mbit per customer; their own internal core network isn't anywhere near enough to withstand even 20Mbit per customer at the minute.

Though the laws of average contention say they don't need to accomodate exactly 20Mbit per customer, it really should be a lot better than it is at times.

[dogbref]

Have to agree about the speed. I have a 10 mb line but speeds vary immensley

[nicky munchkin]

Originally Posted by dogbref

Have to agree about the speed. I have a 10 mb line but speeds vary immensley

10mb Virgin line? Shouldn't they have upped it to 20 for free?

[dogbref]

Maybe, but I had already persuaded them to upgrade to the 10 from 4 as a free upgrade when we moved house. as far as I know we are only paying the 4 meg price . Even I cant be that cheeky!!
But..... as we are moving again in a couple of weeks you never know LOL

[Sub]

4 is changing to 10 for free anyway now so you didn't get anything 'extra' they just paddled you the existing deal early mate