Both cables are shielded though? I also don't understand why in both power cuts were I've monitored the line it takes 10 minutes before the SNR starts going down?

This is a 6-property flat building, and the cabling appears to be decent quality CAT5

Like you I need 12dB before the errors even go down to a low number, although my high Interleaving Depth allows the line to cope at 7dB.

I am under the impression that everyone in this area is experiencing the same problem so I do not see why BT wouldn't be interested in fixing it.

As you have said the problem is between the property and nearest cab it seems odd that everyone in the area has the same problem. Depends how big an area you mean I suppose - maybe all served by the same cab?

As for the shielding.. sure it helps... but it's never perfect. And has it even been checked to be connected correctly and continuous on both the telco and mains?

BT (more accurately Openreach) aren't interested in fixing it because they don't have too.

You haven't said what LLU provider you are with - but whichever, they will be paying Openreach for access to the copper pair from the exchange to the premises.

The only pair quality Openreach are obliged to provide (as agreed by the industry and Ofcom) is pretty minimal. A copper pair of the minimum quality would be lucky to support DSL at all. There is no correlation ~at all~ in this minimum specification about quality vs. distance.

So your LLU provider has no stick to beat Openreach with to address your issue and Openreach has no incentive to do it at their own expense.

I expect all the engineer visits are being charged to your LLU ISP at circa ~£170 each time as technically - according to the requirements.. there is no fault. I hope your SP doesn't have a policy of passing on charges!

This is a small housing estate and I know people outside of this housing estate get 8Mbps sync (A couple roads away), one of the BT Engineers mentioned another local property getting slower speeds than me. From what I understand, any interference if it is on the mains would only get as far as the Mains Transformer? We have our own transformer just for this estate.

Are you saying that Openreach are obliged to provide Cooper and are not allowed to use Ali?

I don't want to keep incurring costs to my ISP, even though they do not pass on the charges to me. (I'm on Sky, as shown from the broken speedtest images in my first post)

Now I feel bad about trying to get my ISP to sort out the problem. (I understand that wasn't you intention though, its more the fact I know how many engineers they've sent out over the years!)

I guess I'll give up and accept that fact no matter what I'll be stuck with 4-5Mbps until FTTC.

Actually Is it worth me looking into bonding 2 lines?

Edited by Opti (Sun 16-Aug-09 02:05:12)

Your Mains Transformer understanding is incorrect. If the telco bundle from the cab runs parallel to the mains bundle for any distance there will be cross-talk between the two - even if the shielding is intact and in perfect order on both it does not block 100%.

Openreach are not obliged to provide copper, they can use Ali if they see fit. However the use of Ali has not been common for 20 years or so. Places like Milton Keynes are rife with the stuff and it cripples DSL speeds. Openreach are not obliged to replace it with copper (afaik) either. There was a copper overlay for ali areas initiative run by BT at one point, but that was before the industry as a whole decided BT needed spitting up.

I didn't mean to make you feel bad... I was just explaining the reality of the LLU market as it is now and identifying some of the stupid things the industry has agreed to in trying to break the BT monopoly.

It is certainly worth looking at bonding if you really need to boost your peak throughput. However I would suggest not doing it unless you can find an ISP that offers a solution that bonds the PPP sessions rather than just randomly bonding two DSL circuits with something like the Neteyes Cyclone router. The protocol routing is a nightmare.. particularly if you use FTP regularly.

I believe Nildram (now part of the Tiscali.. oops.. Carphone/TalkTalk group) used to (may still do) offer a bonded PPP product.

Bonded PPP is far more effective than doing it yourself. You get 2 routers or in some cases one router with two ADSL interfaces - at the ISP end the PPP session is bonded into one and automagically you get one IP assigned over two sessions. This way you avoid all kinds of issues regarding IP address based session applications and the load balancing across the two is seamless.

They are rare products these days and usually not cheap.

Can Sky offer a 2+ profile / product? Is Be LLU in your exchange?

edit - another typo

Edited by deleted (Sun 16-Aug-09 02:33:03)

Ok, so in this case the people who designed this building were idiots
Is there anything I can do at all to get the shielding improved/checked?

How much affect is this likely to have on VDSL2, which is presently my only hope for faster interent here without it costing a arm and a leg?

I only feel I need around 10Mbps to meet my needs, but it also needs to have lower latency than this connection so I'll need 3 Lines (3x3.5Mbps) to bond to this due to requring a lower interleaving depth.

I looked at Nildram but I get the impression they will never be able to meet my needs. (I pull upwards of 500Gb/month, usually data backups from my servers)

I'm thinking maybe I should buy 3 PCI ADSL2+ Cards and bond via my own servers? They are only 6ms away from my exchange.

But this is going to be costly, is there anyway to get BT line installs cheaper? Anyway I can get around the line rental? We'd be talking about 100pounds/month just for 10Mbps. (I am thinking UK Online for the other two lines)

Edited by Opti (Sun 16-Aug-09 04:00:20)

A little harsh perhaps? As far as I know architects don't take into consideration DSL performance when designing buildings. And when tasked to a building co. to construct with a budget they will do the most cost effective thing which is commonly to pull all utilities in together to a common point and distribute from there.

As for VDSL2 - sorry I don't have any information on local interference.

Why do you need the low latency?

How do you know it's 6ms to your exchange? In any case it's only relevant what your first hop to your ISP BRAS is.

BT (Retail) are offering free line installs at the moment subject to conditions. Search this forum for detail because I don't know them

I wonder what you are doing that requires half a terrabyte a month (I assume you meant 500 GB not 500Gb) with low latency and 10Mbps. Not a normal residential user profile for sure so don't expect to do it on residential packages. Maybe a niche 2+, no cap, 1:1, QoS for relevant traffic package. These are available.

The speedtest images don't really mean much. You've probably got the exchange virtually to yourself during a power cut. Likewise, there's going to be virtually no crosstalk in the bundled cables from the cab.

I'm more intrigued why you're on G.DMT rather than ADSL2 or 2+.

John.

Edited by deleted (Sun 16-Aug-09 09:53:34)

In reply to a post by Opti:

Hi all, first post here. I'll try and keep this post short despite the length of the on-going issue.

My area can only get around 5Mbps on LLU (Even less on BT Wholesale ISP's due to a very high training target SNR), but this doesn't add up because I've seen people getting ~14Mbps with the same attenuation (~38dB) as me on ADSL2+, and many many people getting full 8Mbps sync with the same attentuation on ADSL2.

On top of this, my line works how I'd expect it to every time there is a power-cut. (UPS ) It even lasts for 10 minutes after a power-cut, at which point suddenly the SNR plummets until Sync is lost. It then re-syncs and I'm back to my laggy 4meg of throughput.

BT point-blank denied any issues until recently when a Engineer confirmed the line gives several more megabips at the nearest CAB. However they have still yet to do fix the source of this problem.

My full router stats are posted below, and i'm hoping some of you can help finally solve this. I have a portable AM radio here if that can help at all?

Power-Cut Performance
[IMG]http://speed.io/pics/2179/0434/speed.io.png[/img]
Normal Performance
[IMG]http://speed.io/pics/2327/3185/speed.io.png[/img]

Text

1 23 45 67 89 1011 12

ADSL driver and PHY status Status: ShowtimeRetrain Reason: 1Channel: INTR, Upstream rate = 768 Kbps, Downstream rate = 5024 Kbps Link Power State: L0Mode:                   G.DMT Channel:                InterleaveTrellis:                ON Line Status:            No DefectTraining Status:        Showtime                 Down            UpSNR (dB):       6.9             14.0 Attn(dB):       38.0            25.0

Obviously there's a lot of noise on your line, probably caused by local interference. By local, I mean in your house.

We're not talking mains interference here more likely RF (radio frequency) interference.

Who is your ISP?
Why are you on g.dmt not ADSL2+?
Have you removed your ringwire?

(I'm on Sky, as shown from the broken speedtest images in my first post)

John.

Ah, that implies the sky-box, a well-known source of RFI. It also explains why g.dmt not ADSL2+.