dropping speeds infinity 2 / infinity 1

Hi all,

Bit of a long winded one, but I reckon I am not the only one in this predicament.

2 months ago, our village went live with BDUK funding. I was monitoring the dslchecker religiously and was one of the first to sign up to Infinity 2, based on the checker stating that I could get up to 45mb and the fact that my phone line is 4 years old (new build).

Got connected and was originally connected at 45 down / 11 up. All good. I work from home and it made a massive difference.

I got a fritz box 7490, and was able to monitor the stats and a few weeks later noticed that there were lots of errors creeping in and lots of disconnects, then DLM kicked in. My speeds dropped to 30/7. I contacted BT and an engineer came out and detected a fault in an underground chamber about 150m away. They were able to fix it and errors/disconnects dropped dramatically.

2 weeks later and finally DLM has disappeared and I am at full speed, but unfortunately it's 40mb/8.

Looking at the fritz box, it states that the speed at the DSLAM is limited to 40000kbit/s, I.e. Infinity 1 speeds. I have tried several times with bt to have this limit raised, but they claim there is no limit placed on the line. Bt's attitude is that I was sold a minimum of 33.3 therefore I cannot complain, I have asked why I was sold infinity 2 if all I could get was infinity 1 speeds.

I am very happy to pay for infinity 2 if I can get 40-45mb, but not if I am limited to 38mb. Why was I sold infinity 2 if they are only going to limit me to infinity 1.

Now it may be that crosstalk has reduced my possible speed as lots of neighbours have signed up, in which case this has taken my theoretical maximum from 45 to 38, but then bt should reduce my costs as I have gone from infinity 2 speeds to infinity 1.

Does anyone know how I can get the DSLAM limit removed? Any advice on how to deal with the behemoth that is BT? Am I barking up the wrong tree?

What's your upstream sync speed and SNR margin?

As time goes on and more and more subscribers sign up for FTTC, the contention ratio's will increase and the true download speeds will decrease

If it's the sync speed decreasing, then it'll be crosstalk, not contention.

Receive Direction Send Direction
Max. DSLAM throughput kbit/s 40000 10000
Min. DSLAM throughput kbit/s 20000 5000
Attainable data rate kbit/s 40533 7823
Current throughput kbit/s 39993 7823
Seamless rate adaptation off off

Latency fast fast
Impulse Noise Protection 0 0
G.INP off off

Signal-to-noise ratio dB 6 5
Bitswap on on
Line attenuation dB 25 41

Profile 17a
G.Vector off off

Carrier record B43 B43

Here are all my connection details. Seems like even if 40,000kb is raised I will only get a tiny increase in potential download, but still am annoyed that upstream is limited to 10,000

You're on Infinity 1.

Even if you were on Infinity 2 your upload speed would not improve as you're not hitting the cap. You download may increase by 100k.

Edited by deleted (Sun 09-Nov-14 19:33:07)

Could that be banding? I'm not aware of non-banded connections setting a minimum sync, and the minimum on banded is typically half the set maximum.

Thanks, what is banding? Not heard of it

Well, there's no SNR margin left - it's at 6dB. That's syncing at the max I'd say.

In reply to a post by BatBoy:

Well, there's no SNR margin left - it's at 6dB. That's syncing at the max I'd say.

Ok, so due to crosstalk I am now only going to receive 38mb. Shouldn't BT now lower my costs to infinity 1? Through I fault of my own the max connection speed has dropped from above 38 to 38...? How do I approach BT?

Yes, you should be paying Infinity 1 rates.

Is it due to crosstalk? Or is it the attenuation?

What estimate does www.dslchecker.bt.com give for your line?

In reply to a post by BatBoy:

Yes, you should be paying Infinity 1 rates.

Is it due to crosstalk? Or is it the attenuation?

What estimate does www.dslchecker.bt.com give for your line?

On first connection it was 44.3mb, so I signed up for infinity 2. Now it is 39.3mb. Not worth the extra cost. I must not be unique, there must be others whose connection speeds have reduced to around infinity 1 levels and yet are being charged infinity 2.

True, after all Infinity 1 used to have a usage limit whereas Infinity 2 was unlimited. But not anymore.

Ummm. Possibly, possibly not. I admit I hadn't spotted the noise margin and it's a close call. Being so, this bit of the discussion isn't really relevant.

Not quite. You are receiving 40Mbps sync. The 38 in the product description is the figure at least 10% of customers achieve on what used to be described as the 40/10 product. ASA the cause.