My Broadband Connection Speed and expectations

Hi All,

First post here, am after some advice, guidance and hopefully some info to help me tackle an issue with BT Broadband. When I speak to BT shortly I want to guarantee that I am providing them with enough information to get a satisfactory resolution. After reading through multiple forums a full-on approach seems necessary.
The basic details.
1. BT BB option 2.
2. Best sync speed (Downstream) 1834k (Monitored over 9 months, didn�t know about IP Profile or BRAS till about a month ago)
3. Best recorded speedtester.bt.com overall result over 9 months was 1456 kbps

Present results (I know the profile is low part of the issue I think and will come to that later)

Test1 comprises of Best Effort Test: -provides background information.
Download Speed
446 Kbps


0 Kbps 500 Kbps
Max Achievable Speed

Download speed achieved during the test was - 446 Kbps
For your connection, the acceptable range of speeds is 50-500 Kbps.
Additional Information:
Your DSL Connection Rate :1792 Kbps(DOWN-STREAM), 448 Kbps(UP-STREAM)
IP Profile for your line is - 500 Kbps

I�ll keep it short but will give some background. Over the last 9 months. The BT Broadband Option 2 has been slow, intermittently slow speeds and just generally poorer than expected.
My expectations for this connection are for a connection of around 2 mb. (Give or take the variations due to Attn and SNR, length i am form the exchange etc) Think broadband has people only a couple of streets away with connections of around 6mb

I�ve had 1 visit form a BT engineer following a 2 week period of sub 500k speeds. Unfortunately I don�t know what my IP Profile was set to at that time as I have been on a learning experience trying to get to the bottom of it and didn�t know to look for that previously. The sync speed was about 1700 kbps then though.
He replaced the main faceplate on the master socket with an openreach one (has the inline filtering as far as I know). He had the line re-profiled and all was well for another couple of months.
My present stats are (Via the test socket)
ADSL Link Downstream Upstream
Connection Speed 1792 kbps 448 kbps
Line Attenuation 63.0 dB 31.5 dB
Noise Margin 12.5 dB 17.0 dB

I noticed that it was slowing again about 3 weeks ago and since then I have tried to be methodical in my troubleshooting. (Knowing it can take 5 days for the IP Profile to stabilise) I have done the following in this order:
1. Reset the BT HH (It�s a HH1)
2. Removed additional peripherals form the extension lines (Skybox and extensions)
3. Swapped Microfilters on extension socket where router was seated
4. Changed routers to a DGN2000
5. Move it to the Test socket in the master socket. New Microfilter (Up for 48 hours, will leave it up to hopefully improve the IP Profile, so probably still reprofiling that atm.)

They are all new D-Link Microfilters. These were changed at the last call out 2 months ago.

So after lots of reading in the last week on Kitz, SamKnows, digitalspy and the Openworld forums. I have drawn these conclusions on my present connection stats.
My Line Attn is high. According to samknows, I am 1.69km from the exchange (as the crow flies).

http://www.kitz.co.uk/adsl/max_speed_calc.php
With a line attenuation of 63.0 db that would have a cable length of 4.6km this seems crazy to me, is it possible that my cable length could be so long? (I understand some give and take but that is nearly there and back again and then there again)
My SNRM seems low, should be at least 6 dB? Am I correct and have I worked that out correctly?
I�ve been running RouterStats �lite for 2 days and have had a couple of drops, though the router has a 48 hour uptime after its most recent move (i.e. no physical connection drop according to the router). My Speed has been 1792kbps (Via the test socked) Noise 12.8 dB constantly for both without the 2 drops. Which seem instantaneous.

So in conclusion can anyone point out where to start with BT? Are my expectations reasonable? Theory seems to suggest I could get up to 4mb. Dependant on copper quality etc.

Thanks in advance and I hope that that�s not too much info. All suggestions welcome.
James

Hi James, welcome to the forums .

You seem to have learned a lot very quickly about how things work. Just a couple of oddities to straighten out first.

You correctly call your noise margin SNRM, rather than the incorrect SNR that some routers call it, but you say it is low at 12.8dB.

You are right in thinking the (BT) default is 6dB, but 12.8dB is high - not low. Have a read of my page about it, and then the High noise margin page in the Troubleshooting section.

Yes - you should get a 1500kbps IP Profile very soon, as long as nothing messes that up.

Next time you notice a re-connection, or do one yourself, note the noise margin immediately afterwards.

It also seems very odd that on what has all the symptoms of an unstable line the noise margin shown by RSL is constant.

Re the instantaneous drops on the RouterStats Lite, is the down leg of the drop red or is it the normal colour? Red means it just didn't reply to the request for the data. I advise setting the sampling interval to the minimum possible, (I forget if that is 5 or 7 seconds), and making the graph cover something like an hour. Makes analysing oddities easier. I assume you have it saving the graphs so you can look back, and suggest you also log to file as that can be easier to scan to see when something happened. Or to post extracts for people to see.

Edited by RobertoS (Thu 14-Apr-11 15:48:33)

Hi,

Thanks so much for the fast response and the information. I'll have a read over your webpage this evening. I've just chaned RSL to your suggested settings and will leave that running.

I'll report back shortly with any new info. I am still very curious as to what my expected Line Attn should be and would really like to know my calbe length to the exchange. given that it's 1.69 km away (los)

Cheers again.

James

Hi James,

You might be surprised as to how convuluted the cable routing might be.

My attentuation was around 40 db under ADSL, which gave a line length of
something approaching 3km. My distance to the exchange, as the crow flies,
however, comes up as around 1.29 (from Samknows). I strongly suspect that
my line goes down the nearest road, bypassing my house, then continues on
for another 0.5 kms (or so), then goes around the houses to approach my
property from the opposite direction.

Maybe your line takes the "scenic" route, too !

- Alex

can you still do that thing on your phone where it would tell you your rough cable length ?

I forgot what number is was you dialed, then you pressed for loop length option and it told you.

Can you still do it ?

I think it was only meant for BT use, but it worked.

I can't be certain, but I think that they withdrew that feature, due to abuse.

I am quite happy to stand corrected if anyone, more in the know, says otherwise.

- Alex

I think it might still be there via 17070 but BT Engineers now have some sort of RSA token activation on their mobiles. So doubt we can get at it (Grumble....)

Am getting that impression that the cable has been fed back to the exchange by a drunken ferret. (This area was built in 1983 so am hoping the coper should be reasonable quality, though i guess i can't discount a Aluminium run somewhere)

Thanks for the responses.

James

I just came across this on the KITZ site.

Exchange and Line Checker

It gives distance "as the crow flies" and by road.

I am not sure how it works out which route to take, but it seems to
give a closer value to the one calculated by attenuation.

- Alex

P.S
I don't think that Openreach have started employing drunken
ferrets yet, but I know what you mean !

Cheers Alex, I just gave that a go.

Distance:- Direct: 1.65 km
(appx)*
By Road: 1.93 km
Status
ADSL enabled: March 31, 2001
DSL Max enabled: March 31, 2006
SDSL enabled : Not Enabled
21CN due : (PSTN) N/A
21CN WBC (Broadband) Enabled 28.02.11
Broadband Access�
Market 2

So the 4.6km via Attn seems horrid. I have read on antoher forum that there and are often long runs of cable left inside the exchange. (Soemthing to do with when the exchanges when DSL live)

Thanks again

James

also jimmy, please note that most routers dont report attenuations over 63 or 63.5db so you line is probably even longer.

Magic! perhaps it was a druken ferret with no sense of direction being lead by a drunken squirell high on acorns.

Seems extraordinary that would pass any sort of IQ or OQ.

Thanks for the heads up though Lemzip.

James

It's academic how long your line actually is. All you'll ever know is that the attn. is > 63 dB, so your line is at least 4.6 Km and you'll never get more than 2 Meg out of it

Thanks XRaySpex,

If however I could prove that there was unused cable in the exchange or there was a differnet method of routing to that exchange then surely that could only be benefical.

Perhaps as you say thats academic, its just hard to live with.

James

Beneficial to your blood pressure but nothing else.
BT is under no obligation to provide you DSL at any speed.

If your line proves stable and the wandering IP profile indicates it is not, then the target noise margin could be reduced and you might sync at 2.3 to 2.6Meg giving a 2Meg IP Profile. Effort expended in that area rather than chasing a mythical line length is more important.

BTW 60dB = 5.5km of cable based on BT calculations. When properties are built they invariably take the line from where there is spare capacity.

Thanks for that response Andrew,

It was certainly not my intention to come on here as some form of catharsis.

That is definitely my aim. With the root cause hopefully diagnosed now (Noisy extensions and Sky HD box) i am hoping the profile can become more stable. At he moment i would happily settle for a 1500kbps profile, and then try to improve it.

As i see it, it is pointless aiming for anything better than that till i know it is at least theoretically feasible.

Can anyone substantiate that there might be coils of unused cable on the end of my line between the telephony and DSL equipent at the end of the exchange, is this something i can perhaps get BT to look in to.

Another alternative is getting BT to visit once I have a stable Profile and paying that £90 for the 500k increase. Thoughts on this please?

Thanks again

James

Regarding that BT visit:

Might be wrong about this, but I thought that all they do was,
try to improve your internal wiring, by disconnecting bell wires
or fitting an "i-plate" (something along those lines).

It's possibly something that you could for yourself, given some
advice from the experts on this site.

- Alex

Edited by deleted (Fri 15-Apr-11 11:42:30)

Thanks Alex,

I'd be more than happy doing that myself (Am reasonably skilled) If BT do it i think at the momment they are offering that £90 back if they can' get the speed increase. Hence someone possibley doing it for free.

Thanks

James

The free version of what they do http://www.thinkbroadband.com/faq/sections/radsl.htm...

Also what is holding your speed back is the target noise margin, reset that and

1) You will sync faster
2) The line might be more unstable, leading to the IP Profile not increasing.

Without knowing the address/area it is hard to comment, its not uncommon for sites estimating line length/routes to get things wrong.

You are clutching at invisible straws on the there may be a few km of cable on the end of you phone line in the exchange.

As i am running from the test socket, as i understand it, that�s the equivalent of having no bell wire in. (If the line stabilises like this, I would have gone down that road anyway)

How do I reset my target noise once i have a stable profile?

I didn't expect there to be Km�s of unused cable, on another forum an Openreach engineer said it was not uncommon for there to be 400-500 meters. Over 5km of cable to an exchange 1.69 km way still doesn�t sound in anyway reasonable to me. Hence the question.

I am happy to provide the exchange code if you think that will help. It�s a small town, the Exchange is one side and I am the other, the whole town has a circumference of about 4km.

This lead me to the conclusion (Rightly or wrongly) that the quality of the install might not be that high in the first instance. I know BT are only governed by Ofcom�s Code of Practice for this. On BT�s own website it says �BT supports Ofcom's Code of Practice on Speed and we're committed to providing you with the best speeds possible for your phone line.�

If that is true and there is an issue caused by something that they have potentially done negligently or is of poor quality overall, then I would like to understand where that leaves me as a consumer. Particularly as swapping to another ISP wouldn�t benefit me if the infrastructure is poor.

How far does that commitment run, can I use that as leverage, would Ofcom support the assertions that might mean BT have to look at the line length etc, the quality of the infrastructure. This is not me being belligerent, I just want to understand that if things don�t improve that I have recourse. 9 months of intermittent issues makes this feel likely.

Thanks again for all contributions to date.

James

Have you tried asking some of your neighbours what speeds they get? If it is spare cable on your line then you would expect some variation of speeds across the local neighbourhood as presumably they won't all have km's of spare cable (if they do then you would think BT would be recovering it as copper is not cheap and the amount of space that much cable would take up is significant).

Hi and thanks

I get on well with my nextdoor neighbour and will have a chat with him this weekend. he's been away this week and his kids didn't know.

Yeah am trying to build a picture so i can present a reasonable case to BT if needed.

James

Edited by deleted (Fri 15-Apr-11 19:47:59)

100 to 200m cable to get around inside the exchange building is not unusual, and anyone who has done a wiring job for a large ethernet install will know how easy it is for cable lengths to be less than optimum.

The speed code is nothing to do with BT optimising routing of phone cables or reducing their lengths, it is simply about giving you an estimate of the speed your line may achieve at the time of ordering.

As for reducing target noise margin, you need to talk to the ISP support team, if after a few weeks of stability the automatic systems have not reduced the target margin.

You have little recourse, as BT is well within its rights to say, this is the best we can reasonably acheive and if not good enough you have a choice

1. Take it
2. We turn off the service say goodbye, and mark the line as not suitable for xDSL services.

Ofcom says that all a BT phone line has to support is phone calls and a 28Kbps internet connection using a dial-up modem.

If I recall you said this was a new build, and it may be something as simple as all the cabling going a direct to your area was already in use, but spare capacity was available on other cables that took a longer route. Remember that until ADSL appeared the distance a phone line travelled was largely irrelevant.

A choke point such as a bridge/river/railway line/motorway all add complications and often drastically affect cable routing.

maps.thinkbroadband.com can give you an idea of what neighbours report, and if the the estimated speed points (one per postcode) can suggest whether you are barking up the wrong tree.

Jimmy, I kind of feel your pain.

I live 1.56 km from my exchange and can get 5Mb. My attenuation is 50db and I literally have no idea how my line can be so long. It must go around every estate around here and then eventually arrive at mine.

I saw BT feeding loads of cable into the floor by the cab the other day. I should have asked how long our E Side is.

According to the Be* checker our line is 5.4Km long.

Not sure if they are still providing that service though.

Be checker was invariably wrong, with figures wildly wrong.

Attenuation is the best guide. Obviously if aluminium cables are present the attenuation per km is a lot higher.

If BT were to try and optimise routing of cables with respect to xDSL cable lengths then not sure the councils would accept the amount of duct work changes needed.

Latests Speedtester results in. (This was done peak time)

Test1 comprises of Best Effort Test: -provides background information.

Download Speed
1379 Kbps

0 Kbps 2000 Kbps
Max Achievable Speed

Download speedachieved during the test was - 1379 Kbps
For your connection, the acceptable range of speeds is 400-2000 Kbps.
Additional Information:
Your DSL Connection Rate :1792 Kbps(DOWN-STREAM), 448 Kbps(UP-STREAM)
IP Profile for your line is - 1500 Kbps

I'll continue to monitor, though i still want to get my SNRM sorted. I need also to see what happens with my Line Attn at 63dB it is to high i think. I'll hope that thats comes down soonish. Thanks for the advice all!



James

In reply to a post by JimmyW77:

I need also to see what happens with my Line Attn at 63dB it is to high i think. I'll hope that that comes down soonish.

Attns. never come down of their own accord; only with some deliberate improvement to house wiring.

Ah ok, i am clearly getting confused. I was under the impression that BT reset that over a 15 -30 day period. I know SNRM changes and fluctuates so it must be that that BT changes (When i say BT i mean the exchange equipment), however i thought that as I am running with no extensions at all (No bell wire either) that it would also improve.

Obviously got myself in a muddle.

Attenuation is basically a measure of how much of the ADSL signal is lost from when it leaves the exchange to when it arrives at your modem's input port.

Quite a few things can have a secondary effect on it, but the factor with by far the largest effect is simply the length of the cable.

You have, but this is the 1st time you've shown it.

OK, BT DLM messes about with your NM and therefore your Sync. but it doesn't touch your attn. which is determined solely by your physical line, principally by its length, which you seemed to understand previously.

Yeap all clear again in the head now. Long Monday, heavy weeked - slow James.

Thanks for being gentle, and again for everyones input.

James