Slow speeds on fixed rate line

Hi all,

For the past two weeks I have been experiencing slow speeds on my 512 fixed speed business line (Business 500-BTconnect.com). Prior to this my download speeds have been very consistent at about 450-470 kbps for over 5 years. I am about 5+ km from my exchange (Kilmarnock) which is currently shown as status green.

Having spent a frustrating 1.5 hours with the BT Business HD which resulted in no improvement I was wondering if any of the resident experts on here might be able to comment. The BT helpdesk laddie insists there is no fault on the line.

A bit of system background first.

Windows XP Pro SP2
Netgear DG834N
Line connected direct to master socket. (Although I have a conventional BT socket it appears to be wired oddly as there is no wiring to the test socket.

Router stats below

Port Status TxPkts RxPkts Collisions Tx B/s Rx B/s Up Time
WAN PPPoA 59047 60763 0 617 2365 03:39:43
LAN 10M/100M 61946 60503 0 2489 724 03:40:00

ADSL Link Downstream Upstream
Connection Speed 576 kbps 288 kbps
Line Attenuation 59.0 db 31.5 db
Noise Margin 21.1 db 19.0 db

The uptime reflects the fact that I rebooted the router today. I've never had any disconnections and before rebooting the uptime was over 2000 hrs.

I've done all the conventional things such as rebooting my router as well as powering down for a minute or so then restarting the router. I've changed filters as well. I get the about the same d/load speed when I connect my laptop to the router. The only thing I haven't tried is a different router as I don't have access to one.

I've run numerous speed tests on BT Tester, Thinkbroadband tester, Dan Elwell, etc. Although there is a predictable amount of variance between the actual throughputs all appear to be well below my typical d/load speeds of prior to two weeks ago.

TBB Speed test results below

05/08/08 15:40 231.58 Kbps 241.71 Kbps
05/08/08 14:12 342.44 Kbps 241.68 Kbps
05/08/08 09:39 351.66 Kbps 241.77 Kbps
04/08/08 09:46 409.64 Kbps 241.52 Kbps
30/07/08 19:19 393.58 Kbps 241.94 Kbps
27/07/08 21:14 348.40 Kbps 241.76 Kbps
26/07/08 20:00 455.17 Kbps 240.75 Kbps
23/07/08 23:40 297.45 Kbps 241.77 Kbps

BT Tester Results

24/7/08 220 kbps
28/7/08 134 kbps
29/7/08 385 kbps
31/7/08 218 kbps
3/8/08 356 kbps
5/8/08 165 kbps (10:10)
5/8/08 213 kbps (13:20)
5/8/08 247 kbps (13:55)

It's frustrating enough having a low speed connection due to the laws of physics without this further deterioration.

Any and all help gratefully welcomed!

Drummy

It does look like nothing is wrong with the ADSL line, there are hundreds of miles of fibre network, which have varying amounts of congestion which can easily explain your speed variations.

As for a low speed connection, technically it will run a lot faster, potentially 2000Kbps to 2907Kbps. Just needs a provider to give you a rate adaptive service, though how stable this will be depends on how much your noise margin varies across the day.

I would try and get a regrade to a current package - connect 500 is very old now.

Mr S,
Thanks for your help. So, do you think is it just coincidence that the speed drop has appeared in the past two weeks despite over 5 years of rock steady download speeds?

I realise that the line could certainly handle a higher throughput on ADSL Max but the BT line checker insists that the line cannot handle more than 512! I have spoken to BT about this in the past but they were singularly uncooperative when I asked for a written guarantee that if I upgraded and the service became more unstable that I could be returned to my fixed rate line and not held to a new 12 month contract. Hence I am still on fixed rate. As it's my primary method of business communication I don't want to risk a move to a potentially less stable rate adaptive service. Mind you, if the low download speed continues I might consider a move to Max on the basis that even if it only bottoms out at 750 I would be better off than now!

I notice too that my exchange is due to have 21C operational later this month. Could work related to this in the exchange be a possible cause of the speed drop?

Once again thanks for your help.

Drummy

Looks like coincidence, and possibly to do with summer holidays, and kids home from school hammering the BT Retail network to death in your area maybe

The basic business services are not fully immune from the usage from the consumer market, for that you would have to pay more.

ADSL has no guarantees about anything unless paying �200+ a month.

Frankly, I very much doubt that it could do worse than the fixed 512 you have now.

http://www.kitz.co.uk/adsl/max_speed_calc.php

Gives you an idea of the likely sync speed you would acheive.

Thanks Shtu, but I've already done all those checks so have a good idea of what should be realistic to expect on a Max product.

The 'speed' is excelling itself this morning. BT Speedtester recorded 65 kbps at 9 am. Just as well I have no major files to download.

Cheers

Drummy

As MrS and others have said, there appears to be nothing wrong with the line. Have you changed any PC settings or Windows updates recently?

Have you checked and tweaked your MTU and RWIN settings? I recently sorted out a problem for a friend of a friend who had a similar (but worse) problem. His settings were the cause, changing them sorted it out. We then removed a recent set of Windows updates, then reloaded the same and the problem returned. Using DrTCP to change them again and all returned to normal.

Just thinking about the OPs situation, if you move to rate adaptive, and wind up having massive stability problems (you're still likely to be faster than 512kb fixed), you can have a "fixed profile" applied to the line, these are equivalent to the old 512k, 1M, 2M fixed speed products.

I reckon you could get a useful speed boost (and probably a new router, broadband talk and a lower price) by moving to a new product. I'm guessing by the name you use to refer to it you've been on that deal for a good few years?

MHC,

Thanks m8. I've never been a great one for tweaking due to basic ignorance! It wouldn't surprise me to find that my probs might be caused by an MS upgrade but I can't see anything which might have arrived on my system about the time the speeds died.

Any suggestions as to what RWIN & MTU I should be using?

Ta.
Drummy