Does this sound strange to anyone else?

Yesterday I posted the following in a ticket/question to plusnet:-

Over the last week or so I have noticed a drastic fall-off in my download speed. Usually I can get around 2Mb in the evenings and weekends. Now I am getting around 200kbps download speed. In fact this is slower than my upload speed which remains around 240kbps. This is a very recent problem, last week I was running at the usual speeds. My router stats are below:-

................................Downstream Upstream

Margin [dB] :...............23..................23

Attenuation [dB] :........23..................10


(ticket reference number 22151883 )

Before I get too much further into the happy game of ticket tennis that this question appears to be heading towards - does anybody think this is a symptom of a line fault or does it sound more like some sort of strange throttling? In particular I am suspicious of the fact that my upload speed hasn't changed at all. Exchange contention has also been suggested, but I'm not sure that would manifest itself as such a sudden degradation of service.

Any opinions/help gratefully received, and should a PlusNet rep read this please could you check out your end in case something unexpected has happened.

Thanks,
Rob Allen

I saw something similar, ended up at dialup speeds in the end, all down to a fault on the line. Raise a speed issue, do the speed tests and work it from there. Are you hearing any noise on voice calls? does your router disconnect when the voice side is used?

Hi,

What speed is the line sync'd at? It could be a number of different things depending on whether you're seeing a decrease in the sync speed or whether it's just the throughput speed.

I've never known that. My router doesn't have a way of telling me.

I'm also assuming that its not contention at the exchange as my Dad is also a PlusNet customer and he lives three miles further away from the same exchange as me - he is still getting 1.1 Mb.

If you can see line stats then the router sync speeds should also be shown with it.

What ADSL router are you using?

A SpeedTouch 570 v1.

All the ADSL info it can give me is pasted below. If I've overlooked something I'd be very happy to stand corrected.

Modemstate : up

Operation Mode : G.DMT Annex A [ POTS Overlay Mode ]

Channel Mode : interleaved

Number of resets : 1



Vendor (ITU) Local Remote

Country : 0f ff

Vendor : ALCB GSPN

VendorSpecific : 0000 0008

StandardRevisionNr : 01 01



Downstream Upstream

Margin [dB] : 21 24

Attenuation [dB] : 24 10



Available Bandwidth Cells Kbits

Downstream : 0 0

Upstream : 0 0





Transfer statistics

Total since power On Cells Kbits

Downstream : 3950203 1516877

Upstream : 522264 200549

Current Connection

Downstream : 3950143 01516854

Upstream : N/Avail N/Avail

Errors

Received FEC : 7214635

Received CRC : 0

Received HEC : 0

I think the values under Available Bandwidth are the sync speeds, but for some reason these are shown as zero.

The Received FEC error count seems unduly high to me in comparison with Cells Received. I would interpret this as indicating a line problem; do others agree?

I would too in many cases.

However, I am concerned at the very high noise margin seen on the line.

Such figures are never normally associated with such a high error count as can clearly be seen in this case.

I would be very interested to see the following were possible.

1: Power down the ADSL equipment for at least 30 mins.
This will ensure the device is allowed to cool, ensure that any software glitches after being powered on for so long are not present and in general, allow things to settle.

2: Power the equipment back on and give it a few minutes.

3: Take a full capute of the data as you have now.

4: Again, allow 30 mins and if possible, use the connection. This will ensure that errors are generted.

5: After 30 mins, capture the data again and post the two sets. Just ensure you notify us which is which (though this should be obvious).

The 30 mins of use, should provide figures to give a very rough "errors per hour" figure. This should give us a little extra to go on.

OK I have done the test you suggested and the results are below. Before I get to them though I do have a couple of related questions:-

a) Why do your CSC agents keep asking me to run a BT speed test? I have been asking them to look at my account from their end to see if anything was wrong and if they had done that surely they would have noticed that I am on Tiscali LLU and therefore the BT spped test won't work.

b) My usual line rate is around 2Mb, now considering that I live half a mile from my local exchange and that there is a road directly connecting me to the exchange - where all the cables are located - is it reasonable for me to expect something somewhat faster than this? Especially as other members of my family live a couple of miles further out from the same exchange and get almost as much speed as I do.(I have asked this question several times before, but never got anything near an answer).

Anyway the test results. I switched the router off before going out for a couple of hours and switched it back when I got home then got the following:-

Modemstate : up

Operation Mode : G.DMT Annex A [ POTS Overlay Mode ]

Channel Mode : interleaved

Number of resets : 1



Vendor (ITU) Local Remote

Country : 0f ff

Vendor : ALCB GSPN

VendorSpecific : 0000 0008

StandardRevisionNr : 01 01



Downstream Upstream

Margin [dB] : 21 24

Attenuation [dB] : 24 10



Available Bandwidth Cells Kbits

Downstream : 0 0

Upstream : 0 0





Transfer statistics

Total since power On Cells Kbits

Downstream : 531 203

Upstream : 512 196

Current Connection

Downstream : 530 00000203

Upstream : N/Avail N/Avail

Errors

Received FEC : 0

Received CRC : 0

Received HEC : 0


Then used my connection fairly constantly for around 30 minutes (downloading stuff, watching YouTube etc) Then got the following:-

Modemstate : up

Operation Mode : G.DMT Annex A [ POTS Overlay Mode ]

Channel Mode : interleaved

Number of resets : 1



Vendor (ITU) Local Remote

Country : 0f ff

Vendor : ALCB GSPN

VendorSpecific : 0000 0008

StandardRevisionNr : 01 01



Downstream Upstream

Margin [dB] : 21 24

Attenuation [dB] : 24 10



Available Bandwidth Cells Kbits

Downstream : 0 0

Upstream : 0 0





Transfer statistics

Total since power On Cells Kbits

Downstream : 750407 288156

Upstream : 83027 31882

Current Connection

Downstream : 750395 00288151

Upstream : N/Avail N/Avail

Errors

Received FEC : 0

Received CRC : 0

Received HEC : 0


The errors seem to have vanished so presumably they can be discounted as a source of my problem.

NB. I tried to raise a fault using the http://faults.free-online.net link but it doesn't seem to work. I just get a blank screen that just sits there doing nothing for several minutes then I get bored and close it.

Regards,
Rob

Having looked at this, I have raised a report on your account for you. Some of the questions asked have been filled with generic information due to what is going on, but the guys that deal with the Tiscali stuff, are pretty much on the ball and will notice this anyhow.

I can't provide a full response to the ticket itself, as I don't have access to all my normal matterial (I am sat here on holiday as I type).

In regards to the BT Speedtester response, this is another case of people not reviewing the account properly. This should have been seen, as it's pretty hard to miss.

In regards to line rates, it would seem the line rate has not changed and it looks so far like a throughput issue. The line rate I am seeing from the quick DSLAM checks, show around 4mbps. There is a single errored second on the ubstream and a couple more corrected blocks. I wouldn't expect this to cause anything significant other than a few kbps loss.

Right now, it's not an immediate question we can answer as to why though, as the more serious issue regarding the huge loss in speed would need adressing first.