Line stats check please

Duke said:
Bit of an update. It seems the line is being re-profiled at the connection speed in the router has dropped a lot and the line stats have changed (are they looking better?).
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The downstream target noise margin has been significantly increased, probably in an attempt to confer greater connection stability, and the upstream noise margin has dropped, probably as a result of ongoing interference. As a result, downstream sync has gone from 4576 -> 2752 -> 480 kbps and upstream sync from 448 -> 384 kbps. The answer is no.

What we've covered:
  • Interference / connection instability effect changes to the noise margins.
  • Target and modem-reported noise margins affect the sync rate.
  • Sync rate affects the IP profile.
  • IP Profile limits the 'speed' you see, e.g. downloads, speed tests.
  • 4576 kbps sync with 15-20 kB/s download speed with some periods of "up to about 1 mbit" connected to the test socket on 29-Apr-10.
  • 2752 kbps sync and <20 kB/s download speed connected to the master socket on 23-Jun-10, 09:16.
  • 480 kbps sync with 135 kbps IP Profile on 23-Jun-10, 17:26.
This could suggest that the test socket scenario on Virgin, while displaying a reasonable sync rate, was subject to traffic shaping or congestion for the most part as you mentioned increased speeds were noted at other times of the day.

Migrate to Plusnet, remove the modem from the test socket and the sync rate dropped significantly. You need to identify the reason for this, e.g. ring wire, unfiltered telephones on extensions, sky box, cordless telephones...

Most recently the connection appears to be subject to a lot of noise and the modem is sync'ing at a terribly low rate. This could just be a continuation of a problem relating to a suggestion in my previous paragraph or, given that you've tried a different device and microfilter, a line fault external to the household or something attributable to random electrical noise.

In addition to troubleshooting the test socket / master socket issue you should consider monitoring the connection throughout the day rather than just noting the sync rates each morning. Use RouterStats to follow the noise margins and maybe DMT v.8.07 for a look at SNR as a function of frequency.
 
ncjok said:
The downstream target noise margin has been significantly increased, probably in an attempt to confer greater connection stability, and the upstream noise margin has dropped, probably as a result of ongoing interference. As a result, downstream sync has gone from 4576 -> 2752 -> 480 kbps and upstream sync from 448 -> 384 kbps. The answer is no.

What we've covered:
  • Interference / connection instability effect changes to the noise margins.
  • Target and modem-reported noise margins affect the sync rate.
  • Sync rate affects the IP profile.
  • IP Profile limits the 'speed' you see, e.g. downloads, speed tests.
  • 4576 kbps sync with 15-20 kB/s download speed with some periods of "up to about 1 mbit" connected to the test socket on 29-Apr-10.
  • 2752 kbps sync and <20 kB/s download speed connected to the master socket on 23-Jun-10, 09:16.
  • 480 kbps sync with 135 kbps IP Profile on 23-Jun-10, 17:26.
This could suggest that the test socket scenario on Virgin, while displaying a reasonable sync rate, was subject to traffic shaping or congestion for the most part as you mentioned increased speeds were noted at other times of the day.

Migrate to Plusnet, remove the modem from the test socket and the sync rate dropped significantly. You need to identify the reason for this, e.g. ring wire, unfiltered telephones on extensions, sky box, cordless telephones...

Most recently the connection appears to be subject to a lot of noise and the modem is sync'ing at a terribly low rate. This could just be a continuation of a problem relating to a suggestion in my previous paragraph or, given that you've tried a different device and microfilter, a line fault external to the household or something attributable to random electrical noise.

In addition to troubleshooting the test socket / master socket issue you should consider monitoring the connection throughout the day rather than just noting the sync rates each morning. Use RouterStats to follow the noise margins and maybe DMT v.8.07 for a look at SNR as a function of frequency.
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Thanks for the post.

Just to clarify a few things about the sockets. They have three sockets. One in the kitchen which is the master socket and had the test socket behind it. This doesn't have a phone connected to it. There are two other sockets; one in the living room which has a phone connected and the second in the office room which has just the ADSL router on it. So its quite a simple set up with just two filters required. They don't have Skyv or fax machine etc.

The speed on the office line used to be about 1500k and was 2500k on the master socket and 4500k on the test socket behind it. All of them still had the 'cap' issue.

Since then, BT have come out as where the line comes in on the wall (via telegraph pole) it has a bunch of the small cables sticking out of the box, so I advised this was probably causing the slight crackling on the line and wasn't helping the ADSL issue. BT have put a new box up there and it looks new now and have removed the kitchen socket entirely (as they just had new kitchen put in and don't need it there) so apparently the master socket is somewhere upstairs in the roof or something. The connection speed at the office increased a little to 2500k which seemed about right as BT said he was losing a bit of speed due to the internal wiring, which they resolved.

As mentioned before, they were using a USB Modem which would have been off each night and mixed with the slightly dodgy line, would make sense for the low profile set.

The odd thing is this has been corrected at least a week or two ago but the profile issue still exists.

I only had the router on the test socket for an hour or so but am sure the internal wiring shouldn't be a problem.

I'll give it a couple of days as the profile and connection speed has changed in the last day, to see if it now resolves itself.

Would it be worth while removing the bell wire from the office socket later on?
 
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I would remove the bell/ring wire from the master socket. And If you can, place the modem at the master socket.
 
Duke said:
Thanks for the post.

Just to clarify a few things about the sockets. They have three sockets. One in the kitchen which is the master socket and had the test socket behind it. This doesn't have a phone connected to it. There are two other sockets; one in the living room which has a phone connected and the second in the office room which has just the ADSL router on it. So its quite a simple set up with just two filters required. They don't have Skyv or fax machine etc.

The speed on the office line used to be about 1500k and was 2500k on the master socket and 4500k on the test socket behind it. All of them still had the 'cap' issue.
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As we have covered, your so-called 'cap' (IP Profile) should ultimately correlate with the downstream sync rate. We don't have a record of how it has changed over the course of this thread moving from 4576 -> 2752 -> 480 kbps, only the latter, slowest case. It wouldn't be unheard of for the profile to be stuck, in which case you should follow the advice on the Performance Tester page and suggest it to the ISP.

Since then, BT have come out as where the line comes in on the wall (via telegraph pole) it has a bunch of the small cables sticking out of the box, so I advised this was probably causing the slight crackling on the line and wasn't helping the ADSL issue. BT have put a new box up there and it looks new now and have removed the kitchen socket entirely (as they just had new kitchen put in and don't need it there) so apparently the master socket is somewhere upstairs in the roof or something. The connection speed at the office increased a little to 2500k which seemed about right as BT said he was losing a bit of speed due to the internal wiring, which they resolved.
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You should consider checking the sync rate in the test socket at the new master socket location to find out how much speed you are giving away. It gets covered time and again that it is beneficial to connect the modem to the household's master socket rather than an extension socket in a distant room.

As mentioned before, they were using a USB Modem which would have been off each night and mixed with the slightly dodgy line, would make sense for the low profile set.
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Dodgy line, yes. USB modem switched off each night, no.

I'll give it a couple of days as the profile and connection speed has changed in the last day, to see if it now resolves itself.
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I would generally agree, but I don't think the 135 kbps IP Profile correlates with a 480 kbps sync rate. Even going from 480 -> 992 kbps sync should effect a change in IP Profile within 24 hours.
 
Thanks for the post. I always put the router in the master socket where possible but in this instance the kitchen wasn't appropriate and loft isn't easy to get to and would need wireless kit. I haven't got them to do the bt speed checker today but will do on Monday to see if it's resolved or not.
 
Remove the ring wire anyway, if the extensions are on half decent cable it wont be far off the speed off the master socket.
 
Right am just here now.

The connection speed increased each day; 480 - 992 - 2624 - 1920 but dropped back down today to under 200. The IP profile was still the same the whole time so they didn't actually 'get' the increased speed.

I've just removed the bell wire from the socket the ADSL is on, and will do the other socket and will check the master one shortly.

I noticed the connection time was about 11 hours on arrival, is it normal for it to disconnect whilst the IP profile is changing? Or could that be causing the issue?

I just rebooted the router after removing the ring wire and it jumped back up to 2400k but obviously still same profile for now at least.

Couple of screenshots below of before and after ring wire removal/reboot.

beforeringwire.jpg


afterringwireandreboot.jpg
 
The one that really needs the bell wire removing is the master socket... Those stats look promising though...
 
Yep I had a good look at the wiring at the master socket, which BT relocated into the roof.

It basically just splits into two, going to both sockets downstairs. I took the bell wire off this socket which would have been easier to start with :p

The speed went up as pictured below, which was the same speed when I had it in the test socket a month ago, but only had it in there for an hour.

73919751.jpg


I've asked them to again leave it and note down the down/up and IP Profile for the next day or two.
 
Thats a much more reasonable sync rate. You should be able to get that SNR down to arround 6db though, giving you maybe 7000kbps sync rate.
 
Sync rate is still about 4000 but the IP Profile hasn't increased from 135k. What is the next course of action - contact Plusnet I take it?
 
Quick update - the IP profile is sat at ~1700 now, so all working again :) Not sure why it took so long for it to change but glad its going. It may improve further as the line should do 3mbit but for now that is great.

Thanks to all those that helped :)
 
Well the IP profile dropped again a couple of week ago on this one. Spoke to Plusnet and got things moving a bit more now. They said the line keeps disconnecting for a split second every day or so, hence the profile dropping. They are hopefully getting an engineer out to the exchange soon.
 
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