Strange noise graph

[Dopamine]

I've been trying to help a friend who's been suffering low IP profiles and frequent disconnects for ages. After years with BT, she finally tired of their foreign help desk and migrated to IDNet, which has completely solved the regular PPP session losses. However, the line remains poor and I've been remotely monitoring its noise margin, which fluctuates rather strangely. A continuous graph, plotted every 10 seconds, can be seen here: (it's 12,000 pixels wide, so you'll have to scroll)

http://youwho.www.idnet.com/router-stats.jpg

Unusually, this is the first time for ages that these margin drops have not resulted in a loss of sync, which has been constant at 2752 for over 3 days now. Line attenuation is 60db. More usually, there will be a sync loss at the bottom of one of the troughs, and an immediate resync at somewhere around 700-800kbps, which plays havoc with her IP profile.

My question is for those familiar with noise margin graphs. Does this one look normal? There are few sudden spikes, just smooth rises and falls at varying times of day and night. As can be seen, the first 24 hours have very little margin change at all, thereafter it fluctuates. This happens whenever the router is disconnected from the phone line for more than a couple of minutes, but not if it is simply rebooted, almost as if the exchange is being given a breather.

Have tried 3 different routers, connected to the master socket and an extension, and the results are similar. On the 30th July, the house was empty, all electrical appliances except the router and fridge/freezer were disconnected, and the boiler was turned off, but there was still a big fluctuation in margin, as can be seen on the graph.

If the sync losses stop, then I'm not worried, but experience of this line suggests that they'll come back. Before I ask her to contact IDNet support to report a fault to BT, I'd like to hear anyone's opinions and suggestions.

Many thanks.

[Rik]

I have a nasty feeling that BT will not do very much about the line, do you know what the FTR is set to?

The graph suggests an overhead cable run to me, with a lot of cyclical noise pickup, ie there is a 12db swing in noise margin. If it's not being generated locally (I assume you've done all the usual wiring/filter checks), then it comes down to whether BT will act, and if the line is above FTR they won't.

[Dopamine]

Thanks Rik. What's an FTR, and how do I find it?

Yes, all wiring has been checked, filters changed etc. BT engineers have apparently been out to the house six times in the last two years (before I got involved) and fitted the current master socket and extension (made no difference), cleaned up various joints in the line between the house and exchange, and tried other changes. I've double checked the internal wiring and found no difference in sync between the test socket, master socket and extension.

All the time the line holds sync, which it's done now for almost 5 days (a record), I'm happy, and in any event it would be difficult in those circumstances to make the case of a fault being present, but I'm pretty confident it'll lose sync soon and resync very low, when we'll then be forced to wait for a quiet period so we can force a resync to a better speed.

I'll probably just have to wait for that to happen, hope I can get a good graph of it, and see whether BT will do anything then, unless anyone has any other ideas......

[Dopamine]

Would you believe it?! As I posted that last reply, the line's just resynced to 1600. Noise margin now back to 15db and falling rapidly, so it looks like the IP profile will be back to 1000 or lower pretty soon. So very frustrating.

[Rik]

The FTR is the fault threshold rate, which is set at 70% of the maximum stable rate during the initial training period. If the current speed is above that, BT don't regard the line as faulty.

I think the problem you now face is that BT have put a lot of time into the line already. If you push too hard, one of their options is to declare the line as unsuitable for ADSL and withdraw the service. You can't appeal against such a decision, so talk to support and see what they have to say (they will know the FTR). Given that the line is already at maximum noise margin, it might be that limiting the sync speed to something sustainable would be an option.

Have you thought about trying a 2700 router? That's the sort of line which could well benefit from the 2 Wire's incredible ability to 'resist' noise.

[Dopamine]

That's valuable advice Rik. Thanks. Hadn't realised BT could declare lines unsuitable. It's quite amazing really, as the house is not in the middle of nowhere, but part of an estate on the outskirts of a large town, so others must have similar problems too, I'd guess.

I'll look in to buying a 2700 from somewhere. Nothing to lose really, as it's impractical for me to keep looking at my PC monitoring a remote line.

Fortunately I was working here today as it resynced, and 10 minutes later there was a sudden rise in noise margin to 19db, so I took advantage of it and forced a resync which came in at 2144, hopefully soon enough not to have dropped the profile too far.

One big benefit of IDNet's static IP addresses, I can monitor her line remotely . With BT and a dynamic address, I either left her router open to everyone to access (not too happy about that), or had to ring her and ask for the new address each time it dropped connection or was rebooted.

[Rik]

Sadly, there's no universal service obligation when it comes to ADSL, so if a line is proving expensive to them, BT are able to remove the service at their sole discretion. Not an ideal situation.

I live in Milton Keynes, one of the fastest growing towns in the country, but because aluminium was used when the area was being developed, I'm limited to 3Mb, but at least that's stable, so your friend is not alone in having these kinds of problems. (My neighbours, btw, get between 512k and 2M - being an early adopter, I got the best pair the engineer could find for me. )

[Dopamine]

Re: 2700s. Do they have remote management facility, preferably that can be permanently enabled for one IP address? And has anyone managed to get RouterStats to work with them?

I don't want to buy one only to find that I can't do much with it from afar, as she's technophobic and wouldn't thank me for wasting her money!

[Rik]

Routerstats works fine with 2700s, not sure about remote management, I've never needed it so I've never looked for it.

[Sebby]

I tried remote management on a 2700 once. I think the only thing that held me back from trying it was finding out which port it uses!

[Dopamine]

BT take a fairly regular (and usually deserved ) beating on this and many other forums, so I thought I'd share some good news in the hope it may give others hope.

Last Sunday, the connection I've been trying to monitor and help with died completely at 5.30pm. No sync at all. I waited, waited some more, but come Monday morning it was still down, so at 11am I visited said friend's house armed with two different routers, connected both in turn to the test socket, but still no sync.

OK, must definitely be a BT problem, so I'll phone IDNet support just as soon as I've plugged back in the original router.....

Plug router in, and surprise surprise, immediate sync at the highest I've ever seen, 3104, 15db noise margin, 60db attenuation. Since then the line has been rock solid with just a 0.2db fluctuation in noise margin. It looks as if BT have at long last upgraded or repaired something somewhere, and that 3 years of woe have finally ended.

So, for anyone pulling their hair out in frustration at a poorly performing line, have patience. BT might eventually get round to your line too!


The irony of this though is that if BT had fixed the line just a month earlier, my friend would still be a BT customer and not now with IDNet   Poor old BT

[Lance]

Great news! Shame it took three years though!

[Rik]

The wheels within BT move exceedingly slowly, but a great result.