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Frequent Loss of Sync

PaulEvans
Dabbler
Posts: 20
Registered: 29-06-2012

Frequent Loss of Sync

I have raised a fault on this, but thought it was worth seeking input from the wider forums. I've been with Plus Net 2 weeks now, having moved from another ISP. With my old ISP I would get very occasional disconnects and have to reboot the router. With PlusNet I am gettiing disconnects every 30-60 minutes - then for no reason I'll get a stable 6-7 hours - then can get disconnects every half hour again. My router is currently plugged into the BT test socket on my master socket, so no internal wiring being used.
I have swapped all my microfilters for XF-1e's and it makes no difference.
The router is a netgear DG834v2 with firmware V3.01.31.
I am around 1.5KM from the exchange.
I have a replacement router on order from PlusNet but until it turns up  I am still using my existing router
Router log always shows "loss of synchronisation" as the problem.
The router stats are downstream speed 12132, upstream 445, Downstream line att 26db, upstream 7db, Downstream noise is 9db, upstream 25db.
Anybody have any helpful hints?
Cheers .
Paul
39 REPLIES
Plusnet Help Team
Plusnet Help Team
Posts: 13,017
Thanks: 145
Fixes: 48
Registered: 27-04-2007

Re: Frequent Loss of Sync

Glad to see you've raised this as a fault, that's definitely the right thing to do. Incidentally I've run some line tests and have copied the results onto your account so that we can use them comparatively against tests done with your "usual" set up.
They don't reveal any obvious issues or a high number of errors so lets see how things go with the new router, I'd imagine that should reach you very soon.
If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team
Community Veteran
Posts: 19,100
Thanks: 437
Fixes: 21
Registered: 31-08-2007

Re: Frequent Loss of Sync

You should definitely be getting better performance from that line, unless you are just unlucky with lots of noise pickup.
As Adam's tests didn't reveal anything obvious, I'm wondering why your Noise Margin is at 9dB and possibly your internal wiring may be an influence.
Whilst you are plugged into the Test socket can you tell us what colour wires are connected to the faceplate you've taken off and what terminal numbers they are connected to?
PaulEvans
Dabbler
Posts: 20
Registered: 29-06-2012

Re: Frequent Loss of Sync

With respect to master socket wiring - terminal 2 is blue, terminal 3 is orange, terminal 5 is white.
Just rebooted and lasted 4 mins before lost sync. Then had to reboot again and lasted one minute before lost sync.
Service is effectively unusable. This is VERY frustrating.
Thanks for the input guys.
Paul
Community Veteran
Posts: 19,100
Thanks: 437
Fixes: 21
Registered: 31-08-2007

Re: Frequent Loss of Sync

Stop rebooting. That will be the quickest way to get your Target Noise Margin raised further, or banding, which will cause further loss of speed.
From now on, I recommend that whenever you need to reboot/resync or swap anything - use this Disconnect method -
Do a Disconnect of your PPP Internet session with the ISP - you need to login to the modem/router interface and look for the Disconnect button to click on. On the Thomson modem/routers you will typically find it in the box marked Internet as shown here.
Now wait a few minutes, power down. Then wait 10 minutes (during this time swap any filters, modem/router, connect to test socket, etc. - it doesn't matter if you take longer than 10 minutes) and then power up again (You may need to login to the modem/router and click on Connect to re-establish the PPP Internet session). Check the stats immediately (The Noise Margin [SNRM] shown is usually the current Target Noise Margin).
I usually recommend you do this no more than 5 times in an hour, and then leave it alone for the rest of the day.  
Remember the reason for this procedure is to help prevent the Exchange DLM from thinking you have a dropping connection (or a worse one than you may have).
(Also note, you can use the Disconnect/Connect (without a power down) to Gateway hop.)
OK, your internal wiring may be contributing to or the cause of your initial problem as the bell wire is still connected. This acts like an aerial as well as unbalancing the line, picking up all sorts of interference, and it is not needed in a broadband situation. If you happen to have an older phone that needs a bell wire, one is provided by each filter, and doesn't cause the issues.
Do the Disconnect procedure above and whilst you are powered off, remove the orange bell wiire form Terminal 3 by gently pulling it vertically out of the terminal. Be very careful not to pull out the outher wires and make sure that they seem secure in their connections. Do not poke a screwdriver or other object down the slot otherwise you may open out the jaws of the terminal and provide a bad connection.
Whilst you are powered down, plug a corded phone directly into the test socket. Have a listen to your phone, can you hear audible crackling noises? In which case you have a faulty phone line which needs to be reported to your Line rental provider (and don't mention the broadband or you may get the run around).
I would also change the filter whilst you are powered off, just in case a poor connection there is causing the symptom you've just described.
When you've done all that, power up again, and if you haven't got a phone line fault, one can only hope things may be a bit more stable. But whatever the cause of the current problem, when that is fixed and you go back to your normal setup, you should have an improved poerformance.
PaulEvans
Dabbler
Posts: 20
Registered: 29-06-2012

Re: Frequent Loss of Sync

Anotherone, thanks for that, much appreciated. Disconnected, powered off and reconnected as you said, also disconnected orange wire from master socket (but I am using test socket so this is not connected).
Let's see how it goes....
Paul
Community Veteran
Posts: 19,100
Thanks: 437
Fixes: 21
Registered: 31-08-2007

Re: Frequent Loss of Sync

Well I do hope it improves, I guess you may have an external fault from what you've described, did you hear any noises on the phone? That's always the quickest way to get things fixed if it is a faulty line.
PaulEvans
Dabbler
Posts: 20
Registered: 29-06-2012

Re: Frequent Loss of Sync

Not hearing any noises on the phone. 1st time I tried your method (around 8PM) I had a 35 minute period of no loss of sync. Then lost sync, so tried it again around 10PM. this time had 8 loss of sync events in 20 minutes.
Do i need to disconnect orange wire from all the slave sockets?
Thanks
Paul
PaulEvans
Dabbler
Posts: 20
Registered: 29-06-2012

Re: Frequent Loss of Sync

Ok latest on this - Anotherone's advice to use disconnect rather than reboot seems to be helping, more stable. I've just been reconnecting immediately not powering down (so gateway hop). When I get loss of sync it's always when the noise figure falls to zero DB. It's flat and very stable most of the time, but sometimes drops very steeply to zero for 30 secs to 1 minute, them climbs just as steeply to it's previous flat stable state. Sometimes the noise events come in clusters - 3 over a period of 5 mins, then nothing for an hour or so.
Community Veteran
Posts: 19,100
Thanks: 437
Fixes: 21
Registered: 31-08-2007

Re: Frequent Loss of Sync

Hi Paul,
A loss of sync will always cause the Noise Margin to drop to zero pretty instantaneously and it will go back up again in a similar manner when sync is re-established. During those loss of sync instances, did you have a listen to your phone line? Always a good idea, it may help to see what is going on. Sometimes you won't hear any noise at all on a line until the instant that it becomes intermittent and then it clears again.
I take it that the other modem/router hasn't yet arrived - that would at least help to prove if the fault is external.
Gateway hopping won't I'm afraid help if it's an intermittent line problem, but when you terminate a  PPP session and then power down before changing anything or disconnecting, the Exchange DLM shouldn't interpret that event as a line problem.
PaulEvans
Dabbler
Posts: 20
Registered: 29-06-2012

Re: Frequent Loss of Sync

Thanks for that Anotherone.
OK latest - I have now moved the router back to it's slave socket in the office, no longer using the test socket on the master socket. Before doing this I checked all the slave sockets in the house, disconnected the bell wires from all of them, and found that one of them had no white wire connected, just blue and orange. Which won't have affected the test socket, but also won't have helped in the first week and a half of service.
For some reason, since I moved everything back service has been perfect. (crossed fingers) 10Mpbs and 12db downstream noise, the traces on routerstats are ruler-straight, up time 5 hours and counting.
I am confused, but so long as this continues, I will be happy.....
I did not have a listen to the phone line during the loss of sync, they only last 30-60 secs but will try to do so if they recur.
I had thought the noise margin dropping to zero was a cause of the loss of sync, but sounds from what you say as if something else is causing the loss of sync and the loss of sync is causing the noise margin to fall - do I have that right?
Thanks again for all your advice.
Paul
Community Veteran
Posts: 19,100
Thanks: 437
Fixes: 21
Registered: 31-08-2007

Re: Frequent Loss of Sync

Well it could be either way, a damn big spike of interference could do that, if disconnects seem to occur at specific times etc then go hunting for likely causes. Central heating/Hot water firing up, fridges/freezers starting etc. It was just the way you've described the events - 8 losses of sync in 20 minutes - well it could be electrical but less likely with the possible exception of flickering fluorescent lights /energy saving lights sort of thing.
I did forget to say, it's good practise to take the orange off the extension sockets, good job you checked, I take it you reconnected the white (not with a screwdriver down the slot I hope, just either side if you haven't got the IDC tool)!
x47c
Grafter
Posts: 878
Registered: 14-08-2009

Re: Frequent Loss of Sync

A  gradual fall in noise margin (typically winter evenings) may cause a re-sync if it gets low enough.
So the margin will not actually reach zero prior to the re-sync being ordered as the router can no longer hold the line up.
This will depend on the router and a few other things as to at what point it gives up.
Alternatively a blast of noise onto the line which obliterates the ADSL signal totally will cause the margin to drop to near zero.
This will obviously causes a instant re-sync order.
During the actual re-sync process of say 30 seconds the margin will become zero whatever is the cause of the event.
Once the re-sync has happened the noise margin will return initially near to the "target margin".  This is the margin the exchange aims at when determining the sync values at any re-sync event. Common values are 3,6,9,12,15.
As to whether routerstats sees these events - it depends on the sampling rate - which is a science in itself.
Say you have RS sampling at 1 min intervals and the re-sync takes 30 seconds to do, then it is quite possible RS never samples during the event so you will only see the sync and noise margins change to new values and never see the zero event.
Change the sampling rate to 15 seconds and you will see such events when everything drops to zero as your sampling rate is now higher than the sync event cycle rate.
However some routers (such as mine) don't like the RStats sampling rate to be set too small.  The program starts to miss points as the router sometimes returns a load of zeros to R.Stats requests as it's busy elsewhere and the channel which reports the stats has a lower priority within the router.  
This can result in R.Stats showing glitches in the graph and drops to zero in both the sync and margin which do not actually occur in practice. I've found R.Statslite to be better in this respect than the full R.Stats which can be set to ask for a huge amount of data from the router.
Community Veteran
Posts: 19,100
Thanks: 437
Fixes: 21
Registered: 31-08-2007

Re: Frequent Loss of Sync

I sample at 8 seconds 900 points per page.
PaulEvans
Dabbler
Posts: 20
Registered: 29-06-2012

Re: Frequent Loss of Sync

OK problems have started again, between 18:40-ish and 20:15 I have 9 losses of sync, of which 8 were in pairs of 2, 3-5 minutes or so apart, one single one. 
Got to the phone during one event and the phone line did seem to have static - not very loud but not normal.
Routerstats is currently set to sample at 15 sec intervals and I am seeing the noise fall to zero, so think I can leave it as is?
And yes I did use an IDC tool on the phone sockets!
There are thunderstorms round here tonight (near manchester) so I guess it could be that...
Paul