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[duckson]

Evening,

Can any of you experts cast your eyes over the following router stat graphs and give me an idea if you've seen anything like this before:-

http://www.duckworth.myzen.co.uk/router/Netgear/

Note that the connection had been fine for a few years at 8128kbps, this has started happening over the past 4 weeks or so (7150 profile to a 4000 profile the other week, now at a 5000 profile). I have a solid setup with ADSLNation faceplate and ADSLNation "PRO" ADSL cable but have tried 3 other filters, 4 other ADSL cables and 2 other routers to the current Netgear DG834GT i'm using with no change to the results, i am confident its not my side of things at fault!
I have also tried powering down alot of household electrics with no success and have tried the stereo at mid 600khz checking for REIN....nothing found that i can tell.

Strange thing with the fault is that if i reboot the router it will sync at mid 7000kbps's, noise margin will be holding tight to 9db (BT put it up from 6db recently) but then minutes or a few hours later i will get a very large noise spike in the region of 15db which takes the noise margin well into the negative and forces a resync. If the router ends up resyncing at around 6000kbps with a 14/15db noise margin i will not get a massive noise spike again but i will get 5/6db spikes on occasion as can be seen in the above graphs. I dont see 5/6db noise spikes when i'm connected at 9db, they are always large spikes causing the resync.....any ideas why???

The noise spikes dont appear to be at a set interval though they are usually 1-2 hours apart and happen mostly through the night but have recently started occuring during the day as well.
I have logged the fault with Zen who are looking into it but i'm not holding my breath and will seriously consider leaving them if they try and fob me off saying its "normal"....i aint paying a cost premium for nothing!

Has anyone seen this before or have an idea what could be the cause? I'm pinning my hopes on faulty BT equipment at the exchange...

Many thanks and Happy New Year.

Stu

[waltergmw]

Hi Stu,

It is perhaps unwise to postulate that there is no local problem. We have recently seen different problems solved by the replacement of a thermostat and an ADSL Nation faceplate.
Modems do sometimes become unreliable. It might be better to start from first principles; use the test socket with a different filter, perhaps a different modem, keep Zen informed etc.

Kind regards,
Walter

[Azzaka]

... The noise spikes dont appear to be at a set interval though they are usually 1-2 hours apart and happen mostly through the night but have recently started occuring during the day as well.
I have logged the fault with Zen who are looking into it but i'm not holding my breath and will seriously consider leaving them if they try and fob me off saying its "normal"....i aint paying a cost premium for nothing!
...

G'Day Stu,

Its NOT Normal. Can you PM your fault ref please and any issues you have with the person dealing with the fault.  The noise spikes could be related to the weather but by the sounds of things you may have a break in a cable.

Leo

[duckson]

Walter - I'm using a completely different setup to what i started out with. Gone from an ADSLNation faceplate with ADSLNation PRO cable to a 3COM Officeconnect rotuer to ADSLNation XF-1e filter in the test port with a standard modem cable and a Netgear DG834GT router. Zen are looking into it, i have also tested from my parents house who are with Zen and on the same exchange and about 200 yards nearer the exchange and the rotuerstat graphs dont show the same problem.


Leo - PM sent.

[duckson]

BT now booked for Saturday....fingers crossed it proves to be straight forward.

I've run DMT tool and got the following results:-




Not entirely sure what i'm looking for but does this look "normal" or not, it seems to me to be showing SNR spikes although routerstats didnt show anything at the time, its been holding mid 14db's since the last 5/6db spike at 9.20am?

[jeffbb]

Hi


quote : noise margin will be holding tight to 9db (BT put it up from 6db recently) but then minutes or a few hours later

BT do not reset Target SNR margin this is part of the negotiation between your router and the DSLAM at the exchange .

quote "If the router ends up resyncing at around 6000kbps with a 14/15db noise margin

ad your latest DMT show SNR margin at 14.4db

This suggests that your targrt SNR is now over 12db maybe 15 . It seems that you have some problem with either your connection to the exchange or some serious noise being generated .This has coused your increase in the target SNRM and so the reduction in synch speed .

see this link 

quote I have logged the fault with Zen who are looking into it but i'm not holding my breath and will seriously consider leaving them if they try and fob me off saying its "normal"

personally I have never found Zen to be anything but professional. Have you taken up
Azzaka offer ?

regards jeff

[duckson]

By BT putting it up i meant "BT's equipment".  
Yes Leo has sorted it for me, BT coming out on Saturday morning.....up to now i have no complaints with Zen, very good service, i even got my parents with Zen as all has been good up to now.

I havent resynced in a couple of days (since last drop on graph below) but when i have been resyncing before that from being sat at the same 5000/6000kbps and a 14/15db noise margin it resyncs at low/mid 7000kbps's and the noise margin is 9db give or take 0.5db. Over minutes or hours it will drop and resync at least once maybe twice and then sit at 5000/6000kbps and a 14/15db noise margin. Is this not normal then? Should it be trying to hit 9db noise margin even if it drops it at this noise margin?

For example:-



Note the massive noise spikes only occur when my nosie margin is around 9db for some odd reason, at 14/15db it doesnt spike that much "only" a 5/6db loss.

[jeffbb]

Hi
Can you do a  bt speed test . This will give your profile

It does seem to be behaving in a very odd fashion .The only thing I can think of is that when it resynchs ,after the spike the noise is still there so the synch rate is dropped until you achieve stability . The odd thing is that the snr is then so high ,its as if the noise causing the problem has gone . Have you been tweaking the target SNR margin at all?

Regards Jeff

[duckson]

No tweaking from me! I've just left it as is, never tweaked it, although now having a DG834GT i could do that if i flashed it with DGteam firmware.

Results:-
 Download speed achieved during the test was - 4363 Kbps
 For your connection, the acceptable range of speeds is 600-7150 Kbps.
 Additional Information:
 Your DSL Connection Rate :5984 Kbps(DOWN-STREAM), 448 Kbps(UP-STREAM)
 IP Profile for your line is - 5000 Kbps

Although i can also get the IP Profile from my Zen customer portal...very handy. It also lists the profile changes and any noise margin changes that have occured.

[waltergmw]

Hi again Stu,

Do be aware that the data Zen provide is only what BT transmit some time in the future. It can lag by many hours so the safer solution is to grind on with the BT speed test once in every three  hours.

Happy New Year,
Walter

[duckson]

Anyone know what/if the following DMT run is good/bad/indifferent? Obviously the massive 15db noise spike at 16:09 disconnected me and i resynced at 1000kbps less but with a ~4db rise in noise margin.

[duckson]

BT man has been and found nothing, only tested from my end...used the Hawk as well as the standard laptop/modem and said the line to him appears fine. I thought it would as i dont often get spikes during the day, if he had turned up before 9am and connected for 30-45mins he'd of seen the margin drop. Then again he did say it wouldnt give them much to go on even then.... 
He did say it could be one of those ones that goes back and forth a few times until they find something and they cant (wont) do anything in the exchange or anywhere else cus they didnt find anything today and might even make it worse if they fiddle with the line. 
He did say that Zen would have to request a change in the exchange.

[waltergmw]

Hi Stu,

Not unsurprising when you observe the frequency of the drops. I suspect you're going to have to record Routerstats and log every & date time that a drop happens. Zen then have some information from the end user demonstrating the problem so that BT O can be persuaded that there is a problem to be solved.

Kind regards,
Walter

[duckson]

Not long after he left i reconnected and have been out the house since...come back to this (i reconnected the router at 11:00, 3 drops in an hour and it even tried to sync me to a sub 7db noise margin though my profile is 9db??? this gave me the 8128kbps sync i've always had until now!):-



And DMT which i ran after i plugged the router back in:-



It says i am on Fast Path as well, odd because i've been on Interleaved for ever!!! Since i've been on ADSLMax i've been on Interleaved and that was mid 2006.
Has the BT bod been messing at the exchange do you think, he said there was nothing more he could do at this time?

Any other comments?  

[jeffbb]

HI
Just don't know what to make of these results . Just surprised that with these drop outs your synch  is so good .Maybe the BT guy did do something ?. Cannot see how one resynch would have gone back to default 6db and synch of 8128kbps, considering the problems you are having .

Regards Jeff.