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[Johnn]

Hello,
I have a problem with my connection where the PPPoA drops - just for a few seconds but the ADSL stays connected. How often this happens depends on how much is downloading at the time but it can be as often as every 2-3 mins.

My set-up
ISP - TalkTalk Business
SNR Margin - 9 Loop Att. 63 (I'm quite a distance from the exchange)
ADSL - G.992.1

What I've tried so far -
Disconnected the 2 orange ringer wires.
Changed the ADSL filters 3 times.
Changed the DSL Cable.
installed a NTE5 faceplate.
Tried 3 different routers/modems and made sure all firmware is up-to-date.
Contacted ISP who have run a line test - which came back ok, no problems.

Is there anything else I should/could try or has anyone got any ideas as to what the problem could be?

TTB have said they will pass the problem on to a 'Special Faults Investigator' (not sure when they'll get round to that!) but I'm still nervous I may have missed something and it might be a problem my end.

any help will be very much appreciated. thanks

[burakkucat]

Welcome to the Kitz forum.    Sorry for the delay in this response . . .

I've looked through the details of your circuit and all that you have tried in terms of testing.

I see you explicitly mention G.992.1 and wonder if you have tried configuring the modem/router to use G.992.3 mode? I appreciate that your circuit may be connected to an exchange with only 20CN equipment available, however I also notice you mention TalkTalk Business. As far as I am aware, your circuit would therefore be connected to TalkTalk's own equipment (most likely a Huawei MSAN) which should be capable of operating in G.992.3 mode.

To be honest, I don't think there is anything else that you can try -- other than a test with a different modem/router. Also I fail to understand why TalkTalk have suggested an Openreach SFI visit . . . but if they have suggested it and they are prepared to pay the cost, then let's see what is the outcome.

[Johnn]

Hello burakkucat
thanks for your reply...
Sorry my mistake - its not G.9921 that should be G.DMT... I think I'd been reading up on so much tech stuff relating to my connection I type the wrong one! 

an update -
an Open Reach BB engineer came out to have a look, and as you've suggested he was a bit confused as to why he'd been sent out as he didn't have full access to TTB network like he has with the BT network...

So he did as much as he could, which was to check the line to the exchange and my set up this side of the master plug and guess what everything was 100% perfect. The line was not dropping any packets and was noise free. My 'LAN' (cables, router etc) were all checking out ok as well. He even went round with his RF monitor (ghost hunter style ) He did find a strip light that was buzzing a bit but it's not always on and even turning it off the problem persisted. He did say that it wasn't that bad and didn't think it was enough buzz to interfere.

So after shrugging his shoulders he said there only one other thing he could try and brought back from his van a talktalk business router - just like the one they currently supply. He said 'I shouldn't really have this'  But because it has on the front lights indicating an ADSL connection AND internet access he said it will prove that it's their network that's wrong. So plugged it in, logged on and set a load of stuff downloading to cause the PPPoA to drop.
and it did - several times. The ADSL connection light stayed green but the internet access light turned red every time the PPPoA dropped.

So, his conclusion was that it is a problem with their network - that he can't access - and would report back telling them that.

I have now had a message from TTB saying that they have booked another BB engineer for Monday morning to come out.
Not really sure what this engineer is going to find out or do! but I'll report back when he's been.

cheers

[aesmith]

My opinion, if PPP is dropping while the DSL stays connected, then it's not a line issue, and probably not a misconfiguration in terms of G.DMT/G.992.x either as I think that would effect the DSL.   Could be the router, or could be ISP's equipment (possibly BT Wholesale equipment in between the exchange and the ISP?).   

[Chunkers]

I had this issue, in my case it turned out to be the Asus AC68U that I was using as a router was causing the problem. changing it out solved the problem for me.  Given that you have tried different routers and it hasn't solved the issue then I guess this post is of no help

Hope you get it sorted soon

Chunks

[davinci8128]

If your service is working fine on the physical layer with little to no errors (FEC and CRC) and you have already tried multiple different modem/routers but the connection is dropping PPP session, then the problem might be with the DSLAM card/chipset/port. Also, are you aware what your DLM profile is? Are you on fastpath on the upstream and what is the target noise margin?

In any case, this needs to be looked at by TalkTalk's NOC team.

[Johnn]

davinci8128, I'm not sure if I know enough to answer all your questions but I have grabbed this from my router/modem via telnet.
I hope that answers some of them!

Code: [Select]

> show adsl
  --------------------------- ATU-R Info (hw: annex A, f/w: annex A) -----------
Running Mode               :    G.DMT       State                : SHOWTIME
   DS Actual Rate          :  1472000 bps   US Actual Rate       :   512000 bps
   DS Attainable Rate      :  1472000 bps   US Attainable Rate   :   664000 bps
   DS Path Mode            :  Interleave    US Path Mode         :  Interleave
   DS Interleave Depth     :       16       US Interleave Depth  :        2
   NE Current Attenuation  :       63 dB    Cur SNR Margin       :       10  dB
   DS actual PSD           :    16. 6 dB    US actual PSD        :    12. 6   dB
ADSL Firmware Version      : 232201_A
  -------------------------------- ATU-C Info ---------------------------------
   Far Current Attenuation :       31 dB    Far SNR Margin       :       10  dB
   CO ITU Version[0]       : 00004946       CO ITU Version[1]    : 0000544e
   DSLAM CHIPSET VENDOR    : < IFTN >


[ejs]

G.dmt is sometimes used to indicate G.992.1 (ADSL1).
G.dmt.bis is less commonly used to indicate G.992.3 (ADSL2).

It should be better on ADSL2, but that's a general optimisation rather than a fix for the specific problem.

I agree, it does sound like the problem is at a higher level than the physical phone line and the DSL layer.

[burakkucat]

I've just got back to this thread and have reviewed all the latest posts.

From everything that has been reported, I am certain (just like ejs) that the problem is not with the physical layer. It has to originate in a higher software layer, somewhere within TalkTalk Business' domain.

[Johnn]

Thank you all for your helpful insights.

Another BB engineer is booked for Monday morning so I'll see what he has to say!
I'll report back!

[Johnn]

Update....

So another OR engineer came out to have a look yesterday... He couldn't find a problem (not a big surprise there!)
So he went back to the exchange and changed something there (though I'm not sure what. he did say but in one ear and out the other )
when he came back we tested the connection it seemed like it was working - the PPPoA didn't drop for over 10 mins even when I maxed out the connection. Great and the speed was a little quicker. He then said he was going to do a final line test and would go as it seemed to now be working ok which he did and left.

Unfortunately, it did not sort the problem out. Soon after he left and the router reconnected after the line test the SNR margin went up to 12, the speed dropped and the PPPoA was dropping out almost constantly (the PPPoA is a little more stable now but still as bad as it ever has been)
I've noticed that the ADSL mode has changed from G.DMT to ADSL2(G.992.3)... which obviously has not sorted the problem.

Just grabbed this -

Code: [Select]

> adsl status
  --------------------------- ATU-R Info (hw: annex A, f/w: annex A) -----------
Running Mode            : ADSL2(G.992.3)       State                : SHOWTIME
   DS Actual Rate          :   983685 bps   US Actual Rate       :   601288 bps
   DS Attainable Rate      :  1008000 bps   US Attainable Rate   :   600000 bps
   DS Path Mode            :  Interleave    US Path Mode         :  Interleave
   DS Interleave Depth     :       16       US Interleave Depth  :        2
   NE Current Attenuation  :       65 dB    Cur SNR Margin       :       12  dB
   DS actual PSD           :    15. 2 dB    US actual PSD        :    12. 6   dB
ADSL Firmware Version   : 232201_A
  -------------------------------- ATU-C Info ---------------------------------
   Far Current Attenuation :       36 dB    Far SNR Margin       :       12  dB
   CO ITU Version[0]       : 00004946       CO ITU Version[1]    : 0000544e
   DSLAM CHIPSET VENDOR    : < IFTN >
>
So today I've had a message from TTB saying that they have "reprofiled the connection which should stabilise it a little more" and asking "Have you been advised at any point to try the test logins to make sure that your static IP is not the issue?" which is a no.

that everything up to date.

I have a question that someone might be able to answer - If I switched over to fibre would this problem go away or would it still be an issue?

thanks

[burakkucat]

I have a question that someone might be able to answer - If I switched over to fibre would this problem go away or would it still be an issue?

That question is very difficult to answer as we do not know the cause of the symptoms which you are experiencing.

To migrate to a G.993.2 (VDSL2) based service will mean that the length of the metallic pathway will be shortened, as the signal will then originate from a street cabinet and not the exchange building. The signal modulation mode will change from G.992.3 (ADSL2) to G.993.2 (VDSL2). The transfer mode will change from ATM to PTM. The PPPoA sessions will become PPPoE and, finally, a tagged VLAN will be used for the new service.

My feeling (tingles in the whiskers, etc) is that migration to a G.993.2 based service may well provide a solution to your current problem . . . But I would also like to read what others think. 

[Johnn]

another update...

I got a message from TTB this morning asking me to log in using their test credentials, which I've done - obviously, this doesn't use a static ip.
Not wanting to tempt fate at the moment it seems to be working - the PPPoA has not dropped once since logging in with the test username and PW which was 2 hours ago now.

TTB have asked if I can test it for 24h and report back and if its ok they'll change my static ip address  - but at the moment it seems all ok 

I'll post an update when I have any new information.

[burakkucat]

Thank you for that update.

I will be interested to know the logic behind TTB's suggestion and their proposed fix (if all goes well).

[Dray]

Someone else has the same IP address?