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REIN trouble (mostly fixed)

Community Veteran
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Registered: 10-06-2010

REIN trouble (mostly fixed)

For the last 3 evenings my broadband has been rendered almost completely unusable, according to my router stats I think pretty much every second is being counted as a Severely Err Sec. I can hear a loud buzz on 612kHz AM on my old walkman. At about 6am this morning, the buzz on the radio wasn't present and the severely err secs weren't ticking up at a ridiculous rate. I haven't been able to locate a source of the interference, although it appears to be radiating from the telephone wiring in the house.
For some reason, the DLM hasn't yet done anything whatsoever in the way of reducing the sync speed in an attempt to fix the problem. Bizarrely the ADSL remains connected, although the connection is almost complete unusable. That's on ADSL2, if I set the router to ADSL1 it won't be able to remain connected for more than a few seconds.
AR7 DSL Modem Statistics:
--------------------------------
[DSL Modem Stats]
       US Connection Rate:     684     DS Connection Rate:     3166
       DS Line Attenuation:    60.3    DS Margin:              6.9
       US Line Attenuation:    36.8    US Margin:              4.3
       US Payload :            532560  DS Payload:             4072176
       US Superframe Cnt :     67469   DS Superframe Cnt:      67469
       US Transmit Power :     0       DS Transmit Power:      0
       LOS errors:             0       SEF errors:             0
       Errored Seconds:        10      Severely Err Secs:      1163
       Frame mode:             0       Max Frame mode:         0
       Trained Path:           1       US Peak Cell Rate:      1613
       Trained Mode:           16      Selected Mode:          1
       ATUC Vendor Code:       54535443        ATUC Revision:  3
       Hybrid Selected:        3       Trellis:                1
       Showtime Count:         1       DS Max Attainable Bit Rate: 3292 kbps
       BitSwap:                1       US Max Attainable Bit Rate: 1077523 bps
       Annex:                  AnxA    psd_mask_qualifier: 0x0000
       Power Management Status: L0     DS HLINSC: 0
       US ACTPSD:              -345    DS ACTPSD: -366
       Total init. errors:     0       Total init. timeouts: 0
       Showtime init. errors:  0       Showtime init. timeouts: 0
       Last showtime init. errors: 0   Last showtime init. timeouts: 0
       ATUC ghsVid:  b5 00 54 53 54 43 05 10
       T1413Vid: 00 00         T1413Rev: 00            VendorRev: 00
       ATUR ghsVid:  b5 00 54 53 54 43 00 00
       T1413Vid: 00 00 T1413Rev: 00    VendorRev: 00
       [Upstream (TX) Interleave path]
       CRC:    0       FEC:    33883   NCD:    0
       LCD:    0       HEC:    0
       [Downstream (RX) Interleave path]
       CRC:    62574   FEC:    1030859 NCD:    0
       LCD:    0       HEC:    0

After a telephone call to Plusnet I'm awaiting a new TG582n to prove my DG834Gv3 from 2006 isn't the problem.
Edit: typo
Edit2: changed title
Edit3: changed title, problem no longer kills broadband
109 REPLIES
Community Veteran
Posts: 19,099
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Registered: 31-08-2007

Re: Where's the DLM when you need it?

Any Openreach work been going on nearby? Any problems with the electric supply? Had much rain the last 24hours?
That US margin is a bit low, is it normally as low as that? Is it a cordless phone? What happens if you have an incoming call?
If your SNRM isn't starting to drop a bit as dusk approaches, I'd be inclined to try a second filter into the first for the phone, see if that alters anything. Depending on the outcome I'd probably do a complete filter change.
PS. with those speeds, you wouldn't want DLM!
Community Veteran
Posts: 4,969
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Registered: 10-06-2010

Re: Where's the DLM when you need it?

The microfilters were replaced today with new adslnation ones from tandyonline. Not that that made any difference. Anyway I now think the interference was coming from my nearest next door neighbour, so I'll talk to them tomorrow morning. Especially if I can track down when whatever it is gets switched on or off. The interference seemed to be particularly strong from their satellite dish and the cable going up to it.
The DLM hasn't even lifted a finger despite all the disconnections this evening going through all the scripted suggestions, including stabbing my router in the back (resetting it). Which of course achieved nothing useful. Although I discovered it doesn't even reset some of the lower level tweaks. If I undo them (the most significant is the +2db noise margin extra stability tweak) I could get even higher speeds:
ADSL2:

US Connection Rate:     708     DS Connection Rate:     3550
       DS Line Attenuation:    60      DS Margin:              7
       US Line Attenuation:    36      US Margin:              5

ADSL1 - even faster but less stable (drops every few seconds, maybe the DLM would do something about that if I left it going long enough)

US Connection Rate:     864     DS Connection Rate:     3648
       DS Line Attenuation:    58      DS Margin:              8
       US Line Attenuation:    31      US Margin:              6

The sync speed doesn't really matter if you have 26% packet loss and a completely unusable connection that can't load a single webpage. The entire point of the DLM is to fix problems by reducing the speed, not just to make people terrified of switching off their modem/router. I the meantime I've disabled images in Firefox and set my MTU to 500 in the hope smaller packets have more chance of making it through intact.
Community Veteran
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Registered: 10-06-2010

Re: Where's the DLM when you need it?

The horrendous packet loss stopped at about 00:35 this morning, which is presumably when the source of the interference was switched off.
Community Veteran
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Re: Where's the DLM when you need it?

The interference resumed at about 09:30 today, unfortunately my neighbour couldn't think of anything that has changed, and they also seem to be suffering from the same problem. I really don't think there is anything wrong with my router (even after the poor thing being unplugged, reset etc. yesterday), the buzz on the AM radio was present yesterday even with the router switched off and unplugged.
nanotm
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Re: Where's the DLM when you need it?

ask them to turn off there sky box and see if it improves
if it does they will need there provider /.repair company to come check it out, a simple test would be to plug a different sat receiver into where there current one is,
if its a sky box then I am sorry to say its most likely a problem of age, either with the LNB the box or the cable, my sky box had a similar problem caused by being too close to the wifi router and its broadcast filter getting damaged which in turn lead to the inevitable blue screen on the sky box and after an engineer replacing everything lead to me disabling wifi in that part of the house (I put a wireless access point in the loft so its far enough away not to cause the same problem)
just because your paranoid doesn't mean they aren't out to get you
Community Veteran
Posts: 4,969
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Registered: 10-06-2010

Re: Where's the DLM when you need it?

I was told their sky box was switched off, their TV wasn't on, although I didn't personally nose around every room in their house unplugging things. This morning, unlike yesterday evening, I thought the interference was even stronger from my own freesat dish and cabling, although our main TV wasn't on and I was told the other satellite TV also wasn't on. Each satellite dish is on the wall on the side of the house opposite the other house, the side walls are a few metres apart.
Apparently the neighbour further along on the afflicted side is also having trouble with their virgin cable connection, they have been sent a new superhub or whatever but are still having problems I think. The neighbour on the other side, a bit further along because the garages are between the houses on that side, has FTTC from BT which is OK.
I was told that there were jackdaws (birds) on the roof the first day of the trouble started, which I initially dismissed since there isn't any telephone cabling up there, but I suppose the jackdaw theory could be possible.
Community Veteran
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Registered: 10-06-2010

Re: Where's the DLM when you need it?

I forgot about the oddity in the router stats: frame mode 0 rather than the usual 3. It always used to be:
Frame mode:             3       Max Frame mode:         0

What the framing mode is:
Quote
G.dmt Framing Mode
G.dmt defines four types of framing mode in Table 1. Many types are defined for complexity to
support ATM, STM , dual latency, and single latency application. However, ATM mode with
single latency dominates current ADSL market. Almost no one really use STM based ADSL
modem, or dual latency ADSL modem. As a result, most silicon today only support framing
mode three (3) to reduce the overhead.
Table 1. Definition of Framing Modes
0 Full overhead framing with asynchronous bit-to-modem timing. (i.e., enabled synchronization
control mechanism)
1 Full overhead framing with synchronous bit-to-modem timing. (i.e., disabled synchronization
control mechanism)
2 Reduced overhead framing with separate fast and sync byte in fast and interleaved latency
buffer respectively. (i.e., 64K bits framing overhead)
3 Reduced overhead framing with merged fast and sync byte, using either the fast or the
interleaved latency buffer. (i.e., 32K bits framing overhead)

However that could be more the result of all the router resetting and settings clearing yesterday rather than anything else. It hasn't been rebooted again yet.
Community Veteran
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Re: Where's the DLM when you need it?

I'm following with interest, I know you don't need me to make suggestions. If I spot or think of something, I'll pipe up.
RobPN
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Re: Where's the DLM when you need it?

It would be good to keep some sort of log - possibly using Routerstats (Lite) - which records the times the interference appears and disappears (by graphing and logging your SNR Margin) to see if these are regular.
I had a REIN problem a few months ago which Routerstats Lite clearly proved was occurring on/off at the same times everyday, although they did vary over time as the timer which was controlling the 'offending' equipment was adjusted.  Using the MW radio method I pinpointed where the interference was coming from.  As suspected, the problem was being caused by dodgy horticultural activities in a flat nearby, and stopped when I put a letter through their door warning them to sort the interference out or .....
Community Veteran
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Re: Where's the DLM when you need it?

Regarding the framing mode, I think that's a non issue. Framing mode 0-3 isn't applicable to ADSL2, ADSL2 has different framing parameters. But that particular stat isn't cleared on switching from ADSL1 to ADSL2. It does get cleared if I reboot the router (or unload and reload the adsl driver kernel module).
Bizarrely, the interference isn't really showing in the SNR margin, it's only really visible in the CRC error counts, and the Severely Err Secs count - when the interference is present, pretty much every second will be a  Severely Err Sec, yet the Errored Seconds count isn't increasing.
And it's still a bit weird how the DLM hasn't increased the SNR margin, presumably it just hasn't noticed any problem. Perhaps Texas Instruments AR7 chipset isn't reporting correct error counts to the exchange, or perhaps the DLM doesn't care because the connection isn't dropping (apart from all the faffing about yesterday running through all the checks). On ADSL2 it's able to remain connected, but to no useful purpose. On ADSL1 the DSL probably won't even stay in sync long enough for the router to establish the ppp connection. ping with small packets doesn't even reflect the scale of the packet loss - larger have a much higher chance of being destroyed in transit.
Community Veteran
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Registered: 10-06-2010

Re: Where's the DLM when you need it?

With my computer's MTU set to the minimum allowed value which appears to be 256, I actually managed to get the BT speedtester to load and complete a test.
nanotm
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Re: Where's the DLM when you need it?

if you have 2 portable am/mw radio's it might be an idea the next time you have the interference ticking up to use them both to scan for the interference,
this should allow you to track the noise at its strongest point from 2 different angles and allow you to direction find (look where the pathways intersect) in its most basic form this could be using them both in the same room but starting from opposite sides until they meet,
also it might sound strange but run the antenna around near all your pc equipment near your router, just this week I had a fan go "funny" in my main pc it through out all kinds of signals before it finally burnt out, and I have read of old or substandard mains adapters (for things like set top boxes or routers /mobiles) causing similar signal generation

if your satisfied it isn't simple things like the satellite boxes or the associated LNB's suffering breakdown eliminate the simple stuff, then look for the bizarre (anything electrical including heating or hot water timers or boilers) then check the signal levels for any interference signal  at higher levels in the home (including the attic or out of upstairs windows)  if your property has that shiny loft insulation it could be acting as a signal concentrator and reflector (in which case an earth lead could help eliminate it) but truly if your suffering from low level harmonic wave interference from an external source that's getting rebroadcast by the wiring inside your home there will be very little you can do cheaply unless your able to identify and rectify the source
just because your paranoid doesn't mean they aren't out to get you
Community Veteran
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Registered: 10-06-2010

Re: Where's the DLM when you need it?

The interference stopped at about 01:10 today, and hasn't re-appeared yet. The computer downstairs nearest the router is now on, it's not on at midnight.
Pretty much every AC/DC adapter I've got outputs a fair amount of interference if you hold an AM radio next to it, including the router's power supply. The power socket is close to that telephone socket, but it's always been like that. I don't believe the router's power supply somehow went wrong at 09:30 yesterday but somehow healed itself at 01:10 today. If a PSU fault is temperature related, that doesn't make sense because it's even hotter today and the interference isn't present. Although I suppose I could try replacing it anyway, since I have various similar 12V adapters.
nanotm
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Re: Where's the DLM when you need it?

no time based decay problems don't tend to heal themselves but are more often heat /dust dependant, sometimes your devices will draw more power so there will be a slightly higher heat build-up and that can do funny things with capacitors resistors or diodes that are nearing there effective life span.
and yes it can be something that appears and disappears randomly over time gradually getting more frequent and or longer lasting, then becoming almost permanent and finally the dodgy item dies, sometimes it can reach a failure point faster with a bang or pop or fizzle at anypoint during the gradual decay glide,
yes I appreciate that pretty much every electrical device emits a small amount of "noise" but things that are going belly up tend o be emitting more and a greater range than those operating *normally*
this might sound daft but I have all of my power adaptors plugged into a surge protector strip, however my phone line (after I had some serious problems 2 decades ago with a surge strip) is always a straight line from the socket to the device (no protection other than micro filters)
since adopting this my devices have suffered failure far less frequently than before (typical uk power supply swings can be from 220v ac > 250v ac  and nothing other than a flicker of the lights will be noticed unless it swings below 235v ac) because of the constant fluctuations causing components to wear out faster
just because your paranoid doesn't mean they aren't out to get you