SNR magically increased by DLM

[#1]

For weeks I have had a very stable line....  Yesterday I have a resync for some reason, after 28days uptime, and my target SNR has gone from 3dB to 9dB 
As far as I am aware I have had no spates of resyncs.  Also what was odd, my wife, also reported some internet slowdowns, and on checking I was getting just about 2meg, even though both BT and Plusnets profiles were 6.3.  A few hours after the resync I had a random PPP drop, and speeds now seem to be back to normal, although speedtests are a little choppy, normal browsing and streaming is fine.
Current stats are
Link Information

Uptime: 1 day, 0:06:46
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 888 / 7,235
Data Transferred (Sent/Received) [GB/GB]: 1.20 / 11.86
Output Power (Up/Down) [dBm]: 12.8 / 0.0
Line Attenuation (Up/Down) [dB]: 25.3 / 45.5
SN Margin (Up/Down) [dB]: 10.0 / 9.0
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / IFTN
Loss of Framing (Local/Remote): 36 / 0
Loss of Signal (Local/Remote): 112 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 445,524 / 1
FEC Errors (Up/Down): 14,528 / 300,823,652
CRC Errors (Up/Down): 60 / 4,635,674
HEC Errors (Up/Down): 123 / 2,183,438
Anyone any ideas as to why the DLM has taken such action.  Is there any way of fixing my SNR at 6dB permanently?

[#2]

300 million downstream FEC errors if they were recorded in just over 24 hours uptime.  The CRC errors are also very high for an interleaved line.
See if those figures continue to increment insanely over next 24 hours.

[#3]

Well the error seconds count can't have been reset since there are only 86,400 seconds in a day. The DLM would have acted on the error rates.

[#4]

Thanks... oddly enough only 5mins after the resync I checked the errors and crc and hec errors were zero. Phone line shows no noise at all. Any ideas what could be causing these errors? And is it something I should be worried about... Would it be an idea to completely power down the router to make sure the error counts are reset and monitor from there?

[#5]

Well it resynced again 4 1/2 hrs ago, but oddly enough target margin at resync was reported as 7.1dB
xDSL linestate up (ITU-T G.992.5; downstream: 6655 kbit/s, upstream: 888 kbit/s; output Power Down: 20.6 dBm, Up: 12.8 dBm; line Attenuation Down: 45.5 dB, Up: 25.3 dB; snr Margin Down: 7.1 dB, Up: 11.3 dB)
Very odd.... Current stats
ink Information

Uptime: 0 days, 4:48:27
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 888 / 6,655
Data Transferred (Sent/Received) [GB/GB]: 1.20 / 11.90
Output Power (Up/Down) [dBm]: 12.8 / 0.0
Line Attenuation (Up/Down) [dB]: 25.3 / 45.5
SN Margin (Up/Down) [dB]: 10.8 / 5.3
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / IFTN
Loss of Framing (Local/Remote): 45 / 0
Loss of Signal (Local/Remote): 113 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 461,207 / 1
FEC Errors (Up/Down): 376 / 64,231
CRC Errors (Up/Down): 0 / 16
HEC Errors (Up/Down): 0 / 78
Can the DCT supply my radius graphs for the last 3 days, and also post up my line profile please. 
I am going to power down the router, and restart, and see what happens.  I will post up the resync stats.

[#6]

Resync stats, after cold reboot
xDSL linestate up (ITU-T G.992.5; downstream: 6653 kbit/s, upstream: 888 kbit/s; output Power Down: 20.4 dBm, Up: 12.7 dBm; line Attenuation Down: 45.5 dB, Up: 25.2 dB; snr Margin Down: 6.3 dB, Up: 11.8 dB)
I would have thought sync would have been a little higher, but I suppose it is 21:15... 
After 2 mins of uptime, I have 171 FEC errors, and no CRC or HEC errrors.

[#7]

I think you are on a 3328-6656 kbps banded profile.

[#8]

i would be shocked if I was banded, after almost a month of stability, and 2 resyncs, unless the DLM has taken offence to the errors on the line, and become very agressive with the line.
Can the digi care team, see if I am banded, and whats been happening with the line recently... I will start a faults procedure if this is whats needed to remove the banding, but I suspect we need to find the root cause of this before banding is removed.

[#9]

Hi Penfold,
As requested:
<img src="http://community.plus.net/visualradius/generated/image13769275637092.png"/>
Your line is currently banded on the profile spraxyt mentions.
I can see that your line is currently erroring every second, has anything changed?
Are you connected to your test socket?

[#10]

Absolutely nothing has changed chris. Router is connected to the master socket, via a vdsl faceplate fitted by openreach about 18mnths ago during a previous fault. Only have 1 phone and no extensions. Line is completely quiet... current stats are
Link Information
Uptime: 0 days, 22:11:34
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 888 / 6,653
Data Transferred (Sent/Received) [MB/MB]: 22.09 / 118.39
Output Power (Up/Down) [dBm]: 12.7 / 0.0
Line Attenuation (Up/Down) [dB]: 25.2 / 45.5
SN Margin (Up/Down) [dB]: 9.5 / 7.8
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / IFTN
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 22 / 0
FEC Errors (Up/Down): 9,153 / 102,116
CRC Errors (Up/Down): 34 / 36
HEC Errors (Up/Down): 55 / 501
Dosnt seem to be erroring as much now. Could it just have been a burst of noise. Fttc is coming very soon to my cab, its available in some areas, and cabs are appearing all over. Could this have anything to do with it?  What do you suggest the next course of action. Should I raise a fault, or can you do a linetest without thia

[#11]

Unsure if this is related, but something very odd happened tonight... got home from work, wife was using the laptop, so I thought I would use the tablet to access the router. I noticed however that the tablet refused to connect to any webpages. It was connected to the router, had a valid ip etc. I rebooted it, but still the same. Laptop was fine, as was my android phone, but the sky box also refused to connect to internet. I could access ondemand ok, but it just hung when trying to download anything. Eventually making the tablet  forget the wireless settings and resetting them, and resetting the sky network settings cured it, but oddly enough reboots didnt. It was like they couldnt resolve dns.... my wife mentioned the tablet had been working fine earlier on in the day. Coincidence???? Or something else, such as router issues. Only thing in router I have changed recently was the dns servers friday night via telnet commands fron plusnets to opendns.  Also router webpages seem a hell of a lot more responsive now, they were always very sluggish
Just noticed had a resync at 20.15 preceded by what appears to be a fair few port scans, mbus atomic sync successful. Stats after an hour below
Link Information
Uptime: 0 days, 1:04:42
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 888 / 6,655
Data Transferred (Sent/Received) [MB/MB]: 26.21 / 153.61
Output Power (Up/Down) [dBm]: 12.8 / 0.0
Line Attenuation (Up/Down) [dB]: 25.3 / 45.5
SN Margin (Up/Down) [dB]: 11.8 / 5.3
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / IFTN
Loss of Framing (Local/Remote): 9 / 0
Loss of Signal (Local/Remote): 1 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 35 / 0
FEC Errors (Up/Down): 120 / 12,935
CRC Errors (Up/Down): 0 / 2
HEC Errors (Up/Down): 0 / 3

[#12]

Quote from: penfold

Unsure if this is related, but something very odd happened tonight... got home from work, wife was using the laptop, so I thought I would use the tablet to access the router. I noticed however that the tablet refused to connect to any webpages. It was connected to the router, had a valid ip etc. I rebooted it, but still the same. Laptop was fine, as was my android phone, but the sky box also refused to connect to internet. I could access ondemand ok, but it just hung when trying to download anything.

Seems strange why these wouldn't work and other devices would, I'd keep an eye on that and see if it happens again.
I've placed a SNR reset on your line and this has completed so your line is now unbanded. I'd monitor this over the next few days and we'll go from there if there are any issues.

[#13]

Thanks Chris
I will keep an eye on things and see how they go.  If it happens again I will post back.
Rgrds
Chris

[#14]

No resyncs since the snr reset, stats below. Errors are better but still are they alot for an interleaved line... probably got a burst of noise triggering alot of errors and dlm must have reacted...
Link Information
Uptime: 2 days, 10:34:09
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 888 / 8,253
Data Transferred (Sent/Received) [MB/MB]: 87.02 / 399.95
Output Power (Up/Down) [dBm]: 12.8 / 0.0
Line Attenuation (Up/Down) [dB]: 25.2 / 45.5
SN Margin (Up/Down) [dB]: 10.5 / 3.9
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / IFTN
Loss of Framing (Local/Remote): 18 / 0
Loss of Signal (Local/Remote): 2 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 1,048 / 0
FEC Errors (Up/Down): 19,309 / 1,751,075
CRC Errors (Up/Down): 139 / 1,676
HEC Errors (Up/Down): 244 / 18,294

[#15]

It does look better, I'd monitor it over the weekend and see how it is.