20cn to 21cn speed collapse

[#1]

I'm not sure whats happend here but I suspect a line fault.
I was under 20 cn sitting on a line that did 5 to 7mb line that was on Line Attenuation of 43db and snr of 6 to 12db,.
Recently its been stable at 5.6mb (line speed).
Roll on the upgrade to 21cn it initially synced at 6.7mb (annex m).. and then dropped to the following.
Uptime: 2 days, 1:36:49
DSL Type: G.992.3 annex A
Bandwidth (Up/Down) [kbps/kbps]: 440 / 2,215
Data Transferred (Sent/Received) [kB/kB]: 0.00 / 0.00
Output Power (Up/Down) [dBm]: 13.0 / 0.0
Line Attenuation (Up/Down) [dB]: 21.0 / 42.0
SN Margin (Up/Down) [dB]: 25.0 / 9.5
Vendor ID (Local/Remote): TMMB / 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): 0
Error Seconds (Local/Remote): 0 / 0
FEC Errors (Up/Down): 4,294,967,264 / 22,532
CRC Errors (Up/Down): 4,294,967,264 / 47
HEC Errors (Up/Down): 0 / 41
Test socket
Link Information

Uptime: 0 days, 0:00:47
DSL Type: G.992.3 annex A
Bandwidth (Up/Down) [kbps/kbps]: 440 / 2,393
Data Transferred (Sent/Received) [kB/kB]: 0.00 / 0.00
Output Power (Up/Down) [dBm]: 12.5 / 0.0
Line Attenuation (Up/Down) [dB]: 21.0 / 40.5
SN Margin (Up/Down) [dB]: 23.5 / 9.5
Vendor ID (Local/Remote): TMMB / 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): 0
Error Seconds (Local/Remote): 0 / 0
FEC Errors (Up/Down): 0 / 4
CRC Errors (Up/Down): 0 / 0
HEC Errors (Up/Down): 7 / 0
After 20 mins connected to the test socket
Link Information

Uptime: 0 days, 0:19:20
DSL Type: G.992.3 annex A
Bandwidth (Up/Down) [kbps/kbps]: 440 / 2,393
Data Transferred (Sent/Received) [kB/kB]: 0.00 / 0.00
Output Power (Up/Down) [dBm]: 12.5 / 0.0
Line Attenuation (Up/Down) [dB]: 21.0 / 40.5
SN Margin (Up/Down) [dB]: 23.5 / 10.0
Vendor ID (Local/Remote): TMMB / 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): 0
Error Seconds (Local/Remote): 0 / 0
FEC Errors (Up/Down): 4,294,967,264 / 144
CRC Errors (Up/Down): 4,294,967,264 / 0
HEC Errors (Up/Down): 0 / 0

User name: krusty
Acc type; small biz premier ..
Router : tg 585v7 - 7.4.4.7 generic firmware.

[#2]

When did you change to 21CN? If it's recent you could still be in the training period and you may need to wait until the 10 days are up.
Having said that, 2393 is definitely a low speed for your attenuation.
Than initial 'Annex M' is strange. You shouldn't be on that unless you specifically asked for it. In any case, it restricts downstream speed while boosting upstream speed, so if you were getting 6.7mb/s with Annex M it shows that your line's capable of at least that speed with normal ADSL2(+).
Interesting that you get a lower attenuation when connected to your test socket. I wonder if something in your internal wiring caused the drop. Your downstream SN margin is on the high side at 9.5, but maybe that will change if your line stays stable after you've connected via the test socket for a couple of days. That speed's still pretty low, though.
You're currently on ADSL2 (G.992.3) rather than ADSL2+ (G.992.5). I wouldn't have thought that was standard for a line with only a 40.5dB attenuation rate, but it may be connected to whatever caused your speed to drop in the first place. It probably won't make much difference even if you get back up to around 6mb/s.
It doesn't look like you're on one of the dreaded 'banded profiles' because you're not syncing at the upper limit of a band (the closest would be around 2272 or 3072). It also doesn't look like your problem is a stuck profile, though it would be useful if you could a) show us your 'current line speed' as displayed in the 'High Speed Broadband' area of 'Connection Settings' in your Plusnet Member Centre area and b) show us the output of a BT speed test (at www.speedtester.bt.com).
Plusnet staff should be able to help on Monday, and in the meantime other people might chip in with ideas and advice.
(Good problem report, by the way.)
Graham

[#3]

Changed Wednesday just gone ..
G.992.5 i got the 6.7mb I was also stable on that with normal adsl.
pn current line speed : 5mb .
Bt speed test: (already done)..
Test1 comprises of two tests
1. Best Effort Test: -provides background information.
Download  Speed
1958 Kbps

0 Kbps 2000 Kbps
Max Achievable Speed
Download speedachieved during the test was - 1958 Kbps
For your connection, the acceptable range of speeds is 800-2000 Kbps.
Additional Information:
Your DSL Connection Rate :2393 Kbps(DOWN-STREAM), 440 Kbps(UP-STREAM)
IP Profile for your line is - 2110 Kbps
2. Upstream Test: -provides background information.
Upload Speed
331 Kbps

0 Kbps 440 Kbps
Max Achievable Speed
>Upload speed achieved during the test was - 331 Kbps
Additional Information:
Upstream Rate IP profile on your line is - 440 Kbps
There is only one phone and sky plugged in .. on the test socket (i only achieved 100k increase) so its not internal wiring..

[#4]

OP says they are on some business package - that could account for the annex M
I'd agree on the attenuation comment above. Removing a few yards from the line by putting unit into the master socket rather than an extension on a line that is probably 3Km+ long or so should not change the attenuation by anything measurable on the router.
The CRC errors are a joke - or a misprint   4billion errors!
If true I'm surprised it works at all
Need Plusnet Staff on monday to see if there have been disconnections on the line

[#5]

Am wondering if its a duff line card .. The 4billion errorrs is a clue that something isn't quite right.
just checked the router stats again
" Link Information

Uptime: 0 days, 2:08:40
DSL Type: G.992.3 annex A
Bandwidth (Up/Down) [kbps/kbps]: 443 / 2,695
Data Transferred (Sent/Received) [kB/kB]: 0.00 / 0.00
Output Power (Up/Down) [dBm]: 12.5 / 0.0
Line Attenuation (Up/Down) [dB]: 21.0 / 40.5
SN Margin (Up/Down) [dB]: 24.5 / 7.0
Vendor ID (Local/Remote): TMMB / IFTN
Loss of Framing (Local/Remote): 22 / 0
Loss of Signal (Local/Remote): 2 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 2 / 0
FEC Errors (Up/Down): 0 / 0
CRC Errors (Up/Down): 0 / 1,920
"
As i'm away from the home/office tomorrow  so i can't really deal with it .. hence the forum post and because its weird issue some input from other peps is good.
edit i think i was on G.992.5 annex A when i got the 6.7mb on adsl 2+ (not sure why i was thinking of annex m) 😛

[#6]

Hmmm. The Kitz speed calculator suggests that your ADSL2+ sync speed ought to be either 8.3Mbps (at 42dB) or 9Mbps (at 40dB). It also shows that the estimated line length alters by 100 metres for those 2dB - so you really shouldn't see such a change by moving from extension to test socket.
So, for some reason, the modem/exchange synchronisation process has decided to use ADSL2 rather than 2+, and when it has synchronised , it has done so at a pretty low speed. Usually, when the speed is a lot lower than expected, we would see a high noise margin - because the exchange has set it this way from its analysis of the line conditions.
In this case the noise margin is *not* particularly high - certainly not high enough to go with low speeds caused by intermittant noise problems.
However, if there is constant noise on the line that is seen (and catered for) during the synch process, that certainly could result in low speeds associated with continuing low noise margins. It might also explain why the exchange has chosen to not use ADSL2+.
Don't worry about the 4 billion *upstream* errors - some routers misreport these stats, and this has all the hallmarks of being such an issue (to a techie, it looks like the positive equivalent of a number held internally that is really negative - around -32, I think).
On the positive side is the fact that you aren't experiencing many downstream CRC errors. If there is noise on the line, it isn't being felt there.
It has to be worth getting a line test run, so I guess one of the DCT folk will be along tomorrow.

[#7]

On the last check there is around 1,200 crc errors.. I've lost alot of snr on the line in the last 3 months.
a quick look at the router (7.20)
Link Information

Uptime: 0 days, 17:39:10
DSL Type: G.992.3 annex A
Bandwidth (Up/Down) [kbps/kbps]: 443 / 2,695
Data Transferred (Sent/Received) [kB/kB]: 0.00 / 0.00
Output Power (Up/Down) [dBm]: 12.5 / 0.0
Line Attenuation (Up/Down) [dB]: 21.0 / 40.5
SN Margin (Up/Down) [dB]: 24.5 / 6.0
Vendor ID (Local/Remote): TMMB / IFTN
Loss of Framing (Local/Remote): 22 / 0
Loss of Signal (Local/Remote): 2 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 2 / 0
FEC Errors (Up/Down): 0 / 0
CRC Errors (Up/Down): 0 / 24,969
HEC Errors (Up/Down): 0 / 3,829
25k crc downstreem errors

[#8]

Hi taras,
Can you plug into the test socket and try a different filter to see if we can get a better sync rate.
Jojo

[#9]

I tried it with the test socket with it unfiltered .. (with nothing else)..
I will do another test with different filters. as well for you

[#10]

update

some line stats
Link Information

Uptime: 1 day, 4:06:00
DSL Type: G.992.3 annex A
Bandwidth (Up/Down) [kbps/kbps]: 443 / 2,695
Data Transferred (Sent/Received) [kB/kB]: 0.00 / 0.00
Output Power (Up/Down) [dBm]: 12.5 / 0.0
Line Attenuation (Up/Down) [dB]: 21.0 / 40.5
SN Margin (Up/Down) [dB]: 24.5 / 6.5
Vendor ID (Local/Remote): TMMB / IFTN
Loss of Framing (Local/Remote): 22 / 0
Loss of Signal (Local/Remote): 2 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 2 / 0
FEC Errors (Up/Down): 0 / 0
CRC Errors (Up/Down): 0 / 43,455
HEC Errors (Up/Down): 0 / 6,574
17.46 16/1/12
Link Information

Uptime: 1 day, 19:25:34
DSL Type: G.992.3 annex A
Bandwidth (Up/Down) [kbps/kbps]: 443 / 2,695
Data Transferred (Sent/Received) [kB/kB]: 0.00 / 0.00
Output Power (Up/Down) [dBm]: 12.5 / 0.0
Line Attenuation (Up/Down) [dB]: 21.0 / 40.5
SN Margin (Up/Down) [dB]: 24.5 / 6.5
Vendor ID (Local/Remote): TMMB / IFTN
Loss of Framing (Local/Remote): 22 / 0
Loss of Signal (Local/Remote): 2 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 2 / 0
FEC Errors (Up/Down): 0 / 0
CRC Errors (Up/Down): 0 / 63,495
HEC Errors (Up/Down): 0 / 9,481
9.09 17/1/12
Below is 34s with test socket, with speedtouch adsl filter
Link Information

Uptime: 0 days, 0:00:34
DSL Type: G.992.3 annex A
Bandwidth (Up/Down) [kbps/kbps]: 443 / 2,439
Data Transferred (Sent/Received) [kB/kB]: 0.00 / 0.00
Output Power (Up/Down) [dBm]: 13.0 / 0.0
Line Attenuation (Up/Down) [dB]: 20.5 / 42.0
SN Margin (Up/Down) [dB]: 24.5 / 6.5
Vendor ID (Local/Remote): TMMB / IFTN
Loss of Framing (Local/Remote): 33 / 0
Loss of Signal (Local/Remote): 3 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 3 / 0
FEC Errors (Up/Down): 0 / 0
CRC Errors (Up/Down): 0 / 7
HEC Errors (Up/Down): 7 / 1
9.17 17/1/12
This last one at 9.17 is with a different filter and directly connected to the test socket
Is it normal for the Line Attenuation to increase by 1.5 by going to the test socket within 10 mins of two different readings.

[#11]

HI taras,
Just tried calling you. I'm a bit flummoxed as to what's going on there. I would suggest raising a fault and see what we can find from there.
Jojo

[#12]

sorry i was in another room ..
can you try calling again thanks .

[#13]

Thanks for your time on the phone. Let me know when you've tried the other router and/or raised a fault.

[#14]

am on the older westel 6100 (which is spose to be a adsl2+ router)
Transceiver Revision: 1.0.9.0
Vendor ID Code:        4
Line Mode:              G.DMT Mode
Data Path:              Interleaved
Transceiver Information Down Stream Path Up Stream Path
DSL Speed (Kbits/Sec) 3136 448
Margin (dB) 6.5 23.0
Line Attenuation (dB) 42.0 22.5
Transmit Power (dBm) 16.8 11.1

Not sure why its showing up as g.dmt mode.
I will leave the router plugged  on over night for you . I will swap over around 10am ish

[#15]

bt speed test results.
Test1 comprises of two tests
1. Best Effort Test: -provides background information.
Download  Speed
2468 Kbps

0 Kbps 4000 Kbps
Max Achievable Speed
Download speedachieved during the test was - 2468 Kbps
For your connection, the acceptable range of speeds is 1200-4000 Kbps.
Additional Information:
Your DSL Connection Rate :3136 Kbps(DOWN-STREAM), 448 Kbps(UP-STREAM)
IP Profile for your line is - 2766 Kbps
2. Upstream Test: -provides background information.
Upload Speed
359 Kbps

0 Kbps 448 Kbps
Max Achievable Speed
>Upload speed achieved during the test was - 359 Kbps
Additional Information:
Upstream Rate IP profile on your line is - 448 Kbps