Upstream speed dropping to 256K or less

Hi Folks,

Over the past few days, I've noticed some dramatic drops in my upstream sync speed, while my downstream stays fine.

Usually near-rock-solid at 1400ish down and 448up, in the past few days I've noticed a dramatic drop in the upstream speed - 300ish, 256, 96, you name it.

Hard rebooting the HH hasn't brought back 448 at any time, just various (slower) upstream speeds, yet the downstream stays near-enough constant.

Regular readers will know I have a filtered faceplate, with wiring sorted to be as near ideal as possible, virtually no internal run, just the drop from the pole into the house, and the master.

I'm hoping this isn't connected to my other posts about my neighbour getting broadband - they are actually about 1/4 of a mile away across the fields. Might get them to disconnect it, they are away on holiday in a few days.

Line stats for the fact fans,

Link Information

Uptime: 0 days, 0:47:51
Modulation: G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]: 256 / 1,408
Data Transferred (Sent/Received) [KB/MB]: 306.00 / 1.03
Output Power (Up/Down) [dBm]: 12.0 / 16.0
Line Attenuation (Up/Down) [dB]: 31.5 / 63.5
SN Margin (Up/Down) [dB]: 6.0 / 4.0
Vendor ID (Local/Remote): TMMB / TSTC
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 / 265,179
CRC Errors (Up/Down): 0 / 52
HEC Errors (Up/Down): 0 / 26
Line Profile: Interleaved

Any ideas, kids? Even in the dark days of a 135k profile I got 448k upstream, and I always thought the downstream would drop first, as it uses the higher tones?

EDIT - STOP PRESS, UPDATE, ETC.

I just realised, in a forehead-slapping moment of clarity that I had a brand-new faceplate lying on the desk. Screwdriver out, swap 'em over and bingo, 448k back! Will watch it over the next few days, I may have a dud faceplate to return.

Link Information

Uptime: 0 days, 0:03:04
Modulation: G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]: 448 / 1,408
Data Transferred (Sent/Received) [KB/KB]: 31.00 / 36.00
Output Power (Up/Down) [dBm]: 12.0 / 16.0
Line Attenuation (Up/Down) [dB]: 31.5 / 63.5
SN Margin (Up/Down) [dB]: 7.0 / 5.5
Vendor ID (Local/Remote): TMMB / TSTC
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 / 258
CRC Errors (Up/Down): 0 / 0
HEC Errors (Up/Down): 0 / 0
Line Profile: Interleaved

Edited by deleted (Mon 19-May-08 22:23:11)

Hmm, something is definitely Not Right.

After a day of the new faceplate, the sync speed has dropped back to where it shouldn't be. I've swapped 'em to and fro and have some more line stats if anyone has any opinions?

The downstream is pretty much as good as it's ever been, but the upstream is rubbish!

----New faceplate

Link Information

Uptime: 0 days, 13:20:17
Modulation: G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]: 224 / 1,408
Data Transferred (Sent/Received) [MB/MB]: 2.64 / 5.85
Output Power (Up/Down) [dBm]: 12.0 / 16.0
Line Attenuation (Up/Down) [dB]: 31.5 / 63.5
SN Margin (Up/Down) [dB]: 7.0 / 6.5
Vendor ID (Local/Remote): TMMB / TSTC
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 3 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 1,900 / 0
FEC Errors (Up/Down): 0 / 4,022,921
CRC Errors (Up/Down): 0 / 36,320
HEC Errors (Up/Down): 0 / 24,470
Line Profile: Interleaved

----Original faceplate

Link Information

Uptime: 0 days, 0:01:10
Modulation: G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]: 288 / 1,344
Data Transferred (Sent/Received) [KB/KB]: 8.00 / 6.00
Output Power (Up/Down) [dBm]: 12.0 / 15.5
Line Attenuation (Up/Down) [dB]: 31.5 / 63.5
SN Margin (Up/Down) [dB]: 6.0 / 6.0
Vendor ID (Local/Remote): TMMB / TSTC
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 / 16
CRC Errors (Up/Down): 0 / 0
HEC Errors (Up/Down): 0 / 0
Line Profile: Interleaved

-----Back to new faceplate

Link Information

Uptime: 0 days, 0:00:27
Modulation: G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]: 256 / 1,376
Data Transferred (Sent/Received) [KB/KB]: 1.00 / 1.00
Output Power (Up/Down) [dBm]: 12.0 / 15.5
Line Attenuation (Up/Down) [dB]: 31.5 / 63.5
SN Margin (Up/Down) [dB]: 7.0 / 6.5
Vendor ID (Local/Remote): TMMB / TSTC
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 / 0
CRC Errors (Up/Down): 0 / 0
HEC Errors (Up/Down): 0 / 0
Line Profile: Interleaved

Final update for tonight.

Unplugging\replugging the router without powering off (won't do that too often) and got the upstream back to 416K.

Also did a quiet line test while doing this. Interesting,

1) Unplugging the ADSL line removed the ever-present background hiss COMPLETELY.
2) When plugging back in, there was a BZZ-BZZ as it was replugged, then what I can only describe as a faint meemeemeemeemeemeemeemee noise as the "broadband" light on the router flashed.
3) As the light went solid, the hiss returned.

Hmm. HR connection somewhere?

Wouldn't a poor filter be more likely?

Either is possible, and a faulty filter can easily be checked by substitution.

Yes.

I have two ADSLnation faceplates here now, one is brand new. The stats above show no significant difference between the two. (ok, the new one is a tiny fraction better)

Interestingly, I seemed to regain most (not all) of the upstream sync when I resynced during the quiet line test, ie phone off hook.

Edited by deleted (Wed 21-May-08 09:06:18)

Progress.

Just had a play with this, and tonight I caught some rustling and other noise during the quiet line test.

I've cleaned and bent the contacts in the master socket a touch, to give a better connection, and the audible noise has gone (hiss seems a bit better, but not 100% on that)

Got most, but not all of the upstream back. Is there any profiling or similar done on the upstream side?

Stats now,

Link Information

Uptime: 0 days, 0:01:43
Modulation: G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]: 320 / 1,344
Data Transferred (Sent/Received) [KB/KB]: 19.00 / 12.00
Output Power (Up/Down) [dBm]: 12.0 / 15.5
Line Attenuation (Up/Down) [dB]: 31.5 / 63.5
SN Margin (Up/Down) [dB]: 7.0 / 6.5
Vendor ID (Local/Remote): TMMB / TSTC
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 / 27
CRC Errors (Up/Down): 0 / 0
HEC Errors (Up/Down): 0 / 0
Line Profile: Interleaved

In reply to:

---

Is there any profiling or similar done on the upstream side?

---

None at all. No DLM either. Your kit sets the upstream IP rate profile.

Quick Update.

I think this may be related to my neighbour's connection going live. They are on holiday at the moment, and they agreed to turn their router off while they are away.

Connection's back to normal. Have to say, the error rate looks higher than I remember, but it's synced to the sort of values I've been getting for several months.

So, is it really possible for another ADSL line going live to stuff up the upstream sync so badly?

I think it might be time to break out the big gun of routers, the 2wire 2700 that's in the cupboard.

Link Information

Uptime: 1 day, 5:51:30
Modulation: G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]: 448 / 1,408
Data Transferred (Sent/Received) [MB/MB]: 13.45 / 20.56
Output Power (Up/Down) [dBm]: 12.0 / 16.0
Line Attenuation (Up/Down) [dB]: 31.5 / 63.5
SN Margin (Up/Down) [dB]: 9.0 / 6.5
Vendor ID (Local/Remote): TMMB / TSTC
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 3 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 942 / 0
FEC Errors (Up/Down): 0 / 18,555,677
CRC Errors (Up/Down): 0 / 114,562
HEC Errors (Up/Down): 0 / 68,250
Line Profile: Interleaved

So, is it really possible for another ADSL line going live to stuff up the upstream sync so badly?

Anything's possible (ADSL is a bit like colour VHS recorders, shouldn't really work, it's a fudge, and amazing that it works as well as it does).

If you cable (and you neighbours) come down the same drop wire (or are adjacent for a reasonable length), then crosstalk could be an issue, especially on a line as long as yours - I'd estimate yours to be around 7-8km (based on connection speed, and the reported line attenuation being at, or above, the highest number your router can report).

It could be made worse if your neighbour has somehow managed to get ADSL2/2+ (although I don't see how they'd have managed that, on such a long line).

I think it might be time to break out the big gun of routers, the 2wire 2700 that's in the cupboard.

Well, it probably won't be as stable as your Speedtouch (the 2-wire syncs too high to be stable), but plug it in and keep an eye on the impulse noise counter.
The impulse noise reading is a very useful feature of this router, and it starts to go mental just before a noise induced re-sync (which is how I traced a problem to a dodgy cheapo DVD player - every time it played a disc, the impulse noise counter on the 2700 went nuts, and a re-sync followed).