Linestats after second line enabled...

Right, I've had a line on FTTC since the beginning of last year with pretty good stats. The other line in the house on the same dropwire was on ADSL2.

Today the ADSL2 line got switched to FTTC and I expected a bit of worsening in stats and speed however I was wrong.

Previously the stats were...

xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 33812 Kbps, Downstream rate = 106000 Kbps
Bearer: 0, Upstream rate = 19999 Kbps, Downstream rate = 79999 Kbps
Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 Kbps
Link Power State: L0
Mode: VDSL2 Annex B
VDSL2 Profile: Profile 17a
TPS-TC: PTM Mode(0x0)
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 13.2 15.7
Attn(dB): 8.9 0.0
Pwr(dBm): 12.8 -9.9

After the second line has been activated the stats have dropped to

xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 27121 Kbps, Downstream rate = 86144 Kbps
Bearer: 0, Upstream rate = 19999 Kbps, Downstream rate = 79999 Kbps
Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 Kbps
Link Power State: L0
Mode: VDSL2 Annex B
VDSL2 Profile: Profile 17a
TPS-TC: PTM Mode(0x0)
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 7.8 11.2
Attn(dB): 8.9 0.0
Pwr(dBm): 12.8 -9.9

Is that expected? I mean the two lines are only together from the pole to the house, ~40 metres or so...would that have such an effect on it? :|

In reply to a post by NBK:

... I expected a bit of worsening in stats and speed however I was wrong.

Don't you mean "... speed and I was right"?

Re the lines being together, they may be so all the way from the cabinet.

Have you got the stats for the second line?

In reply to a post by RobertoS:

In reply to a post by NBK:

... I expected a bit of worsening in stats and speed however I was wrong.

Don't you mean "... speed and I was right"?

Re the lines being together, they may be so all the way from the cabinet.

Have you got the stats for the second line?

I wasn't wrong, it's more than a bit
The second line is using a smart hub and it reports...
Maximum data rate: 19999 / 80809
Noise margin: 15.4 / 6.7
Line attenuation: 9.6
Signal attenuation is blank

The assumption is that it is a large worsening rather than a bit. The max attainable has gone down by about 20%. However, the actual sync speed has not been affected.

In reality the service hasn't changed at all. I don't entirely trust the routers calculations of max attainable and how the lines are managed.

Post deleted by RobertoS

Edited by RobertoS (Fri 09-Sep-16 14:59:25)

From the original post:

I expected a bit of worsening

I'd said I expected a bit of worsening however i got a lot more than a bit

Just for a laugh I turned off the router on the other line and my linestats went to...

xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 34292 Kbps, Downstream rate = 107528 Kbps
Bearer: 0, Upstream rate = 19999 Kbps, Downstream rate = 79999 Kbps
Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 Kbps
Link Power State: L0
Mode: VDSL2 Annex B
VDSL2 Profile: Profile 17a
TPS-TC: PTM Mode(0x0)
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 13.6 19.9
Attn(dB): 8.9 0.0
Pwr(dBm): 12.8 -9.9

In reply to a post by NBK:

Today the ADSL2 line got switched to FTTC and I expected a bit of worsening in stats and speed however I was wrong.

That's right, your speed on Line1 is unchanged and much improved on Line2.

The lines, as already mentioned, could be together all the way from the cabinet (and possibly exchange). With ADSL there was only cross talk at the low end however, with two VDSL lines the cross talk will be all the way up to 17MHz and could affect every tone.

Have you been unlucky? Yes.

Is there anything you can do? No - apart from turn off one line!

Will a complaint be entertained? No.


It might be worth turning off each modem in turn and then disconnecting it. Wait say 15 minutes and then recheck the line stats on the line remaining active. Does your old line go back to the former levels, or better?

You posted this as I replied to your original post. It certainly seems to confirm that it is only cross talk causing the degradation.



What are the new line stats? Both with and without the original line running.