Im supprised that with SNR of 17.9 and Attenuation of 7.3 max is only 76. Shouldf be much higher no? On my line with SNr of 12.3 and Attn of 10 my max is 103 Mb, so in my opinon your max should be above 100 Mb.

My stats:
xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 36188 Kbps, Downstream rate = 102044 Kbps
Bearer: 0, Upstream rate = 19999 Kbps, Downstream rate = 79987 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): 12.4 23.1
Attn(dB): 10.0 0.0
Pwr(dBm): 12.8 -4.6

so your line stats are better then mine and still lower values...

Edited by deleted (Wed 18-Feb-15 19:01:19)

MHC is right and I am afraid you aren't.

You stated that the upstream would drop to 19999. The work "drop" is wrong:

Either, the sync will increase from 9999 to 19999

or

The max attainable will continue to be 26328 (ish)

Neither of these will drop by going from 40/10 to 80/20.

Theoretical question:

If the line was getting such high max rates is it possible that it has dialled back the power? By dialling back the power could this impact on the accuracy of the "guess" at max sync attainable?

This is a possibility too

At the end of the day the only way to know is to try and run the line at the faster speeds

In reply to a post by MrSaffron:

This is a possibility too

At the end of the day the only way to know is to try and run the line at the faster speeds

That's certainly a thought. And I see no point in a modem shouting when it has no need, it does no favours for crosstalk.

Thanks for everyone's contributions...I knew what you all meant

The OP has current sync speeds of 40/10 (capped by choice of package) while yours is 80/20.

The extra spare SNR (12dB) for him will give him an extra 36Mbps, while your spare SNR (6dB) will give you 20Mbps.

I note from you line profile that DLM has not intervened (INP=0.0 and delay=0), yet the modems have negotiated to turn FEC protection on, but without interleaving - in both upstream & downstream directions.

This protection is using 16 bytes out of every 255 bytes as the FEC protection overhead - which means it is using around 6% of your bandwisth.

I don't know whether that would give you the extra 2.5Mbps on top of the attainable if you switched package; when DLM intervenes, that attainable figure becomes less trustworthy - so I don't know whether it would be wrong here too.

From the error stats, it doesn't look like the downstream FEC protection is working too well, nor that it is particularly needed.