VDSL Bit loading indicating a fault?

Hi,

My FTTC has slowly reduced the attainable rate over the past few months. (I have a flashed HG612 so can see the line stats).

I have been using rs-w which shows a graph of the bit loading. One interesting thing I see is that the loading for the lower tones (100 to 900 ish ) almost half every few minute and then restore after a few seconds.

Would this indicate a fault?

Here are the two images:
https://dl.dropbox.com/u/50662537/Bitloading-2013-04...
https://dl.dropbox.com/u/50662537/Bitloading-2013-04...

Tom

No one is going to worry about fixing attainable rates, what has happened to the actual sync speeds?

Yes, I had a similar experience with rs-w but it didn't seem to affect my speeds. I couldn't say if it was a bug in rs-w as I can't see the raw data. However, the alternative from Bald_Eagle gives a way to see the data http://www.freewarefiles.com/HG612-Modem-Stats_progr...

Edited by BatBoy (Tue 02-Apr-13 13:16:22)

I think it's a bug. I've never seen it in the graphs produced by Bald Eagle's software. It also seems the least likely bands to be affected by interference. Anything funny going on there ought to hit the upper tones first I think.

In reply to a post by MrSaffron:

No one is going to worry about fixing attainable rates, what has happened to the actual sync speeds?

I upgraded from 40/10 to 80/20 but saw no increase. I raised the ticket with my ISP who sent out a BT Engineer (SFI engineer if I recall). He found a connection fault in the junction box where the line fixes to the house. After fixing that, the CRC errors decreased but I saw no change in the connection speed etc.

Here are the graphs of the CRC and SNR Margin for today:

https://dl.dropbox.com/u/50662537/CRC-2013-04-02-23....
https://dl.dropbox.com/u/50662537/SNRMargin-2013-04-...

I am only about 600 metres away from the cabinet and when I was on ADSL2+ I got around 18 or 19mb sync which surely shows that the line was in a pretty good condition?

I've seen this with the graphing scripts too, it's always happened. The log shows the bitloading change and the bitswap value increases. Why it flaps about so much though I've no idea.