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[les-70]

  I had to restart my PC so the bit swap/tone below is just a short early evening period.  it shows how my line has most swaps in band D3 and as noted this may well lead to different results c.f. lines that don't show this.

[kitz]

Ive just reset my bitswap graph so I'll post that later.  It may give us a more comparable result as regards to time span

[roseway]

Don't take that graph too literally. The modem doesn't actually supply bitswaps per tone information. I assemble the graph by analysing the changes in bitloading on each tone, and making the assumption that there's some correlation between bitloading changes and bitswaps.

[les-70]

  I guessed that would be the case.  I am taking it as an indicator of the tones which have a time variation in their SNRM.

[kitz]

Here you go, as promised...  I know its not exactly 24hrs, but I hope its of some use. 

[les-70]

   Thanks for that.  It definitely looks like your line has less noise variations than mine and a lot less in the D3 band where the 63168 chipsets seem to increase bit loading.  I guess that may indeed be the reason for our different experiences with the 63168 devices.  It is plausible that on my line putting more bits in D3 will increase error rates.

  Separate from this thread I am now running with a HG612 and the old NTE2005 adsl v1,0 SSFP which unlike the Mark2 and Mark3 has no "RF3" type device in it.  With the NTE-2005 I get a higher attainable, due again to more bit loading in D3.  So far the error rate has reduced too but it is too soon to be sure about. The impact is a smaller version change seen when running my line on an actual RF3 and then removing it. Hence me thinking it may be real.  If the lower errors with the NTE-2005 persist I may retest the 8800NL on the new arrangement. 

[kitz]

Out of interest have you tried a lantiq chipset.. and if so is it any better/worse?

[les-70]

The BT ECI/r modem gave me a lower sync and although it is unlocked I don't think it is easy (possible?) to get the error stats.  I gave up quite quickly though as the BCM chipset devices are so much more convenient.

[Chrysalis]

for the 2 devices is it possible to have a sticky with recommended firmwares?

for lantiq they sync lower kitz even on a ECI dslam.

my fritzbox 3370 is lantiq and it syncs extremely low on interleaving and a bit lower on fast path.

[kitz]

   Thanks for that.  It definitely looks like your line has less noise variations than mine and a lot less in the D3 band where the 63168 chipsets seem to increase bit loading.  I guess that may indeed be the reason for our different experiences with the 63168 devices.  It is plausible that on my line putting more bits in D3 will increase error rates.

Mine seems to have a lot more variation in the D1 & D2 bands, but like you say not as much in D3. 
My D1 band tends to get a lot of variance at around tone 250 and just below..  this is where when I had the Lantiq on I could see a lot of shifting of the SNR in real-time in an area that I suspect is due to adsl/adsl2+ crosstalk.   I think this same issue relates even as far back as when on adsl2+ because I could see the telltale shallow dish over those same tones even then.

Just proves that every line is different and that none are perfect. :/

[kitz]

for the 2 devices is it possible to have a sticky with recommended firmwares?

Theres a sticky here with the Zyxel firmware.  Im still using  V100AAKL4b2.bin which Im happy with.
Theres a discussion in the Billion 8800NL thread about firmware..  and [I think] les is trying to find which is best - which [i think] is partially what led him to opening this thread.

for lantiq they sync lower kitz even on a ECI dslam.

my fritzbox 3370 is lantiq and it syncs extremely low on interleaving and a bit lower on fast path.

Yes I find the same on my line - the lantiqs arent a patch on the BCM (and most others), but there are still some who swear by the Lantiqs so I was curious how it performed on les-70's line due to him having issues with the bcm 63168 that none of the rest of us appear to have seen.

[Chrysalis]

ok thanks.

[les-70]

  I have been testing to see how much I have to reduce the sync of the 8800NL in order to achieve the same error rate as my HG612.  I have just considered the ES/hour counts as they are the most stable thing to compare.  I found that with the 039 dsl driver firmware I need to use capping to reduce the sync by an extra 8-10Mb/s i.e. ~2db SNRM gain in order to get the same error rate as the HG612.  With the 038 dsl driver the needed reduction was less at 6-8Mb/s.   I would therefore be cautious of the 63168 devices if your connection speed is error rate limited.  e.g. a non-interleaved connection that may go interleaved or DLM banded with much higher errors.  To be clear - just cautious - as not all lines seem to suffer from the issues I see my line.  In fact my line may or may not be a good test case.

  The other finding from this study is that as the SNRM gets bigger e.g. at 9db the difference in performance on my line is less than with the SNRM at 6-7db.  e.g.

                       HG612 ES/hour    8800NL-039 ES/hour     
     ~6 db               ~10                       ~15
     ~9 db                 ~6                        ~7

  This may mean that some with a high SNR might find that the 6368 chipset is better for errors should their SNRM reduce to 6.

  Edit --  Note that all these result are with no interleaving.  With interleaving the situation could be quite different and the extra attainable speed of the 63168 chipset might or might not come with an error impact.

[kitz]

Interesting observations thanks.   
I cant recreate this because I have a larger SNRm and any capping will only further increase it..  but it could explain why I see less errors on the Zyxel?

Ronski's may be another good case to compare. It shows that on his line there is less aggressive bitswap.  Interesting that he also sees the evening peaks though when it ramps up similar to when on the HG612.  - See the screen caps in his thread here.

Looking at his graph today, I notice that as predicted he will now see more ES due to the fact that interleaving depth was reduced on the 26th but it still seems to be performing within acceptable parameters. Whilst he is getting more E/S its not bothering the DLM .. plus he's getting a sync increase of 2.5Mbps.
On the whole I'd say Ronski's line seems to be doing quite nicely with the VMG8324 and seems pretty stable. 

[les-70]

  Thanks for pointing out Ronski's case.  It is interesting but I would not wish to extrapolate these results on my line to any line with interleaving. 

    I had interleaving once for about 8 days and it took my prevailing  ES rate on the HG612 from ~10/hour  to less than 1/hour.   I was quite impressed with how effective it was.  For comparison the same speed reduction via a sync cap only took me about 5/hour.

  I will add a note to the above post reminding that is all on fast path.