I have replaced an old modem happily chundering on ADLS2 whith 7800N to take advantage of 2+ (and rationalise other networking bits - switches, APs, IPV6, etc.) However the 2+ performance is terrible compared to 2 with the 7800N. Downloading a 1.2MB file over ftp gave ~700KB/s on ADSL2 (same as my old modem) and only 7KB/s with ADSL2+ which lots of stalls.
All I need to do to change performance is to toggle 2+ from the ADSL op mode modulator list and resync, all other router settings are the same. The ADSL status shows no problems and gives a downstream value of ~12000 with ADSL2+, only 9655 with ADSL2.
FTR the line stats are:
SNR Margin(Upstream) 6.5
SNR Margin(Downstream) 3.2
Line Attenuation(Upstream) 20.3
Line Attenuation(Downstream) 29.0
I also turned off Annex M mode even though I don't have it. Firmware is 1.06e. The WAN status page shows no errors or drops with either 2 or 2+
Where to go with this? Since it is my own modem, not the ISP's (PlusNET) I assume they will say the down/up-stream numbers look good from their end. Or is it possibly an exchange issue they can chase up? Or chase up with Billion as a firmware issue? Or some cunning router setting I have missed?