I have an ADSL2+ (Annex B) line, which uses Rate-Adaptive-Mode. It synced fine with 6000/600 kBit/s down/up for 2 years, which resulted in around 6/0.6 MBit download/upload-speed in my LAN. Now, since about a week or so, client download-speed dropped to 2MBit/s while upload remains stable. The router shows a 6000/600 kBit/s down/up sync speed. Nothing changed in cabling to the router and even if you connect it directly onto the phone-line the same symptoms appear.
How does DSL-RAM work? Can sync with high bandwidth (which is shown in Router/DSLAM, which ISP told me) but software dynamically throttles if the cable is too bad? Or is the bandwidth shown physically possible at the moment?
Or might this be a hardware-fault?