I recently installed a new broadband connection at my office with plan 291 which provides 20mbps speed however my line profile was set to 2mbps downstream and 512kbps upstream with snr 40 downstream and 12 upstream and attenuation is 12,i called up the jto who increased my downstream rate to 8mbps and said thats what you can get but I doubt that because my snr was 40 and it dropped to 15 when the line rate was increased to 8mbps.
Now the question is that why the snr dropped so much and why my upstream snr is so low as it should have been around 40 as well and also the attainable rate is around 11mbps whereas it should have been 20mbps plus and also i have seen my neighbours have an upstream snr around 25 with attenuation 17.