i was wondering if i could get some help in figuring out an issue recently with my internet connection. I'm based in the middle east and was using an ADSL connection (4 Mbps). My ISP recently upped the quality of their lines in my area and as a loyalty upgrade, i got a bump to 20 Mbps (although i was told i have now been moved to VDSL) . The trouble was, the ISP ran out of VDSL modems which they were providing their customers, so while the port was configured as a VDSL they asked me and a few dozen other customers to continue using their ADSL modems till they received stock.
since i know a few of the other customers who also had to continue using ADSL modems till the VDSL ones arrived, we all faced something rather strange. The SNR was low and we were getting low throughputs the entire time we using the ADSL modems , and the SNRs literally doubled when we changed to VDSL modems.
how exactly does a change of modems increase your speed? the ISP's lines were rehab'd to support up to 20 Mbps on ADSL2+. The port had been upgraded at the ISP end to vDSL as per a confirmation message i got.
so my question is, with VDSL configured at ISP end, why would i get low SNR with my ADSL2+ modem and double the SNR when i switch to VDSL? what exactly is the logic behind this?