After many tests, I found that my 1811 decreases the download speed from ibackup.com a lot. Without any routers or with the other simple router, it is around 90-120K/sec, but when traffic comes through 1811, it comes down to 20K/sec.
So far, ibackup.com shows extremely slow speed, and yousendit.com shows half speed if the traffic comes through 1811.
I am sure that it is because of my setting on the router, but I cannot find out what to check.
Speed test (speakeasy.net/speedtest) always shows a good number. There is no internal congestion.
Could you help me to find out what setting I should take a look?
Thank you very much.