It is asymmetrical, but say you are hosting a lot of www sites and have mostly out-going traffic this solution will work and give you 10, or even 100 meg FDDI out, but only the size of your transit pipe in.
The main problem with is is that A) It is not ethical B) the provider you are doing this to will figure it out someday and see you in court C) it is not nice. :-)
This is something a few of our routing engineers have been joking a mom&pop ISP could do. They get a 10 or 45Mbit connection from big six provider A. They get a 100Mbit connection at Nap B. They default all of their traffic at Nap B to Provider A's router at Nap B. This way they get [theoretically] up to 145Mbits into provider A's network and get the traffic back inside of provider A's network. What are the various opinions on this behavior? Regards, -Deepak.