hot/cold-potato routing

[Vandy Hamidi <vhamidi () insweb com>]

I'm new to the world of high-end/ISP-level routing and traffic manipulation.
I recently heard of "cold-potato and hot-potato routing" and have developed
an understanding of what it means and why hot-potato is default because of
BGPs very nature.
My question is, How is Cold-Potato routing implemented, and how are ISPs
like Above Net able to just switch over when a backbone connection is lost?
Are MEDs involved?
Thanks,

        -=Vandy=-