same network, I would think that this idea was ok. From my
experience, however, most multihomed customers have their second
connection to a different network. Hopefully this will change but it
is reality for now.
Not only is it reality, it is, from the customers point of view, a good
idea. Greater diversity is better redundancy. For technical reasons -
we've seen examples of providers bringing down their entire network, and
for administrative/policy reasons (provider xxx decides to triple
prices on their new contract).
There is a solution to the customer who wants to be dual-homed
to two providers and not contribute to the "routers can't handle the
tables" problem. Just don't announce your more specifics to your backup
provider unless you know your primary is down. Some type of automated
script can do it.