I have a customer with a single router dual-homed to ISP 1 and ISP 2 (leaving the names of the ISP's out). The customer has their own BGP ASN number assigned by ARIN, but they do not have their own class C assigned from ARIN.
ISP 1 assigned a class C from their address space to the customer. We would like to use ISP 2 as the primary path (it has more bandwidth) and ISP 1 as the secondary path. As-Prepends have been setup accordingly to accomplish this task.
Customer can get to all of their sites across the internet through ISP 2 except one location. ISP 2 states that since the class C is allocated to ISP 1, they need to get their own Class C from ARIN.
Below is a url that links to a document from Sprint published in 2001. On page 8 it shows a scenario (Case 1 and Case 2), whereby this practice is acceptable. The class C from ISP 1 would be a "traffic magnet" through ISP 2, but this outcome is fine by us.
It's my belief that at one time, a class C (whether it's assigned from an ISP or ARIN), may be advertised from any one point to any other point across the internet.
Has this changed since 2001? (I know it's been 8 years.)
Any feedback would be greatly appreciated.