My company owns a class-B network. This network is currently being sent to the Internet via individual /24 nets. We have one ASN.
There is a need to put two separate DNS systems up, but we may not be able to obtain new ASNs. Each site will advertize the SAME /24 nets as eachother.
My concern is that our main site, and each of these two new sites, do not have in-band connectivity to eachother.
Given that the query-response nature of UDP/DNS is the only service planned for deployment at the new sites, I'm not overly worried about route fluctuation on the Internet core breaking a long-running TCP session by suddenly switching which site is getting the packets.
My concern is that some ISP out there may think they can reach our "site-a" via "site-b" simply because the same ASN is in use multiple times -- yet they are really three separate autonomous systems from a pure routing standpoint.