I need your opinion, we have a customer who needs to be multihomed (via our ISP and another ISP) to achieve redundancy, he wants to run BGP via private-as (he won't have the justification to own his own PI addresses and ASN).
The solution i reached (actually i found many ISPs using it) is using 2 class Cs, one from us and the other from the other ISP, and the customer should advertise both to both of us via BGP, and both ISP would have to remove the private-as and both ISP will advertise both classes to the internet (each will be primary for its class and backup for the other ISP class - using the perpending).
And of course we will need to have 2 route objects for both classes at RIPE (to attach the 2 classes to the 2 ASN of the 2 ISPs in order to be accepted on the internet routers through our upstream providers).
The issue here is, since this types of routes is seen as inconsistent-as in the internet routing table, would this have any drawbacks or impact, is there any problem going through with this solution, has any one experienced this solution, if so please give me your feedback.
Thanks in advance for your replies.
I was looking at this better. There are currently about 800 prefixes announced with inconsistent as, although most people is liberal in accepting routes, I don't know what the general consensus on using them.