I am investingating the option of connecting our business network to 2 separate ISPs for redundancy.
Since we have a couple of B2B services which need to be accessible from outside, in order to have automatic failover not only from inside out, but also from outside in, as I understand, we should implement BGP and have our own (optimally provider independent [PI]) Autonomous System (ASN).
It seems that IPv4 ASNs are depleted and -- especially global ones -- are comparatively expensive and hard to obtain.
A couple of ISPs are offering IPv4 ASNs, however, they are giving provider aggregated ones, which would mean we would be stuck with the provider as long as we use them.
The question is:
- is there any other way to provide reasonable failover connection to my network beside ASN+BGP?
- alternatively, is it feasible and recommended to get IPv6 PI ASN -- as I understand those should be available easier and cheaper, but I haven't been able to find the info yet. Would a pure IPv6 network be reacable from the rest of the Internet nowadays anyway?