dns anycasting can also be done solely with provider-assigned space and no ASN of your own. for ISC we have three anycast clouds, one for f-root which has its own prefix and its own ASN, one for our public benefit secondary service which has its own prefix adjacent to f-root, and one for our commercial secondary service which uses provider-assigned address space for each named server.
the advantage to using provider-assigned space is that the global routing table carries no separate burden on your behalf. i call this "green networking" since it's more ecologically friendly. the disadvantage is that if you want to change providers you have to renumber. renumbering in this case isn't all that painful since you are in control of the NS target name. there's a description at <http://www.isc.org/solutions/sns-anycast>. note that the term "anycast" is sometimes overloaded to mean "DNS CDN" where each server decides what answer to give for an A or AAAA request based on that server's current guess about the client's locality relative to various web farms. if the original question is really about that, then the answer will have to go beyond routing policy. (ISC does not do this, so my description above does not cover it.) paul _______________________________________________ dns-operations mailing list [email protected] https://lists.dns-oarc.net/mailman/listinfo/dns-operations dns-jobs mailing list https://lists.dns-oarc.net/mailman/listinfo/dns-jobs
