On 10/16/2012 12:51 PM, Patrick W. Gilmore wrote: > On Oct 16, 2012, at 08:33 , paul vixie <[email protected]> wrote: > >> ... <http://www.isc.org/solutions/sns-anycast>. > This works, although limits your anycast nodes to a single provider.
we have several name servers, each in some provider, each having nodes on several continents. i'm clarifying this because the terminology "anycast node" means to some people what "name server" means to me. if it is the target of an NS RR for some zone it is a "name server" which can be anycasted across some number of "nodes". > While there is nothing wrong with single-provider anycast, I would argue > having anycast instances in multiple providers is beneficial. it can be, and that's why f-root and ISC's public benefit secondary name service do it that way. > Also, it is difficult to find a network with truly global reach, limiting > your choices if you want nodes in every corner of the globe. Moreover, the > few networks that are present on very continent all have restrictive peering > policies, limiting their reach to certain networks in many places. to the first, i note that DNS has its own high availability characteristics -- recursive name servers will sample all "name servers" for a zone and will stick to the one with the lowest observed RTT. this means not every "name server" must have anycast nodes in every corner of the globe. given that every prefix added to the global routing table is an irreversible and universal burden on the internet core, we have to look at the cost:benefit ratio of doing anything not truly necessary. to the second, i'm pretty happy with the providers we use for our commercial secondary name service, but i also know that pressure from us as a customer has led at least one of them to be more aggressive about their international peering. the libertarians call this "using your dollar votes" and it's working. > To be clear, using your own space doesn't guarantee global reach either. But > it gives you more flexibility, at the expense of greatly increased > complexity, time, and effort. and also at the expense of a small burden for everyone, for every prefix added to the global routing table. i know that most business planners won't take that kind of "footprint" cost into account, but some will and it's important in these public threads to make sure we enumerate such. paul -- "I suspect I'm not known as a font of optimism." (VJS, 2012) _______________________________________________ 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
