bert hubert wrote: > On Wed, Dec 13, 2017 at 05:36:32PM +0800, [email protected] wrote: > > so far as i know, many CDNs already use similar methods as you mentioned > > in PowerDNS 4.1.1 > > but i think only the Authoritative Server change is not enough, support > > on the recursive server is also very important . > > because the resolver determines the reponse to clients. > > This is true. A typical resolver will serve around 50,000 to 2,000,000 > users (although this is rare). This means that for 60 seconds, you shift > around 'a hundred thousand' potential users. > > In practice, this appears to be good enough from what I hear. > > Or let me put it another way, before we burden the DNS protocol with another > record type we have to add downgrade/workaround/DNSSEC support for, we > should have numbers that say it solves a problem. > > CDNs could maybe chime in.
Hi, With my CDN hat on, I don't see any need to turn over scheduling decisions to resolvers. Extremely precise amounts of traffic can already be scheduled to individual CDN nodes because you have a large pool of owner names to work with, not a single owner name, and every (QNAME, QTYPE, resolver IP, client subnet [if present], anycast location that receives the query) tuple is an opportunity to make a unique scheduling choice. Generally, however, assignments to CDN nodes should be relatively sticky. You want to be shifting traffic for performance reasons, not capacity reasons. Or, put another way, we like existing resolver implementations just fine, we just wish there were a lot more resolver instances, and closer to clients :-) -- Robert Edmonds _______________________________________________ DNSOP mailing list [email protected] https://www.ietf.org/mailman/listinfo/dnsop
