Re: [DNSOP] Ask for advice of 3 new RRs for precise traffic scheduling

[Robert Edmonds <[e-mail]>]

bert hubert wrote:
> On Wed, Dec 13, 2017 at 05:36:32PM +0800, [e-mail] 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