Re: [DNSOP] I-D Action: draft-moura-dnsop-authoritative-recommendations-04.txt

[Bob Harold <[e-mail]>]

On Tue, Jun 11, 2019 at 8:46 AM <[e-mail]> wrote:

>
> A New Internet-Draft is available from the on-line Internet-Drafts
> directories.
> This draft is a work item of the Domain Name System Operations WG of the
> IETF.
>
>         Title           : Considerations for Large Authoritative DNS
> Servers Operators
>         Authors         : Giovane C. M. Moura
>                           Wes Hardaker
>                           John Heidemann
>                           Marco Davids
>         Filename        :
> draft-moura-dnsop-authoritative-recommendations-04.txt
>         Pages           : 17
>         Date            : 2019-06-11
>
> Abstract:
>    This document summarizes recent research work exploring DNS
>    configurations and offers specific, tangible considerations to
>    operators for configuring authoritative servers.
>
>    This document is not an Internet Standards Track specification; it is
>    published for informational purposes.
>
> Ed note
>
>    This draft will be renamed to draft-moura-dnsop-large-authoritative-
>    considerations in case adpoted by the WG, to reflect the new title.
>
>    Text inside square brackets ([RF:ABC]) refers to:
>
>    o  individual comments we have received about the draft, and
>       enumerated under <https://github.com/gmmoura/draft-moura-dnsop-
>       authoritative-recommendations/blob/master/reviews/reviews-
>       dnsop.md>.
>
>    o  Issues listed on our Github repository
>
>    Both types will be removed before publication.
>
>    This draft is being hosted on GitHub - <https://github.com/gmmoura/
>    draft-moura-dnsop-authoritative-recommendations>, where the most
>    recent version of the document and open issues can be found.  The
>    authors gratefully accept pull requests.
>
>
> The IETF datatracker status page for this draft is:
>
> https://datatracker.ietf.org/doc/draft-moura-dnsop-authoritative-recommendations/
>
> There are also htmlized versions available at:
>
> https://tools.ietf.org/html/draft-moura-dnsop-authoritative-recommendations-04
>
> https://datatracker.ietf.org/doc/html/draft-moura-dnsop-authoritative-recommendations-04
>
> A diff from the previous version is available at:
>
> https://www.ietf.org/rfcdiff?url2=draft-moura-dnsop-authoritative-recommendations-04
>
>
In section "7.  C5: Consider longer time-to-live values whenever possible"

   o  Longer caching results in faster responses, given that cache hits
      are faster than cache misses in resolvers.  [Moura19a
<https://tools.ietf.org/html/draft-moura-dnsop-authoritative-recommendations-04#ref-Moura19a>]
shows that
      the change in TTL for .uy TLD from 1 day to 5 minutes reduced the
      RTT from 15k Atlas vantage points significantly: the median was
      reduced from 28.7ms to 8ms, while the 75%ile decreased from 183ms

      to 21ms.

I don't understand how changing to a shorter TTL (from 1 day to 5 minutes)
reduced the RTT.  Seems backwards.

-- 
Bob Harold