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Re: [RRG] Why delaying initial packets matters



Stig -

One solution, which is a bit of a kludge, could be to have some kind of
interaction between DNS and the mapping system, where the necessary
mappings can be installed (based on DNS replies), before the DNS reply
is given to the application.  [...]

Right, I had been thinking about this also.  Few thoughts:

- Piggybacking mapping records to DNS replies would enable pre-loading
  of an edge network's local mapping caches -- reactively, but still
  before the transport protocol launches its session and starts waiting
  for timeouts.

- DNS-based mapping resolution does not imply per-address mappings; new
  DNS records may well describe mappings on an address-block basis.

- DNS-based mapping resolution could be used in conjunction with another
  mapping system, as an optimization.  One could leave it up to an edge
  network to decide whether or not to support the optimization by
  attaching mapping records to DNS replies generated by its DNS servers.

- It may be unwise to rely *exclusively* on DNS-based mapping resolution
  because the technique does not work that well when a host starts a new
  session without an initial DNS look-up.  In such a case, DNS-based
  mapping resolution would likely have to involve reverse DNS because
  the look-up key would not be an FQDN, but an identifier IP address.
  And this will be really costly in terms of delay.

Comments are welcome.

- Christian



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