[mailto:owner-ietf-mailsig(_at_)mail(_dot_)imc(_dot_)org] On Behalf Of Tony
Finch
I think this will be less of a problem than you might expect
(though my experience and evidence is at the tens of
thousands of users level rather than the millions of users level).
Despite my background in extreme parallel systems I think that thousands
of users is the right level at which to consider the issue in the group
at large.
The number of ISPs that handle milions of customers are very few, they
are all one off installations and most importantly they are quite
capable of working out if it is a problem themselves.
We have a very good cross section of the major providers in the group
and none of them is complaining that this is a show stopper for them.
Of course there are going to be resource issues for million plus user
ISPs, that is the case with absolutely any change you make at that
scale. Its just standard operating procedure.
The DNS cache issue is bogus, you only see the effect if you CHOOSE to
turn on verification. People who run million plus user installations do
not just turn on resource hungry features without thinking through the
consequences. Nor are they likely to be crippled by a problem that is
easily solved by adding a few Gb of RAM to the DNS server.