(other points, i.e., not TCP mandatory or timeouts)

 In your previous mail you wrote:

>  this means that while it's not ideal, it's not as broken as it could be.
>  with changes to recommended initiator behaviour, we could make these
>  existing servers more broken, or we could preserve their present level
>  of brokenness, but we cannot make them less broken. i'm going to argue,
>  below, for preserving their present level of brokenness.

=> IMHO this means we need to introduce a bit of signaling before
trying a better behaviour at any side, so legacy initiators and
servers are recognized.

>  i am comfortable with this approach, but i would like to also specify
>  (in one of the tcp related documents now circulating, or in a new one,
>  that's a detail) that initiators SHOULD NOT remain connected and idle
>  unless they are acting under some later specification under which
>  idleness has been explicitly negotiated.

=> at the exception of the SOA + xXFR case I don't believe that
idling initiators are common today.

>  obviously, any existing
>  initiators will not obey the SHOULD NOT, but i would like to preserve
>  the responders' present level of brokenness by not adding any new TCP
>  connection idlers until and unless there is a protocol change by which a
>  responder can signal its willingness to participate in an idle mesh.

=> I fully agree and fortunately we can publish 3966bis before even
adopting one of the signaling proposal.

>  note that
>  <http://tools.ietf.org/html/draft-ietf-dnsop-edns-tcp-keepalive-01> is
>  an example of a protocol revision by which idleness could be explicitly
>  negotiated. i think a simpler approach could work, like adding one bit
>  of the EDNS extended-flags mask to say "the sender of this message would
>  be happy about remaining connected but idle". my reason for thinking
>  this would be enough is, there's no way to reliably tune specific idle
>  periods, and a TCP speaker who signals their willingness to remain idle
>  must also be prepared to close least-recently-used connections when the
>  pool of potential connections is running dry.

=> the advantage of the keepalive proposal is the server can give the
timeout it wants to use. And a bit carries too few infos, e.g.,
how to announce the initiator is smart but in this case allows
(or wants) the server to close after the response?

Thanks

[email protected]

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