MPA startup sequence issues (1) and (2)

This is the first of several emails whose goal is to achieve
mailing list consensus on issues discussed in Seoul.  This
email covers issues (1) and (2), which concern permissible
startup sequences for MPA.  The Seoul minutes say:

  (1) Fast FPDU return (responder need not wait for first pdu). 
  Tentative proposal: leave as-is (responder must wait). 
  No dissension in room.  This is not needed for client/server,
  as the server expects to wait for the client.  Need to take
  proposal to the list. 

  (2) Active/Active startup. Tentative proposal: leave as-is (no 
  support for active/active). No dissension in room.  Note, no 
  known applications require it.  Need to take proposal to the list.

For both of these issues, the rationale for not supporting
the expanded functionality (Fast FPDU return, Active/Active
startup) centers around practical issues for dual-stack
implementations.  draft-culley-mpa-issueresponses-00.txt
contains an extensive discussion of these implementations,
why they're of interest, and the difficulties that these
two features pose to that class of implementation, which
the WG clearly considers to be important.

In other words, this is a "what is reasonable to build
in practice" engineering rationale, as opposed to a "what
is possible in principle" design rationale, which is a good
way to go about making decisions in the IETF.  For the
purpose of starting discussion, since Caitlin Bestler is
the only person I can recall strongly advocating these
two features, I believe that there is rough consensus
not to support them (and hence also not to support them
in the SCTP mapping for consistency).

Not supporting these features means senders MUST NOT
attempt them, and they are an error case at the receiver
if they occur.

For further discussion ...

Thanks,
--David
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David L. Black, Senior Technologist
EMC Corporation, 176 South St., Hopkinton, MA  01748
+1 (508) 293-7953             FAX: +1 (508) 293-7786
[email protected]        Mobile: +1 (978) 394-7754
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