RE: ISCSI: More on Urgent pointer

[Black_David@emc.com]

With my WG co-chair hat firmly on ...

> There are two cases here.  One where the iSCSI proposal is repaired to
> reflect normal operation of TCP and another case where the present
proposal
> stands as written.  As written, there is an expectation of there being a
> record mark for every TCP segment that contains the beginning of the first
> PDU

... let me make it completely clear that the WG must pursue the first
case.  We do not have license to make changes to RFC 793, and iSCSI
MUST be capable of working with unmodified host TCP stacks.  These
matters are not open to discussion; send me email directly with questions
and clarifications.  I note that about a week ago I indicated that the
text Doug is objecting to is incorrect and has to be modified.

I also believe that based on discussion on the list, WG rough consensus
does NOT exist for requiring this use of the URG flag and Urgent pointer,
(too many people have objected to making them mandatory), and hence
the current "MUST" will have to be replaced.  Off the list, someone has
also pointed out that setting the URG flag is likely to break header
prediction in some existing host TCP stacks.  Further discussion on
whether this ought to be a "SHOULD" or a "MAY" is welcome, and I
note that Vern has added himself to the list of people asking for details
on exactly when this makes how much of a difference and how often
that's likely to occur.

--David

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