Re: iSCSI Data Integrity - Digests

[David Robinson <David.Robinson@EBay.Sun.COM>]

Y P Cheng wrote:
> Mike, if iSCSI is deployed through the use of an adapter which collapses all
> three layers, SCSI, iSCSI, and TCP, into a single set of microcode, then,
> you got a new implementation of TCP anyway.  All those sacrosanct talks that
> forbid changes of TCP implementations do not apply to an iSCSI adapter which
> at login time will exchange text parameters with each other to deploy new
> TCP options.  Everything you wanted can be inside an iSCSI adapter.
> However, the right place to talk about what you want from TCP is in the
> end2end group, not here, as so many people repeatedly pointed out to me. :-)

YP,
While I understand and can appreciate all the tricks that can be done
with
a merged stack that avoids the implementation layer, I strongly object
to
this WG allowing standard options that change the standard TCP wire
protocol.
Even if both ends agree to do the "special" processing, other nodes and
protocols generally share these wires and "special" non-standard options
can have nasty indirect effects.  If your custom adapter does things
that
are not changes in the protocol, like always putting an iSCSI request in
a
single segment which allows the other end to fast-path processing, is
an acceptable implementation trick as either end not "knowing" about the
trick will function correctly, although maybe not optimally.

Any changes to the standard TCP must go through end2end, this WG MUST
NOT
allow options that circumvent that process.

	-David