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    RE: [Tsvwg] RE: iSCSI: No Framing

    > Lloyd,
    > On Wed, 06 Feb 2002, Lloyd Wood wrote:
    > > On Wed, 6 Feb 2002, Brian F. G. Bidulock wrote:
    > >
    > > > What is lost by throwing layering out the window?
    > >
    > > modularity, ease of understanding, and portability.
    > Modularity can be acheived without layering.  The entire
    > field of OOAD proves this.
    > Ease of understanding is acheived through accurate
    > interface description.  Again OO shows this.
    > Portability can also be acheived through OO approaches.
    > The classical layering of communications functions
    > into functional groupings is not a necessary condition
    > for any of these benefits.
    Unlike a typical play dough program, this stuff is more like working with
    concrete.  A portion of each application demanding a direct placement
    feature would be included in hardware or intelligent adapters if using FIM
    and TCP, or framing and TCP, for the most part.  SCTP allows layering for
    this "clean modularity" needed if one is to design an adapter that need not
    understand the complexities and structures of every application that desires
    this function.  The adapter interface only needs to understand SCTP and not
    the application.  By using the unordered delivery mode, a shim would be able
    to implement generalized structures for including Direct Data Placement or
    even a full implementation of RDMA.  It would be possible for more elaborate
    interfaces to built upon this foundation, but at least this establishes the
    modularity, ease of understanding, and portability desired, if one is going
    to start working in concrete.
    Unlike the case with FIM and TCP, this would introduce NIC devices that will
    be forever sensitive to even minor changes to structures employed in these
    applications and the desire for this feature does not even begin to end at
    just one application.
    > --brian
    > --
    > Brian F. G. Bidulock


Last updated: Wed Feb 06 14:17:57 2002
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