    Network Working Group                                        A. McKenzie
    Request for Comments #93                                             BBN
    Updates RFC's 66, 80                                        January 1971

                          Initial Connection Protocol

            A review of the Initial Connection Protocol (ICP) first
    described in RFC #66 and restated in RFC #80 has revealed an area of
    ambiguity, which in turn reflects an ambiguity in the Host-Host
    Protocol Document No. 1.  This is the definition of the message sent
    over the connection from "Server socket #1".  In both referenced
    RFC's, the message is defined as "exactly an even 32 bit number".  It
    is not clear, however, whether this 32 bit number is meant to follow
    an eight-bit "message data type" code or not, stemming from the fact
    that the Host-Host Protocol makes provision for such codes but does
    not seem to absolutely demand them.

            Only one implementation of an ICP has been documented in the
    NWG literature - that at UCSB (RFC #74).  The implementers of this ICP
    have apparently interpreted the Host-Host Protocol as demanding a
    message data type code, and therefore do transmit a code of zero.

            Steve Crocker indicates (private communication) that the Host-
    Host Protocol was intended to require a message data type code.  We
    therefore recommend that RFC numbers 66 and 80 be amended to show that
    the "even 32 bit number" is preceded by a message data type code of
    zero (zero is the only code currently defined).

           [ This RFC was put into machine readable form for entry ]
            [ into the online RFC archives by James Thompson 4/97 ]

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