RFC 48 (rfc48) - Page 1 of 18

Possible protocol plateau

Network Working Group                                          J. Postel
Request for Comments: 48                                      S. Crocker
                                                                    UCLA
                                                          April 21, 1970


                      A Possible Protocol Plateau

I. Introduction

   We have been engaged in two activities since the network meeting of
   March 17, 1970 and, as promised, are reporting our results.

   First, we have considered the various modifications suggested from
   all quarters and have formed preferences about each of these.  In
   Section II we give our preferences on each issue, together with our
   reasoning.

   Second, we have tried to formalize the protocol and algorithms for
   the NCP, we attempted to do this with very little specification of a
   particular implementation.  Our attempts to date have been seriously
   incomplete but have led to a better understanding.  We include here,
   only a brief sketch of the structure of the NCP.  Section III gives
   our assumptions about the environment of the NCP and in Section IV
   the components of the NCP are described.

II. Issues and Preferences

   In this section we try to present each of the several questions which
   have been raised in recent NWG/RFC's and in private conversations,
   and for each issue, we suggest an answer or policy.  In many cases,
   good ideas are rejected because in our estimation they should be
   incorporated at a different level.

      A. Double Padding

         As BBN report #1822 explains, the Imp side of the Host-to-Imp
         interface concatenates a 1 followed by zero or more 0's to fill
         out a message to an Imp word boundary and yet preserve the
         message length.  Furthermore, the Host side of the Imp-to-Host
         interface extends a message with 0's to fill out the message to
         a Host word boundary.

         BBN's mechanism works fine if the sending Host wants to send an
         integral number of words, or if the sending Host's hardware is
         capable of sending partial words.  However, in the event that





Postel & Crocker