Network Working Group                                          J. Postel
Request for Comments: 128                                           UCLA
Category: C.2, D.                                       Computer Science
NIC #5844                                                     21 April 71
Obsoletes: none
Updates: none


                                BYTES

  It is somewhat unclear what to do with the Byte size parameter now
  allowed by the 2nd level protocol.  I can conceive of an
  implementation in which the 3rd level programs never see this
  parameter.  Crocker implies in RFC 123 that control of this parameter
  is given to the 3rd level programs and that both sender and receiver
  may specify values of the byte size to the NCP.

  There are at least two interpretations if the sender and receiver
  specify different byte sizes.

  I.  The first is that the connection is illegal.

  II.  The second is that the NCP must parse the data stream on receipt
      from the network and into a buffer according to be byte size of
      the sender, and subsequently parse the data stream on transfer
      from the buffer to the receiver.  In this second case there are
      two sub cases.

      A. One is to consider bits as the basic unit.

         For example, if the sender specified byte size = 5 and the
         receiver specified byte size = 3 then

         Receiver                   NCP                    Sender
         -+---+---+---+---+      +--------+      +-----+-----+---
          |000|001|010|011| <--- | Buffer | <--- |00000|10100|11
         -+---+---+---+---+      +--------+      +-----+-----+---


      B. The other is to consider bytes as the significant unit and pad
         (on the right or left?) or truncate to make things fit, or
         other transformation.

  At UCLA-Computer Science we are contemplating allowing sender and
  receiver to specify different byte sizes and consider bits as the
  basic unit (Case II.A.).  This does not rule out our considering the
  second subcase (Case II.B.).  We may allow 3rd level programs to
  specify a library or user supplied routine to perform the



Postel                                                          [Page 1]

RFC 128                          Bytes                        April 1971


  transformation between sender and receiver bytes.  Perhaps these
  transformation routines would be written in the Data Reconfiguration
  Language.

        [ This RFC was put into machine readable form for entry ]
           [ into the online RFC archives by Duncan de Waal 03/98 ]













































Postel                                                          [Page 2]