RFC 442 (rfc442) - Page 1 of 7

Current flow-control scheme for IMPSYS

Alternative Format: Original Text Document
Next >
Network Working Group                                            V. Cerf
Request for Comments: 442                                24 January 1973
NIC: 13774


               The Current Flow-Control Scheme for IMPSYS

   BB&N quarterly report #13 outlines part of the current flow control
   scheme in the IMP operating system.  A meeting held March 16, 1972,
   at BB&N was devoted to the description of this new scheme for the
   benefit of interested network participants.

   This note represents my understanding of the flow control mechanism.
   The essential goal is to eliminate unnecessary retransmissions when
   the load is heavy, eliminate the retransmission time-out period when
   the load is light, increase bandwidth, prevent re-assembly lock-up,
   control traffic from HOSTS into the net more strictly than the
   earlier link blocking method, and secure the rights of life, liberty,
   and the pursuit of happiness for ourselves and our posterity,...oops.

Source IMP-to-Destination IMP Protocol

   There are two different protocols depending on message length (i.e.
   single or multi-packet).  We illustrate first the single packet case.

          Source Imp                        Destination Imp
          ----------                        ---------------

case 1)   message (1) + implicit req (1)--->
                                         no room, don't respond
                                        
          [discard copy of msg]
Next >