File Transfer and Error Recovery

Network Working Group                                      R. L. Sunberg
Request for Comments: 133                             Harvard University
NIC 6710                                                   27 April 1971
[Categories C.4, C.5, C.6, D.4, D.7, D.7]


                    FILE TRANSFER AND ERROR RECOVERY


1   FILE TRANSFER PROTOCOL

1A   Handshaking

   I think that Mr Bhushan(RFC #114, NIC 5823) is not strict enough in
   his concept of a transaction sequence.  Every transaction should
   prompt a response from its recipient (recall Kalin's crates --
   RFC #60, NIC 4762).  Control should pass back and forth until the
   server terminates.  The server _always_ gets the last word (more on
   error recovery later).

   Some sample interchanges are given.

       User                Server       Comments

       <...>       ==>                  Establish a connection
                   <==     <...>
       <...>    ==>                  Identify self
                   <==     <+>          Ok, ready

       <...>    ==>                  Retrieval request
                   <==              I've got your file
               ==>                  Send it
                   <==     <,><...>     Here's the first part
               ==>                  Got it
                   <==     <+>          All done

       <...>    ==>                  Store request
                   <==              Ok, go ahead