RFC 907
     
     
     
     
     
     
                    HOST ACCESS PROTOCOL SPECIFICATION
     
     
     
                                 July 1984
     
     
     
     
     
     
     
     
                               prepared for
     
                 Defense Advanced Research Projects Agency
                           1400 Wilson Boulevard
                         Arlington, Virginia 22209
     
     
     
     
     
     
     
     
                                    by
     
                   Bolt Beranek and Newman Laboratories
                             10 Moulton Street
                      Cambridge, Massachusetts 02238
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     RFC 907                                      Host Access Protocol
     July 1984                                           Specification
     
     
     
     Preface (Status of this Memo)
     
          This document specifies  the  Host  Access  Protocol  (HAP).
     Although  HAP was originally designed as the network-access level
     protocol for the DARPA/DCA sponsored  Wideband  Packet  Satellite
     Network,  it is intended that it evolve into a standard interface
     between hosts and  packet-switched  satellite  networks  such  as
     SATNET  and  TACNET (aka MATNET) as well as the Wideband Network.
     The HAP specification presented here is a minor revision of,  and
     supercedes,  the  specification  presented  in  Chapter  4 of BBN
     Report No. 4469, the  "PSAT  Technical  Report".   As  such,  the
     details  of  the  current  specification  are  still most closely
     matched to the characteristics if the Wideband Satellite Network.
     Revisions  to  the  specification  in the "PSAT Technical Report"
     include  the  definition  of  three  new  control  message  types
     (Loopback Request, Link Going Down, and NOP), a "Reason" field in
     Restart Request control messages, new Unnumbered Response  codes,
     and  new  values  for  the setup codes used to manage streams and
     groups.
     
          HAP is an experimental protocol, and  will  undergo  further
     revision as new capabilities are added and/or different satellite
     networks  are  supported.   Implementations  of  HAP  should   be
     performed  in coordination with satellite network development and
     operations personnel.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     RFC 907                                      Host Access Protocol
     July 1984                                           Specification
     
     
     
                             Table of Contents
     
     
     
     
     1   Introduction.......................................... 1
     2   Overview.............................................. 3
     3   Datagram Messages..................................... 8
     4   Stream Messages...................................... 14
     5   Flow Control Messages................................ 17
     6   Setup Level Messages................................. 24
     6.1   Stream Setup Messages.............................. 32
     6.2   Group Setup Messages............................... 44
     7   Link Monitoring...................................... 58
     8   Initialization....................................... 62
     9   Loopback Control..................................... 68
     10   Other Control Messages.............................. 72
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
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     RFC 907                                      Host Access Protocol
     July 1984                                           Specification
     
     
     
                                  FIGURES
     
     
     
     
     DATAGRAM MESSAGE.......................................... 9
     STREAM MESSAGE........................................... 15
     ACCEPTANCE/REFUSAL WORD.................................. 19
     ACCEPTANCE/REFUSAL MESSAGE............................... 21
     UNNUMBERED RESPONSE...................................... 22
     SETUP MESSAGE HEADER..................................... 26
     NOTIFICATION MESSAGE..................................... 29
     SETUP ACKNOWLEDGMENT..................................... 31
     STREAM EXAMPLE........................................... 33
     CREATE STREAM REQUEST.................................... 35
     CREATE STREAM REPLY...................................... 37
     CHANGE STREAM PARAMETERS REQUEST......................... 39
     CHANGE STREAM PARAMETERS REPLY........................... 41
     DELETE STREAM REQUEST.................................... 42
     DELETE STREAM REPLY...................................... 43
     GROUP EXAMPLE............................................ 45
     CREATE GROUP REQUEST..................................... 47
     CREATE GROUP REPLY....................................... 48
     JOIN GROUP REQUEST....................................... 50
     JOIN GROUP REPLY......................................... 52
     LEAVE GROUP REQUEST......................................