RFC 80 (rfc80) - Page 2 of 9

Protocols and Data Formats

RFC 80                 Protocols and Data Formats        1 December 1970


            1              4                 3          1     1
         +-----+---------------------+---------------+-----+-----+
         | RTS |          US         |      SERV     |  1  |  P  |
         +-----+---------------------+---------------+-----+-----+

         over link 1, where P is the receive link.

      2. The serving process (SERV) may decide to refuse to the call, in
         which case it closes the connection.  If it accepts the call,
         the serving process completes the connection (via an INIT
         system call, hence an STR).

            1           3          1            4
         +-----+----------------+-----+--------------------+
         | STR |      SERV      |  1  |         US         |
         +-----+----------------+-----+--------------------+

      3. When the connection is completed, the user process allocates a
         nominal amount of space to the connection, resulting in the NCP
         sending:

            1     1            4
         +-----+-----+--------------------+
         | ALL |  P  |       SPACE        |
         +-----+-----+--------------------+

         where SPACE is the amount.

      4. The serving process then selects the socket pair it wishes to
         assign this user.  It sends exactly an even 32 bit number over
         the connection.  This even 32 bit number (SS) is the receive
         socket in the serving HOST.  This socket and the next higher
         numbered socket are reserved for the using process.

      5. It then closes the connection.  The serving NCP sends (step 4):

                    4
         +---------------------+
         |         SS          |
         +---------------------+

         on link P, and (step 5):









Harslem, et. al.