RFC 952 (rfc952) - Page 2 of 6

DoD Internet host table specification

RFC 952                                                     October 1985
DOD INTERNET HOST TABLE SPECIFICATION


   host table described herein each address is represented by four
   decimal numbers separated by a period.  Each decimal number
   represents 1 octet.

   3. If the first bit of the first octet of the address is 0 (zero),
   then the next 7 bits of the first octet indicate the network number
   (Class A Address).  If the first two bits are 1,0 (one,zero), then
   the next 14 bits define the net number (Class B Address).  If the
   first 3 bits are 1,1,0 (one,one,zero), then the next 21 bits define
   the net number (Class C Address) [See RFC-943].

      This is depicted in the following diagram:

      +-+------------+--------------+--------------+--------------+
      |0|  NET  |         LOCAL ADDRESS                |
      +-+------------+--------------+--------------+--------------+

      +---+----------+--------------+--------------+--------------+
      |1 0|      NET          |  LOCAL ADDRESS        |
      +---+----------+--------------+--------------+--------------+

      +-----+--------+--------------+--------------+--------------+
      |1 1 0|            NET                 | LOCAL ADDRESS|
      +-----+--------+--------------+--------------+--------------+

   4. The LOCAL ADDRESS portion of the internet address identifies a
   host within the network specified by the NET portion of the address.

   5. The ARPANET and MILNET are both Class A networks.  The NET portion
   is 10 decimal for ARPANET, 26 decimal for MILNET, and the LOCAL
   ADDRESS maps as follows: the second octet identifies the physical
   host, the third octet identifies the logical host, and the fourth
   identifies the Packet Switching Node (PSN), formerly known as an
   Interface Message Processor (IMP).

      +-+------------+--------------+--------------+--------------+
      |0|  10 or 26  |    HOST      | LOGICAL HOST |   PSN (IMP)  |
      +-+------------+--------------+--------------+--------------+

      (NOTE:  RFC-796 also describes the local address mappings for
      several other networks.)

   6. It is the responsibility of the users of this host table to
   translate it into whatever format is needed for their purposes.

   7. Names and addresses for DoD hosts and gateways will be negotiated
   and registered with the DDN PMO, and subsequently with the NIC,


Harrenstien & Stahl & Feinler