RFC 1797 (rfc1797) - Page 1 of 4

Class A Subnet Experiment

Network Working Group                                               IANA
Request for Comments: 1797                                           ISI
Category: Experimental                                        April 1995


                       Class A Subnet Experiment

Status of this Memo

   This document defines an Experimental Protocol for the Internet
   community.  This does not specify an Internet standard of any kind.
   Discussion and suggestions for improvement are requested.
   Distribution of this memo is unlimited.

Discussion

   There appears to be some interest in experimenting with subnetting
   the class A addresses.

   There is some evidence that not all the routing software in use will
   deal correctly with subnetted class A addresses.  It also appears
   that actual use of subnetted class A addresses may be necessary in
   the not too distant future.  It is suggested that conducting an
   experiment now to identify and fix any software that does not
   properly handle subnetted class A addresses would be useful and
   important.

   To further this experiment the IANA will temporarily designate the
   class A network number 39 to be used in the following way:

   The high order octet of the 4-octet IPv4 address is the class A
   network number 39.  There are two cases for low order 24 bits.

   Case 1:

      In the first case, the high order bit of these 24 bits is zero and
      the next 15 bits are the low order 15 bits of a previously
      assigned Autonomous System number (AS), as registered by a network
      registry and listed in the RWhois database system.

      Using the AS number in this way allows the experiment to get
      underway quickly in that it automatically allocates some addresses
      to each service provider and does not require a registration step.

      One concern is that this might cause a run on AS numbers, since by
      getting an AS number you automatically get some address space.
      This concern should be offset by the fact that the amount of
      address space one gets under this plan is the same as one class C



IANA