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Network Working Group                                               IANARequest for Comments: 1797                                           ISICategory: Experimental                                        April 1995Class A Subnet ExperimentStatus 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 CIANA                                                            [Page 1]

RFC 1797               Class A Subnet Experiment              April 1995      network number (and it should be easier to get a single class C      allocated than to get an AS number allocated), and that this is a      limited time experiment so that these addresses will be temporary.      The low order octet of the 4-octet IPv4 address is for local use.      It is expected that an address of this form will be used to      identify a specific publicly accessible Internet host.                +--------+-+-------+--------+--------+                |   39   |0| low 15 bits AS | local  |                +--------+-+-------+--------+--------+   Case 2:      In the second case, the high order bit of these 24 bits is one,      and the remaining 23 bits are assigned by the IANA (currently      reserved for future use).                +--------+-+-------+--------+--------+                |   39   |1| variable prefix + local |                +--------+-+-------+--------+--------+      The general intent is to find a way to assign to experimenters      prefixes of differing lengths so that a variety of experiments can      be conducted with the prefix/local-address boundary at different      points.   It is not intended that either of these address allocation schemes is   the model for how subnetted class A addresses will be actually   allocated in the future.   It is expected, to make the experiment interesting, that some   providers will use these addresses for servers supplying popular   material via the Web or FTP.   For example, if the service provider registered to use AS 690 wished   to use this style of address to provide access to a server of popular   information on local host 7, the address would be:                +--------+--------+--------+--------+                |   39   |    2   |   178  |    7   |                +--------+--------+--------+--------+IANA                                                            [Page 2]

RFC 1797               Class A Subnet Experiment              April 1995   The support for DNS name and address resolution should be provided.   For example, if Alternet wanted to put up a database of interesting   information using the hostname "Interesting.Alter.Net" using the   address 39.2.189.7, they would need to put the name to address   mapping in their name server using the A record        Interesting.Alter.Net. IN A 39.2.189.7   Similarly, the address to name PTR record should be supported        7.189.2.39.IN-ADDR.ARPA. PTR Interesting.Alter.Net.   which means that the 189.2.39 branch of the IN-ADDR tree would be   delegated to Alternet for the purposes of this experiment.   To support this, the 39.IN-ADDR.ARPA branch is delegated to the IANA   to be managed at ISI.  The nameserver for this branch is   IN-ADDR.EP.NET (39.17.199.10).  Participants in this experiment   should contact the administrator of this nameserver to have their   portion of the address space further delegated.  The administrator   for this server can be reached at <aexpreg@isi.edu>.   Another aspect of the testing that should be performed is to have   providers interchange addresses to test the portability of subnetted   class A addresses.  It is not intended that this would be the model   for actual use.      For example, if AS 690 and AS 1800 want to try out routing holes      in each others' allocations within their AS, that should be      encouraged.  That is, suppose AS 690 handed some address of their      addresses to AS 1800, and vice-versa.  This type of testing will      be necessary to see if the addresses can be made portable in      larger sub-A allocations.   This is experiment will be of limited duration and these addresses   may be reassigned to other uses when the experiment is over.   This experiment will begin on 1-May-95.   The current date for the termination of this experiment is 1-Dec-95.IANA                                                            [Page 3]

RFC 1797               Class A Subnet Experiment              April 1995Security Considerations   Security issues are not discussed in this memo.Author's Address   Internet Assigned Numbers Authority (IANA)   Information Sciences Institute   University of Southern California   4676 Admiralty Way, Suite 1001   Marina del Rey, CA 90292-6695   Phone: 1-310-822-1511   EMail: iana@isi.eduIANA                                                            [Page 4]