RFC 2770 (rfc2770) - Page 2 of 5

GLOP Addressing in 233/8

RFC 2770                GLOP Addressing in 233/8           February 2000


   The MALLOC working group is looking at a specific strategy for global
   multicast address allocation [MADCAP, MASC]. This experiment will
   proceed in parallel. MADCAP may be employed within AS's, if so
   desired.

   This document proposes an experimental method of statically
   allocating multicast addresses with global scope. This experiment
   will last for a period of one year, but may be extended as described
   in section 6.

2. Address Space

   For purposes of the experiment described here, the IANA has allocated
   233/8. The remaining 24 bits will be administered in a manner similar
   to that described in RFC 1797:

       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |      233      |           16 bits AS          |  local bits   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

2.1. Example

   Consider, for example, AS 5662. Written in binary, left padded with
   0s, we get 0001011000011110. Mapping the high order octet to the
   second octet of the address, and the low order octet to the third
   octet, we get 233.22.30/24.

3. Allocation

   As mentioned above, the allocation proposed here follows the RFC 1797
   (case 1) allocation scheme, modified as follows: the high order octet
   has the value 233, and the next 16 bits are a previously assigned
   Autonomous System number (AS), as registered by a network registry
   and listed in the RWhois database system. This allows a single /24
   per AS.

   As was the case with RFC 1797, 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.

3.1. Private AS Space

   The address space mapped to the private AS space [RFC 1930] is
   reserved for future allocation.





Meyer & Lothberg              Experimental