Some thoughts: As a method of doing globally unique site local addressing:
Assuming aggregability is not an issue within a 'site' sized network, consider generating site local subnet identifiers at the router, based on IEEE EUI-48 identifiers (such as MAC addresses). For example, generate as fec0::/12: 12 bits: fef 48 bits: MAC 4 bits: 0 or subnets or, if we don't want them in fec0::/10 10 bits: fe0 48 bits: MAC 6 bits: 0 or subnets The '0 or subnets' is to allow for the possibility of choosing one EUI-48 on a router and using that to allocate all appropriate subnets. By piggybacking on the existing registration scheme, we generate "unique" site-local subnet ids at the router without needing external registration or administration. Despite the zero-config nature of this, administration on the router is still necessary, both to enable this mode (probably don't want site-local behaviour enabled by default) and to determine whether a router is authoritative for the link. An administrator may wish to configure a multi-router link with the subnet prefix of only one router. An internet-draft describing this in more detail is written and will be submitted in the next day or so. Comments welcome. Another comment on uniqueness: Under IPv6, even an ambiguous prefix is likely to not resolve to an address because of the MAC generated machine id, so the likelihood of collision is lower than might be expected from the prefix. Final thought: Whatever the outcome of the site local discussions, renumbering will remain a serious problem under IPv6, that needs to be considered. Making renumbering easier is a hard problem, but a good solution will help reduce a variety of other problems. -- Andrew White [EMAIL PROTECTED] -------------------------------------------------------------------- IETF IPng Working Group Mailing List IPng Home Page: http://playground.sun.com/ipng FTP archive: ftp://playground.sun.com/pub/ipng Direct all administrative requests to [EMAIL PROTECTED] --------------------------------------------------------------------
