2013-02-02 12:46, Brian E Carpenter <brian.e.carpen...@gmail.com> : ... >> IMHO The only combination that has operational value for the purpose of >> mapping IPv6 address to MAC today is: >> u==1 && g==0 && (concatenated with unicast IPv6/64 prefix[2000::/3] || >> link local address [fe80::/10]) && SLAAC (RFC4862) >> >> We've never had this sort of reverse mapping in IPv4, and "sh arp" on >> the local router was generally considered good enough operationally >> speaking. >> I 'd presume "show ipv6 neighbor binding" would also suffice. > > Maybe, but every little helps.
I support that IIDs that have u=1 MAY be used to extract some meaningful information, doing it or not remaining a vendor choice. Pending any new IID reservations, what is possible is AFAIK the following: - At an Ethernet interface, if an assigned IID has u=1, u=0, bits 24-39 = 0xFE, and OUI bits 0-24 aren't 00-00-5E (the IANA OUI, ref https://tools.ietf.org/html/rfc5342#section-1.2.1), then the MAC address should be that of IID bits 0-23 followed by bits 40-127. If the 4rd reserved IID prefix is confirmed to be 0x0300, this is complemented with the following: - At a customer site entry that is assigned an IPv6 prefix up to /64, if an destination IID starts with 0x0300, then IID bits 16-47 should be those of a global IPv4 address usable in this site, exclusively or shared depending on which 4rd CE mapping rule applies to the site. In addition, IID bits 48-64 should be the opposite of the one's complement sum of the five 16-bit fields from address bits 0-79. Regards, RD -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
