I've read the draft. Quote: It should be noted that IIDs known or guessed to have been created according to RFC 4941 could be transformed back into MAC addresses, for example during fault diagnosis. For that reason, keeping the "u" and "g" bits in the IID has operational value. Therefore, the EUI-64 to IPv6 IID transformation defined in RFC 4941 MUST be used for all cases where an IID is derived from a MAC address.
Dumb question: I don't get this. 4941 is "privacy extensions for SLAAC" and generates random IIDs with u=0. How can you "transform" a privacy extension for SLAAC IID back to a MAC address? 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. Brian E Carpenter wrote: > Hi, > > We've put this together to address the general question of the > u/g bits in Interface IDs. Discussion is requested. > > Brian + Sheng > > -------- Original Message -------- > Subject: I-D Action: draft-carpenter-6man-ug-00.txt > Date: Fri, 01 Feb 2013 00:10:13 -0800 > From: [email protected] > Reply-To: [email protected] > To: [email protected] > > > A New Internet-Draft is available from the on-line Internet-Drafts > directories. > > > Title : The U and G bits in IPv6 Interface Identifiers > Author(s) : Brian Carpenter > Sheng Jiang > Filename : draft-carpenter-6man-ug-00.txt > Pages : 7 > Date : 2013-02-01 > > Abstract: > The IPv6 addressing architecture defines a method by which the > Universal and Group bits of an IEEE link-layer address are mapped > into an IPv6 unicast interface identifier. This document clarifies > the status of those bits for interface identifiers that are not > derived from an IEEE link-layer address. > > > The IETF datatracker status page for this draft is: > https://datatracker.ietf.org/doc/draft-carpenter-6man-ug > > There's also a htmlized version available at: > http://tools.ietf.org/html/draft-carpenter-6man-ug-00 > > > Internet-Drafts are also available by anonymous FTP at: > ftp://ftp.ietf.org/internet-drafts/ > > _______________________________________________ > I-D-Announce mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/i-d-announce > Internet-Draft directories: http://www.ietf.org/shadow.html > or ftp://ftp.ietf.org/ietf/1shadow-sites.txt > > -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
