Hi, Mark Thanks for your comment. I like the concept of separating "_address configuration_ methods" and "address aging methods", if we could initiate the subsequence work, it should be considered.
All the best Bing > -----Original Message----- > From: Mark Smith [mailto:markzzzsm...@yahoo.com.au] > Sent: Wednesday, February 27, 2013 4:35 AM > To: Liubing (Leo); ipv6@ietf.org; v6...@ietf.org > Cc: re...@ietf.org > Subject: Re: SLAAC/DHCPv6 addr-conf operational gaps > > Hi, > > I've had a quick read though, I'll try to do a thorough one in the next week > or > so. > > Thanks for writing this, I've been thinking about doing something similar over > the last few months since, IIRC, I heard about Windows 7 invalidating IPv6 > addresses learned via DHCPv6 when SLAAC was enabled and DHCPv6 was > disabled on a link. > > A few thoughts I've had which may be useful - > > Firstly, I came to realise that the mistake being made by Windows 7 was the > assumption that the aging of the assigned IPv6 addresses was tightly coupled > to the DHCPv6 session state, meaning that if DHCPv6 went away, so would > the assigned addresses. This is generally the way DHCPv4 has worked. > However, in IPv6/DHCPv6, it seems the address lifetime values in the IA_NA > are not coupled to the T1 and T2 times, so if DHCPv6 goes away (perhaps > because the M bit was switched off in a latter RA), the configured IPv6 > addresses should be left to age out as per their preferred and valid > lifetimes. > > The other thing I noticed was that the M RA flag and the PIO A flags aren't > mutually exclusive - I couldn't find any text in RFC4861 that says if the M > bit > is switched on, the PIO A flags must be switched off and vice-versa. So that > suggests that the DHCPv6 and SLAAC can co-exist, and I think that is quite > reasonable if you're transitioning a link from DHCPv6 to SLAAC address > configuration or vice-versa. > > Thinking about it more, I came realise that DHCPv6 and SLAAC are _address > configuration_ methods, but are not address aging methods - IPv6 takes care > of address aging via it's preferred and valid aging mechanisms, regardless of > the address configuration method. Static assignment is also just an address > configuration method, although typically the addresses don't age out, but > only because they're normally set to infinity. Perhaps in the future there > might be other address configuration methods. > > I didn't seem to be able to find an RFC that made it clear that address > configuration and address aging are quite separate, so perhaps this ID could > be the one. > > Regarding this text: > > 'For the host behavior, there is an explicit rule in the SLAAC specification > [RFC4862]: "If the Autonomous flag is not set, silently ignore the Prefix > Information option."' > > I think RFC5942, "IPv6 Subnet Model: The Relationship between Links and > Subnet Prefixes." updates that advice, as the PIO option is used to indicates > which prefix/range of addresses are on-link, via the PIO O bit, even if the > PIO > A bit is switched off. > > Best regards, > Mark. > > >________________________________ > > From: Liubing (Leo) <leo.liub...@huawei.com> > >To: "ipv6@ietf.org" <ipv6@ietf.org>; "v6...@ietf.org" <v6...@ietf.org> > >Cc: "re...@ietf.org" <re...@ietf.org> > >Sent: Tuesday, 26 February 2013 6:14 PM > >Subject: SLAAC/DHCPv6 addr-conf operational gaps > > > >Hi, 6man & v6ops > > > >We submitted a new draft to discuss the SLAAC/DHCPv6 interaction gaps. > > > >As we know there are several flags in RA messages regarding with the host > configuration behavior, which are A (Autonomous) flag, M (Managed) flag, > and O (Otherconfig) flag. > >For some reason, the host behavior of interpreting the flags is ambiguous in > the standard (mainly RFC4862). I presented a draft discussing M flag > behavior in 6man @ietf84, and there were some feedbacks arguing the same > issue. This draft analyzed all the three flags, and provided test result of > current implementations, it showed the behavior of different mainstream > desktop OSes have varied. The ambiguous and variation might cause > operational problems, such as renumbering (used to discuss in 6renum WG > and been documented in the WG drafts), cold start problem, and > management gaps .etc. > > > >Your review and comments would be appreciated very much. > > > >All the best, > >Bing > > > >> -----Original Message----- > >> From: internet-dra...@ietf.org [mailto:internet-dra...@ietf.org] > >> Sent: Monday, February 25, 2013 5:52 PM > >> To: Liubing (Leo) > >> Cc: rbon...@juniper.net > >> Subject: New Version Notification for > >> draft-liu-bonica-dhcpv6-slaac-problem-01.txt > >> > >> > >> A new version of I-D, draft-liu-bonica-dhcpv6-slaac-problem-01.txt > >> has been successfully submitted by Bing Liu and posted to the > >> IETF repository. > >> > >> Filename: draft-liu-bonica-dhcpv6-slaac-problem > >> Revision: 01 > >> Title: DHCPv6/SLAAC Address Configuration Interaction > Problem > >> Statement > >> Creation date: 2013-02-25 > >> Group: Individual Submission > >> Number of pages: 12 > >> URL: > >> > http://www.ietf.org/internet-drafts/draft-liu-bonica-dhcpv6-slaac-problem- > >> 01.txt > >> Status: > >> http://datatracker.ietf.org/doc/draft-liu-bonica-dhcpv6-slaac-problem > >> Htmlized: > >> http://tools.ietf.org/html/draft-liu-bonica-dhcpv6-slaac-problem-01 > >> Diff: > >> > http://www.ietf.org/rfcdiff?url2=draft-liu-bonica-dhcpv6-slaac-problem-01 > >> > >> Abstract: > >> This document analyzes the host behavior of DHCPv6/SLAAC > interaction > >> issue. It reviews the standard definition of the host behaviors and > >> provides the test results of current mainstream implementations. > Some > >> potential operational gaps of the interaction are also described. > >> > >> > >> > >> > >> The IETF Secretariat > > > >-------------------------------------------------------------------- > >IETF IPv6 working group mailing list > >ipv6@ietf.org > >Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 > >-------------------------------------------------------------------- > > > > > > -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
