I like your rule7bis algorithm. When RFC3484 was discussed, it was clear that it will need to be revisited over time to cover new types of addresses or new use cases.
- Alain. > -----Original Message----- > From: James Carlson [mailto:[EMAIL PROTECTED] > Sent: Tuesday, October 24, 2006 3:52 PM > To: [email protected] > Subject: address selection and DHCPv6 > > I've done quite a bit of searching over the archives and over > various web resources, but I haven't seen this issue > addressed directly. > Apologies if I've just missed it. > > RFC 3484 ("Default Address Selection for Internet Protocol version 6 > (IPv6)") section 5 gives a set of ordered comparisons for > source address selection. However, missing from this list is > a distinction implied by RFCs 2461 and 2462: some systems may > have a mix of addresses acquired by stateless address > autoconfiguration, stateful > (DHCPv6) configuration, and manual addressing. How are these > distinguished? > > Rule 7 does address the temporary (RFC 3041) addresses, but > what about these other flavors of addresses? Are they > distinguished only by scope? > > Was this issue addressed and intentionally omitted from the > RFC? (If so, I don't see it in the archives.) > > I suspect that some clients may need to distinguish among the > various flavors here. I'd suggest amending Rule 7 to read: > > Rule 7: Prefer stable, public addresses. > If SA is a manually-configured address and SB is automatic or > temporary, then prefer SA. If SA is automatically configured via > stateful (DHCPv6) methods and SB is automatically configured via > stateless methods or temporary, then prefer SA. If SA is > automatically configured via stateless methods and SB is temporary, > prefer SA. > > Similarly, if SB is a manually-configured address and SA is not, > then prefer SB. If SB is stateful and SA is stateless or > temporary, prefer SB. If SB is stateless and SA is temporary, > prefer SB. > > When the application has the "prefer temporary address" flag > enabled, all temporary addresses are (within this rule) elevated in > preference above manually-configured addresses. The other > preferences are unaltered. (In other words, the preference order > with this flag set becomes temporary first, then manual, stateful, > and stateless last.) > > ... or, to simplify, defining a "stability_of_address(A)" > function that can work here. > > -- > James Carlson, KISS Network > <[EMAIL PROTECTED]> > Sun Microsystems / 1 Network Drive 71.232W Vox +1 > 781 442 2084 > MS UBUR02-212 / Burlington MA 01803-2757 42.496N Fax +1 > 781 442 1677 > > -------------------------------------------------------------------- > IETF IPv6 working group mailing list > [email protected] > Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 > -------------------------------------------------------------------- > -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
