I've been editing a new version of rfc2462bis, mainly addressing AD comments, and I found one minor issue in Section 5.5.3 (creation of global addresses using RA):
According to rfc2462bis-06, step (d) of the procedure can be represented as follows: d-1 check whether the prefix in RA is equal to the prefix of an address stateless autoconfiguration in the address list d-2 if not, do some sanity checks, and form an address by concatenating the prefix with the interface identifier d-3 add the new address to the list But what if an address identical which is not configured by stateless autoconfiguration (i.e., either manually or by DHCPv6) happens to be identical to the address being configured? The check in d-1 cannot detect this since it only checks the prefix of a stateless-autoconfigured address (note that this restriction is one of rfc2462bis clarifications based on the wg consensus). A naive implementation would configure duplicated addresses, which should not be the appropriate behavior (I actually made this mistake in my initial attempt of implementing rfc2462bis). Original RFC2462 also seems to have this issue, while the point is vaguer due to its own unclear wording. Such conflict should be rare, but I believe it makes sense to note this explicitly in rfc2462bis. The appropriate behavior in this case might also be controversial, but I think the natural reaction is to simply avoid configuring the duplicate address. So, I'd like to propose to revise the last paragraph of bullet (d) of Section 5.5.3 from: If an address is formed successfully, the host adds it to the list of addresses assigned to the interface, initializing its preferred and valid lifetime values from the Prefix Information option. to: If an address is formed successfully and the address is not yet in the list, the host adds it to the list of addresses assigned to the interface, initializing its preferred and valid lifetime values from the Prefix Information option. Note that the check against the prefix performed at the beginning of this step cannot always detect the address conflict in the list. It could be possible that an address already in the list, configured either manually or by DHCPv6, happens to be identical to the newly created address whereas such a case should be atypical. Comments? JINMEI, Tatuya Communication Platform Lab. Corporate R&D Center, Toshiba Corp. [EMAIL PROTECTED] -------------------------------------------------------------------- IETF IPv6 working group mailing list [EMAIL PROTECTED] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------