Hi Jinmei, I am wondering whether you are talking about the duplicate address (/128) or duplicate prefix. Let us say, you have an address configured using DHCP with differe IID and if you are using SLAAC using differe IID but same prefix; is this okay?
-Syam ----- Original Message ----- From: <JINMEI Tatuya / [EMAIL PROTECTED]@C#:H (B <[EMAIL PROTECTED]>)> To: <[EMAIL PROTECTED]> Sent: Thursday, December 09, 2004 3:10 PM Subject: [rfc2462bis] a minor nit in creation of global addresses > 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 > -------------------------------------------------------------------- > > -------------------------------------------------------------------- IETF IPv6 working group mailing list [EMAIL PROTECTED] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
