Subject: [mobile-ip] closing mipv6 issue #273 (cn becomes ha; ha becomes cn)

From: Jari Arkko <[email-masked]>
Date: Fri, 11 Apr 2003 08:49:00 +0300

Here's a proposal to close issue #273, what to do
if CN becomes a HA or the other way around.

In IETF-56, the consensus was that this is an issue, and that if the
peer refuses to make the transition, it should send an error message.
Mike Thomas asked whether it would make sense to allow CN->HA
transitions. In principle yes, but I'd like to avoid that if at all
possible, because it would create a special case in the text.

The proposed text changes are:

Add a new status code in Section 6.1.8 (BA):

     139  Registration type change disallowed

Add the following to Section 9.5.1 (BU processing):

    If a binding already exists for the given home address, and the its
    home registration flag has a different value than the Home
    Registration (H) bit in the Binding Update, then the receiving node
    MUST send back a Binding Acknowledgement with status code 139 (registration
    type change disallowed).

Also change the paragraph about the silent discard as follows:

    For packets carrying Binding Updates that fail to satisfy all of
    these tests for any reason other than insufficiency of the Sequence
    Number, registration type change, or expired nonce index values
    MUST be silently discarded.

My understanding is that we don't need to change the mobile node
section due to this. Mobile nodes have BULs and should not change the
type of registration just like that.