Subject: [MEXT] [mext] #12: BErr sent by HA too, not only by CN [Alexandru Petrescu <[email-masked]>]

From: "mext" <[email-masked]>
Date: Fri, 11 Jul 2008 16:39:33 -0000

Ticket #12: BErr sent by HA too, not only by CN  [Alexandru Petrescu
<[email-masked]>]

 [see also previous discussion as part of issue #3]

 Vijay Devarapalli  <[email-masked]>:

    ...           This email is about the HA sending binding error
 messages.

 RFC 3775 already supports the HA sending Binding Error with
 status '2'.

 Section 9.2 (CN considerations section) says

     o  The MH Type field MUST have a known value (Section 6.1.1).
        Otherwise, the node MUST discard the message and issue a Binding
        Error message as described in Section 9.3.3, with Status field set
        to 2 (unrecognized MH Type value).

 Section 10.2 (HA considerations section) says

     All IPv6 home agents MUST observe the rules described in Section 9.2
     when processing Mobility Headers.

 So I think we should make the change Alex has suggested for
 the Binding Error message at
 http://www.ietf.org/mail-archive/web/mext/current/msg00374.html

 There is still an issue about whether the home agent is also
 allowed to send the Binding Error message with status '1'. This
 is not clear in RFC 3775. From what I remember, this was
 designed mainly for the CN to tell the MN that there is no
 binding cache entry if the MN sends a packet with the home
 address option to the CN thinking it already has a binding at
 the CN. IMO, the home agent has no use for this. In fact RFC
 3775 already says packets received with home address option
 without a corresponding binding cache entry should be silently
 dropped unless the packet contains a binding update. This was
 pointed out by Ahmad in
 http://www.ietf.org/mail-archive/web/mext/current/msg00495.html

 ---------------------------------------------------------------------

 Brian Haley <[email-masked]>

 I would change <the> last sentence to say:

     Binding Error

        The Binding Error is used by the correspondent node or the home
        agent to signal an error related to mobility, such as an
        inappropriate attempt to use the Home Address destination option
        without an existing binding, or when an unrecognized Mobility
        Header is received.

 ---------------------------------------------------------------------

 Alexandru Petrescu  <[email-masked]>

 I agree, at least one goal for HA to send the BErr is when the HA
 received and MH which it doesn't understand.  Like "when an unrecognized
 Mobility Header Type is received (section 9.2 second bullet)".  This is
 what I implemented.

 As for HA sending BErr when there's no BC entry for the HoA in a DO, it
 may be worth implementing at HA (in addition to CN), or I can live
 without.

 ---------------------------------------------------------------------

 Julien Laganier <[email-masked]>

 ...  As of now it seems we have consensus on
 modifying the description of Binding **Error** as below ...

 OLD TEXT:

    Binding Error

    The Binding Error is used by the correspondent node to signal an
    error related to mobility, such as an inappropriate attempt to use
    the Home Address destination option without an existing binding.

 NEW TEXT:

    Binding Error

    The Binding Error is used by the correspondent node or the home
    agent to signal an error related to mobility, such as an
    inappropriate attempt to use the Home Address destination option
    without an existing binding, or when an unrecognized Mobility
    Header is received.

 ---------------------------------------------------------------------

----------------------------------------+-----------------------------------
 Reporter:  [email-masked]       |       Owner:  [email-masked]
     Type:  defect                      |      Status:  new                  
 Priority:  minor                       |   Milestone:                       
Component:  draft-ietf-mext-rfc3775bis  |     Version:                       
 Severity:  Active WG Document          |    Keywords:  Binding Error        
----------------------------------------+-----------------------------------
-- 
Ticket URL: <http://wiki.tools.ietf.org/wg/mext/trac/ticket/12>
mext <http://tools.ietf.org/wg/mext/>
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