MN-2-2-1-1-001 - BU accepted (Status = 0)




                                  R       CN0
                                  |        |
                     -----+-------+--------+---------------- LinkZ
                          R2                      NUTY
                          |                         |
                     -----+-------+-----------------+------- LinkY
                                  R1              NUTX
                                  |                 |
                     -----+-------+-----------------+------- LinkX
                         HA0             Node0    NUT0
                          |               |         |
    ----------------------+---------------+---------+------- Link0
Link0 3ffe:501:ffff:100::/64 home link
LinkX 3ffe:501:ffff:102::/64  
LinkY 3ffe:501:ffff:103::/64  
LinkZ 3ffe:501:ffff:104::/64  
HA0(Link0) 3ffe:501:ffff:100:200:ff:fe00:a0a0  
Node0(Link0) 3ffe:501:ffff:100:200:ff:fe00:a3a3  
R1(LinkX) 3ffe:501:ffff:102:200:ff:fe00:a4a4  
R2(LinkY) 3ffe:501:ffff:103:200:ff:fe00:a6a6  
CN0(LinkZ) 3ffe:501:ffff:104:200:ff:fe00:a8a8  


 1. Selection Option
    - home registration Binding Update Retransmissions : YES
 2. Position of Mobile Node
    - none


       HA0     NUT0     R1      R2      CN0
        |       |       |       |        |
        | ----> |       |       |        | 1.Router Advertisement
        |       |       |       |        |
        |      NUTX     |       |        |
        |       |       |       |        |
        |       | <---- |       |        | 2.Router Advertisement
        |       |       |       |        |
        | <---- |       |       |        | 3.Neighbor Solicitations
        |       |       |       |        | 4.(no reply:3 seconds)
        |       |       |       |        |
        | <---- |       |       |        | 5.Binding Update
        | ----> |       |       |        | 6.Binding Acknowledgement
        |       |       |       |        | 7.(wait) (*1)
        |       |       |       |        |
        1. Send Router Advertisement. (HA0 -> HA0_allnode_multi)
        2. Send Router Advertisement. (R1 -> R1_allnode_multi)
        3. Receive Neighbor Solicitations. (NUT0 -> HA0)
        4. (no reply)
            # Wait during a maximum of 3 seconds(RFC2461).
        5. Receive Binding Update. (NUTX -> HA0)
        6. Send Binding Acknowledgement. (HA0 -> NUTX)
            # The Status field is set to 0(Binding Update accepted).
        7. (wait)
            # Wait during enough retransmission timer.
        Packet Format is:
          6. Binding Acknowledgement


 (*1) PASS: HA0 does not receive the retransmitting of Binding Update.


11.7.3 Receiving Binding Acknowledgements
   Upon receiving a packet carrying a Binding Acknowledgement, a mobile
   node MUST validate the packet according to the following tests:
   o  The packet meets the authentication requirements for Binding
      Acknowledgements, defined in Section 6.1.8 and Section 5.  That
      is, if the Binding Update was sent to the home agent, underlying
      IPsec protection is used.  If the Binding Update was sent to the
      correspondent node, the Binding Authorization Data mobility option
      MUST be present and have a valid value.
   o  The Binding Authorization Data mobility option, if present, MUST
      be the last option and MUST not have trailing padding.
   o  The Sequence Number field matches the Sequence Number sent by the
      mobile node to this destination address in an outstanding Binding
   Any Binding Acknowledgement not satisfying all of these tests MUST be
   silently ignored.
   When a mobile node receives a packet carrying a valid Binding
   Acknowledgement, the mobile node MUST examine the Status field as
   o  If the Status field indicates that the Binding Update was accepted
      (the Status field is less than 128), then the mobile node MUST
      update the corresponding entry in its Binding Update List to
      indicate that the Binding Update has been acknowledged; the mobile
      node MUST then stop retransmitting the Binding Update.  In
      addition, if the value specified in the Lifetime field in the
      Binding Acknowledgement is less than the Lifetime value sent in
      the Binding Update being acknowledged, then the mobile node MUST
      subtract the difference between these two Lifetime values from the
      remaining lifetime for the binding as maintained in the
      corresponding Binding Update List entry (with a minimum value for
      the Binding Update List entry lifetime of 0).  That is, if the
      Lifetime value sent in the Binding Update was L_update, the
      Lifetime value received in the Binding Acknowledgement was L_ack,
      and the current remaining lifetime of the Binding Update List
      entry is L_remain, then the new value for the remaining lifetime
      of the Binding Update List entry should be
         max((L_remain - (L_update - L_ack)), 0)
      where max(X, Y) is the maximum of X and Y.  The effect of this
      step is to correctly manage the mobile node's view of the
      binding's remaining lifetime (as maintained in the corresponding
      Binding Update List entry) so that it correctly counts down from
      the Lifetime value given in the Binding Acknowledgement, but with
      the timer countdown beginning at the time that the Binding Update
      was sent.
      Mobile nodes SHOULD send a new Binding Update well before the
      expiration of this period in order to extend the lifetime.  This
      helps to avoid disruptions in communications, which might
      otherwise be caused by network delays or clock drift.
   o  Additionally, if the Status field value is 1 (Accepted but prefix
      discovery necessary), the mobile node SHOULD send a Mobile Prefix
      Solicitation message to update its information about the available
   o  If the Status field indicates that the Binding Update was rejected
      (the Status field is greater than or equal to 128), then the
      mobile node can take steps to correct the cause of the error and
      retransmit the Binding Update (with a new Sequence Number value),
      subject to the rate limiting restriction specified in Section
      11.8.  If this is not done, or it fails, then the mobile node
      SHOULD record in its Binding Update List that future Binding
      Updates SHOULD NOT be sent to this destination.