NAME

MN-3-3-1-1-002 - Use the old router when the old router is reachable


TARGET

Host


TOPOLOGY

                    
                                  |
                                  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  


INITIALIZATION

 1. Selection Option
    - none.
 2. Position of Mobile Node
       HA0     NUT0     R1      R2      CN0
        |       |       |       |        |
        | ----> |       |       |        | 1.Router Advertisement
        |       |       |       |        |
        |      NUTX     |       |        |
        |       |       |       |        |
        |       | <---- |       |        | 2.Router Advertisement
        |       |       |       |        |
        | <---- |       |       |        | 3.Neighbor Solicitations(NUD)
        |       |       |       |        | 4.(no reply)
        |       |       |       |        |
        | <---- |       |       |        | 5.Binding Update
        | ----> |       |       |        | 6.Binding Acknowledgement
        |       |       |       |        |
                    
        1. Send Router Advertisement. (HA0 -> HA0_allnode_multi)
        2. Send Router Advertisement. (R1 -> R1_allnode_multi)
        3. Receive Neighbor Solicitations(NUD). (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)


TEST PROCEDURE

                    
       HA0     NUTX     R1      R2      CN0
        |       |       |       |        |
        |       | <---- |       |        | 1.Router Advertisement
        |       |       |       |        |
        |       | <------------ |        | 2.Router Advertisement
        |       |       |       |        |
        |       | ----> |       |        | 3.Neighbor Solicitations(NUD)
        |       | <---- |       |        | 4.Neighbor Advertisement
        |       |       |       |        |
        |       |       |       |        | 5.(wait) (*1)
        |       |       |       |        |
                    
        1. Send Router Advertisement. (R1 -> R1_allnode_multi)
        2. Send Router Advertisement. (R2 -> R2_allnode_multi)
        3. Receive Neighbor Solicitations(NUD). (NUTX -> R1)
        4. Send Neighbor Advertisement. (R1 -> R1_allnode_multi)
        5. (wait)
                    


JUDGEMENT

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


REFERENCE

                    
(draft-ietf-mobileip-ipv6-24.txt)
                    
11.5.1 Movement Detection
                    
(snip)
                    
   Due to the temporary packet flow disruption and signaling overhead
   involved in updating mobility bindings, the mobile node should avoid
   performing an L3 handover until it is strictly necessary.
   Specifically, when the mobile node receives a Router Advertisement
   from a new router that contains a different set of on-link prefixes,
   if the mobile node detects that the currently selected default router
   on the old link is still bi-directionally reachable, it should
   generally continue to use the old router on the old link rather than
   switch away from it to use a new default router.