Home Agent Reliability Protocol draft-ietf-mip6-hareliability-00.txt

							Home Agent Reliability
      Protocol
draft-ietf-mip6-hareliability-00.txt



         HA Reliability DT
                              Status

   2006 March DT was formed

   2006 June
       draft-ietf-mip6-hareliability-00.txt was submitted


   Any comments are appreciated.
                    Goal of this work

   No reliability scheme is provided to HA, though
    MIP6 and NEMO rely on home agent availability
       Hardware based solutions are still possible, but a protocol
        based solution is also required


   Providing redundancy and reliability to home agent
    without the mobile node being aware of it

   Two modes are proposed in the draft
       Home Agent Virtual Switch
       Home Agent Hard Switch
           Home Agent Virtual Switch
   Assumptions
       The IPsec states are
                                                                  backup
        synchronized among a
                                          2001::a                 2001::a
        redundancy home agent set
        (HA1 and HA2)                      HA1                     HA2
       The HA address is shared                    2) SA and Binding
                                                    States Exchange
        among the redundancy home
        agent set


   1) MN establishes IPsec SA with       1) BU
    HA and sends BU
   2) HA exchange binding and
    IPsec SA states with backup-HA
   3) When the HA fails, backup-HA
    automatically takes over the    How to synchronize IPsec is out of scope
    failed HA
               Home Agent Hard Switch
   Assumptions
       IPsec SA states are not synchronized
        among a redundancy home agent set                                    backup
       Each HA has distinct IP address            2001::a                   2001::b
   1) MN pre-establishes IPsec SAs with all         HA1                         HA2
    the HAs                                                  3) Binding States
   2) MN sends BU to one of HA as                              Exchange
    RFC3775
   3) Binding States are exchanged among
    HAs
   4) If HA is failed, backup-HA sends a HA          2)BU            5)BU
    switch message to MNs by using the pre-
    established SA.
                                                                                 4)HA switch
   5) MN then re-associates with the backup
    HA by:
       sending BU to backup-HA
       update binding information and tunnel        1) IPsec SA pre-establishment
        end points by trigger of the received HA        to both HAs
        switch message
        Protocol Operation between home agents
                                          (active)
   HELLO messages
       exchange HA information            HA1                     HA2
                                                       HELLO
       heartbeat for failure detection

   Switch Over Req/Rep
    messages                              (active)
       are used by a standby HA to
        become an active HA                 HA1                     HA2
                                                      Switchover
                                                                   (active)
   Switch Back Req/Rep
    messages
       are used by an active HA to                                (active)
        become an inactive HA
       The receiver HA will be active      HA1                      HA2
                                                      SwitchBack
                                           (active)
                      HA Discovery
   For HA virtual switch, it follows bootstrapping
    scheme

   For HA hard switch, MN must acquires multiple HA
    addresses in order to establish SA beforehand.
       Split scenario: MN query DNS SRV records with service
        name and DNS returns multiple HA addresses
       Integrated scenario: DHCP server replies with multiple HA
        addresses.

   No technical changes, but only operational changes
    are described.
               Messages and Options
   New Mobility Header Messages
       Home Agent Hello Request Message
       Home Agent Hello Message
       State Synchronization Request Message
       State Synchronization Message
       Home Agent SwitchOver Request Message
       Home Agent SwitchOver Reply Message
       Home Agent SwitchBack Request Message
       Home Agent SwitchBack Reply Message

   New Mobility Options
       Binding Cache Information Option
       AAA Information Option
       Vendor Specific Information Option .
                    To be addressed

   Which states should be synchronized among HAs
       binding states, AAA information, vendor specific
        information


   Optimized HA switch procedure
       Can MN updates binding states when a HA switch
        message is received, instead of sending BU?
         RFC3776 states that IPsec SA is updated when a BU is
          received
       May need to update draft-ietf-mip6-ha-switch-00.txt
                          Conclusion
   This draft addresses HA reliability solution providing
       Inter HAs messages such as HELLO, SwitchBack, SwichOver
        messages
       State Synchronization scheme
       Failure Detection scheme
       Failure Recovery scheme
       Multiple HA discovery (for Hard Switch Mode only)

   The design team is still working on the solution
       please send comments to MIP6 list!!!