[MOBILE-IP] Private addresses

[Raffaele Pellicciotta <[e-mail]>]

Hi, I desire to have information about use of private addresses on Mobile IP!!!
    What is its state of art?
    Thanks a lot,
        Raffaele

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   A.4. Requirements for Limited Private Address Support


      10.10.1.2
     |----|                        IF1=COA1|-------|        HAA2   |-----|
     | MN1|--------------------------------|  FA   |---------------| HA2 |
     |----|                      |---------|       |               |-----|
                                 | IF2=COA2|-------|
                  |--------------|         |
                  |                        |
               |-----|                     |
               | MN2 |                     |
               |-----|                     |
                10.10.1.2                  |
                                           | HAA1
                                        |------|
                                        | HA1  |
                                        |------|

             Figure:  ??

   The above figure X presents a possible scenario for private address
   deployment.  In this simple private address deployment scenario, only
   mobile node home addresses are  private addresses. Private addresses
   are strictly those defined in RFC1918. The foreign agent FA has publicly
   routable addresses on all of it's advertising interfaces. In the above
   scenario, FA advertises COA1 and COA2 on two different advertising
   interfaces. Similarly both HA2 and HA1 have publicly routable home agent
   addresses. COA1 and COA2 are topologically connected with HAA1 and HAA2
   respectively, i.e, it's possible that HAA1 is reachable via a physical
   interface other than IF1 from the foreign agent, but the tunnels between FA
   and HA1 are configured using COA1 and HAA1 addresses.
   Also, note that two different mobile-nodes with same private address
   are visiting the same FA.

   Requirements for the above private address scenario:

   Mobile node requirements:
        Mobile nodes (MN) intending to use private address mobile-ip
        MUST use the 'T' bit and employ reverse tunneling. Mobile node's
        private addresses within a given address space MUST be unique.
        Thus two mobile nodes belonging to single home agent cannot
        have overlapping private addresses. In this scenario the mobile-
        nodes always remain outside their home network. If the mobile node
        happens to register with multiple home agents simultaneously through
        the same foreign agent and through the same link, then the mobile node
        MUST use unique home address for each connection to the home agents.

  Foreign agent requirements:
        All advertising interfaces of the foreign agent MUST have publicly
        routable Care Of Addresses (COA). Thus a MN with a private address
        visits the foreign agent only in it's publicly routable network.

        Foreign agent MUST support reverse tunneling in order to support
        private addressed mobile-nodes. (Q: Should it reject a registration
        request with turned off 'T' bit from a private addressed MN ? )
        For simplicity of implementation, foreign agent may not support
        overlapping private  addressed mobile nodes per link. Foreign agent
        MUST disambiguate among overlapping private addressed mobile nodes
        (see figure X) in both direction of packet delivery by using link
        layer information like GRE key id, interface identifier and others
        listed previously (Appendix section A.2 and A.3). A foreign agent
        in absence of route optimization, should make sure that two mobile
        nodes visiting the same foreign agent corresponds with each other
        through their respective home agents.

        If a foreign agent supports reverse tunneling and is able to process
        'T' bit in the registration request, then it MUST support the simple
        scenario of private address support described in this section.

  Home agent requirements:

        Home agent address which is used by the mobile node for registration
        request MUST be a publicly routable address. Home agent will not
        support overlapping private home addresses, thus each private home
        address of a mobile node registered with a home agent is unique.
        When 'T' bit is set in the registration request from the mobile node,
        Home agent MUST recognize and accept registration request from mobile
        nodes with private addresses and the home agent should also be able to
        assign private addresses as home address from it's address pool.
        This does not contravene home agent processing in section 3.8 of
        RFC2002-bis.