RADIUS attribute from rfc6572

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Mobile-Node-Identifier

The Mobile-Node-Identifier attribute (Type value 145) is of type
   String and contains the mobile node identifier (MN-Identifier), see
   , in a form of a Network Access Identifier (NAI) .
   This identifier and the identifier used for access authentication may
   be different; however, there needs to be a mapping between the two
   identities as specified in.  This attribute
   is used on the interface between the MAG and the AAA server.  The
   Mobile-Node-Identifier attribute is designed for deployments where
   the identity used during network access authentication and the
   identity used for mobility management is decoupled.  It may also be
   the case where the MAG does not have means to find out the MN
   identity that could be used in subsequent PBU and Proxy Binding
   Acknowledgement (PBA) exchanges (e.g., due to identity hiding during
   the network access authentication) or when the HAAA wants to assign
   periodically changing identities to the MN.

   The Mobile-Node-Identifier attribute MAY be returned by the HAAA in
   the RADIUS Access-Accept message that completes a successful
   authentication and authorization exchange between the MAG and the
   HAAA.  The MAG MUST use the received MN-Identifier.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      Type     |   Length      |   Mobile Node Identifier...   ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type:
     Mobile-Node-Identifier 145.

   Length:
      In octets, including Type and Length fields (>= 3).

   Mobile Node Identifier:
      This field is of type String and contains the MN-Identifier
      of the MN to be used in the PBU/PBA exchange.

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