RADIUS attribute from rfc5447

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MIP6-Feature-Vector

Diameter  reserves AVP Code space 1-255 as RADIUS attribute
   compatibility space.  The MIP6-Feature-Vector attribute (Type value
   124) defined in  is of type OctetString and contains a
   64-bit flags field of supported mobility capabilities.  This document
   reserves two new capability bits according to the rules in ,
   and reuses the PMIPv6 capability bits defined by .  The
   following capability flag bits are used or defined in this document:

   PMIP6_SUPPORTED (0x0000010000000000)

      This capability bit is used as defined in .

   IP4_HOA_SUPPORTED (0x0000020000000000)

      This capability bit is used as defined in .  Assignment
      of the IPv4-HoA (Home Address) is defined by .LOCAL_MAG_ROUTING_SUPPORTED (0x0000040000000000)

      This capability bit is used as defined in .

   IP4_TRANSPORT_SUPPORTED (0x0000800000000000)

      This capability bit is used for negotiation of the IPv4 transport
      support between the MAG and AAA.  When the MAG sets this flag bit
      in the MIP6-Feature-Vector, it indicates the ability of the MAG to
      provide IPv4 transport (i.e., IPv4-based encapsulation) for
      carrying IP traffic between the MAG and the LMA.  If this flag bit
      is unset in the returned MIP6-Feature-Vector attribute, the AAA
      does not authorize the use of IPv4 transport on the MAG-to-LMA
      tunnel.

   IP4_HOA_ONLY_SUPPORTED (0x0001000000000000)

      This capability bit is used for determination of the authorized
      PMIPv6 mobility mode.  When this bit is set by the AAA, it
      indicates PMIPv6 mobility with IPv4 support has only been
      authorized for the MN.  As a result, the RADIUS Access-Accept
      SHOULD NOT carry the IPv6 Home Network Prefix (IPv6 HNP).  When
      this bit is set, the PMIP6_SUPPORTED flag MUST also be set and the
      IP4_HOA_SUPPORTED flag MUST NOT be set.

   To summarize the use of the MIP6-Feature-Vector the following
   capability bit combination settings mean:

      PMIP6-SUPPORTED bit set - only IPv6 mobility is supported and
      authorized.

      PMIP6-SUPPORTED and IP4-ONLY-HOA-SUPPORTED bits set - only IPv4
      mobility is supported and authorized.

      PMIP6-SUPPORTED and IP4-HOA-SUPPORTED bits set - both IPv6 and
      IPv4 mobility are supported and authorized.

   The MIP6-Feature-Vector attribute is also used on the LMA to the
   RADIUS AAA interface.  This capability announcement attribute enables
   direct capability negotiation between the LMA and the AAA.  The
   capabilities that are announced by both parties in the MIP6-Feature-
   Vector are known to be mutually supported.  The LMA may use this
   mechanism during authorization of the received PBU against the AAA to
   check individual PMIPv6 feature permissions for a particular MN.

   If the RADIUS Access-Accept contains a contradicting combination of
   the capability flag bits such as both the IP4_HOA_ONLY_SUPPORTED and
   the IP4_HOA_SUPPORTED flags being set, then the RADIUS client MUSTtreat the Access-Accept as an Access-Reject and SHOULD log the event.
   Similarly, if the RADIUS Access-Request contains a contradicting
   combination of the capability flag bits, then the RADIUS server MUST
   reply with an Access-Reject message and SHOULD log the event.

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