RADIUS attribute from rfc6572


The PMIP6-Home-HN-Prefix attribute (Type value 151) is of type IPv6
   prefix.  It contains the Mobile Node - Home Network Prefix (MN-HNP),
   which is the IPv6 prefix assigned to the link between the MN and the
   MAG.  The MN configures its IP interface from its home network
   prefix(es).  When the LMA is located in the home network, the PMIP6-
   Home-HN-Prefix attribute is used to deliver the MN-HNP from the HAAA
   to the MAG.The PMIP6-Home-HN-Prefix attribute is also used on the LMA-to-HAAA
   interface containing the prefix assigned to the MN.  If the LMA
   delegates the MN-HNP assignment to the HAAA, the attribute MUST
   contain all zeroes in the address of (i.e., '::') the Access-Request
   message.  The attribute MUST be present in the RADIUS Access-Accept
   message if the prior request already included one and SHOULD carry
   the MN-HNP the HAAA assigned to the MN.

    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   |    Reserved     | Prefix-Length |
   |                        Home MN-HNP
                            Home MN-HNP
                            Home MN-HNP
                            Home MN-HNP                            |

      PMIP6-Home-HN-Prefix 151.

      = at least 4 and no larger than 20.

      Reserved for future use.  The bits MUST be set to zero by the
      sender and MUST be ignored by the receiver.

      The 8-bit unsigned integer indicating the prefix length of
      the home network prefix (at least 0 and no larger than 128).
      If the home network prefix contains an address of all zeroes
      (i.e., '::'), then the Prefix-Length MUST be set to 128.

   Home Network Prefix:
      The home network prefix for the MN's IPv6 address configuration.
      The Prefix field is up to 16 octets in length.  Bits outside of
      the Prefix-Length, if included, must be zero.