RADIUS attribute from rfc6572


The PMIP6-Visited-HN-Prefix attribute (Type value 152) 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 MNand the MAG.  The MN configures its IP interface from its home
   network prefix(es).  When the LMA is located in the visited network,
   the PMIP6-Visited-HN-Prefix attribute is used to deliver the MN-HNP
   from the VAAA to the MAG.

   The PMIP6-Visited-HN-Prefix attribute is also used on the LMA-to-VAAA
   interface containing the IPv6 prefix assigned to the MN.  If the LMA
   delegates the assignment of the MN-HNP to the VAAA, the attribute
   MUST contain an address of all zeroes (i.e., '::') in the RADIUS
   Access-Request message.  The attribute MUST be present in Access-
   Accept message if the prior request already included one and SHOULD
   carry the MN-HNP the VAAA assigned to the MN.

   The attribute SHOULD NOT be included if the use of LMA in the home
   network is authorized (the PMIP6-Home-HN-Prefix and/or PMIP6-Home-
   LMA-IPv6-Address attributes are already present).  However, if the
   VAAA local policy allows both home and visited LMA addresses to be
   delivered to the MAG, then this attribute MAY also be included.

    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 |
   |                       Visited MN-HNP
                           Visited MN-HNP
                           Visited MN-HNP
                           Visited MN-HNP                          |

      PMIP6-Visited-HN-Prefix 152.

      = 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 Visited MN-HNP (at least 0 and no larger than 128).  If
      the visited home network prefix contains an address of all zeroes
      (i.e., '::'), then the Prefix-Length MUST be set to 128.Visited 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.