RADIUS attribute from rfc5904

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PKM-SAID

The PKM-SAID Attribute is of type string .  It is 4
      octets in length and contains a PKM Security Association
      Identifier (, Section 11.9.7).  It MAY be
      included in an Access-Request message.

   A summary of the PKM-SAID Attribute format is shown below.  The
   fields are transmitted from left to right.

                        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     |      Len      |            SAID               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      141 for PKM-SAID

   Len

      4

   SAID

      The SAID field is two octets in length and corresponds to the
      Value field of the 802.16 PKM SAID attribute

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