RADIUS attribute from rfc8045

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IP-Port-Range-Start

The format of IP-Port-Range-Start TLV is shown in Figure 12.  This
   attribute carries IPFIX Information Element 361, "portRangeStart",
   which is the smallest port number of a range of contiguous transport
   ports (refer to ).

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    TLV-Type   |     Length    |         portRangeStart
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
             portRangeStart        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 12

   TLV-Type

      9

   Length

      Six octets

   portRangeStart

      Integer.  This field contains the data (unsigned16) of
      portRangeStart (361) defined in IPFIX, right justified, and unused
      bits MUST be set to zero.

   IP-Port-Range-Start TLV is included as part of the IP-Port-Range
   Attribute (refer to), identified as 241.6.9.

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