RFC 3078 (rfc3078) - Page 2 of 12

Microsoft Point-To-Point Encryption (MPPE) Protocol

RFC 3078                     MPPE Protocol                    March 2001


   MPPE session keys are changed frequently; the exact frequency depends
   upon the options negotiated, but may be every packet.

   MPPE is negotiated within option 18 [4] in the Compression Control
   Protocol.

2.  Configuration Option Format


   Description

      The CCP Configuration Option negotiates the use of MPPE on the
      link.  By default (i.e., if the negotiation of MPPE is not
      attempted), no encryption is used.  If, however, MPPE negotiation
      is attempted and fails, the link SHOULD be terminated.

   A summary of the CCP Configuration Option format is shown below.  The
   fields are transmitted from left to right.

       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     |        Supported Bits         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Supported Bits         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      18

   Length

      6

   Supported Bits

      This field is 4 octets, most significant octet first.

         3                   2                   1
       1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |             |H|                               |M|S|L|D|     |C|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+







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