RFC 3145 (rfc3145) - Page 2 of 10

L2TP Disconnect Cause Information

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RFC 3145           L2TP Disconnect Cause Information           July 2001


   disconnect information to its peer.  This AVP should be used in
   conjunction with, and not as a replacement for, the L2TP Result and
   Error Code AVPs.

   The PPP Disconnect Cause Code AVP can also be used to provide a
   human-readable disconnect reason to the user.  This AVP should not
   have any effect on either the functioning of the tunnel or the
   functioning of the PPP session; it is for informational and logging
   purposes only.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in BCP 14 [2].

2.  PPP Disconnect Cause Code AVP

   The AVP is valid in the L2TP Call-Disconnect-Notify (CDN) message
   only, and it MUST NOT be marked Mandatory.

   The PPP Disconnect Cause Code AVP is encoded with Vendor ID 0 and an
   Attribute Type of PPP Disconnect Cause Code (46).  The length of the
   Value field MUST be at least 11 octets.  If the length is more than
   11 octets, the additional octets MUST contain a descriptive text in
   UTF-8 [3] format that can be displayed to the user or in a log file.
   The format of the AVP is shown below.

      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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |M|H| rsvd  |      Length       |          Vendor ID          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         Attribute Type        |       Disconnect Code       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |    Control Protocol Number    |   Direction   | Message...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

                  Figure 1: PPP Disconnect Cause Code AVP

   Mandatory (M) bit: MUST be 0.

   Hidden (H) bit: MAY be 1 if the attribute is hidden.

   Length: The length of the entire attribute in octets, expressed as a
   single octet.  The length MUST be at least 11.

   Vendor ID: A two octet value in network byte order; set to 0 to
   indicate that this is an IETF-assigned attribute.




Verma, et al.               Standards Track
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