RFC 3145 (rfc3145) - Page 1 of 10


L2TP Disconnect Cause Information



Alternative Format: Original Text Document



Network Working Group                                           R. Verma
Request for Comments: 3145                           Deloitte Consulting
Category: Standards Track                                       M. Verma
                                                        3Com Corporation
                                                              J. Carlson
                                                        Sun Microsystems
                                                               July 2001


                   L2TP Disconnect Cause Information

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

Abstract

   This document provides an extension to the Layer 2 Tunneling Protocol
   ("L2TP"), a mechanism for tunneling Point-to-Point Protocol (PPP)
   sessions.  L2TP lacks a mechanism for a host to provide PPP-related
   disconnect cause information to another host.  This information,
   provided by the extension described in this document, can be useful
   for accounting and debugging purposes.

1.  Introduction

   L2TP [1] defines a general-purpose mechanism for tunneling PPP over
   various media.  By design, it insulates L2TP operation from the
   details of the PPP session that is being encapsulated by L2TP.  There
   are, however, cases where it may be desirable for PPP-specific
   disconnect information to be provided to an L2TP host (L2TP Access
   Concentrator [LAC] or L2TP Network Server [LNS]) in a descriptive
   format.  The lack of this information is especially a problem when
   the LAC and LNS are not owned or managed by the same entities.

   The Result and Error Codes defined for L2TP specify only L2TP-
   specific disconnect information.  This document provides an
   additional Attribute Value Pair (AVP), called PPP Disconnect Cause
   Code, that MAY be used by an L2TP host to provide PPP-specific




Verma, et al.               Standards Track