RFC 3437 (rfc3437) - Page 1 of 10


Layer-Two Tunneling Protocol Extensions for PPP Link Control Protocol Negotiation



Alternative Format: Original Text Document



Network Working Group                                          W. Palter
Request for Comments: 3437                                       zev.net
Category: Standards Track                                    W. Townsley
                                                           Cisco Systems
                                                           December 2002

              Layer-Two Tunneling Protocol Extensions for
                 PPP Link Control Protocol Negotiation

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 (2002).  All Rights Reserved.

Abstract

   This document defines extensions to the Layer Two Tunneling Protocol
   (L2TP) for enhanced support of link-specific Point to Point Protocol
   (PPP) options.  PPP endpoints typically have direct access to the
   common physical media connecting them and thus have detailed
   knowledge about the media that is in use.  When the L2TP is used, the
   two PPP peers are no longer directly connected over the same physical
   media.  Instead, L2TP inserts a virtual connection over some or all
   of the PPP connection by tunneling PPP frames over a packet switched
   network such as IP.  Under some conditions, an L2TP endpoint may need
   to negotiate PPP Link Control Protocol (LCP) options at a location
   which may not have access to all of the media information necessary
   for proper participation in the LCP negotiation.  This document
   provides a mechanism for communicating desired LCP options between
   L2TP endpoints in advance of PPP LCP negotiation at the far end of an
   L2TP tunnel, as well as a mechanism for communicating the negotiated
   LCP options back to where the native PPP link resides.












Palter & Townsley           Standards Track