RFC 3301 (rfc3301) - Page 2 of 19

Layer Two Tunnelling Protocol (L2TP): ATM access network extensions

RFC 3301          L2TP: ATM access network extensions          June 2002


   3.4 Framing ......................................................  6
   4. Service model issues ..........................................  7
   4.1 Authentication ...............................................  7
   4.2 Authorization ................................................  7
   5. New and extended AVPs .........................................  7
   5.1 New AVP Summary ..............................................  7
   5.2 New AVP definition ...........................................  8
   5.3 Changed AVP Definition ....................................... 12
   6. IANA considerations ........................................... 16
   7. Security considerations ....................................... 17
   8. Acknowledgements .............................................. 17
   9. References .................................................... 17
   10. Authors Addresses ............................................ 18
   11. Full Copyright Statement ..................................... 19

1. Introduction

   L2TP [RFC 2661] defines the procedures for tunneling PPP sessions
   between a so called L2TP Access Concentrator (LAC) and an L2TP
   Network Server (LNS).  The main focus of [RFC 2661] is on supporting
   HDLC based ISDN/PSTN access networks.

   This document augments the procedures described in [RFC 2661] to
   further support ATM SVC or PVC based access networks.  Support for
   ATM access networks requires extensions to the present L2TP
   procedures so as to cope with :

   (a) the traffic management aspects of ATM connections (e.g.
       asymmetric bandwidth allocation and service category selection
       capabilities),

   (b) the addressing format to be used in switched ATM networks [AESA]
       and

   (c) the limitations imposed on LCP negotiation by transporting PPP
       over AAL5 over the access network segment of the PPP connection
       [RFC 2364].

   Within this document, the necessary extensions to [RFC 2661] are
   defined to cope with issues (a) and (b), issue (c) which is not
   specific to ATM may be solved as described in [L2TP_link].

1.1 Conventions

   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 [RFC 2119].




T'Joens, et al.             Standards Track