RFC 3496 (rfc3496) - Page 2 of 6

Protocol Extension for Support of Asynchronous Transfer Mode (ATM) Service Class-aware Multiprotocol Label Switching (MPLS) Traffic Engineering

Alternative Format: Original Text Document

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RFC 3496    ATM Service Class-aware MPLS Traffic Engineering  March 2003


1. Overview

   This document defines a Resource ReSerVation Protocol-Traffic
   Engineering (RSVP-TE) protocol addition to support ATM (Asynchronous
   Transfer Mode) Service Class-aware MPLS (MultiProtocol Label
   Switching) Traffic Engineering.

   This protocol addition is used with all MPLS Label Switched Routers
   (LSRs) and link types (including, but not restricted to, Packet over
   SONET, Ethernet, and ATM links) to signal traffic engineered paths
   that can support the ATM service classes as defined by the ATM Forum
   [TM].  This document does not specify HOW to actually implement the
   functionality in the MPLS LSRs to emulate the ATM Forum service
   classes (such as necessary queuing and scheduling mechanisms), only
   how to signal that the TE path must support the ATM Forum service
   classes.  A useful application for such paths is the carriage of ATM
   cells encapsulated in IP or MPLS packets in order to use MPLS
   networks as functional replacements for ATM networks.

2. Extended RSVP-TE Path Message Format

   One new RSVP-TE Object is defined in this document: the
   ATM_SERVICECLASS Object.  Detailed description of this Object is
   provided below.  This new Object is applicable to PATH messages.
   This specification only defines the use of the ATM_SERVICECLASS
   Object in PATH messages used to establish LSP (Label Switched Path)
   Tunnels in accordance with [RSVP-TE].  Such PATH messages contain a
   Session Object with a C-Type equal to LSP_TUNNEL_IPv4 and a
   LABEL_REQUEST object.

   Restrictions defined in [RSVP-TE] for support of establishment of LSP
   Tunnels via RSVP-TE are also applicable to the establishment of LSP
   Tunnels supporting ATM Service Class-aware traffic engineering.  For
   instance, only unicast LSPs are supported and Multicast LSPs are for
   further study.

   This new ATM_SERVICECLASS object is optional with respect to RSVP-TE
   so that general RSVP-TE implementations not concerned with ATM
   Service Class-aware traffic engineering MPLS LSP setup do not have to
   support this object.











Malis & Hsiao                Informational

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