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Network Working Group                                        A. G. MalisRequest for Comments: 3496                                      T. HsiaoCategory: Informational                                  Vivace Networks                                                              March 2003Protocol Extension for Support of Asynchronous Transfer Mode (ATM)Service Class-aware Multiprotocol Label Switching (MPLS)Traffic EngineeringStatus of this Memo   This memo provides information for the Internet community.  It does   not specify an Internet standard of any kind.  Distribution of this   memo is unlimited.Copyright Notice   Copyright (C) The Internet Society (2003).  All Rights Reserved.Abstract   This document specifies a Resource ReSerVation Protocol-Traffic   Engineering (RSVP-TE) signaling extension for support of Asynchronous   Transfer Mode (ATM) Service Class-aware Multiprotocol Label Switching   (MPLS) Traffic Engineering.Table of Contents1.  Overview......................................................22.  Extended RSVP-TE Path Message Format..........................22.1 PATH Message Format.......................................33.  ATM_SERVICECLASS Object.......................................34.  Handling the ATM_SERVICECLASS Object..........................45.  Non-support of the ATM_SERVICECLASS Object....................46.  Security Considerations.......................................47.  IANA Considerations...........................................58.  References....................................................59.  Authors' Addresses............................................510. Full Copyright Statement......................................6Malis & Hsiao                Informational                      [Page 1]

RFC 3496    ATM Service Class-aware MPLS Traffic Engineering  March 20031. 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                      [Page 2]

RFC 3496    ATM Service Class-aware MPLS Traffic Engineering  March 20032.1 PATH Message Format   The format of the extended PATH message is as follows:   <PATH Message> ::=      <Common Header> [ <INTEGRITY> ]                                <SESSION> <RSVP_HOP>                            <TIME_VALUES>                            [ <EXPLICIT_ROUTE> ]                            <LABEL_REQUEST>                            [ <SESSION_ATTRIBUTE> ]                            [ <DIFFSERV> ]                            [ <ATM_SERVICECLASS> ]                            [ <POLICY_DATA> ... ]                            [ <sender descriptor> ]   <sender descriptor> ::=  <SENDER_TEMPLATE> [ <SENDER_TSPEC> ]                            [ <ADSPEC> ]                            [ <RECORD_ROUTE> ]3. ATM_SERVICECLASS Object   The ATM_SERVICECLASS object format is as follows:   Class Number = 227, C_Type = 1    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   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+   |                       Reserved                          | SC  |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+   Reserved : 29 bits        This field is reserved. It must be set to zero on transmission        and must be ignored on receipt.   SC : 3 bits        Indicates the ATM Service Class. Values currently allowed are:        0: UBR (Unspecified Bit Rate)        1: VBR-NRT (Variable Bit Rate, Non-Real Time)        2: VBR-RT (Variable Bit Rate, Real Time)        3: CBR (Constant Bit Rate)        4-7: reservedMalis & Hsiao                Informational                      [Page 3]

RFC 3496    ATM Service Class-aware MPLS Traffic Engineering  March 20034. Handling the ATM_SERVICECLASS Object   To establish an LSP tunnel with RSVP-TE, the sender LSR creates a   PATH message with a session type of LSP_Tunnel_IPv4 and with a   LABEL_REQUEST object as per [RSVP-TE].  The sender LSR may also   include the DIFFSERV object as per [DIFF-MPLS].   If the LSP is associated with an ATM Service Class, the sender LSR   must include the ATM_SERVICECLASS object in the PATH message with the   Service-Class (SC) field set to signify the desired ATM Service   Class.   If a path message contains multiple ATM_SERVICECLASS objects, only   the first one is meaningful; subsequent ATM_SERVICECLASS object(s)   must be ignored and must not be forwarded.   Each LSR along the path that is ATM_SERVICECLASS-aware records the   ATM_SERVICECLASS object, when present, in its path state block.   The destination LSR responds to the PATH message by sending a RESV   message without an ATM_SERVICECLASS object (whether the PATH message   contained an ATM_SERVICECLASS object or not).5. Non-support of the ATM_SERVICECLASS Object   An LSR that does not recognize the ATM_SERVICECLASS object Class   Number must behave in accordance with the procedures specified in   [RSVP] for an unknown Class Number with the binary format 11bbbbbb,   where b=0 or 1 (i.e., RSVP will ignore the object but forward it   unexamined and unmodified).   An LSR that recognizes the ATM_SERVICECLASS object Class Number but   does not recognize the ATM_SERVICECLASS object C-Type, must behave in   accordance with the procedures specified in [RSVP] for an unknown   C-type (i.e., it must send a PathErr with the error code 'Unknown   object C-Type' toward the sender).   In both situations, this causes the path setup to fail.  The sender   should notify management that a LSP cannot be established and   possibly might take action to retry reservation establishment without   the ATM_SERVICECLASS object.6. Security Considerations   The solution is not expected to add specific security requirements   beyond those of Diff-Serv and existing TE.  The security mechanisms   currently used with Diff-Serv and existing TE can be used with this   solution.Malis & Hsiao                Informational                      [Page 4]

RFC 3496    ATM Service Class-aware MPLS Traffic Engineering  March 20037. IANA Considerations   The IANA has registered a new RSVP Class Number for ATM_SERVICECLASS   (227).  (Seehttp://www.iana.org/assignments/rsvp-parameters).8. References   [DIFF-MPLS] Le Faucheur, F., Wu, L., Davie, B., Davari, S., Vaananen,               P., Krishnan, R., Cheval, P. and J. Heinanen, "Multi-               Protocol Label Switching (MPLS) Support of Differentiated               Services",RFC 3270, May 2002.   [RSVP]      Braden, R., Ed., Zhang, L., Berson, S., Herzog, S. and S.               Jazmin , "Resource ReSerVation Protocol (RSVP) -- Version               1 Functional Specification",RFC 2205, September 1997.   [RSVP-TE]   Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.               and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP               Tunnels",RFC 3209, December 2001.   [TM]        ATM Forum Traffic Management Specification Version 4.0,               af-tm-0056.000, April 1996.9. Authors' Addresses   Andrew G. Malis   Vivace Networks, Inc.   2730 Orchard Parkway   San Jose, CA 95134   EMail: Andy.Malis@vivacenetworks.com   Tony Hsiao   Vivace Networks, Inc.   2730 Orchard Parkway   San Jose, CA 95134   EMail: Tony.Hsiao@VivaceNetworks.comMalis & Hsiao                Informational                      [Page 5]

RFC 3496    ATM Service Class-aware MPLS Traffic Engineering  March 200310.  Full Copyright Statement   Copyright (C) The Internet Society (2003).  All Rights Reserved.   This document and translations of it may be copied and furnished to   others, and derivative works that comment on or otherwise explain it   or assist in its implementation may be prepared, copied, published   and distributed, in whole or in part, without restriction of any   kind, provided that the above copyright notice and this paragraph are   included on all such copies and derivative works.  However, this   document itself may not be modified in any way, such as by removing   the copyright notice or references to the Internet Society or other   Internet organizations, except as needed for the purpose of   developing Internet standards in which case the procedures for   copyrights defined in the Internet Standards process must be   followed, or as required to translate it into languages other than   English.   The limited permissions granted above are perpetual and will not be   revoked by the Internet Society or its successors or assigns.   This document and the information contained herein is provided on an   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.Acknowledgement   Funding for the RFC Editor function is currently provided by the   Internet Society.Malis & Hsiao                Informational                      [Page 6]