Network Working Group N. Bahadur, Ed. Internet-Draft R. Aggarwal, Ed. Intended status: Standards Track D. Ward, Ed. Expires: February 23, 2011 Juniper Networks, Inc. T. Nadeau BT N. Sprecher Y. Weingarten Nokia Siemens Networks August 22, 2010 LSP-Ping and BFD encapsulation over ACH draft-ietf-mpls-tp-lsp-ping-bfd-procedures-01 Abstract LSP-Ping and BFD for MPLS are existing and widely deployment OAM mechanisms for MPLS LSPs. This document describes an ACH encapsulation for LSP-Ping, that would enable use of LSP-Ping for networks where IP addressing is not in use. This document also clarifies the use of BFD for MPLS LSPs using ACH encapsulation, when IP addressing may not be available and/or it may not be desirable to encapsulate BFD packets in IP. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on February 23, 2011. Bahadur, et al. Expires February 23, 2011 [Page 1] Internet-Draft LSP-Ping and BFD encapsulation over ACH August 2010 Copyright Notice Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Conventions used in this document . . . . . . . . . . . . . 3 1.2. LSP-Ping and BFD over ACH . . . . . . . . . . . . . . . . . 3 2. LSP-Ping extensions . . . . . . . . . . . . . . . . . . . . . . 3 2.1. LSP-Ping packet over ACH for LSPs . . . . . . . . . . . . . 3 2.2. LSP-Ping packet over ACH for PWs . . . . . . . . . . . . . 4 2.3. Source Address TLV . . . . . . . . . . . . . . . . . . . . 4 2.4. MEP and MIP Identifier . . . . . . . . . . . . . . . . . . 5 3. Running BFD over MPLS-TP LSPs . . . . . . . . . . . . . . . . . 5 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 5.1. New ACH Channel Types . . . . . . . . . . . . . . . . . . . 7 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 6.1. Normative References . . . . . . . . . . . . . . . . . . . 7 6.2. Informative References . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Bahadur, et al. Expires February 23, 2011 [Page 2] Internet-Draft LSP-Ping and BFD encapsulation over ACH August 2010 1. Introduction LSP-Ping [RFC4379] and BFD for MPLS [RFC5884] are OAM mechanisms for MPLS LSPs. This document describes an ACH encapsulation for LSP-Ping for networks that do not use IP addressing. When IP addressing is in use, the LSP-Ping procedures specified in [RFC4379] apply as is. This document also clarifies the use of BFD for MPLS LSPs using ACH encapsulation [RFC5586], when IP addressing may not be available and/or it may not be desirable to encapsulate BFD packets in IP. 1.1. Conventions used in this document 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 [RFC2119]. 1.2. LSP-Ping and BFD over ACH In certain MPLS-TP deployment scenarios IP addressing might not be available or it may be preferred to use non-IP encapsulation for LSP- Ping and BFD packets. The remainder of this document defines extensions to LSP-Ping and procedures for using BFD, for such scenarios. Section 2.1 and Section 2.2 describe a new ACH code-point for performing LSP-Ping over ACH. Section 3 describes procedures for using BFD over ACH. 2. LSP-Ping extensions 2.1. LSP-Ping packet over ACH for LSPs [RFC5586] defines an ACH mechanism for MPLS LSPs. This document defines a new ACH channel type for LSP-Ping, when IP addressing is not in use, for LSP-Ping over associated bi-directional LSPs and co- routed bi-directional LSPs. ACH TLVs MAY be associated with this channel type. 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 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 1|Version| Reserved | LSP-Ping Channel Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: LSP-Ping ACH Channel Type Bahadur, et al. Expires February 23, 2011 [Page 3] Internet-Draft LSP-Ping and BFD encapsulation over ACH August 2010 When ACH header is used, an LSP-Ping packet will look as follows: 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 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MPLS Label stack | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | GAL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 1|Version| Reserved | LSP-Ping Channel Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ACH TLV Header | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ACH TLVs | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LSP-Ping payload | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: LSP-Ping packet with ACH When using LSP-Ping over the ACH header, the LSP-Ping Reply mode [RFC4379] in the LSP-Ping echo request MUST be set to 4 (Reply via application level control channel). 2.2. LSP-Ping packet over ACH for PWs [RFC4385] defines an PW-ACH mechanism for pseudowires. The ACH channel type for LSP-Ping defined in Section 2.1 will be re-used for pseudowires so that IP addressing is not needed when using LSP-Ping OAM over pseudowires. 2.3. Source Address TLV When sending LSP-Ping packets using ACH, without IP encapsulation, there MAY be a need to identify the source address of the packet. This source address will be specified via the Source Address TLV, being defined in [I-D.ietf-mpls-tp-ach-tlv]. No more than 1 source address TLV MAY be present in a LSP-Ping packet. The source address MUST specify the address of the originator of the packet. If more than 1 such TLV is present in a LSP-Ping request packet, then an error code of 1 (Malformed echo request received), [ Section 3.1 [RFC4379]], SHOULD be returned. If more than 1 source address TLV is present, then the packet SHOULD be dropped without further Bahadur, et al. Expires February 23, 2011 [Page 4] Internet-Draft LSP-Ping and BFD encapsulation over ACH August 2010 processing. 2.4. MEP and MIP Identifier When sending LSP-Ping packets using ACH, there MAY be a need to identify the maintenance end point (MEP) and/or the maintenance intermediate point (MIP) being monitored [I-D.ietf-mpls-tp-rosetta-stone]. The MEP/MIP identifiers defined in [I-D.ietf-mpls-tp-identifiers] MAY be carried in the ACH TLVs [I-D.ietf-mpls-tp-ach-tlv] for identification. 3. Running BFD over MPLS-TP LSPs [RFC5884] describes how BFD can be used for Continuity Check of MPLS LSPs. The procedures described in [RFC5884] MUST be used when IP encapsulation is in use. This section clarifies the usage of BFD in the context of MPLS-TP LSPs when it is not desirable to use IP encapsulation. When using BFD over MPLS-TP LSPs, the BFD discriminator MUST either be signaled via LSP-Ping or be statically configured. The BFD packets MUST be sent over ACH when IP encapsulation is not used. This document defines a new ACH channel type for BFD over G-ACH, when IP addressing is not in use, for running BFD over associated bi- directional LSPs and co-routed bi-directional LSPs. ACH TLVs MAY be associated with this channel type. 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 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 1|Version| Reserved | BFD over G-ACH Channel Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: BFD over G-ACH Channel Type BFD packets, for both directions, MUST be sent over the MPLS-TP LSP and IP forwarding SHOULD NOT be used for the reverse path. The format of a BFD packet when using it as an OAM tool for MPLS-TP LSPs SHOULD be as follows: Bahadur, et al. Expires February 23, 2011 [Page 5] Internet-Draft LSP-Ping and BFD encapsulation over ACH August 2010 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 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MPLS Label stack | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | GAL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 1|Version| Reserved | BFD over G-ACH Channel Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ACH TLV Header | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ACH TLVs | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BFD payload | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4: BFD packet over MPLS-TP LSPs [RFC5885] specifies how BFD can be used over MPLS PWs. One MAY use BFD over G-ACH channel type to run BFD over PWs if ACH TLV support is needed. BFD supports continuous fault monitoring and thus meets the pro- active Continuity Check and verification requirement specified in [RFC5860]. BFD SHOULD be run pro-actively. This function SHOULD be performed between End Points (MEPs) of PWs, LSPs and Sections. For point to multipoint Continuity Check, there is work in progress on using BFD for P2MP MPLS LSPs ( [I-D.katz-ward-bfd-multipoint]) and this can be leveraged for MPLS-TP LSPs as well. Failure of a BFD session over a LSP can be used to trigger protection switching or other fault remedial procedures. When sending BFD packets using ACH, there MAY be a need to identify the maintenance end point (MEP) being monitored. The MEP identifier defined in [I-D.ietf-mpls-tp-identifiers] can be carried in the ACH TLVs [I-D.ietf-mpls-tp-ach-tlv] for identification. 4. Security Considerations The draft does not introduce any new security considerations. Those discussed in [RFC4379] are also applicable to this document. Bahadur, et al. Expires February 23, 2011 [Page 6] Internet-Draft LSP-Ping and BFD encapsulation over ACH August 2010 5. IANA Considerations 5.1. New ACH Channel Types New Channels type are defined in Section 2.1 and Section 3. IANA is requested to assign new values from the "PW Associated Channel Type" registry, as per IETF consensus policy. Value Meaning ----- ------- TBD Associated Channel carries LSP-Ping packet TBD Associated Channel carries BFD over G-ACH 6. References 6.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4379] Kompella, K. and G. Swallow, "Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures", RFC 4379, February 2006. [RFC4385] Bryant, S., Swallow, G., Martini, L., and D. McPherson, "Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for Use over an MPLS PSN", RFC 4385, February 2006. 6.2. Informative References [I-D.ietf-mpls-tp-ach-tlv] Boutros, S., Bryant, S., Sivabalan, S., Swallow, G., Ward, D., and V. Manral, "Definition of ACH TLV Structure", draft-ietf-mpls-tp-ach-tlv-02 (work in progress), March 2010. [I-D.ietf-mpls-tp-identifiers] Bocci, M. and G. Swallow, "MPLS-TP Identifiers", draft-ietf-mpls-tp-identifiers-02 (work in progress), July 2010. [I-D.ietf-mpls-tp-rosetta-stone] Sprecher, N., "A Thesaurus for the Terminology used in Multiprotocol Label Switching Transport Profile (MPLS-TP) drafts/RFCs and ITU-T's Transport Network Recommendations.", draft-ietf-mpls-tp-rosetta-stone-02 Bahadur, et al. Expires February 23, 2011 [Page 7] Internet-Draft LSP-Ping and BFD encapsulation over ACH August 2010 (work in progress), May 2010. [I-D.katz-ward-bfd-multipoint] Katz, D. and D. Ward, "BFD for Multipoint Networks", draft-katz-ward-bfd-multipoint-02 (work in progress), February 2009. [RFC5586] Bocci, M., Vigoureux, M., and S. Bryant, "MPLS Generic Associated Channel", RFC 5586, June 2009. [RFC5860] Vigoureux, M., Ward, D., and M. Betts, "Requirements for Operations, Administration, and Maintenance (OAM) in MPLS Transport Networks", RFC 5860, May 2010. [RFC5884] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow, "Bidirectional Forwarding Detection (BFD) for MPLS Label Switched Paths (LSPs)", RFC 5884, June 2010. [RFC5885] Nadeau, T. and C. Pignataro, "Bidirectional Forwarding Detection (BFD) for the Pseudowire Virtual Circuit Connectivity Verification (VCCV)", RFC 5885, June 2010. Authors' Addresses Nitin Bahadur (editor) Juniper Networks, Inc. 1194 N. Mathilda Avenue Sunnyvale, CA 94089 US Phone: +1 408 745 2000 Email: nitinb@juniper.net URI: www.juniper.net Rahul Aggarwal (editor) Juniper Networks, Inc. 1194 N. Mathilda Avenue Sunnyvale, CA 94089 US Phone: +1 408 745 2000 Email: rahul@juniper.net URI: www.juniper.net Bahadur, et al. Expires February 23, 2011 [Page 8] Internet-Draft LSP-Ping and BFD encapsulation over ACH August 2010 David Ward (editor) Juniper Networks, Inc. 1194 N. Mathilda Avenue Sunnyvale, CA 94089 US Phone: +1 408 745 2000 Fax: Email: dward@juniper.net URI: www.juniper.net Thomas D. Nadeau BT BT Centre 81 Newgate Street London EC1A 7AJ United Kingdom Email: tom.nadeau@bt.com Nurit Sprecher Nokia Siemens Networks 3 Hanagar St. Neve Ne'eman B Hod Hasharon 45241 Israel Phone: +972-9-775 1229 Email: nurit.sprecher@nsn.com Yaacov Weingarten Nokia Siemens Networks 3 Hanagar St. Neve Ne'eman B Hod Hasharon 45241 Israel Phone: +972-9-775 1827 Email: yaacov.weingarten@nsn.com Bahadur, et al. Expires February 23, 2011 [Page 9]