Network Working Group N. Bahadur Internet-Draft R. Aggarwal Intended status: Standards Track Juniper Networks, Inc. Expires: April 22, 2010 S. Boutros Cisco Systems, Inc. E. Gray Ericsson October 19, 2009 LSP-Ping extensions for MPLS-TP draft-nitinb-mpls-tp-lsp-ping-extensions-00 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 April 22, 2010. Copyright Notice Copyright (c) 2009 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 in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Bahadur, et al. Expires April 22, 2010 [Page 1] Internet-Draft LSP-Ping extensions for MPLS-TP October 2009 Abstract LSP-Ping is an existing and widely deployment OAM mechanism for MPLS LSPs. This document describes extensions to LSP-Ping so that LSP- Ping can be used to perform OAM on MPLS-TP LSPs. It also clarifies the procedures to be used for processing the OAM packets. Further, it describes how LSP-Ping can be used to perform Connectivity Verification, Route Tracing and Adjacency functions in MPLS-TP networks. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Conventions used in this document . . . . . . . . . . . . 3 1.2. LSP-Ping for MPLS-TP LSPs using IP encapsulation . . . . . 3 1.3. LSP-Ping for MPLS-TP LSPs using non-IP encapsulation . . . 3 2. LSP-Ping extensions . . . . . . . . . . . . . . . . . . . . . 4 2.1. New address type for Downstream Mapping TLV . . . . . . . 4 2.2. Source Address TLV . . . . . . . . . . . . . . . . . . . . 4 2.3. Destination Address TLV . . . . . . . . . . . . . . . . . 4 2.4. MEP and MIP Identifier . . . . . . . . . . . . . . . . . . 5 2.5. Specifications for statically provisioned LSPs . . . . . . 5 3. Performing LSP-Ping over MPLS-TP LSPs . . . . . . . . . . . . 5 3.1. LSP-Ping with IP encapsulation . . . . . . . . . . . . . . 5 3.2. Non-IP based LSP-Ping . . . . . . . . . . . . . . . . . . 6 3.3. P2MP Considerations . . . . . . . . . . . . . . . . . . . 6 4. Performing LSP Traceroute over MPLS-TP LSPs . . . . . . . . . 7 4.1. LSP Traceroute with IP encapsulation . . . . . . . . . . . 7 4.2. Non-IP based LSP Traceroute . . . . . . . . . . . . . . . 7 4.2.1. Ingress node procedure for sending echo request packets . . . . . . . . . . . . . . . . . . . . . . . 7 4.2.2. Ingress node procedure for receiving echo response packets . . . . . . . . . . . . . . . . . . . . . . . 7 4.2.3. Transit and egress node procedure . . . . . . . . . . 8 4.3. P2MP Considerations . . . . . . . . . . . . . . . . . . . 8 4.4. ECMP Considerations . . . . . . . . . . . . . . . . . . . 8 5. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 8 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 8. Contributing Authors . . . . . . . . . . . . . . . . . . . . . 9 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 9.1. Normative References . . . . . . . . . . . . . . . . . . . 9 9.2. Informative References . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10 Bahadur, et al. Expires April 22, 2010 [Page 2] Internet-Draft LSP-Ping extensions for MPLS-TP October 2009 1. Introduction LSP-Ping [RFC4379]is an OAM mechanism for MPLS LSPs. This document describes extensions to LSP-Ping so that LSP-Ping can be used to perform OAM on MPLS-TP LSPs. It also clarifies the procedures to be used for processing the OAM packets. Further, it describes how LSP- Ping can be used to perform Connectivity Verification, Route Tracing and Adjacency functions specified in [I-D.ietf-mpls-tp-oam-requirements]. 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 for MPLS-TP LSPs using IP encapsulation LSP-Ping requires IP addressing on the egress and transit LSRs for performing OAM on MPLS signaled LSPs and pseudowires. In particular, in these cases the LSP-Ping packets generated by an ingress LSR are encapsulated in an IP/UDP header with the destination address from the 127/8 range and then encapsulated in the MPLS label stack ([RFC4379] , [I-D.ietf-bfd-mpls]). Egress LSRs use the presence of the 127/8 destination address to identify the OAM packets and rely further on the UDP port number to determine whether the packet is a LSP-Ping packet. It is to be noted that this determination does not require IP forwarding capabilities. It requires the presence of an IP host stack which enables egress LSRs to process packets with a destination address from the 127/8 range. [RFC1122] allocates the 127/8 range as "Internal host loopback address" and [RFC1812] states that "a router SHOULD NOT forward, except over a loopback interface, any packet that has a destination address on network 127". 1.3. LSP-Ping for MPLS-TP LSPs using non-IP encapsulation 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. In such scenarios, LSP-Ping must be run without IP addressing, using the ACH channel type specified in [I-D.nitinb-mpls-tp-lsp-ping-bfd-procedures]. Sections Section 3.2 and Section 4.2 describe the theory of operation for performing LSP-Ping over MPLS-TP LSPs with a non-IP encapsulation. Bahadur, et al. Expires April 22, 2010 [Page 3] Internet-Draft LSP-Ping extensions for MPLS-TP October 2009 2. LSP-Ping extensions 2.1. New address type for Downstream Mapping TLV [RFC4379] defines the Downstream Mapping TLV. This document defines the following new Address type which is added to the Downstream Mapping TLV: Type # Address Type K Octets ------ -------------- -------- 0 Not Applicable 8 Figure 1: Downstream Mapping TLV new Address Type The new address type indicates that no address is present in the Downstream Mapping TLV. Multipath type MAY be set to 0 (no multipath) when using this address type. When this address type is used, on receipt of a LSP-Ping echo request, interface verification MUST be bypassed. Thus the receiving node SHOULD only perform mpls label control-plane/data-plane consistency checks. The new address type is also applicable to the Detailed Downstream Mapping TLV defined in [I-D.ietf-mpls-lsp-ping-enhanced-dsmap]. 2.2. 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]. Only 1 source address TLV MUST 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 of "Malformed echo request received" SHOULD be returned. If more than 1 source address TLV is present, then the packet SHOULD be dropped without further processing. 2.3. Destination Address TLV When sending LSP-Ping packets using ACH, without IP encapsulation, there MAY be a need to identify the destination address of the packet. This destination address will be specified via the Destination Address TLV, being defined in [I-D.ietf-mpls-tp-ach-tlv]. One or more of this TLVs MAY be included. The destination address MUST specify the intended receipient(s) of the packet. If the Bahadur, et al. Expires April 22, 2010 [Page 4] Internet-Draft LSP-Ping extensions for MPLS-TP October 2009 destination address specified in any of the Destination Address TLVs does not match any address associated with the node which receives the LSP-Ping packet, then the LSP-Ping packet SHOULD be dropped without further 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. The MEP/MIP identifiers defined in [I-D.swallow-mpls-tp-identifiers] MAY be carried in the ACH TLVs [I-D.ietf-mpls-tp-ach-tlv] for identification. Only one identifier (MEP or MIP) may be present in a packet. The MEP/MIP identifiers associated with the packet MUST be checked for the MPLS-TP LSP path/section that is being monitored. If the identifier does not match the LSP path/section, then the packet MUST be dropped. 2.5. Specifications for statically provisioned LSPs Details of LSP-Ping for statically provisioned LSPs will be specified in a future revision of this document. 3. Performing LSP-Ping over MPLS-TP LSPs This section specifies how LSP-Ping ping can be used in the context of MPLS-TP LSPs. The LSP-Ping ping function meets the Connectivity Verification requirement specified in [I-D.ietf-mpls-tp-oam-requirements]. This function SHOULD be performed on-demand. This function SHOULD be performed between End Points (MEPs) and Intermediate Points (MIPs) of PWs and LSPs, and between End Points of PWs, LSPs and Sections. In order for the LSP- Ping packet to be processed at the desired MIP, the TTL of the MPLS label should be set such that it expires at the MIP to be probed. 3.1. LSP-Ping with IP encapsulation LSP-Ping packets as specified in [RFC4379] are sent over the MPLS LSP for which OAM is being performed and contain an IP/UDP packet within them. The IP header is not used for forwarding (since the LSP is forward using MPLS label switching). The IP header is used mainly for addressing and can be used in the context of MPLS-TP LSPs. This form of LSP-Ping OAM MUST be supported for MPLS-TP LSPs when IP addressing is in use. The LSP-Ping Reply mode [RFC4379] in the LSP- Ping echo request MUST be set to 4 (Reply via application level control channel). The LSP-Ping echo response message MUST be sent on the reverse path Bahadur, et al. Expires April 22, 2010 [Page 5] Internet-Draft LSP-Ping extensions for MPLS-TP October 2009 of the LSP. The reply MUST contain IP/UDP headers followed by the LSP-Ping payload. The destination address in the IP header MUST be set to that of the sender of the echo request message. The source address in the IP address MUST be set to a valid address of the replying node. 3.2. Non-IP based LSP-Ping The OAM procedures defined in [RFC4379] require the use of IP addressing and in some cases IP routing to perform OAM functions. When the ACH header is used, IP addressing and routing is not needed. This section describes procedures for performing lsp-ping without a dependency on IP addressing and routing. 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). The ingress node MAY attach a Source Address TLV (Section 2.2) to identify the node originating the request. The LSP-Ping reply message MUST be sent on the reverse path of the LSP using ACH. The LSP-Ping payload MUST directly follow the ACH header (and any ACH TLVs) and no IP and/or UDP headers MUST be attached. If the request message contained the Source Address TLV and a response is being sent to the originator, then a Destination Address TLV (Section 2.3) SHOULD be added to the reply message. The contents of the LSP-Ping request Source Address TLV should be copied into the LSP-Ping response Destination Address TLV. The responding node MAY attach a Source Address TLV to identify the node sending the response. If a node receives an MPLS echo request packet over ACH, without IP/ UDP headers and if that node does not have a return MPLS LSP path to the echo request source, then the node MUST drop the echo request packet and not attempt to send a response. 3.3. P2MP Considerations [I-D.ietf-mpls-p2mp-lsp-ping] describes how LSP-Ping can be used for OAM on P2MP LSPs with IP encapsulation. This MUST be supported for MPLS-TP P2MP LSPs when IP addressing is used. When IP addressing is not used, then the procedures described in Section 3.2 can be applied to P2MP MPLS-TP LSPs as well. Bahadur, et al. Expires April 22, 2010 [Page 6] Internet-Draft LSP-Ping extensions for MPLS-TP October 2009 4. Performing LSP Traceroute over MPLS-TP LSPs This section specifies how LSP-Ping traceroute can be used in the context of MPLS-TP LSPs. The LSP-Ping traceroute function meets the Adjancency and Route Tracing requirement specified in [I-D.ietf-mpls-tp-oam-requirements]. This function SHOULD be performed on-demand. This function SHOULD be performed between End Points and Intermediate Points of PWs and LSPs, and between End Points of PWs, LSPs and Sections. When performing lsp-ping traceroute, the ingress node inserts a Downstream Mapping TLV to get the downstream node information and to enable LSP verification along the transit nodes. The Downstream Mapping TLV can be used as is for performing the traceroute. If IP addressing is not in use, then the Address Type field in the Downstream Mapping TLV can be set to "Not applicable" (Section 2.1). The Downstream Mapping TLV address type field can be extended to include other address types as need be. 4.1. LSP Traceroute with IP encapsulation The mechanics of LSP-Ping traceroute are similar to that described for ping in Section 3.1. Traceroute packets sent by the LSP ingress MUST follow procedures described in [RFC4379]. This form of LSP-Ping OAM MUST be supported for MPLS-TP LSPs, when IP addressing is used. 4.2. Non-IP based LSP Traceroute This section describes the procedures for performing LSP traceroute when using the ACH header and without any dependency on IP addressing. The procedures specified in Section 3.2 with regards to Source Address TLV, Destination Address TLV and MEP/MIP identifiers apply to LSP traceroute as well. 4.2.1. Ingress node procedure for sending echo request packets Traceroute packets sent by the LSP ingress MUST adhere to the format described in Section 3.2. MPLS-TTL expiry (as described in [RFC4379]) will be used to direct the packets to specific nodes along the LSP path. 4.2.2. Ingress node procedure for receiving echo response packets The LSP-Ping traceroute responses will be received on the LSP itself and the presence of an ACH header with channel type of LSP-Ping is an indicator that the packet contains LSP-ping payload. Bahadur, et al. Expires April 22, 2010 [Page 7] Internet-Draft LSP-Ping extensions for MPLS-TP October 2009 4.2.3. Transit and egress node procedure When a echo request reaches the transit or egress, the presence of the ACH channel type of LSP-Ping will indicate that the packet contains LSP-Ping data. The LSP-Ping data, the label stack and the MEP/MIP identifier should be able to identify the LSP associated with the echo request packet. In case if there is an error and the node is unable to idenfity the LSP on which the echo response should to be sent, the node MUST drop the echo request packet and not send any response back. All responses MUST always be sent on a LSP path using the ACH header and ACH channel type of LSP-Ping. 4.3. P2MP Considerations [I-D.ietf-mpls-p2mp-lsp-ping] describes how LSP-Ping can be used for OAM on P2MP LSPs. This MUST be supported for MPLS-TP P2MP LSPs when IP addressing is used. When IP addressing is not used, then the procedures described in Section 4.2 can be applied to P2MP MPLS-TP LSPs as well. 4.4. ECMP Considerations LSP-Ping using ACH SHOULD NOT be used when there is ECMP (equal cost multiple paths) for a given LSP. The addition of the additional ACH header may modify the hashing behavior for OAM packets which may result in incorrect monitoring of path taken by data traffic. 5. Applicability The non-IP addressing based procedures specified in this document apply only to MPLS-TP LSPs. They also apply to PWs when IP encapsulation is not desired. However, when IP addressing is used, as in non MPLS-TP LSPs, procedures specified in [RFC4379] MUST be used. 6. Security Considerations The draft does not introduce any new security considerations. Those discussed in [RFC4379] are also applicable to this document. 7. IANA Considerations This document has no actions for IANA. Bahadur, et al. Expires April 22, 2010 [Page 8] Internet-Draft LSP-Ping extensions for MPLS-TP October 2009 8. Contributing Authors The following individuals also contributed to this document: o Thomas D. Nadeau, BT o Nurit Sprecher, Nokia Siemens Networks o Yaacov Weingarten, Nokia Siemens Networks 9. References 9.1. Normative References [I-D.nitinb-mpls-tp-lsp-ping-bfd-procedures] Bahadur, N., Aggarwal, R., Nadeau, T., Sprecher, N., and Y. Weingarten, "LSP-Ping and BFD for MPLS-TP", draft-nitinb-mpls-tp-lsp-ping-bfd-procedures-00 (work in progress), July 2009. [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. 9.2. Informative References [I-D.ietf-bfd-mpls] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow, "BFD For MPLS LSPs", draft-ietf-bfd-mpls-07 (work in progress), June 2008. [I-D.ietf-mpls-lsp-ping-enhanced-dsmap] Bahadur, N., Kompella, K., and G. Swallow, "Mechanism for performing LSP-Ping over MPLS tunnels", draft-ietf-mpls-lsp-ping-enhanced-dsmap-03 (work in progress), July 2009. [I-D.ietf-mpls-p2mp-lsp-ping] Yasukawa, S., Farrel, A., Ali, Z., Fenner, B., Swallow, G., Nadeau, T., and S. Saxena, "Detecting Data Plane Failures in Point-to-Multipoint Multiprotocol Label Switching (MPLS) - Extensions to LSP Ping", draft-ietf-mpls-p2mp-lsp-ping-08 (work in progress), August 2009. [I-D.ietf-mpls-tp-ach-tlv] Boutros, S., Bryant, S., Sivabalan, S., Swallow, G., and Bahadur, et al. Expires April 22, 2010 [Page 9] Internet-Draft LSP-Ping extensions for MPLS-TP October 2009 D. Ward, "Definition of ACH TLV Structure", draft-ietf-mpls-tp-ach-tlv-00 (work in progress), June 2009. [I-D.ietf-mpls-tp-oam-requirements] Vigoureux, M., Ward, D., and M. Betts, "Requirements for OAM in MPLS Transport Networks", draft-ietf-mpls-tp-oam-requirements-03 (work in progress), August 2009. [I-D.swallow-mpls-tp-identifiers] Bocci, M. and G. Swallow, "MPLS-TP Identifiers", draft-swallow-mpls-tp-identifiers-01 (work in progress), July 2009. [RFC1122] Braden, R., "Requirements for Internet Hosts - Communication Layers", STD 3, RFC 1122, October 1989. [RFC1812] Baker, F., "Requirements for IP Version 4 Routers", RFC 1812, June 1995. Authors' Addresses Nitin Bahadur 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 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 April 22, 2010 [Page 10] Internet-Draft LSP-Ping extensions for MPLS-TP October 2009 Sami Boutros Cisco Systems, Inc. 3750 Cisco Way San Jose, CA 95134 US Phone: Fax: Email: sboutros@cisco.com URI: Eric Gray Ericsson 900 Chelmsford Street Lowell, MA 01851 US Phone: +1 978 275 7470 Fax: Email: eric.gray@ericsson.com URI: Bahadur, et al. Expires April 22, 2010 [Page 11]