PALS Workgroup P. Jain Internet-Draft S. Boutros Intended status: Standards Track Cisco Systems, Inc. Expires: September 10, 2015 March 9, 2015 Definition of P2MP PW TLV for LSP-Ping Mechanisms draft-jain-pals-p2mp-pw-lsp-ping-00 Abstract LSP-Ping is a widely deployed Operation, Administration, and Maintenance (OAM) mechanism in MPLS networks. This document describes a mechanism to verify connectivity of Point-to-Multipoint (P2MP) Pseudowires (PW) using LSP Ping. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on September 10, 2015. Copyright Notice Copyright (c) 2015 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 Simplified BSD License. Jain & Boutros Expires September 10, 2015 [Page 1] Internet-Draft P2MP PW LSP Ping March 2015 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Specification of Requirements . . . . . . . . . . . . . . . . 3 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Identifying a P2MP PW . . . . . . . . . . . . . . . . . . . . 3 4.1. FEC 130 Pseudowire Sub-TLV . . . . . . . . . . . . . . . 3 5. Operations . . . . . . . . . . . . . . . . . . . . . . . . . 4 6. Encapsulation of OAM Ping Packets . . . . . . . . . . . . . . 5 7. Echo Reply using Downstream Assigned Label . . . . . . . . . 6 8. Controlling Echo Responses . . . . . . . . . . . . . . . . . 6 9. Security Considerations . . . . . . . . . . . . . . . . . . . 6 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 12.1. Normative References . . . . . . . . . . . . . . . . . . 6 12.2. Informative References . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 1. Introduction A Point-to-Multipoint (P2MP) Pseudowire (PW) emulates the essential attributes of a unidirectional P2MP Telecommunications service such as P2MP ATM over PSN. Requirements for P2MP PW are described in [RFC7338]. P2MP PWs are carried over P2MP MPLS LSP. The Procedure for P2MP PW signaling using LDP for single segment P2MP PWs are described in [I-D.ietf-pwe3-p2mp-pw]. Many P2MP PWs can share the same P2MP MPLS LSP and this arrangement is called Aggregate P-tree. The aggregate P2MP trees require an upstream assigned label so that on the tail of the P2MP LSP, the traffic can be associated with a VPN or a VPLS instance. When a P2MP MPLS LSP carries only one VPN or VPLS service instance, the arrangement is called Inclusive P-Tree. For Inclusive P-Trees, P2MP MPLS LSP label itself can uniquely identify the VPN or VPLS service being carried over P2MP MPLS LSP. The P2MP MPLS LSP can also be used in Selective P-Tree arrangement for carrying multicast traffic. In a Selective P-Tree arrangement, traffic to each multicast group in a VPN or VPLS instance is carried by a separate unique P-tree. In Aggregate Selective P-tree arrangement, traffic to a set of multicast groups from different VPN or VPLS instances is carried over a same shared P-tree. The P2MP MPLS LSP are setup either using MLDP [RFC6388] or P2MP RSVP- TE [RFC4875]. Mechanisms for fault detection and isolation for data plane failures for P2MP MPLS LSPs are specified in [RFC6425]. This document describes a mechanism to detect data plane failures for P2MP PW carried over P2MP MPLS LSPs. Jain & Boutros Expires September 10, 2015 [Page 2] Internet-Draft P2MP PW LSP Ping March 2015 This document defines a new FEC 130 Pseudowire sub-TLV for Target FEC Stack for P2MP PW. The FEC 130 Pseudowire sub-TLV is added in Target FEC Stack TLV by the originator of the Echo Request to inform the receiver at P2MP MPLS LSP tail, of the P2MP PW being tested. Multi-segment Pseudowires support is out of scope of this document at present and may be included in future. 2. Specification of Requirements 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]. 3. Terminology ATM: Asynchronous Transfer Mode LSR: Label Switching Router MPLS-OAM: MPLS Operations, Administration and Maintenance P2MP-PW: Point-to-Multipoint PseudoWire PW: PseudoWire TLV: Type Length Value 4. Identifying a P2MP PW This document introduces a new LSP Ping Target FEC Stack sub-TLV, FEC 130 Pseudowire sub-TLV, to identify the P2MP PW under test at the P2MP LSP Tail/Bud node. 4.1. FEC 130 Pseudowire Sub-TLV The FEC 130 Pseudowire sub-TLV fields are taken from P2MP PW FEC Element (FEC Type 0x82) defined in [I-D.ietf-pwe3-p2mp-pw]. The PW Type is a 15-bit number indicating the encapsulation type. It is carried right justified in the field below PW Type with the high- order bit set to zero. All the other fields are treated as opaque values and copied directly from P2MP PW FEC Element (FEC Type 0x82) format. The FEC 130 Pseudowire sub-TLV has the format shown in Figure 1. This TLV will be included in the echo request sent over P2MP PW by the originator of request. Jain & Boutros Expires September 10, 2015 [Page 3] Internet-Draft P2MP PW LSP Ping March 2015 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| PW Type | AGI Type | AGI Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ AGI Value ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AII Type | SAII Length | SAII Value | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ SAII Value (continued) ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: FEC 130 Pseudowire sub-TLV format For Inclusive and Selective P2MP MPLS P-trees, the echo request will be sent using the P2MP MPLS LSP label. For Aggregate Inclusive and Aggregate Selective P-trees, the echo request will be sent using a label stack of [P2MP MPLS P-tree label, upstream assigned P2MP PW label]. The P2MP MPLS P-tree label is the outer label and upstream assigned P2MP PW label is inner label. 5. Operations In this section, we explain the operation of the LSP Ping over P2MP PW. Figure 2 shows a P2MP PW PW1 setup from T-PE1 to remote PEs (T- PE2, T-PE3 and T-PE4). The transport LSP associated with the P2MP PW1 can be MLDP P2MP MPLS LSP or P2MP TE tunnel. Jain & Boutros Expires September 10, 2015 [Page 4] Internet-Draft P2MP PW LSP Ping March 2015 |<--------------P2MP PW---------------->| Native | | Native Service | |<--PSN1->| |<--PSN2->| | Service (AC) V V V V V V (AC) | +-----+ +------+ +------+ | | | | | P1 |=========|T-PE2 |AC3 | +---+ | | | | .......PW1.........>|-------->|CE3| | |T-PE1|=========| . |=========| | | +---+ | | .......PW1........ | +------+ | | | . |=========| . | +------+ | | | . | | . |=========|T-PE3 |AC4 | +---+ +---+ |AC1 | . | | .......PW1.........>|-------->|CE4| |CE1|------->|... | | |=========| | | +---+ +---+ | | . | +------+ +------+ | | | . | +------+ +------+ | | | . |=========| P2 |=========|T-PE4 |AC5 | +---+ | | .......PW1..............PW1.........>|-------->|CE5| | | |=========| |=========| | | +---+ | +-----+ +------+ +------+ | Figure 2: P2MP PW When an operator wants to perform a connectivity check for the P2MP PW1, the operator initiate a LSP-Ping request with the Target FEC Stack TLV containing FEC 130 Pseudowire sub-TLV in the echo request packet. The echo request packet is sent over the P2MP MPLS LSP using the P2MP MPLS LSP label for Inclusive P-tree or with a label stack with Upstream assigned P2MP PW label as inner label and P2MP MPLS LSP label as the top label. The intermediate P router will do swap and replication based on the MPLS LSP label. Once the packet reaches remote terminating PEs, the T-PEs will process the packet and perform checks for the FEC 130 Pseudowire sub-TLV present in the Target FEC Stack TLV as described in Section 4.4 in [RFC4379] and respond according to [RFC4379] processing rules. 6. Encapsulation of OAM Ping Packets The LSP Ping Echo request IPv4/UDP packets will be encapsulated with the MPLS label stack as described in previous sections, followed by the GAL Label [RFC6426]. The GAL label will be followed by the ACH with the Pseudowire Associated Channel Type 16 bit value in the ACH set to IPv4 indicating that the carried packet is an IPv4 packet. Jain & Boutros Expires September 10, 2015 [Page 5] Internet-Draft P2MP PW LSP Ping March 2015 7. Echo Reply using Downstream Assigned Label Root of a P2MP PW may send an optional downstream assigned p2p MPLS label in the LDP Label Mapping message for the P2MP PW signaling. If the root of a P2MP PW expects leaf to send echo reply using the downstream assigned label signaled in the Label Mapping message of the P2MP PW message, the Reply Mode value of 4 "Reply via application level control channel" should be used in Reply Mode field described in Section 3 in [RFC4379] in echo request message for the P2MP PW. 8. Controlling Echo Responses The procedures described in [RFC6425] for preventing congestion of Echo Responses (Echo Jitter TLV) and limiting the echo reply to a single egress node (Node Address P2MP Responder Identifier TLV) can be applied to P2MP PW LSP Ping. 9. Security Considerations The proposal introduced in this document does not introduce any new security considerations beyond that already apply to [RFC6425]. 10. IANA Considerations This document defines a new sub-TLV type to be included in Target FEC Stack TLV (TLV Type 1) [RFC4379] in LSP Ping. IANA is requested to assign a sub-TLV type value to the following sub-TLV from the "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Parameters - TLVs" registry, "TLVs and sub- TLVs" sub- registry: o FEC 130 Pseudowire sub-TLV (See Section 3). Suggested value 24. 11. Acknowledgments The authors would like to thank Shaleen Saxena, Michael Wildt, Tomofumi Hayashi, Danny Prairie for their valuable input and comments. 12. References 12.1. Normative References [I-D.ietf-pwe3-p2mp-pw] Sivabalan, S., Boutros, S., and L. Martini, "Signaling Root-Initiated Point-to-Multipoint Pseudowire using LDP", draft-ietf-pwe3-p2mp-pw-04 (work in progress), March 2012. Jain & Boutros Expires September 10, 2015 [Page 6] Internet-Draft P2MP PW LSP Ping March 2015 [RFC4379] Kompella, K. and G. Swallow, "Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures", RFC 4379, February 2006. [RFC6425] Saxena, S., Swallow, G., Ali, Z., Farrel, A., Yasukawa, S., and T. Nadeau, "Detecting Data-Plane Failures in Point-to-Multipoint MPLS - Extensions to LSP Ping", RFC 6425, November 2011. [RFC6426] Gray, E., Bahadur, N., Boutros, S., and R. Aggarwal, "MPLS On-Demand Connectivity Verification and Route Tracing", RFC 6426, November 2011. 12.2. Informative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4875] Aggarwal, R., Papadimitriou, D., and S. Yasukawa, "Extensions to Resource Reservation Protocol - Traffic Engineering (RSVP-TE) for Point-to-Multipoint TE Label Switched Paths (LSPs)", RFC 4875, May 2007. [RFC5085] Nadeau, T. and C. Pignataro, "Pseudowire Virtual Circuit Connectivity Verification (VCCV): A Control Channel for Pseudowires", RFC 5085, December 2007. [RFC6388] Wijnands, IJ., Minei, I., Kompella, K., and B. Thomas, "Label Distribution Protocol Extensions for Point-to- Multipoint and Multipoint-to-Multipoint Label Switched Paths", RFC 6388, November 2011. [RFC7338] Jounay, F., Kamite, Y., Heron, G., and M. Bocci, "Requirements and Framework for Point-to-Multipoint Pseudowires over MPLS Packet Switched Networks", RFC 7338, September 2014. Authors' Addresses Parag Jain Cisco Systems, Inc. 2000 Innovation Drive Kanata, ON K2K-3E8 Canada Email: paragj@cisco.com Jain & Boutros Expires September 10, 2015 [Page 7] Internet-Draft P2MP PW LSP Ping March 2015 Sami Boutros Cisco Systems, Inc. 3750 Cisco Way San Jose, CA 95134 USA Email: sboutros@cisco.com Jain & Boutros Expires September 10, 2015 [Page 8]