MPLS Working Group R. Gandhi, Ed. Internet-Draft Z. Ali Intended status: Standards Track C. Filsfils Expires: July 13, 2021 F. Brockners Cisco Systems, Inc. B. Wen V. Kozak Comcast January 09, 2021 MPLS Data Plane Encapsulation for In-situ OAM Data draft-gandhi-mpls-ioam-sr-05 Abstract In-situ Operations, Administration, and Maintenance (IOAM) records operational and telemetry information in the data packet while the packet traverses a path between two nodes in the network. This document defines how IOAM data fields are transported with MPLS data plane encapsulation using new Generic Associated Channel (G-ACh), including Segment Routing (SR) with MPLS data plane (SR-MPLS). 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 https://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 July 13, 2021. Copyright Notice Copyright (c) 2021 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 (https://trustee.ietf.org/license-info) in effect on the date of Gandhi, et al. Expires July 13, 2021 [Page 1] Internet-Draft In-situ OAM for MPLS Data plane January 2021 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Requirement Language . . . . . . . . . . . . . . . . . . 3 2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 3 3. IOAM Data Field Encapsulation in MPLS Header . . . . . . . . 3 4. Edge-to-Edge IOAM . . . . . . . . . . . . . . . . . . . . . . 5 4.1. Edge-to-Edge IOAM Indicator Label . . . . . . . . . . . . 5 4.2. Procedure for Edge-to-Edge IOAM . . . . . . . . . . . . . 5 4.3. Edge-to-Edge IOAM Indicator Label Allocation . . . . . . 6 5. Hop-by-Hop IOAM . . . . . . . . . . . . . . . . . . . . . . . 6 5.1. Hop-by-Hop IOAM Indicator Label . . . . . . . . . . . . . 6 5.2. Procedure for Hop-by-Hop IOAM . . . . . . . . . . . . . . 7 5.3. Hop-by-Hop IOAM Indicator Label Allocation . . . . . . . 8 6. Considerations for IOAM Indicator Label . . . . . . . . . . . 8 6.1. Considerations for ECMP . . . . . . . . . . . . . . . . . 8 6.2. Node Capability . . . . . . . . . . . . . . . . . . . . . 8 6.3. MSD Considerations . . . . . . . . . . . . . . . . . . . 9 6.4. Nested MPLS Encapsulation . . . . . . . . . . . . . . . . 9 7. SR-MPLS Header with IOAM . . . . . . . . . . . . . . . . . . 9 8. Security Considerations . . . . . . . . . . . . . . . . . . . 10 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 10.1. Normative References . . . . . . . . . . . . . . . . . . 11 10.2. Informative References . . . . . . . . . . . . . . . . . 12 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 13 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 1. Introduction In-situ Operations, Administration, and Maintenance (IOAM) records operational and telemetry information within the packet while the packet traverses a particular network domain. The term "in-situ" refers to the fact that the IOAM data fields are added to the data packets rather than being sent within the probe packets specifically dedicated to OAM or Performance Measurement (PM). The IOAM data fields are defined in [I-D.ietf-ippm-ioam-data], and can be used for various use-cases for OAM and PM. The IOAM data fields are further updated in [I-D.ietf-ippm-ioam-direct-export] for direct export use- Gandhi, et al. Expires July 13, 2021 [Page 2] Internet-Draft In-situ OAM for MPLS Data plane January 2021 cases and in [I-D.ietf-ippm-ioam-flags] for Loopback and Active flags. This document defines how IOAM data fields are transported with MPLS data plane encapsulations using new Generic Associated Channel (G-ACh), including Segment Routing (SR) with MPLS data plane (SR- MPLS). 2. Conventions 2.1. Requirement Language 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] [RFC8174] when, and only when, they appear in all capitals, as shown here. 2.2. Abbreviations Abbreviations used in this document: ECMP Equal Cost Multi-Path G-ACh Generic Associated Channel IOAM In-situ Operations, Administration, and Maintenance MPLS Multiprotocol Label Switching OAM Operations, Administration, and Maintenance PM Performance Measurement POT Proof-of-Transit PSID Path Segment Identifier SR Segment Routing SR-MPLS Segment Routing with MPLS Data plane 3. IOAM Data Field Encapsulation in MPLS Header The IOAM data fields defined in [I-D.ietf-ippm-ioam-data] are used. IOAM data fields are carried in the MPLS header as shown in Figure 1. More than one trace options can be present in the IOAM data fields. G-ACh [RFC5586] provides a mechanism to transport OAM and other control messages over MPLS data plane. The IOAM G-ACh header Gandhi, et al. Expires July 13, 2021 [Page 3] Internet-Draft In-situ OAM for MPLS Data plane January 2021 [RFC5586] with new IOAM G-ACh type is added immediately after the the MPLS label stack in the MPLS header as shown in Figure 1, before the IOAM data field(s). 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 0 0 1|Version| Reserved | IOAM G-ACh | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | Reserved | Block Number | IOAM-OPT-Type |IOAM HDR Length| | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ I | | O | | A ~ IOAM Option and Data Space ~ M | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+ | | | | | Payload + Padding | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: IOAM Encapsulation in MPLS Header The fields related to the encapsulation of IOAM data fields in the MPLS header are defined as follows: IP Version Number 0001b: The first four octets are IP Version Field part of a G-ACh header [RFC5586]. Version: The Version field is set to 0, as defined in [RFC4385]. IOAM G-ACh: Generic Associated Channel (G-ACh) Type (value TBA3) for IOAM [RFC5586]. Reserved: Reserved Bits MUST be set to zero upon transmission and ignored upon receipt. Block Number: The Block Number can be used to aggregate the IOAM data collected in data plane, e.g. compute measurement metrics for each block of a flow. It is also used to correlate the IOAM data on different nodes. IOAM-OPT-Type: 8-bit field defining the IOAM Option type, as defined in Section 8.1 of [I-D.ietf-ippm-ioam-data]. Gandhi, et al. Expires July 13, 2021 [Page 4] Internet-Draft In-situ OAM for MPLS Data plane January 2021 IOAM HDR LEN: 8-bit unsigned integer. Length of the IOAM HDR in 4-octet units. IOAM Option and Data Space: IOAM option header and data is present as defined by the IOAM-OPT-Type field, and is defined in Section 5 of [I-D.ietf-ippm-ioam-data]. 4. Edge-to-Edge IOAM 4.1. Edge-to-Edge IOAM Indicator Label The E2E IOAM Indicator Label is used to indicate the presence of the E2E IOAM data field in the MPLS header as shown in Figure 2. If only edge nodes need to process IOAM data then E2E IOAM Indicator Label is used so that transit nodes can ignore it. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Label(1) | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Label(n) | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extension Label (15) | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | E2E IOAM Indicator Label | TC |1| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Packet as shown in Figure 1 | . . +---------------------------------------------------------------+ Figure 2: E2E IOAM Encapsulation in MPLS Header 4.2. Procedure for Edge-to-Edge IOAM The Edge-to-Edge (E2E) IOAM includes IOAM Option-Type as Edge-to-Edge Option-Type [I-D.ietf-ippm-ioam-data]. This section summarizes the procedure for data encapsulation and decapsulation for Edge-to-Edge IOAM in MPLS header. o The encapsulating node inserts the E2E IOAM Indicator Label and one or more IOAM data field(s) in the MPLS header. o The decapsulating node "punts the timestamped copy" of the received data packet as is including IOAM data fields when the node recognizes the IOAM Indicator Label. It is punted with Gandhi, et al. Expires July 13, 2021 [Page 5] Internet-Draft In-situ OAM for MPLS Data plane January 2021 receive timestamp to the slow path for IOAM processing. The receive timestamp is required by various E2E OAM use-cases, including streaming telemetry. Note that it is not necessarily punted to the control-plane. o The decapsulating node processes the IOAM data field(s) using the procedures defined in [I-D.ietf-ippm-ioam-data]. An example of IOAM processing is to export the data fields, send data fields via streaming telemetry, etc. o The decapsulating node also pops the IOAM Indicator Label and the IOAM data fields from received packet. A copy of the decapsulated data packet is forwarded downstream or terminated locally similar to the regular data packets. 4.3. Edge-to-Edge IOAM Indicator Label Allocation The E2E IOAM Indicator Label is used to indicate the presence of the E2E IOAM data field in the MPLS header. The E2E IOAM Indicator Label can be allocated using one of the following methods: o Label assigned by IANA with value TBA1 from the Extended Special- Purpose MPLS Values [I-D.ietf-mpls-spl-terminology]. o Label allocated by a Controller from the global table of the decapsulating node. The Controller provisions the label on both encapsulating and decapsulating nodes. o Label allocated by the decapsulating node and signalled or advertised in the network. The signaling and/or advertisement extension for this is outside the scope of this document. 5. Hop-by-Hop IOAM 5.1. Hop-by-Hop IOAM Indicator Label The HbH IOAM Indicator Label is used to indicate the presence of the HbH IOAM data field in the MPLS header as shown in Figure 3. Different IOAM Indicator Labels are used for E2E and HbH IOAM to optimize processing on transit nodes and for checking if IOAM data fields need to be processed on transit nodes. If only edge nodes need to process IOAM data then E2E IOAM Indicator Label is used so that transit nodes can ignore it. If both edge and transit nodes need to process IOAM data then HbH IOAM Indicator Label is used. Gandhi, et al. Expires July 13, 2021 [Page 6] Internet-Draft In-situ OAM for MPLS Data plane January 2021 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Label(1) | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Label(n) | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extension Label (15) | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | HbH IOAM Indicator Label | TC |1| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Packet as shown in Figure 1 | . . +---------------------------------------------------------------+ Figure 3: HbH IOAM Encapsulation in MPLS Header 5.2. Procedure for Hop-by-Hop IOAM The Hop-by-Hop (HbH) IOAM includes IOAM Option-Types IOAM Pre- allocated Trace Option-Type, IOAM Incremental Trace Option-Type and IOAM Proof of Transit (POT) Option-Type [I-D.ietf-ippm-ioam-data]. This section summarizes the procedure for data encapsulation and decapsulation for Hop-by-hop IOAM in MPLS header. o The encapsulating node inserts the HbH IOAM Indicator Label and one or more IOAM data field(s) in the MPLS header. o The intermediate node enabled with HbH IOAM functions processes the data packet including IOAM data fields as defined in [I-D.ietf-ippm-ioam-data] when the node recognizes the HbH IOAM Indicator Label present in the MPLS header. The intermediate node may 'punt the timestamped copy' of the received data packet including the IOAM data fields as required by the IOAM data field processing. It is punted with receive timestamp to the slow path for IOAM processing. o The intermediate node forwards a copy of the processsed data packet downstream. o The decapsulating node "punts the timestamped copy" of the received data packet as is including IOAM data fields when the node recognizes the IOAM Indicator Label. It is punted with receive timestamp to the slow path for IOAM processing. The receive timestamp is required by various E2E OAM use-cases, Gandhi, et al. Expires July 13, 2021 [Page 7] Internet-Draft In-situ OAM for MPLS Data plane January 2021 including streaming telemetry. Note that it is not necessarily punted to the control-plane. o The decapsulating node processes the IOAM data field(s) using the procedures defined in [I-D.ietf-ippm-ioam-data]. An example of IOAM processing is to export the data fields, send data fields via streaming telemetry, etc. o The decapsulating node also pops the IOAM Indicator Label and the IOAM data fields from received packet. A copy of the decapsulated data packet is forwarded downstream or terminated locally similar to the regular data packets. 5.3. Hop-by-Hop IOAM Indicator Label Allocation The HbH IOAM Indicator Label is used to indicate the presence of the HbH IOAM data field in the MPLS header. The HbH IOAM Indicator Label can be allocated using one of the following methods: o Label assigned by IANA with value TBA2 from the Extended Special- Purpose MPLS Values [I-D.ietf-mpls-spl-terminology]. o Label allocated by a Controller from the network-wide global table. The Controller provisions the labels on all nodes participating in IOAM functions along the data traffic path. 6. Considerations for IOAM Indicator Label 6.1. Considerations for ECMP The encapsulating node needs to make sure the IOAM data field does not start with a well known IP Version Number (e.g. 0x4 for IPv4 and 0x6 for IPv6) as it can alter the hashing function for ECMP that uses the IP header. This is achieved by using the IOAM G-ACh with IP Version Number 0001b after the MPLS label stack [RFC5586]. Note that the hashing function for ECMP that uses the labels from the MPLS header may now include the IOAM Indicator Label. When entropy label [RFC6790] is used for hashing function for ECMP, the procedure defined in this document does not alter the hashing function. 6.2. Node Capability The decapsulating node that has to pop the IOAM Indicator Label, data fields, and perform the IOAM function may not be capable of supporting it. The encapsulating node needs to know if the Gandhi, et al. Expires July 13, 2021 [Page 8] Internet-Draft In-situ OAM for MPLS Data plane January 2021 decapsulating node can support the IOAM function. The signaling extension for this capability exchange is outside the scope of this document. The intermediate node that is not capable of supporting the IOAM functions defined in this document, can simply skip the IOAM processing of the MPLS header. 6.3. MSD Considerations The SR path computation needs to know the Maximum SID Depth (MSD) that can be imposed at each node/link of a given SR path [RFC8664]. This ensures that the SID stack depth of a computed path does not exceed the number of SIDs the node is capable of imposing. The MSD used for path computation MUST include the IOAM Indicator Label. 6.4. Nested MPLS Encapsulation The data packets with IOAM data fields carry only one IOAM Indicator Label in the MPLS header. Any intermediate node that adds additional MPLS encapsulation in the MPLS header may further update the IOAM data fields in the header without inserting another IOAM Indicator Label. 7. SR-MPLS Header with IOAM Segment Routing (SR) technology leverages the source routing paradigm [RFC8660]. A node steers a packet through a controlled set of instructions, called segments, by pre-pending the packet with an SR header. In the SR with MPLS data plane (SR-MPLS), the SR header is instantiated through a label stack. An example of data packet carrying the SR-MPLS header with Path Segment Identifier (PSID) [I-D.ietf-spring-mpls-path-segment] and E2E IOAM encapsulation is shown in Figure 4. The Path Segment Identifier allows to identify the path associated with the data traffic being monitored for IOAM on the decapsulating node. Gandhi, et al. Expires July 13, 2021 [Page 9] Internet-Draft In-situ OAM for MPLS Data plane January 2021 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Label(1) | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . . . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Label(n) | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | PSID | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extension Label (15) | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | E2E IOAM Indicator Label | TC |1| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Packet as shown in Figure 1 | . . +---------------------------------------------------------------+ Figure 4: Example SR-MPLS Header with E2E IOAM 8. Security Considerations The security considerations of SR-MPLS are discussed in [RFC8660], and the security considerations of IOAM in general are discussed in [I-D.ietf-ippm-ioam-data]. IOAM is considered a "per domain" feature, where one or several operators decide on leveraging and configuring IOAM according to their needs. Still, operators need to properly secure the IOAM domain to avoid malicious configuration and use, which could include injecting malicious IOAM packets into a domain. Routers that support G-ACh are subject to the same security considerations as defined in [RFC4385] and [RFC5586]. 9. IANA Considerations IANA maintains the "Special-Purpose Multiprotocol Label Switching (MPLS) Label Values" registry (see ). IANA is requested to allocate IOAM Indicator Label value from the "Extended Special- Purpose MPLS Label Values" registry: Gandhi, et al. Expires July 13, 2021 [Page 10] Internet-Draft In-situ OAM for MPLS Data plane January 2021 +--------+--------------------------+---------------+ | Value | Description | Reference | +--------+--------------------------+---------------+ | TBA1 | E2E IOAM Indicator Label | This document | +--------+--------------------------+---------------+ | TBA2 | HbH IOAM Indicator Label | This document | +--------+--------------------------+---------------+ IANA maintains G-ACh Type Registry (see ). IANA is requested to allocate a value for IOAM G-ACh Type from "MPLS Generalized Associated Channel (G-ACh) Types (including Pseudowire Associated Channel Types)" registry. +-------+-----------------+---------------+ | Value | Description | Reference | +-------+-----------------+---------------+ | TBA3 | IOAM G-ACh Type | This document | +-------+-----------------+---------------+ Table 1: IOAM G-ACh Type 10. References 10.1. Normative References [I-D.ietf-ippm-ioam-data] Brockners, F., Bhandari, S., and T. Mizrahi, "Data Fields for In-situ OAM", draft-ietf-ippm-ioam-data-11 (work in progress), November 2020. [I-D.ietf-ippm-ioam-direct-export] Song, H., Gafni, B., Zhou, T., Li, Z., Brockners, F., Bhandari, S., Sivakolundu, R., and T. Mizrahi, "In-situ OAM Direct Exporting", draft-ietf-ippm-ioam-direct- export-02 (work in progress), November 2020. [I-D.ietf-ippm-ioam-flags] Mizrahi, T., Brockners, F., Bhandari, S., Sivakolundu, R., Pignataro, C., Kfir, A., Gafni, B., Spiegel, M., and J. Lemon, "In-situ OAM Flags", draft-ietf-ippm-ioam-flags-03 (work in progress), October 2020. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . Gandhi, et al. Expires July 13, 2021 [Page 11] Internet-Draft In-situ OAM for MPLS Data plane January 2021 [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, DOI 10.17487/RFC4385, February 2006, . [RFC5586] Bocci, M., Ed., Vigoureux, M., Ed., and S. Bryant, Ed., "MPLS Generic Associated Channel", RFC 5586, DOI 10.17487/RFC5586, June 2009, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8660] Bashandy, A., Ed., Filsfils, C., Ed., Previdi, S., Decraene, B., Litkowski, S., and R. Shakir, "Segment Routing with the MPLS Data Plane", RFC 8660, DOI 10.17487/RFC8660, December 2019, . [RFC8664] Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W., and J. Hardwick, "Path Computation Element Communication Protocol (PCEP) Extensions for Segment Routing", RFC 8664, DOI 10.17487/RFC8664, December 2019, . 10.2. Informative References [I-D.ietf-mpls-spl-terminology] Andersson, L., Kompella, K., and A. Farrel, "Special Purpose Label terminology", draft-ietf-mpls-spl- terminology-05 (work in progress), November 2020. [I-D.ietf-spring-mpls-path-segment] Cheng, W., Li, H., Chen, M., Gandhi, R., and R. Zigler, "Path Segment in MPLS Based Segment Routing Network", draft-ietf-spring-mpls-path-segment-03 (work in progress), September 2020. [RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and L. Yong, "The Use of Entropy Labels in MPLS Forwarding", RFC 6790, DOI 10.17487/RFC6790, November 2012, . Gandhi, et al. Expires July 13, 2021 [Page 12] Internet-Draft In-situ OAM for MPLS Data plane January 2021 Acknowledgements The authors would like to thank Patrick Khordoc, Shwetha Bhandari and Vengada Prasad Govindan for the discussions on IOAM. The authors would also like to thank Tarek Saad, Loa Andersson, Greg Mirsky, Stewart Bryant, and Cheng Li for providing many useful comments. The authors would also like to thank Mach Chen, Andrew Malis, Matthew Bocci, and Nick Delregno for the MPLS-RT reviews. Contributors Sagar Soni Cisco Systems, Inc. Email: sagsoni@cisco.com Authors' Addresses Rakesh Gandhi (editor) Cisco Systems, Inc. Canada Email: rgandhi@cisco.com Zafar Ali Cisco Systems, Inc. Email: zali@cisco.com Clarence Filsfils Cisco Systems, Inc. Belgium Email: cf@cisco.com Frank Brockners Cisco Systems, Inc. Hansaallee 249, 3rd Floor DUESSELDORF, NORDRHEIN-WESTFALEN 40549 Germany Email: fbrockne@cisco.com Gandhi, et al. Expires July 13, 2021 [Page 13] Internet-Draft In-situ OAM for MPLS Data plane January 2021 Bin Wen Comcast Email: Bin_Wen@cable.comcast.com Voitek Kozak Comcast Email: Voitek_Kozak@comcast.com Gandhi, et al. Expires July 13, 2021 [Page 14]