SPRING Working Group R. Gandhi, Ed. Internet-Draft Z. Ali Intended status: Standards Track C. Filsfils Expires: October 27, 2019 F. Brockners Cisco Systems, Inc. B. Wen V. Kozak Comcast April 25, 2019 Segment Routing with MPLS Data Plane Encapsulation for In-situ OAM Data draft-gandhi-spring-ioam-sr-mpls-01 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 points in the network. This document defines how IOAM data fields are transported with the Segment Routing with MPLS data plane (SR-MPLS) encapsulation. 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." Copyright Notice Copyright (c) 2019 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 Gandhi, et al. Expires October 27, 2019 [Page 1] Internet-Draft In-situ OAM for SR-MPLS Data plane April 25, 2019 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 SR-MPLS Header . . . . . . . 3 4. Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4.1. IOAM Indicator Label . . . . . . . . . . . . . . . . . . . 5 4.2. Hashing Function . . . . . . . . . . . . . . . . . . . . . 5 4.3. Node Capability . . . . . . . . . . . . . . . . . . . . . 5 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 6. Security Considerations . . . . . . . . . . . . . . . . . . . 6 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 8. Normative References . . . . . . . . . . . . . . . . . . . . . 7 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 1. Introduction In-situ Operations, Administration, and Maintenance (IOAM) records OAM 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 probe packets specifically dedicated to OAM. Segment Routing (SR) leverages the source routing paradigm [I-D.ietf-spring-segment-routing-mpls]. A node steers a packet through a controlled set of instructions, called segments, by pre- pending the packet with an SR header. In the MPLS data plane, the SR header is instantiated through a label stack. This document defines how IOAM data fields are transported with the SR with MPLS data plane (SR-MPLS) encapsulation. The IOAM data fields carried are defined in [I-D.ietf-ippm-ioam-data], and can be used for various use-cases including Performance Measurement (PM). Gandhi, et al. Expires October 27, 2019 [Page 2] Internet-Draft In-situ OAM for SR-MPLS Data plane April 25, 2019 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: IOAM In-situ Operations, Administration, and Maintenance OAM Operations, Administration, and Maintenance PM Performance Measurement PoT Proof-of-Transit SR Segment Routing SR-MPLS Segment Routing with MPLS Data plane 3. IOAM Data Field Encapsulation in SR-MPLS Header SR-MPLS encapsulation is defined in [I-D.ietf-spring-segment-routing-mpls]. IOAM data fields are carried in the SR-MPLS header, as IOAM data fields. The different IOAM data fields defined in [I-D.ietf-ippm-ioam-data] are added as TLVs. More than one TLVs can be present in the IOAM data fields. The IOAM Indicator Label is added at the bottom of the MPLS label stack (S flag set to 1) to indicate the presence of the IOAM data fields in the MPLS header. Gandhi, et al. Expires October 27, 2019 [Page 3] Internet-Draft In-situ OAM for SR-MPLS Data plane April 25, 2019 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM Indicator Label | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+ | IOAM-Type | IOAM HDR LEN | RESERVED | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ I ! | O ! | A ~ IOAM Option and Data Space ~ M | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+ | | | | | Payload + Padding (L2/L3/ESP/...) | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: IOAM data encapsulation in SR-MPLS Header IOAM Indicator Label as defined in Section 4.1. The fields related to the encapsulation of IOAM data fields in the SR-MPLS header are defined as follows: IOAM-Type: 8-bit field defining the IOAM Option type, as defined in Section 4 of [I-D.ietf-ippm-ioam-data]. IOAM HDR LEN: 8-bit unsigned integer. Length of the IOAM HDR in 4-octet units. RESERVED: 8-bit reserved field MUST be set to zero upon transmission and ignored upon receipt. IOAM Option and Data Space: IOAM option header and data is present as defined by the IOAM-Type field, and is defined in Section 4 of [I-D.ietf-ippm-ioam-data]. 4. Procedure This section summarizes the procedure for IOAM data encapsulation in SR-MPLS. o The ingress node inserts the IOAM Indicator Label and one or more Gandhi, et al. Expires October 27, 2019 [Page 4] Internet-Draft In-situ OAM for SR-MPLS Data plane April 25, 2019 IOAM TLV(s) in the MPLS header. o The egress node "forwards and punts the timestamped copy" of the data packet including IOAM TLVs when the node recognizes the IOAM Indicator Label. o The egress node also pops the IOAM Indicator Label and the IOAM TLVs from the MPLS header. 4.1. IOAM Indicator Label The IOAM Indicator Label can be a allocated using one of the following methods: o Label assigned by IANA with value TBA1. o Label allocated by a controller from the global table of the egress node. The controller provisions the label on both ingress and egress nodes. o Label allocated by the egress node from the global label table of the egress node. The signaling extension for this is outside the scope of this document. 4.2. Hashing Function The ingress node needs to make sure the IOAM TLV does not start with a well known protocol type (e.g. 0x4 for IPv4 and 0x6 for IPv6) and does not alter the hashing function that uses the IP header. Note that the hashing function that uses the label values from the MPLS header may also now include the IOAM Indicator Label. 4.3. Node Capability The egress node that has to pop the IOAM Indicator Label, TLVs, and perform the IOAM function may not be capable of supporting it. The ingress node needs to know if the egress node can support the IOAM function. The signaling extension for this capability exchange is outside the scope of this document. 5. IANA Considerations IANA maintains the "Special-Purpose Multiprotocol Label Switching (MPLS) Label Values" registry (see ). IANA is requested to allocate IOAM Indicator Label Gandhi, et al. Expires October 27, 2019 [Page 5] Internet-Draft In-situ OAM for SR-MPLS Data plane April 25, 2019 value from the "Special-Purpose MPLS Label Values" registry: +---------------+-------------------------+---------------+ | Value | Description | Reference | +---------------+-------------------------+---------------+ | TBA1 | IOAM Indicator Label | This document | +---------------+-------------------------+---------------+ 6. Security Considerations The security considerations of SR-MPLS are discussed in [I-D.ietf-spring-segment-routing-mpls], 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. 7. Acknowledgements The authors would like to thank Shwetha Bhandari and Vengada Prasad Govindan for the discussions on IOAM. Gandhi, et al. Expires October 27, 2019 [Page 6] Internet-Draft In-situ OAM for SR-MPLS Data plane April 25, 2019 8. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/ RFC2119, March 1997. [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", RFC 8174, May 2017. [I-D.ietf-spring-segment-routing-mpls] Bashandy, A., Filsfils, C., Previdi, S., Decraene, B., Litkowski, S., and R. Shakir, "Segment Routing with MPLS data plane", draft-ietf-spring-segment-routing-mpls, work in progress. [I-D.ietf-ippm-ioam-data] Brockners, F., Bhandari, S., Pignataro, C., Gredler, H., Leddy, J., Youell, S., Mizrahi, T., Mozes, D., Lapukhov, P., Chang, R., and Bernier, D., "Data Fields for In-situ OAM", draft-ietf-ippm-ioam-data, work in progress. Contributors Sagar Soni Cisco Systems, Inc. Email: sagsoni@cisco.com Patrick Khordoc Cisco Systems, Inc. Email: pkhordoc@cisco.com Authors' Addresses Rakesh Gandhi (editor) Cisco Systems, Inc. Canada Email: rgandhi@cisco.com Zafar Ali Cisco Systems, Inc. Email: zali@cisco.com Gandhi, et al. Expires October 27, 2019 [Page 7] Internet-Draft In-situ OAM for SR-MPLS Data plane April 25, 2019 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 Bin Wen Comcast Email: Bin_Wen@cable.comcast.com Voitek Kozak Comcast Email: Voitek_Kozak@comcast.com Gandhi, et al. Expires October 27, 2019 [Page 8]