MPLS Y. Liu Internet-Draft ZTE Intended status: Standards Track 6 June 2025 Expires: 8 December 2025 MNA for Metadata in SR-MPLS Service Programming draft-liu-mpls-mna-sr-service-metadata-00 Abstract This document defines MPLS Network Action(MNA) encoding to carry metadata in SR service programming with SR-MPLS data plane. 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 8 December 2025. Copyright Notice Copyright (c) 2025 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 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 Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Liu Expires 8 December 2025 [Page 1] Internet-Draft MNA for Metadata June 2025 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. MNA ISD Encoding for Metadata in SR-MPLS Service Programming . . . . . . . . . . . . . . . . . . . . . . . 3 3.1. Fixed-Length Service Metadata . . . . . . . . . . . . . . 3 3.2. Variable-Length Service Metadata . . . . . . . . . . . . 4 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . 5 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 6.1. Normative References . . . . . . . . . . . . . . . . . . 5 6.2. Informative References . . . . . . . . . . . . . . . . . 6 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6 1. Introduction [I-D.ietf-spring-sr-service-programming] defines data plane functionality required to implement service segments and achieve service programming in SR-enabled MPLS and IPv6 networks. Metadata[RFC7665] provides contextual information about the data packets which traverse a programmed service path. However, there's yet no standard method to carry service metadata with the SR-MPLS data plane, which make the solution for service programming in SR-MPLS incomplete MPLS Network Action (MNA) [I-D.ietf-mpls-mna-fwk] is used to indicate action for Label Switched Paths (LSPs) and/or MPLS packets, and to transfer data needed for the action. [I-D.ietf-mpls-mna-hdr] defines the MNA sub-stack solution for carrying Network Action Indicators and Ancillary Data in the label stack. This document defines MPLS Network Action(MNA) encoding to carry metadata in SR service programming with SR-MPLS data plane. 2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. Liu Expires 8 December 2025 [Page 2] Internet-Draft MNA for Metadata June 2025 3. MNA ISD Encoding for Metadata in SR-MPLS Service Programming The metadata in SR-MPLS Service Programming is placed as part of the ISD block in an MPLS label stack according to the MNA encoding principles defined in [I-D.ietf-mpls-mna-hdr]. Two types of metadata for SR-MPLS service programming are defined: fixed-length service metadata and variable-length service metadata. 3.1. Fixed-Length Service Metadata The format of fixed-length service metadata is shown 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MNA Label | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Opcode = TBA1 | Servie Metadata |R|IHS|S|U| NASL | NAL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1| Servie Metadata |S| | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1| Servie Metadata |S| | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1| Servie Metadata |S| | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Where: * The MNA Label is defined in [I-D.ietf-mpls-mna-hdr]. * S: the Bottom of Stack field [RFC3032]. * Opcode: TBA1, indicating the fixed-length service metadata. * R,IHS and U fields are set as specified in [I-D.ietf-mpls-mna-hdr]. * NASL: The Network Action Sub-Stack Length (NASL) as specified in [I-D.ietf-mpls-mna-hdr]. The value is 3. * NAL: Network Action Length as specified in [I-D.ietf-mpls-mna-hdr]. The number of extra LSEs used for servie metadata encoding. The value is 3. * Opcode is MNA-IOAM-DEX opcode (value TBA2) to be assigned by IANA. * Servie Metadata: 102-bit field to carry metadata Liu Expires 8 December 2025 [Page 3] Internet-Draft MNA for Metadata June 2025 3.2. Variable-Length Service Metadata The format of variable-length service metadata is shown 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MNA Label | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Opcode = TBA2 | Servie Metadata |R|IHS|S|U| NASL | NAL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~1| Servie Metadata |S| ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Where: * The MNA Label is defined in [I-D.ietf-mpls-mna-hdr]. * S: the Bottom of Stack field [RFC3032]. * Opcode: TBA2, indicating the variable-length service metadata. * R,IHS and U fields are set as specified in [I-D.ietf-mpls-mna-hdr]. * NASL: The Network Action Sub-Stack Length (NASL) as specified in [I-D.ietf-mpls-mna-hdr]. * NAL: Network Action Length as specified in [I-D.ietf-mpls-mna-hdr]. The number of extra LSEs used for servie metadata encoding. * Servie Metadata: The field length depends on the value of NAL. 4. IANA Considerations IANA is requested to assign codepoints from its Network Action Opcodes registry (creation requested in [I-D.ietf-mpls-mna-hdr]) as specified in Table 1. Liu Expires 8 December 2025 [Page 4] Internet-Draft MNA for Metadata June 2025 +------+--------------------------------+-------------+ |Opcode| Name | Reference | | | | | +------+--------------------------------+-------------+ | TBA1 | In-Stack Network Action for |This document| | | Fixed-Length Servie Metadata | | +------+--------------------------------+-------------+ | TBA2 | In-Stack Network Action for |This document| | | Variable-Length Servie Metadata| | +------+--------------------------------+-------------+ 5. Security Considerations Security considerations discussed in [I-D.ietf-mpls-mna-fwk], [I-D.ietf-mpls-mna-hdr] and [I-D.ietf-spring-sr-service-programming] apply to this document. 6. References 6.1. Normative References [I-D.ietf-mpls-mna-fwk] Andersson, L., Bryant, S., Bocci, M., and T. Li, "MPLS Network Actions (MNA) Framework", Work in Progress, Internet-Draft, draft-ietf-mpls-mna-fwk-15, 27 December 2024, . [I-D.ietf-mpls-mna-hdr] Rajamanickam, J., Gandhi, R., Zigler, R., Song, H., and K. Kompella, "MPLS Network Action (MNA) Sub-Stack Solution", Work in Progress, Internet-Draft, draft-ietf-mpls-mna-hdr- 12, 3 March 2025, . [I-D.ietf-spring-sr-service-programming] Clad, F., Xu, X., Filsfils, C., Bernier, D., Li, C., Decraene, B., Ma, S., Yadlapalli, C., Henderickx, W., and S. Salsano, "Service Programming with Segment Routing", Work in Progress, Internet-Draft, draft-ietf-spring-sr- service-programming-11, 23 February 2025, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . Liu Expires 8 December 2025 [Page 5] Internet-Draft MNA for Metadata June 2025 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . 6.2. Informative References [RFC7665] Halpern, J., Ed. and C. Pignataro, Ed., "Service Function Chaining (SFC) Architecture", RFC 7665, DOI 10.17487/RFC7665, October 2015, . Author's Address Yao Liu ZTE Nanjing China Email: liu.yao71@zte.com.cn Liu Expires 8 December 2025 [Page 6]