Network Working Group X. Geng Internet-Draft M. Chen Intended status: Experimental Huawei Expires: September 10, 2020 March 09, 2020 Redundancy SID and Merging SID for Redundancy Protection draft-geng-spring-redundancy-protection-sid-00 Abstract Redundancy protection is a method of service protection by sending copies of the same packets of one flow over multiple paths, which includes packet replication, elimination and ordering. This document defines Redundancy SID and Merging SID to support redundancy protection. Requirements 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 . 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 September 10, 2020. Copyright Notice Copyright (c) 2020 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 Geng & Chen Expires September 10, 2020 [Page 1] Internet-Draft Abbreviated-Title March 2020 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. Terminology and Conventions . . . . . . . . . . . . . . . . . 2 3. Redundancy Protection Introduction . . . . . . . . . . . . . 3 4. Redundancy SID . . . . . . . . . . . . . . . . . . . . . . . 3 5. Merging SID . . . . . . . . . . . . . . . . . . . . . . . . . 4 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 7. Security Considerations . . . . . . . . . . . . . . . . . . . 4 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 9. Normative References . . . . . . . . . . . . . . . . . . . . 4 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction Redundancy protection is a method of providing 1+1 protection by sending copies of the same packets of one flow over multiple paths, which includes packet replication, elimination and ordering. This document defines Redundancy SID and Merging SID to support redundancy protection. 2. Terminology and Conventions 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]. Redundancy Node: the start point of redundancy protection, which is a network device that could implement packet replication. Merging Node: the end point of redundancy protection, which is a network node that could implement packet elimination and ordering (optionally). Editor's Note: Similar mechanism is defined as "Service Protection" in the [RFC8655]. In this document, we define a new term "Redundancy Protection" to distinguish with other service protection method. Some of the terms are the similar as [RFC8655]. Geng & Chen Expires September 10, 2020 [Page 2] Internet-Draft Abbreviated-Title March 2020 3. Redundancy Protection Introduction The figure shows how to provide redundancy protection in an Segment Routing Domain. | | |<---------------SR Domain--------------->| | | | +------+T2+----+ | +---+ +---+ +-+-+ +-+-+ +---+ +---+ | E1+----| In|--+T1+--+Red| |Mer|--+T4+--| Eg+----+ E2| +---+ +---+ +-+-+ +-+-+ +---+ +---+ +-----+T3+-----+ The process of redundancy protection is as follows: 1) The flow is replicated in Red(Redundancy Node); 2) Tow replicated flows go through different paths till Mer (Merging Node); When there is any failures happened in one the path, the service continues to deliver through the other path without break; 3) The first received packet of the flow is transmitted from Mer (Merging Node) to Eg(Egress), and the redundant packets are eliminated. 4) Sometimes, the packet will arrive out of order because of redundancy protection, the function of reordering may be necessary in the Merging Node. In this document, we introduces Redundancy SID and Merging SID to implement redundancy protection. The newly defined SIDs apply equally to both SR-MPLS and SRv6. 4. Redundancy SID Redundancy SID is a variation of binding SID defined in [I-D.ietf-spring-segment-routing-policy] Redundancy SID indicates the following operations: o Steering the packet into the corresponding redundancy policy o Packet replication based on the redundancy policy, e.g., the number of replication copies o Encapsulate the packet with necessary meta data (e.g., flow identification, sequence number) if it is not included in the original packet Geng & Chen Expires September 10, 2020 [Page 3] Internet-Draft Abbreviated-Title March 2020 5. Merging SID Merging SID indicates the following operations: o Packet elimination: forward the first received packets and eliminate the redundant packets. o Packet ordering(optional): reorder the packets if the packet arrives out of order 6. IANA Considerations TBD 7. Security Considerations TBD 8. Acknowledgements Thank you for valuable comments from James Guichard and Andrew Mail 9. Normative References [I-D.ietf-spring-segment-routing-policy] Filsfils, C., Sivabalan, S., Voyer, D., Bogdanov, A., and P. Mattes, "Segment Routing Policy Architecture", draft- ietf-spring-segment-routing-policy-06 (work in progress), December 2019. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas, "Deterministic Networking Architecture", RFC 8655, DOI 10.17487/RFC8655, October 2019, . Authors' Addresses Xuesong Geng Huawei Email: gengxuesong@huawei.com Geng & Chen Expires September 10, 2020 [Page 4] Internet-Draft Abbreviated-Title March 2020 Mach(Guoyi) Chen Huawei Email: mach.chen@huawei.com Geng & Chen Expires September 10, 2020 [Page 5]