Network Working Group Z. Li Internet-Draft Z. Hu Intended status: Standards Track J. Dong Expires: September 22, 2022 Huawei Technologies March 21, 2022 Topology Identifier in IPv6 Extension Header draft-li-6man-topology-id-00 Abstract This document proposes a new Hop-by-Hop option of IPv6 extension header to carry the topology identifier, which is used to identify the forwarding table instance created by the Multi Topology Routing or Flexible Algorithm. 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 RFC 2119 [RFC2119]. 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 22, 2022. Copyright Notice Copyright (c) 2022 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 Li, et al. Expires September 22, 2022 [Page 1] Internet-Draft Topology Identifier in IPv6 EH March 2022 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. Terminologies . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 2 4. New IPv6 Extension Header Option for Topologies . . . . . . . 3 5. Security Considerations . . . . . . . . . . . . . . . . . . . 3 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 7.1. Normative References . . . . . . . . . . . . . . . . . . 4 7.2. Informative References . . . . . . . . . . . . . . . . . 4 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction This document proposes a new Hop-by-Hop option of IPv6 extension header to carry the topology identifier, which is used to identify the forwarding table instance created by the Multi Topology Routing or Flexible Algorithm. 2. Terminologies The following terminologies are used in this document. MT: Multi Topology 3. Problem Statement [RFC4915] defines Multi-Topology Routing in OSPF and [RFC5120] defines Multi Topology Routing in ISIS. Through Multi Topology Routing, there can be multiple forwarding tables in the data plane. [I-D.ietf-lsr-flex-algo] can also implement the similar purpose to install multiple forwarding tables for different Flexible Algorithm instances. In the MT IP Forwarding Considerations of [RFC5120],it is explained when multiple MTs share an Interface with overlapping addresses, some additional mechanism is needed to select the correct RIBs for the incoming IP packets to determine the correct RIB to make a forwarding decision. But there is lack of the generic approach of packet to multiple MT RIB mapping over the same inbound interface. Li, et al. Expires September 22, 2022 [Page 2] Internet-Draft Topology Identifier in IPv6 EH March 2022 4. New IPv6 Extension Header Option for Topologies In order to solve the above issue, in the scenario of IPv6, the topology identifier information can be carried in the packet. A new Hop-by-Hop option type "Topology" is defined to carry the topology related Identifier in an IPv6 packet. Its format is shown as below: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Opt Type | Opt Data Len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Topology ID | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1. Topology Option where: o Opt Type: Type value is TBD. 8-bit unsigned integer. Identifier of the type of this Topology Option. o Opt Data Len: 8-bit unsigned integer. It indicates the length of the option Data field of this option, in octets. The value of Opt Data Len of Topology option SHOULD be set to 4. o Topology ID: 2-octet identifier which uniquely identifies the topology associated with the specific forwarding table created by the Multi Topology Routing or Flexible Algorithm. o Reserved: 2-octet reserved field. It MUST be set as 0 and ignored when received. 5. Security Considerations TBD 6. IANA Considerations This document requests IANA to assign a new option type from "Hop-by- Hop Options" registry. Value Description Reference ------------------------------------------ TBD Topology Option this document Li, et al. Expires September 22, 2022 [Page 3] Internet-Draft Topology Identifier in IPv6 EH March 2022 7. References 7.1. Normative References [I-D.ietf-lsr-flex-algo] Psenak, P., Hegde, S., Filsfils, C., Talaulikar, K., and A. Gulko, "IGP Flexible Algorithm", draft-ietf-lsr-flex- algo-18 (work in progress), October 2021. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC4915] Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P. Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF", RFC 4915, DOI 10.17487/RFC4915, June 2007, . [RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi Topology (MT) Routing in Intermediate System to Intermediate Systems (IS-ISs)", RFC 5120, DOI 10.17487/RFC5120, February 2008, . 7.2. Informative References [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", STD 86, RFC 8200, DOI 10.17487/RFC8200, July 2017, . Authors' Addresses Zhenbin Li Huawei Technologies Beijing 100095 China Email: lizhenbin@huawei.com Zhibo Hu Huawei Technologies Beijing 100095 China Email: huzhibo@huawei.com Li, et al. Expires September 22, 2022 [Page 4] Internet-Draft Topology Identifier in IPv6 EH March 2022 Jie Dong Huawei Technologies Beijing 100095 China Email: jie.dong@huawei.com Li, et al. Expires September 22, 2022 [Page 5]