BIER Z. Zhang Internet-Draft Y. Wei Intended status: Standards Track B. Xu Expires: 25 January 2023 ZTE Corporation 24 July 2022 OSPFv3 extensions for BIER-TE (Tree Engineering for Bit Index Explicit Replication) with MPLS and non-MPLS Encapsulation draft-zwx-bier-te-ospfv3-extensions-01 Abstract This document describes the OSPFv3 protocol extension that is required for BIER-TE with MPLS and non-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 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 25 January 2023. 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 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. Zhang, et al. Expires 25 January 2023 [Page 1] Internet-Draft Abbreviated Title July 2022 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Flooding of the BIER-TE Encapsulation Information in OSPFv3 . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.1. MPLS Encapsulation Sub-sub-TLV . . . . . . . . . . . . . 3 3.2. Non-MPLS Encapsulation Sub-sub-TLV . . . . . . . . . . . 4 3.2.1. BIER-TE IPv6 Encapsulation Advertisement . . . . . . 5 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 6.1. Normative References . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 1. Introduction [I-D.ietf-bier-te-arch] describes per-packet stateless strict and loose path steered replication and forwarding for "Bit Index Explicit Replication" (BIER, [RFC8279]) packets. It is called BIER Tree Engineering (BIER-TE) and is intended to be used as the path steering mechanism for Traffic Engineering with BIER. BIER-TE introduces a new semantic for "bit positions" (BP) of link. [I-D.ietf-bier-te-ospfv3] describes OSPFv3 extensions for distributing BitPositions configured on the links in "Bit Index Explicit Replication Traffic Engineering" (BIER-TE) domain. As described in section 2.3 in [I-D.ietf-bier-te-arch], BIER-TE inherits the encapsulation supporting from BIER unchanged. The encapsulation defined in [RFC8296], which specifies a common header format for both MPLS and non-MPLS networks, though the first 20-bits (referred to as BIFT-id) of the header is an "MPLS Label" in case of MPLS networks and is a local 20-bit opaque value in case of non-MPLS networks. As described in section 4.3 of [I-D.ietf-bier-te-arch], it is necessary to distinguish the BIER and BIER-TE packet and forwarding. like [I-D.ietf-bier-ospfv3-extensions] and [I-D.ietf-bier-lsr-non-mpls-extensions], the MPLS and non-MPLS encapsulation needs to be advertised for BIER-TE packet encapsulation. This document describes the OSPFv3 protocol extension that is required for BIER-TE with MPLS and non-MPLS encapsulation associated with link BitPosition distributing. Zhang, et al. Expires 25 January 2023 [Page 2] Internet-Draft Abbreviated Title July 2022 1.1. 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 [RFC2119]. 2. Terminology This document does not introduce more terminologies than [RFC8279], [RFC8296], [I-D.ietf-bier-ospfv3-extensions], [I-D.ietf-bier-te-arch] and [I-D.ietf-bier-te-ospfv3]. 3. Flooding of the BIER-TE Encapsulation Information in OSPFv3 [I-D.ietf-bier-te-ospfv3] defines a BIER-TE Sub-TLV to distribute the Link BitPosition information about the link. This document defines the MPLS Encapsulation Sub-sub-TLV and the Non-MPLS Encapsulation Sub-sub-TLV associate with the BIER-TE Sub-TLV to carry the MPLS and non-MPLS encapsulation information. In case both of the two encapsulation sub-sub-TLVs are advertised by one node, the label in MPLS encapsulation sub-sub-TLV and BIFT-id in non-MPLS encapsulation sub-sub-TLV SHOULD NOT be overlapped. 3.1. MPLS Encapsulation Sub-sub-TLV The following description is the almost same with [I-D.ietf-bier-ospfv3-extensions] since [I-D.ietf-bier-te-arch] inherit the encapsulation of BIER header. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max SI | Label | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |BS Len | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1 Type: TBD1 (To be assigned by IANA). Length: 2-octet. Zhang, et al. Expires 25 January 2023 [Page 3] Internet-Draft Abbreviated Title July 2022 Max SI: A 1-octet field encoding the maximum Set Identifier (SI) (see Section 1 of [RFC8279]) used in the encapsulation for this BIER sub-domain for this BitString length. Label: A 3-octet field, where the 20 rightmost bits represent the first label in the label range. The 4 leftmost bits MUST be ignored. BS Len (BitString Length): A 4-bit field encoding the supported BitString length associated with this BFR-prefix. The values allowed in this field are specified in Section 2 of [RFC8296]. Reserved: SHOULD be set to 0 on transmission and MUST be ignored on reception. The "label range" is the set of labels beginning with the Label and ending with (Label + (Max SI)). A unique label range is allocated for each BitString length and sub-domain-id. The size of the label range is determined by the number of SIs (Section 1 of [RFC8279]) that are used in the network. Each SI maps to a single label in the label range: the first label is for SI=0, the second label is for SI=1, etc. If the label associated with the Maximum Set Identifier exceeds the 20-bit range, the BIER MPLS Encapsulation Sub-TLV containing the error MUST be ignored. If the BitString length is set to a value that does not match any of the allowed values specified in [RFC8296], the BIER MPLS Encapsulation Sub-TLV containing the error MUST be ignored. The "BIFT-id range" is the set of 20-bit values beginning with the BIFT-id and ending with (BIFT-id + (Max SI)). The flooding scope of this information is the same with section 2.2 in [I-D.ietf-bier-ospfv3-extensions]. 3.2. Non-MPLS Encapsulation Sub-sub-TLV The following description is the almost same with section 3.3 in [I-D.ietf-bier-lsr-non-mpls-extensions] since [I-D.ietf-bier-te-arch] inherit the encapsulation of BIER header. Zhang, et al. Expires 25 January 2023 [Page 4] Internet-Draft Abbreviated Title July 2022 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max SI | BIFT-id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |BS Len | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2 Type: TBD2 (To be assigned by IANA). Length: 2-octet. Max SI: A 1-octet field encoding the maximum Set Identifier (SI) (see Section 1 of [RFC8279]) used in the encapsulation for this BIER sub-domain for this BitString length. BIFT-id: A 3-octet field, where the 20 rightmost bits represent the first label in the label range. The 4 leftmost bits MUST be ignored. BS Len (BitString Length): A 4-bit field encoding the supported BitString length associated with this BFR-prefix. The values allowed in this field are specified in Section 2 of [RFC8296]. Reserved: SHOULD be set to 0 on transmission and MUST be ignored on reception. The BIFT-id range, limitation and flooding scope is the same with the MPLS encapsulation sub-sub-TLV. 3.2.1. BIER-TE IPv6 Encapsulation Advertisement As described in section 4 of [I-D.ietf-bier-bierin6], which describes how the existing BIER encapsulation specified in [RFC8296] works in a non-MPLS IPv6 network, a node that requires IPv6 encapsulation MUST advertise the BIER-TE IPv6 encapsulation sub-sub-sub-TLV, which follows the Non-MPLS Encapsulation Sub-sub-TLV, according to local configuration or policy in the BIER domain to request other BFRs to always use IPv6 encapsulation. Zhang, et al. Expires 25 January 2023 [Page 5] Internet-Draft Abbreviated Title July 2022 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3 Type: TBD3 (To be assigned by IANA). Length: 0. 4. IANA Considerations TBD. 5. Security Considerations This document does not introduce more security considerations than [I-D.ietf-bier-te-arch] and [I-D.ietf-bier-te-ospfv3]. 6. References 6.1. Normative References [I-D.ietf-bier-bierin6] Zhang, Z., Zhang, Z., Wijnands, I., Mishra, M., Bidgoli, H., and G. Mishra, "Supporting BIER in IPv6 Networks (BIERin6)", Work in Progress, Internet-Draft, draft-ietf- bier-bierin6-04, March 2022, . [I-D.ietf-bier-lsr-non-mpls-extensions] Dhanaraj, S., Yan, G., Wijnands, I., Psenak, P., Zhang, Z., and J. Xie, "LSR Extensions for BIER non-MPLS Encapsulation", Work in Progress, Internet-Draft, draft- ietf-bier-lsr-non-mpls-extensions-00, March 2022, . [I-D.ietf-bier-ospfv3-extensions] Psenak, P., Nainar, N. K., and I. Wijnands, "OSPFv3 Extensions for BIER", Work in Progress, Internet-Draft, draft-ietf-bier-ospfv3-extensions-05, 19 November 2021, . Zhang, et al. Expires 25 January 2023 [Page 6] Internet-Draft Abbreviated Title July 2022 [I-D.ietf-bier-te-arch] Eckert, T., Menth, M., and G. Cauchie, "Tree Engineering for Bit Index Explicit Replication (BIER-TE)", Work in Progress, Internet-Draft, draft-ietf-bier-te-arch-13, 25 April 2022, . [I-D.ietf-bier-te-ospfv3] Chen, H., McBride, M., Wang, A., Mishra, G. S., Fan, Y., Liu, L., and X. Liu, "OSPFv3 Extensions for BIER-TE", Work in Progress, Internet-Draft, draft-ietf-bier-te-ospfv3-01, July 2022, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., Przygienda, T., and S. Aldrin, "Multicast Using Bit Index Explicit Replication (BIER)", RFC 8279, DOI 10.17487/RFC8279, November 2017, . [RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation for Bit Index Explicit Replication (BIER) in MPLS and Non- MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January 2018, . Authors' Addresses Zheng Zhang ZTE Corporation China Email: zhang.zheng@zte.com.cn Yuehua Wei ZTE Corporation China Email: wei.yuehua@zte.com.cn Benchong Xu ZTE Corporation China Zhang, et al. Expires 25 January 2023 [Page 7] Internet-Draft Abbreviated Title July 2022 Email: xu.benchong@zte.com.cn Zhang, et al. Expires 25 January 2023 [Page 8]