BIER Z. Zhang Internet-Draft Y. Wei Intended status: Standards Track B. Xu Expires: 6 March 2024 ZTE Corporation IJ. Wijnands Arrcus 3 September 2023 IS-IS and OSPF extensions for BIER-TE (Tree Engineering for Bit Index Explicit Replication) with MPLS and non-MPLS Encapsulation draft-zwx-bier-te-extensions-03 Abstract This document describes the IS-IS and OSPF protocol extensions that are required for BIER-TE and RBS 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 6 March 2024. Copyright Notice Copyright (c) 2023 IETF Trust and the persons identified as the document authors. All rights reserved. Zhang, et al. Expires 6 March 2024 [Page 1] Internet-Draft Abbreviated Title September 2023 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Flooding of the BIER-TE/RBS Encapsulation Information in IS-IS . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.1. BIER-TE MPLS Encapsulation Sub-sub-TLV . . . . . . . . . 4 3.2. BIER-TE Non-MPLS Encapsulation Sub-sub-TLV . . . . . . . 4 3.2.1. BIER-TE IPv6 Encapsulation sub-sub-sub-tlv . . . . . 5 4. Flooding of the BIER-TE/RBS Encapsulation Information in OSPF . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4.1. BIER-TE MPLS Encapsulation Sub-TLV . . . . . . . . . . . 6 4.2. BIER-TE Non-MPLS Encapsulation Sub-TLV . . . . . . . . . 7 4.2.1. BIER-TE IPv6 Encapsulation sub-sub-tlv . . . . . . . 8 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 5.1. IS-IS Sub-sub-TLVs for BIER Info sub-TLV Registry . . . . 8 5.2. OSPFv2 Extended Prefix TLV Sub-TLVs Registry . . . . . . 8 5.3. OSPFv3 Extended-LSA Sub-TLVs Registry . . . . . . . . . . 9 6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 7.1. Normative References . . . . . . . . . . . . . . . . . . 9 7.2. Informative References . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 1. Introduction "Bit Index Explicit Replication Traffic Engineering" (BIER-TE) [RFC9262] 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. RBS [I-D.eckert-bier-rbs] introduces a compact data-structure representation of multicast trees called "Recursive Bitstring Structure" (RBS) and its use for (stateless) forwarding of packets that include this structure in their header. Zhang, et al. Expires 6 March 2024 [Page 2] Internet-Draft Abbreviated Title September 2023 BIER-TE and RBS both use a "bit positions" (BP) for the representation of link or adjacency. [I-D.ietf-bier-te-isis], [I-D.ietf-bier-te-ospf], and [I-D.ietf-bier-te-ospfv3] describe IS- IS, OSPF, OSPFv3 extensions respectively for distributing BitPositions configured on the links in BIER-TE domain. As described in section 2.4 in [RFC9262] and section 5 in [I-D.eckert-bier-rbs], BIER-TE/RBS 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 [RFC9262] and section 5 in [I-D.eckert-bier-rbs], it is necessary to distinguish the BIER and BIER-TE/RBS packet and forwarding. like [RFC8401], [RFC8444], [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/RBS packet encapsulation. The advertisement can follow the existed BIER-TE BP advertisement, but it does not work well if there are many BIER-TE links need to be advertised. Too many octets in the advertisement will be consumed even if the same BIFT-id is used for different links. This document describes the IS-IS and OSPF protocol extensions that are required for BIER-TE/RBS with MPLS and non-MPLS encapsulation associated with prefix distributing. 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], [RFC8401], [RFC9262], [I-D.ietf-bier-te-isis], [I-D.ietf-bier-te-ospf], [I-D.ietf-bier-te-ospfv3] and [I-D.eckert-bier-rbs]. Zhang, et al. Expires 6 March 2024 [Page 3] Internet-Draft Abbreviated Title September 2023 3. Flooding of the BIER-TE/RBS Encapsulation Information in IS-IS The BIER-TE MPLS Encapsulation Sub-sub-TLV and BIER-TE non-MPLS Encapsulation Sub-sub-TLV are advertised with BIER-Info Sub-TLV, which is defined in section 6.1 in [RFC8401]. As described in section 4.3 in [RFC9262] and section 5 in [I-D.eckert-bier-rbs], the label for MPLS encapsulation or the BIFT- ID for non-MPLS encapsulation is allocatd per SD:BSL. The flooding scope is the same with section 5 in [RFC8401]. 3.1. BIER-TE MPLS Encapsulation Sub-sub-TLV 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | subdomain-id | BS Len| label | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1 Type: TBD (To be assigned by IANA). Length: 1-octet. subdomain-id: A 1-octet field encoding the Unique value identifying the BIER subdomain. The values allowed in this field are specified in Section 1 of [RFC8279]. 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]. Label: A 20-bit field, first label of the range. The labels are as defined in [RFC8296]. The BIER-TE MPLS encapsulation Sub-sub-TLV may be advertised many times for different subdomain-id or BS Len. 3.2. BIER-TE Non-MPLS Encapsulation Sub-sub-TLV Zhang, et al. Expires 6 March 2024 [Page 4] Internet-Draft Abbreviated Title September 2023 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | subdomain-id | BS Len| BIFT-ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2 Type: TBD (To be assigned by IANA). Length: 1-octet. subdomain-id: A 1-octet field encoding the Unique value identifying the BIER subdomain. The values allowed in this field are specified in Section 1 of [RFC8279]. 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]. BIFT-ID: A 20-bit field, first BIFT-ID of the range. The BIFT-ID is as defined in [RFC8296]. The BIER-TE non-MPLS encapsulation sub-sub-TLV may be advertised many times for different subdomain-id or BS Len. 3.2.1. BIER-TE IPv6 Encapsulation sub-sub-sub-tlv 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 associated Non-MPLS Encapsulation, according to local configuration or policy in the BIER domain to request other BFRs to always use IPv6 encapsulation. 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: TBD (To be assigned by IANA). Zhang, et al. Expires 6 March 2024 [Page 5] Internet-Draft Abbreviated Title September 2023 Length: 0. 4. Flooding of the BIER-TE/RBS Encapsulation Information in OSPF Same with IS-IS, the BIER-TE MPLS Encapsulation Sub-TLV and BIER-TE non-MPLS Encapsulation Sub-TLV are Sub-TLVs of BIER Sub-TLV, which is defined in section 2.1 in [RFC8444]. It is similar for OSPFv3, the BIER-TE MPLS Encapsulation Sub-TLV and BIER-TE non-MPLS Encapsulation Sub-TLV are Sub-TLVs of BIER Sub-TLV, which is defined in section 2.1 in [I-D.ietf-bier-ospfv3-extensions]. As described in section 4.3 in [RFC9262] and section 5 in [I-D.eckert-bier-rbs], the label for MPLS encapsulation or the BIFT- ID for non-MPLS encapsulation is allocatd per SD:BSL. The format defined below works for both OSPFv2 and OSPFv3. The flooding scope for OSPFv2 is the same with section 2.3 in [RFC8444]. The flooding scope for OSPFv3 is the same with section 2.2 in [I-D.ietf-bier-ospfv3-extensions]. 4.1. BIER-TE MPLS Encapsulation Sub-TLV 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 4 Type: TBD (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. 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. Zhang, et al. Expires 6 March 2024 [Page 6] Internet-Draft Abbreviated Title September 2023 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 BIER-TE MPLS encapsulation Sub-TLV may be advertised many times for different subdomain-id or BS Len. 4.2. BIER-TE Non-MPLS Encapsulation Sub-TLV 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 5 Type: TBD (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 value in the 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 BIER-TE non-MPLS encapsulation Sub-TLV may be advertised many times for different subdomain-id or BS Len. Zhang, et al. Expires 6 March 2024 [Page 7] Internet-Draft Abbreviated Title September 2023 4.2.1. BIER-TE IPv6 Encapsulation sub-sub-tlv 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 associated Non-MPLS Encapsulation, according to local configuration or policy in the BIER domain to request other BFRs to always use IPv6 encapsulation. 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 6 Type: TBD (To be assigned by IANA). Length: 0. 5. IANA Considerations The document requests new allocations from the IANA registries as follows: 5.1. IS-IS Sub-sub-TLVs for BIER Info sub-TLV Registry BIER-TE MPLS Encapsulation Sub-sub-TLV: TBD (suggested value 3) BIER-TE non-MPLS Encapsulation Sub-sub-TLV: TBD (suggested value 4) IANA is requested to create a registry for "IS-IS BIER-TE non-MPLS Encapsulation Sub-sub-TLV". The type field for the registry consists of 1 octet, with possible values from 1 to 255 (the value 0 is reserved). The allocation policy for this field is to be "First Come First Serve". A "BIER-TE IPv6 encapsulation Sub-sub-sub-TLV" type (TBD, suggested value 1) is requested to be assigned in it. 5.2. OSPFv2 Extended Prefix TLV Sub-TLVs Registry BIER-TE MPLS Encapsulation Sub-TLV: TBD (suggested value 12) BIER-TE non-MPLS Encapsulation Sub-TLV: TBD (suggested value 13) Zhang, et al. Expires 6 March 2024 [Page 8] Internet-Draft Abbreviated Title September 2023 IANA is requested to create a registry for "OSPFv2 BIER-TE non-MPLS Encapsulation Sub-TLV". The type field for the registry consists of 2 octets, with possible values from 1 to 65535 (the value 0 is reserved). The allocation policy for this field is to be "First Come First Serve". A "BIER-TE IPv6 encapsulation Sub-sub-sub-TLV" type (TBD, suggested value 1) is requested to be assigned in it. 5.3. OSPFv3 Extended-LSA Sub-TLVs Registry BIER-TE MPLS Encapsulation Sub-TLV: TBD (suggested value 12) BIER-TE non-MPLS Encapsulation Sub-TLV: TBD (suggested value 13) IANA is requested to create a registry for "OSPFv3 BIER-TE non-MPLS Encapsulation Sub-TLV". The type field for the registry consists of 2 octets, with possible values from 1 to 65535 (the value 0 is reserved). The allocation policy for this field is to be "First Come First Serve". A "BIER-TE IPv6 encapsulation Sub-sub-sub-TLV" type (TBD, suggested value 1) is requested to be assigned in it. 6. Security Considerations This document does not introduce more security considerations than [RFC9262] and [I-D.ietf-bier-te-isis], [I-D.ietf-bier-te-ospf], [I-D.ietf-bier-te-ospfv3] and [I-D.eckert-bier-rbs]. 7. References 7.1. Normative References [I-D.ietf-bier-bierin6] Zhang, Z., Zhang, Z. J., Wijnands, I., Mishra, M. P., Bidgoli, H., and G. S. Mishra, "Supporting BIER in IPv6 Networks (BIERin6)", Work in Progress, Internet-Draft, draft-ietf-bier-bierin6-07, 27 March 2023, . [I-D.ietf-bier-lsr-non-mpls-extensions] Dhanaraj, S., Yan, G., Wijnands, I., Psenak, P., Zhang, Z. J., and J. Xie, "LSR Extensions for BIER non-MPLS Encapsulation", Work in Progress, Internet-Draft, draft- ietf-bier-lsr-non-mpls-extensions-01, 19 September 2022, . Zhang, et al. Expires 6 March 2024 [Page 9] Internet-Draft Abbreviated Title September 2023 [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-07, 1 December 2022, . [I-D.ietf-bier-te-isis] Chen, H., McBride, M., Wang, A., Mishra, G. S., Fan, Y., Liu, L., and X. Liu, "IS-IS Extensions for BIER-TE", Work in Progress, Internet-Draft, draft-ietf-bier-te-isis-08, 6 July 2023, . [I-D.ietf-bier-te-ospf] Chen, H., McBride, M., Wang, A., Mishra, G. S., Fan, Y., Liu, L., and X. Liu, "OSPFv2 Extensions for BIER-TE", Work in Progress, Internet-Draft, draft-ietf-bier-te-ospf-06, 5 July 2023, . [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-ospfv3-06, 5 July 2023, . [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, . Zhang, et al. Expires 6 March 2024 [Page 10] Internet-Draft Abbreviated Title September 2023 [RFC8401] Ginsberg, L., Ed., Przygienda, T., Aldrin, S., and Z. Zhang, "Bit Index Explicit Replication (BIER) Support via IS-IS", RFC 8401, DOI 10.17487/RFC8401, June 2018, . [RFC8444] Psenak, P., Ed., Kumar, N., Wijnands, IJ., Dolganow, A., Przygienda, T., Zhang, J., and S. Aldrin, "OSPFv2 Extensions for Bit Index Explicit Replication (BIER)", RFC 8444, DOI 10.17487/RFC8444, November 2018, . [RFC9262] Eckert, T., Ed., Menth, M., and G. Cauchie, "Tree Engineering for Bit Index Explicit Replication (BIER-TE)", RFC 9262, DOI 10.17487/RFC9262, October 2022, . 7.2. Informative References [I-D.eckert-bier-rbs] Eckert, T. T., Menth, M., Geng, X., Zheng, X., Meng, R., and F. Li, "Recursive BitString Structure (RBS) Addresses for BIER and MSR6", Work in Progress, Internet-Draft, draft-eckert-bier-rbs-00, 24 October 2022, . 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 Email: xu.benchong@zte.com.cn IJsbrand Wijnands Arrcus Zhang, et al. Expires 6 March 2024 [Page 11] Internet-Draft Abbreviated Title September 2023 Email: ice@braindump.be Zhang, et al. Expires 6 March 2024 [Page 12]