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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-09) exists of draft-ietf-bier-bierin6-04 == Outdated reference: A later version (-03) exists of draft-ietf-bier-lsr-non-mpls-extensions-00 == Outdated reference: A later version (-07) exists of draft-ietf-bier-ospfv3-extensions-05 Summary: 0 errors (**), 0 flaws (~~), 4 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 BIER WG Z. Zhang 3 Internet-Draft ZTE Corporation 4 Intended status: Standards Track A. Przygienda 5 Expires: 2 November 2022 Juniper Networks 6 1 May 2022 8 BIER in BABEL 9 draft-zhang-bier-babel-extensions-07 11 Abstract 13 BIER introduces a novel multicast architecture. It does not require 14 a signaling protocol to explicitly build multicast distribution 15 trees, nor does it require intermediate nodes to maintain any per- 16 flow state. 18 Babel defines a distance-vector routing protocol that operates in a 19 robust and efficient fashion both in wired as well as in wireless 20 mesh networks. This document defines a way to carry necessary BIER 21 signaling information in Babel. 23 Status of This Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at https://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on 2 November 2022. 40 Copyright Notice 42 Copyright (c) 2022 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents (https://trustee.ietf.org/ 47 license-info) in effect on the date of publication of this document. 48 Please review these documents carefully, as they describe your rights 49 and restrictions with respect to this document. Code Components 50 extracted from this document must include Revised BSD License text as 51 described in Section 4.e of the Trust Legal Provisions and are 52 provided without warranty as described in the Revised BSD License. 54 Table of Contents 56 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 57 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 58 3. Conventions Used in This Document . . . . . . . . . . . . . . 3 59 4. Advertisement of BIER information . . . . . . . . . . . . . . 3 60 4.1. BIER BFR-prefix and BIER sub-TLV . . . . . . . . . . . . 3 61 4.1.1. BIER sub-TLV . . . . . . . . . . . . . . . . . . . . 3 62 4.2. BIER MPLS Encapsulation sub-sub-TLV . . . . . . . . . . . 4 63 4.3. BIER non-MPLS Encapsulation sub-sub-TLV . . . . . . . . . 5 64 4.3.1. BIER IPv6 transportation sub-sub-TLV . . . . . . . . 6 65 5. Tree types and tunneling . . . . . . . . . . . . . . . . . . 6 66 6. Security Considerations . . . . . . . . . . . . . . . . . . . 6 67 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 68 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 69 8.1. Normative References . . . . . . . . . . . . . . . . . . 6 70 8.2. Informative References . . . . . . . . . . . . . . . . . 7 71 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 73 1. Introduction 75 [RFC8279] introduces a novel multicast architecture. It does not 76 require a signaling protocol to explicitly build multicast 77 distribution trees, nor does it require intermediate nodes to 78 maintain any per-flow state. All procedures necessary to support 79 BIER are abbreviated by the "BIER architecture" moniker in this 80 document. 82 [RFC8966] define a distance-vector routing protocol under the name of 83 "Babel". Babel operates in a robust and efficient fashion both in 84 ordinary wired as well as in wireless mesh networks. 86 2. Terminology 88 The terminology of this documents follows [RFC8279] and [RFC8966]. 90 3. Conventions Used in This Document 92 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 93 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 94 "OPTIONAL" in this document are to be interpreted as described in BCP 95 14 [RFC2119] [RFC8174] when, and only when, they appear in all 96 capitals, as shown here. 98 4. Advertisement of BIER information 100 In case a router is configured with BIER information, and Babel is 101 the routing protocol used, such a router MAY use Babel protocol to 102 announce the BIER information using the BIER sub-TLV specified below. 104 4.1. BIER BFR-prefix and BIER sub-TLV 106 BFR-prefix and according information is carried in a Babel Update TLV 107 per [RFC8966]. A new sub-TLV is defined to convey further BIER 108 information such as BFR-id, sub-domain-id and BSL. Two sub-sub-TLVs 109 are carried as payload of BIER sub-TLV. 111 The mandatory bit of BIER sub-TLV should be set to 0. If a router 112 cannot recognize a sub-TLV, the router MUST ignore this unknown sub- 113 TLV. 115 4.1.1. BIER sub-TLV 117 The BIER sub-TLV format aligns exactly with the definition and 118 restrictions in [RFC8401] , [RFC8444] and 119 [I-D.ietf-bier-ospfv3-extensions]. It is a sub-TLV of Babel update 120 TLV. The prefix MUST NOT be summarized and the according sub-TLV 121 MUST be treated as optional and transitive. 123 0 1 2 3 124 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 1 125 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 126 | Type | Length | 127 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 128 | BAR | IPA | subdomain-id | 129 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 130 | BFR-id | 131 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 132 | sub-sub-TLVs (variable) | 133 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 134 Figure 1: BIER sub-TLV 136 * Type: as indicated in IANA section. 138 * Length: 1 octet. Include the length of BIER sub-TLV and potential 139 length of the sub-sub-TLVs. 141 * BAR: BIER Algorithm. Specifies a BIER-specific algorithm used to 142 calculate underlay paths to reach BFERs. Values are allocated 143 from the "BIER Algorithms" registry. 1 octet. 145 * IPA: IGP Algorithm. Specifies an IGP Algorithm to either modify, 146 enhance, or replace the calculation of underlay paths to reach 147 BFERs as defined by the BAR value. Values are from the IGP 148 Algorithm registry. 1 octet. 150 * subdomain-id: Unique value identifying the BIER sub-domain. 1 151 octet. 153 * BFR-id: A 2 octet field encoding the BFR-id, as documented in 154 [RFC8279]. If no BFR-id has been assigned this field is set to 155 the invalid BFR-id. 157 4.2. BIER MPLS Encapsulation sub-sub-TLV 159 The BIER MPLS Encapsulation sub-sub-TLV can be carried by BIER sub- 160 TLV. The format and restrictions are aligned with [RFC8401], 161 [RFC8444] and [I-D.ietf-bier-ospfv3-extensions]. This sub-sub-TLV 162 carries the information for the BIER MPLS encapsulation including the 163 label range for a specific BSL for a certain pair. 165 0 1 2 3 166 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 1 167 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 168 | Type | Length | 169 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 170 | Max SI |BS Len | Label | 171 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 172 Figure 2: MPLS Encapsulation sub-sub-TLV 174 * Type: value of 1 indicating MPLS encapsulation. 176 * Length: 1 octet 177 * Max SI: Maximum Set Identifier (Section 1 of [RFC8279]) used in 178 the encapsulation for this BIER subdomain for this BitString 179 length, 1 octet. Each SI maps to a single label in the label 180 range. The first label is for SI=0, the second label is for SI=1, 181 etc. If the label associated with the Maximum Set Identifier 182 exceeds the 20-bit range, the sub-sub-TLV MUST be ignored. 184 * Local BitString Length (BS Len): Encoded BitString length as per 185 [RFC8296]. 4 bits. 187 * Label: First label, 20 bits. The labels are as defined in 188 [RFC8296]. 190 4.3. BIER non-MPLS Encapsulation sub-sub-TLV 192 The BIER non-MPLS Encapsulation sub-sub-TLV can be carried by BIER 193 sub-TLV. The format and restrictions are aligned with 194 [I-D.ietf-bier-lsr-non-mpls-extensions]. This sub-sub-TLV carries 195 the information for the BIER MPLS encapsulation including the label 196 range for a specific BSL for a certain pair. 198 0 1 2 3 199 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 1 200 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 201 | Type | Length | 202 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 203 | Max SI | BIFT-id | 204 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 205 |BS Len | Reserved | 206 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 207 Figure 3: non-MPLS Encapsulation sub-sub-TLV 209 * Type: value of 2 indicating non-MPLS encapsulation. 211 * Length: 1 octet 213 * Max SI: Maximum Set Identifier (Section 1 of [RFC8279]) used in 214 the encapsulation for this BIER subdomain for this BitString 215 length, 1 octet. The first BIFT-id is for SI=0, the second BIFT- 216 id is for SI=1, etc. If the BIFT-id associated with the Maximum 217 Set Identifier exceeds the 20-bit range, the sub-sub-TLV MUST be 218 ignored. 220 * BIFT-id: A 3-octet field, where the 20 rightmost bits represent 221 the first BIFT-id in the BIFT-id range. The 4 leftmost bits MUST 222 be ignored. The "BIFT-id range" is the set of 20-bit values 223 beginning with the BIFT-id and ending with (BIFT-id + (Max SI)). 224 These BIFT-id's are used for BIER forwarding as described in 225 [RFC8279] and [RFC8296]. 227 * Local BitString Length (BS Len): Encoded BitString length as per 228 [RFC8296]. 4 bits. 230 4.3.1. BIER IPv6 transportation sub-sub-TLV 232 The BIER IPv6 transportation sub-sub-TLV can be carried by BIER non- 233 MPLS Encapsulation sub-sub-TLV. The format and restrictions are 234 aligned with [I-D.ietf-bier-bierin6]. A node that requires IPv6 235 encapsualtion MUST advertise the BIER IPv6 transportation sub-sub-TLV 236 according to local configuration or policy in the BIER domain to 237 request other BFRs to always use IPv6 encapsulation. 239 The format is the same with the definition in section 4.1, 240 [I-D.ietf-bier-bierin6]. 242 5. Tree types and tunneling 244 Since Babel is performing a diffusion computation, support for 245 different tree types is not as natural as with link-state protocols. 246 Hence this specification is assuming that normal Babel reachability 247 computation is performed without further modifications. 249 BIER architecture does not rely on all routers in a domain performing 250 BFR procedures. How to support tunnels that will allow to tunnel 251 BIER across such routers in Babel is for further study. 253 6. Security Considerations 255 Security considerations discussed in [RFC8296], [RFC8966] apply to 256 this document 258 7. IANA Considerations 260 A new type of Babel update sub-TLV needs to be defined for BIER 261 information advertisement. 263 8. References 265 8.1. Normative References 267 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 268 Requirement Levels", BCP 14, RFC 2119, 269 DOI 10.17487/RFC2119, March 1997, 270 . 272 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 273 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 274 May 2017, . 276 [RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., 277 Przygienda, T., and S. Aldrin, "Multicast Using Bit Index 278 Explicit Replication (BIER)", RFC 8279, 279 DOI 10.17487/RFC8279, November 2017, 280 . 282 [RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., 283 Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation 284 for Bit Index Explicit Replication (BIER) in MPLS and Non- 285 MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January 286 2018, . 288 [RFC8401] Ginsberg, L., Ed., Przygienda, T., Aldrin, S., and Z. 289 Zhang, "Bit Index Explicit Replication (BIER) Support via 290 IS-IS", RFC 8401, DOI 10.17487/RFC8401, June 2018, 291 . 293 [RFC8444] Psenak, P., Ed., Kumar, N., Wijnands, IJ., Dolganow, A., 294 Przygienda, T., Zhang, J., and S. Aldrin, "OSPFv2 295 Extensions for Bit Index Explicit Replication (BIER)", 296 RFC 8444, DOI 10.17487/RFC8444, November 2018, 297 . 299 [RFC8966] Chroboczek, J. and D. Schinazi, "The Babel Routing 300 Protocol", RFC 8966, DOI 10.17487/RFC8966, January 2021, 301 . 303 8.2. Informative References 305 [I-D.ietf-bier-bierin6] 306 Zhang, Z., Zhang, Z., Wijnands, I., Mishra, M., Bidgoli, 307 H., and G. Mishra, "Supporting BIER in IPv6 Networks 308 (BIERin6)", Work in Progress, Internet-Draft, draft-ietf- 309 bier-bierin6-04, 2 March 2022, 310 . 313 [I-D.ietf-bier-lsr-non-mpls-extensions] 314 Dhanaraj, S., Yan, G., Wijnands, I., Psenak, P., Zhang, 315 Z., and J. Xie, "LSR Extensions for BIER non-MPLS 316 Encapsulation", Work in Progress, Internet-Draft, draft- 317 ietf-bier-lsr-non-mpls-extensions-00, 1 March 2022, 318 . 321 [I-D.ietf-bier-ospfv3-extensions] 322 Psenak, P., Nainar, N. K., and I. Wijnands, "OSPFv3 323 Extensions for BIER", Work in Progress, Internet-Draft, 324 draft-ietf-bier-ospfv3-extensions-05, 19 November 2021, 325 . 328 Authors' Addresses 330 Zheng(Sandy) Zhang 331 ZTE Corporation 332 Email: zhang.zheng@zte.com.cn 334 Tony Przygienda 335 Juniper Networks 336 Email: prz@juniper.net