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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(See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-20) exists of draft-ietf-babel-rfc6126bis-17 ** Obsolete normative reference: RFC 6126 (Obsoleted by RFC 8966) ** Obsolete normative reference: RFC 7557 (Obsoleted by RFC 8966) == Outdated reference: A later version (-04) exists of draft-ietf-bier-lsr-ethernet-extensions-01 == Outdated reference: A later version (-07) exists of draft-ietf-bier-ospfv3-extensions-01 == Outdated reference: A later version (-09) exists of draft-zhang-bier-bierin6-04 Summary: 2 errors (**), 0 flaws (~~), 5 warnings (==), 1 comment (--).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: November 18, 2020 Juniper Networks 6 May 17, 2020 8 BIER in BABEL 9 draft-zhang-bier-babel-extensions-03 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 November 18, 2020. 40 Copyright Notice 42 Copyright (c) 2020 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 47 (https://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 58 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 59 3. Conventions Used in This Document . . . . . . . . . . . . . . 2 60 4. Advertisement of BIER information . . . . . . . . . . . . . . 3 61 4.1. BIER BFR-prefix and BIER sub-TLV . . . . . . . . . . . . 3 62 4.1.1. BIER sub-TLV . . . . . . . . . . . . . . . . . . . . 3 63 4.2. BIER MPLS Encapsulation sub-sub-TLV . . . . . . . . . . . 4 64 4.3. BIER non-MPLS Encapsulation sub-sub-TLV . . . . . . . . . 5 65 4.3.1. BIER IPv6 transportation sub-sub-TLV . . . . . . . . 5 66 5. Tree types and tunneling . . . . . . . . . . . . . . . . . . 6 67 6. Security Considerations . . . . . . . . . . . . . . . . . . . 6 68 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 69 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 70 8.1. Normative References . . . . . . . . . . . . . . . . . . 6 71 8.2. Informative References . . . . . . . . . . . . . . . . . 7 72 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 74 1. Introduction 76 [RFC8279] introduces a novel multicast architecture. It does not 77 require a signaling protocol to explicitly build multicast 78 distribution trees, nor does it require intermediate nodes to 79 maintain any per-flow state. All procedures necessary to support 80 BIER are abbreviated by the "BIER architecture" moniker in this 81 document. 83 [I-D.ietf-babel-rfc6126bis] define a distance-vector routing protocol 84 under the name of "Babel". Babel operates in a robust and efficient 85 fashion both in ordinary wired as well as in wireless mesh networks. 87 2. Terminology 89 The terminology of this documents follows [RFC8279], [RFC6126], 90 [RFC7557] and [I-D.ietf-babel-rfc6126bis]. 92 3. Conventions Used in This Document 94 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 95 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 96 "OPTIONAL" in this document are to be interpreted as described in BCP 97 14 [RFC2119] [RFC8174] when, and only when, they appear in all 98 capitals, as shown here. 100 4. Advertisement of BIER information 102 In case a router is configured with BIER information, and Babel is 103 the routing protocol used, such a router MAY use Babel protocol to 104 announce the BIER information using the BIER sub-TLV specified below. 106 4.1. BIER BFR-prefix and BIER sub-TLV 108 BFR-prefix and according information is carried in a Babel Update TLV 109 per [I-D.ietf-babel-rfc6126bis]. A new sub-TLV is defined to convey 110 further BIER information such as BFR-id, sub-domain-id and BSL. Two 111 sub-sub-TLVs are carried as payload of BIER sub-TLV. 113 The mandatory bit of BIER sub-TLV should be set to 0. If a router 114 cannot recognize a sub-TLV, the router MUST ignore this unknown sub- 115 TLV. 117 4.1.1. BIER sub-TLV 119 The BIER sub-TLV format aligns exactly with the definition and 120 restrictions in [RFC8401] , [RFC8444] and 121 [I-D.ietf-bier-ospfv3-extensions]. It is a sub-TLV of Babel update 122 TLV. The prefix MUST NOT be summarized and the according sub-TLV 123 MUST be treated as optional and transitive. 125 0 1 2 3 126 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 1 127 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 128 | Type | Length | 129 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 130 | BAR | IPA | subdomain-id | 131 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 132 | BFR-id | 133 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 134 | sub-sub-TLVs (variable) | 135 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 136 Figure 1: BIER sub-TLV 138 o Type: as indicated in IANA section. 140 o Length: 1 octet. Include the length of BIER sub-TLV and potential 141 length of the sub-sub-TLVs. 143 o BAR: BIER Algorithm. Specifies a BIER-specific algorithm used to 144 calculate underlay paths to reach BFERs. Values are allocated 145 from the "BIER Algorithms" registry. 1 octet. 147 o IPA: IGP Algorithm. Specifies an IGP Algorithm to either modify, 148 enhance, or replace the calculation of underlay paths to reach 149 BFERs as defined by the BAR value. Values are from the IGP 150 Algorithm registry. 1 octet. 152 o subdomain-id: Unique value identifying the BIER sub-domain. 1 153 octet. 155 o BFR-id: A 2 octet field encoding the BFR-id, as documented in 156 [RFC8279]. If no BFR-id has been assigned this field is set to 157 the invalid BFR-id. 159 4.2. BIER MPLS Encapsulation sub-sub-TLV 161 The BIER MPLS Encapsulation sub-sub-TLV can be carried by BIER sub- 162 TLV. The format and restrictions are aligned with [RFC8401], 163 [RFC8444] and [I-D.ietf-bier-ospfv3-extensions]. This sub-sub-TLV 164 carries the information for the BIER MPLS encapsulation including the 165 label range for a specific BSL for a certain pair. 167 0 1 2 3 168 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 1 169 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 170 | Type | Length | 171 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 172 | Max SI |BS Len | Label | 173 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 174 Figure 2: MPLS Encapsulation sub-sub-TLV 176 o Type: value of 1 indicating MPLS encapsulation. 178 o Length: 1 octet 180 o Max SI: Maximum Set Identifier (Section 1 of [RFC8279]) used in 181 the encapsulation for this BIER subdomain for this BitString 182 length, 1 octet. Each SI maps to a single label in the label 183 range. The first label is for SI=0, the second label is for SI=1, 184 etc. If the label associated with the Maximum Set Identifier 185 exceeds the 20-bit range, the sub-sub-TLV MUST be ignored. 187 o Local BitString Length (BS Len): Encoded BitString length as per 188 [RFC8296]. 4 bits. 190 o Label: First label, 20 bits. The labels are as defined in 191 [RFC8296]. 193 4.3. BIER non-MPLS Encapsulation sub-sub-TLV 195 The BIER non-MPLS Encapsulation sub-sub-TLV can be carried by BIER 196 sub-TLV. The format and restrictions are aligned with 197 [I-D.ietf-bier-lsr-ethernet-extensions]. This sub-sub-TLV carries 198 the information for the BIER MPLS encapsulation including the label 199 range for a specific BSL for a certain pair. 201 0 1 2 3 202 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 1 203 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 204 | Type | Length | 205 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 206 | Max SI | BIFT-id | 207 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 208 |BS Len | Reserved | 209 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 210 Figure 3: non-MPLS Encapsulation sub-sub-TLV 212 o Type: value of 2 indicating non-MPLS encapsulation. 214 o Length: 1 octet 216 o Max SI: Maximum Set Identifier (Section 1 of [RFC8279]) used in 217 the encapsulation for this BIER subdomain for this BitString 218 length, 1 octet. The first BIFT-id is for SI=0, the second BIFT- 219 id is for SI=1, etc. If the BIFT-id associated with the Maximum 220 Set Identifier exceeds the 20-bit range, the sub-sub-TLV MUST be 221 ignored. 223 o BIFT-id: A 3-octet field, where the 20 rightmost bits represent 224 the first BIFT-id in the BIFT-id range. The 4 leftmost bits MUST 225 be ignored. The "BIFT-id range" is the set of 20-bit values 226 beginning with the BIFT-id and ending with (BIFT-id + (Max SI)). 227 These BIFT-id's are used for BIER forwarding as described in 228 [RFC8279] and [RFC8296]. 230 o Local BitString Length (BS Len): Encoded BitString length as per 231 [RFC8296]. 4 bits. 233 4.3.1. BIER IPv6 transportation sub-sub-TLV 235 The BIER IPv6 transportation sub-sub-TLV can be carried by BIER non- 236 MPLS Encapsulation sub-sub-TLV. The format and restrictions are 237 aligned with [I-D.zhang-bier-bierin6]. A node that requires IPv6 238 encapsualtion MUST advertise the BIER IPv6 transportation sub-sub-TLV 239 according to local configuration or policy in the BIER domain to 240 request other BFRs to always use IPv6 encapsulation. 242 The format is the same with the definition in section 4.1, 243 [I-D.zhang-bier-bierin6]. 245 5. Tree types and tunneling 247 Since Babel is performing a diffusion computation, support for 248 different tree types is not as natural as with link-state protocols. 249 Hence this specification is assuming that normal Babel reachability 250 computation is performed without further modifications. 252 BIER architecture does not rely on all routers in a domain performing 253 BFR procedures. How to support tunnels that will allow to tunnel 254 BIER across such routers in Babel is for further study. 256 6. Security Considerations 258 TBD 260 7. IANA Considerations 262 A new type of Babel update sub-TLV needs to be defined for BIER 263 information advertisement. 265 8. References 267 8.1. Normative References 269 [I-D.ietf-babel-rfc6126bis] 270 Chroboczek, J. and D. Schinazi, "The Babel Routing 271 Protocol", draft-ietf-babel-rfc6126bis-17 (work in 272 progress), February 2020. 274 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 275 Requirement Levels", BCP 14, RFC 2119, 276 DOI 10.17487/RFC2119, March 1997, 277 . 279 [RFC6126] Chroboczek, J., "The Babel Routing Protocol", RFC 6126, 280 DOI 10.17487/RFC6126, April 2011, 281 . 283 [RFC7557] Chroboczek, J., "Extension Mechanism for the Babel Routing 284 Protocol", RFC 7557, DOI 10.17487/RFC7557, May 2015, 285 . 287 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 288 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 289 May 2017, . 291 [RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., 292 Przygienda, T., and S. Aldrin, "Multicast Using Bit Index 293 Explicit Replication (BIER)", RFC 8279, 294 DOI 10.17487/RFC8279, November 2017, 295 . 297 [RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., 298 Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation 299 for Bit Index Explicit Replication (BIER) in MPLS and Non- 300 MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January 301 2018, . 303 [RFC8401] Ginsberg, L., Ed., Przygienda, T., Aldrin, S., and Z. 304 Zhang, "Bit Index Explicit Replication (BIER) Support via 305 IS-IS", RFC 8401, DOI 10.17487/RFC8401, June 2018, 306 . 308 [RFC8444] Psenak, P., Ed., Kumar, N., Wijnands, IJ., Dolganow, A., 309 Przygienda, T., Zhang, J., and S. Aldrin, "OSPFv2 310 Extensions for Bit Index Explicit Replication (BIER)", 311 RFC 8444, DOI 10.17487/RFC8444, November 2018, 312 . 314 8.2. Informative References 316 [I-D.ietf-bier-lsr-ethernet-extensions] 317 Dhanaraj, S., Wijnands, I., Psenak, P., Zhang, Z., Yan, 318 G., and J. Xie, "LSR Extensions for BIER over Ethernet", 319 draft-ietf-bier-lsr-ethernet-extensions-01 (work in 320 progress), July 2019. 322 [I-D.ietf-bier-ospfv3-extensions] 323 Psenak, P., Kumar, N., and I. Wijnands, "OSPFv3 Extensions 324 for BIER", draft-ietf-bier-ospfv3-extensions-01 (work in 325 progress), November 2019. 327 [I-D.zhang-bier-bierin6] 328 Zhang, Z., Przygienda, T., Wijnands, I., Bidgoli, H., and 329 M. McBride, "BIER in IPv6 (BIERin6)", draft-zhang-bier- 330 bierin6-04 (work in progress), January 2020. 332 Authors' Addresses 334 Zheng(Sandy) Zhang 335 ZTE Corporation 336 No. 50 Software Ave, Yuhuatai Distinct 337 Nanjing 338 China 340 Email: zhang.zheng@zte.com.cn 342 Tony Przygienda 343 Juniper Networks 345 Email: prz@juniper.net