idnits 2.17.00 (12 Aug 2021) /tmp/idnits30369/draft-wang-bier-rh-bier-01.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- ** There is 1 instance of too long lines in the document, the longest one being 1 character in excess of 72. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == The document doesn't use any RFC 2119 keywords, yet seems to have RFC 2119 boilerplate text. -- The document date (October 25, 2021) is 208 days in the past. Is this intentional? 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(See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-04) exists of draft-ietf-bier-bierin6-00 Summary: 1 error (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 BIER Working Group W. Wang 3 Internet-Draft A. Wang 4 Intended status: Standards Track China Telecom 5 Expires: April 28, 2022 October 25, 2021 7 Routing Header Based BIER Information Encapsulation 8 draft-wang-bier-rh-bier-01 10 Abstract 12 This draft proposes one new encapsulation schema of Bit Index 13 Explicit Replication (BIER) information to transfer the multicast 14 packets within the IPv6 network. By defining a new IPv6 Routing 15 Header type, it keeps the original source address and destination 16 address unchanged in forwarding process. The encapsulation schema 17 can make full use of the existing IPv6 quality assurance methods to 18 provide high-quality multicast service. 20 Status of This Memo 22 This Internet-Draft is submitted in full conformance with the 23 provisions of BCP 78 and BCP 79. 25 Internet-Drafts are working documents of the Internet Engineering 26 Task Force (IETF). Note that other groups may also distribute 27 working documents as Internet-Drafts. The list of current Internet- 28 Drafts is at https://datatracker.ietf.org/drafts/current/. 30 Internet-Drafts are draft documents valid for a maximum of six months 31 and may be updated, replaced, or obsoleted by other documents at any 32 time. It is inappropriate to use Internet-Drafts as reference 33 material or to cite them other than as "work in progress." 35 This Internet-Draft will expire on April 28, 2022. 37 Copyright Notice 39 Copyright (c) 2021 IETF Trust and the persons identified as the 40 document authors. All rights reserved. 42 This document is subject to BCP 78 and the IETF Trust's Legal 43 Provisions Relating to IETF Documents 44 (https://trustee.ietf.org/license-info) in effect on the date of 45 publication of this document. Please review these documents 46 carefully, as they describe your rights and restrictions with respect 47 to this document. Code Components extracted from this document must 48 include Simplified BSD License text as described in Section 4.e of 49 the Trust Legal Provisions and are provided without warranty as 50 described in the Simplified BSD License. 52 Table of Contents 54 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 55 2. Conventions used in this document . . . . . . . . . . . . . . 3 56 3. BIER Routing Header . . . . . . . . . . . . . . . . . . . . . 3 57 4. The transmission process of packets with BIER Routing Header 4 58 4.1. All devices in BIER domain support BIER Routing Header . 5 59 4.2. Some devices in BIER domain do not support BIER Routing 60 Header . . . . . . . . . . . . . . . . . . . . . . . . . 6 61 5. Security Considerations . . . . . . . . . . . . . . . . . . . 8 62 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 63 7. Normative References . . . . . . . . . . . . . . . . . . . . 8 64 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 66 1. Introduction 68 Bit Index Explicit Replication (BIER) is a new multicast technology 69 based on IPv6 defined in [RFC8279]. In BIER domain, the set of 70 destination nodes of multicast message is mapped into a BitString and 71 encapsulated into the BIER header. The position of each bit in the 72 BitString represents an BFER. Compared with the traditional 73 multicast technology, the nodes in BIER domain do not need to 74 maintain a multicast tree and save the multicast flow state for each 75 multicast flow. 77 At present, there are two methods for encapsulating BIER information 78 based on IPv6 in IETF: bierin6([I-D.ietf-bier-bierin6]) and 79 bierv6([I-D.xie-bier-ipv6-encapsulation]). 81 BIERin6 carries BIER information by defining a new IPv6 next header 82 type. In the process of transmission, the source address and 83 destination address in the header will change. BIERv6 carries bier 84 related information by creating an option type of destination options 85 header (i.e. bier option). During transmission, the source address 86 in the header remains unchanged and the destination address will 87 change. 89 There are some differences between the above two BIER encapsulation 90 and forwarding schemes, which is unfavorable to the development of 91 BIER and its derivatives. In addition, when there is an error in the 92 transmission process of the message, the source address and 93 destination address help the operators locate and trace the fault. 94 The change of source address and destination address during 95 transmission will increase the difficulty of fault location and 96 traceability. 98 This draft proposes a BIER information transmission scheme without 99 changing the source and destination addresses. By defining an IPv6 100 Routing Header type, it carries the relevant information of BIER and 101 ensures that the source address and destination address do not change 102 during message transmission. The characteristics of this scheme are 103 conducive to rapid fault location and traceability, and can make full 104 use of the existing IPv6 quality assurance technologies to provide 105 high-quality multicast service. 107 2. Conventions used in this document 109 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 110 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 111 document are to be interpreted as described in [RFC2119] . 113 3. BIER Routing Header 115 One new IPv6 Routing Header is defined according to RFC8200[RFC8200]. 116 The message format is shown in Figure 1. 118 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 119 | Next Header | Hdr Ext Len | Routing Type | Segment Left | 120 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 121 | BIFT-id | Ver | TTL | 122 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 123 | BSL | Entropy | DSCP |OAM| 124 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 125 | BFIR-id |Rsv| Reserved | 126 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 127 | | 128 . . 129 . BitString . 130 . . 131 | | 132 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 134 Figure 1: The format of BIER Routing Header 136 Where: 138 o Next Header(8 bits): indicating the message header type 139 immediately after the routing header. 141 o HDR Ext Len(8 bits): indicating the length of the routing header. 143 o Routing Type(8 bits): TBD. Identifying the newly defined Routing 144 Header to encode BIER information. 146 o Segments Left(8 bits): indicating the number of explicitly listed 147 intermediate nodes to be accessed before reaching the final 148 destination. It is not used here for the time being, and all are 149 set to 0. 151 o BIFT-id(20 bits): each < SD, Si, BSL > is assigned a BIFT-id. 153 o Ver(4 bits): identifying the version of the BIER header. When an 154 unsupported BIER header version is received, the BFR needs to 155 discard the packet and record the error. 157 o TTL(8 bits): indicating the lifetime of the message. It is used 158 to prevent ring. The processing process is the same as that in 159 non MPLS networks. 161 o BSL(4 bits): indicating the length of BitString. 163 o Entropy(20 bits): this field specifies an "entropy" for ECMP. 165 o DSCP(6 bits): this field is used to support different service 166 codes. 168 o OAM(2 bits): by default, this value will be set to 0 by BFIR, and 169 other BFRs will not be modified. Whether to use this field is 170 optional. 172 o BFIR-id(16 bits): indicating BFR ID of BFIR. 174 o Rsv(2 bits): unused, set to 0. 176 o Reserved (14 bits): reserved field, set to 0. 178 o BitString(variable): the length must be reflected in the BSL 179 field. The string saved in this field is used to identify the 180 destination BFER of the packet. 182 4. The transmission process of packets with BIER Routing Header 184 Based on the newly defined BIER Routing Header, the devices support 185 BIER Routing Header resolution will perform the following steps: 187 1) Checking whether there is BIFT corresponding to the BIFT-id 188 locally. 190 2) Checking whether the direct-connected device support BIER Routing 191 Header. If yes, proceed to step 3; otherwise, proceed to step 2.1. 193 2.1) Calculating the IPv6 address of next hop that support BIER 194 Routing Header. 196 2.2) Encapsulating an outer IPv6 Header to the packet. The 197 calculated IPv6 address is used as the destination address of the 198 outer IPv6 Header, and its own IPv6 address is used as the source 199 address of the outer IPv6 Header. BitString will not be changed. 201 2.3) Sending the encapsulated packet to the next-connected device, 202 the device will perform normal IPv6 forwarding according to the outer 203 IPv6 Header. 205 3) Performing the normal BIER forwarding process as described in 206 [RFC8279]. 208 The detail procedures for forwarding the multicast packets based on 209 the newly defined Routing Header are described in the following 210 sections. 212 4.1. All devices in BIER domain support BIER Routing Header 214 +---+ 215 +-----------+ B +----------+ 216 | +---+ | 217 | 0:01000000 | 218 | | 219 | | 220 | | 221 +-+-+ +-+-+ (Packet 2) +---+ (Packet 3)+---+ 222 | A |0:10000000 0:00100000| C +------------+ E +-----------+ F | 223 +-+-+ +-+-+ +---+ +---+ 224 | | 0:00001000 0:00000100 225 | | 226 | | 227 | | 228 | 0:00010000 | 229 | +---+ | 230 +-----------+ D +----------+ 231 (Packet 1) +---+ 233 Packet 1 234 +----------------------------+ 235 IPv6 | Source IP Address = A | 236 Header +----------------------------+ 237 | Destination IP Address = F | 238 BIER +----------------------------+ 240 Routing| BitString = 00101100 | 241 Header +----------------------------+ 243 Packet 2 244 +----------------------------+ 245 IPv6 | Source IP Address = A | 246 Header +----------------------------+ 247 | Destination IP Address = F | 248 BIER +----------------------------+ 249 Routing| BitString = 00001100 | 250 Header +----------------------------+ 252 Packet 3 253 +----------------------------+ 254 Inner | Source IP Address = A | 255 IPv6 +----------------------------+ 256 Header | Destination IP Address = F | 257 +----------------------------+ 258 BIER | BitString = 00000100 | 259 Routing+----------------------------+ 260 Header 262 Figure 2: All devices in BIER domain support BIER Routing Header 264 The topology is shown in Figure 3, device A-F support BIER Routing 265 Header resolution. The packet need to be transmitted from A to F. 266 The change of the Header has been given in the Figure. Each device 267 will perform the following steps after receiving the packet: 269 1. Checking whether there is BIFT corresponding to the BIFT-id 270 locally. If yes, proceed to step 2; otherwise, discard the packet. 272 2. Checking whether the direct-connected device support BIER Routing 273 Header. If yes, forwarding the packet according to the BIFT related 274 to the BIFT-id; otherwise, see sectionSection 4.2 for detail 275 procedures. 277 In this forwarding process, the source address and destination 278 address in the Inner IPv6 Header are not changed, only the BitString 279 in BIER Routing Header is changed. 281 4.2. Some devices in BIER domain do not support BIER Routing Header 283 +---+ 284 +-----------+ B +-----------+ 285 | +---+ | 286 | 0:01000000 | 287 | | 288 | | 289 | | 290 +-+-+ +-+-+ (Packet 2) +---+ (Packet 3) +---+ 291 | A |0:10000000 | C +------------+ E +------------+ F | 292 +-+-+ +-+-+ +---+ +---+ 293 | | 0:00001000 0:00000100 294 | | 295 | | 296 | | 297 | 0:00010000 | 298 | +---+ | 299 +-----------+ D +-----------+ 300 (Packet 1) +---+ 302 Packet 1 303 +----------------------------+ 304 Outer | Source IP Address = A | 305 IPv6 +----------------------------+ 306 Header | Destination IP Address = E | 307 +----------------------------+ 308 Inner | Source IP Address = A | 309 IPv6 +----------------------------+ 310 Header | Destination IP Address = F | 311 +----------------------------+ 312 BIER | BitString = 00001100 | 313 Routing+----------------------------+ 314 Header 315 Packet 2 316 +----------------------------+ 317 Outer | Source IP Address = C | 318 IPv6 +----------------------------+ 319 Header | Destination IP Address = E | 320 +----------------------------+ 321 Inner | Source IP Address = A | 322 IPv6 +----------------------------+ 323 Header | Destination IP Address = F | 324 +----------------------------+ 325 BIER | BitString = 00001100 | 326 Routing+----------------------------+ 327 Header 328 Packet 3 329 +----------------------------+ 330 IPv6 | Source IP Address = A | 331 Header +----------------------------+ 332 | Destination IP Address = F | 333 BIER +----------------------------+ 335 Routing| BitString = 00000100 | 336 Header +----------------------------+ 338 Figure 3: Some devices in BIER domain do not support BIER Routing Header 340 The topology is shown in Figure 4, all devices expect device C 341 support BIER Routing Header resolution. The packet need to be 342 transmitted from A to F. The change of the Header has been given in 343 the Figure 4. When it is found that device C does not support BIER 344 Routing Header resolution, device A will perform the following steps 345 after receiving the packet: 347 1. Calculating the IPv6 address of next hop device that supports 348 BIER Routing Header. 350 2. Encapsulating an outer IPv6 Header to the packet. The calculated 351 IPv6 address is used as the destination address of the outer IPv6 352 Header, and its own IPv6 address is used as the source address of the 353 outer IPv6 Header. BitString will not be changed. 355 3. Sending the packet to device C. 357 After receiving the packet, device C will perform IPv6 forwarding 358 according the information in outer IPv6 Header, and send the packet 359 to device E. Device E will send it to device F according the 360 information in BIER Routing Header. In the forwarding process, the 361 source address and destination address in the Inner IPv6 Header are 362 not changed. 364 5. Security Considerations 366 TBD 368 6. IANA Considerations 370 This document defines a new IPv6 Routing Header - BIER Routing 371 Header. The code point is from the "Internet Protocol Version 6 372 (IPv6) Parameters - Routing Types". It is recommended to set the 373 code point of BIER Routing Header to 7. 375 7. Normative References 377 [I-D.ietf-bier-bierin6] 378 Zhang, Z., Zhang, Z., Wijnands, I., Mishra, M., Bidgoli, 379 H., and G. Mishra, "Supporting BIER in IPv6 Networks 380 (BIERin6)", draft-ietf-bier-bierin6-00 (work in progress), 381 June 2021. 383 [I-D.xie-bier-ipv6-encapsulation] 384 Xie, J., Geng, L., McBride, M., Asati, R., Dhanaraj, S., 385 Zhu, Y., Qin, Z., Shin, M., Mishra, G., and X. Geng, 386 "Encapsulation for BIER in Non-MPLS IPv6 Networks", draft- 387 xie-bier-ipv6-encapsulation-10 (work in progress), 388 February 2021. 390 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 391 Requirement Levels", BCP 14, RFC 2119, 392 DOI 10.17487/RFC2119, March 1997, 393 . 395 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 396 (IPv6) Specification", STD 86, RFC 8200, 397 DOI 10.17487/RFC8200, July 2017, 398 . 400 [RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., 401 Przygienda, T., and S. Aldrin, "Multicast Using Bit Index 402 Explicit Replication (BIER)", RFC 8279, 403 DOI 10.17487/RFC8279, November 2017, 404 . 406 Authors' Addresses 408 Wei Wang 409 China Telecom 410 Beiqijia Town, Changping District 411 Beijing, Beijing 102209 412 China 414 Email: weiwang94@foxmail.com 416 Aijun Wang 417 China Telecom 418 Beiqijia Town, Changping District 419 Beijing, Beijing 102209 420 China 422 Email: wangaj3@chinatelecom.cn