idnits 2.17.1 draft-hu-bier-bfd-06.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 : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (April 29, 2020) is 1451 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in RFCs) == Unused Reference: 'ISO9577' is defined on line 402, but no explicit reference was found in the text == Outdated reference: A later version (-13) exists of draft-ietf-bier-ping-06 == Outdated reference: A later version (-15) exists of draft-mirsky-mpls-p2mp-bfd-10 Summary: 0 errors (**), 0 flaws (~~), 4 warnings (==), 1 comment (--).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 Quan Xiong 3 Internet-Draft Greg Mirsky 4 Intended status: Standards Track ZTE Corporation 5 Expires: October 31, 2020 Fangwei Hu 6 Individual 7 Chang Liu 8 China Unicom 9 April 29, 2020 11 BIER BFD 12 draft-hu-bier-bfd-06.txt 14 Abstract 16 Point to multipoint (P2MP) BFD is designed to verify multipoint 17 connectivity. This document specifies the application of P2MP BFD in 18 BIER network. 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 October 31, 2020. 37 Copyright Notice 39 Copyright (c) 2020 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 2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 57 2.2. Requirements Language . . . . . . . . . . . . . . . . . . 3 58 3. BIER BFD Encapsulation . . . . . . . . . . . . . . . . . . . 3 59 4. BIER BFD Session Bootstrapping . . . . . . . . . . . . . . . 3 60 4.1. BIER OAM Bootstrapping . . . . . . . . . . . . . . . . . 4 61 4.2. IGP protocol Bootstrapping . . . . . . . . . . . . . . . 4 62 4.2.1. IS-IS extension for BIER BFD . . . . . . . . . . . . 4 63 4.2.2. OSPF extension for BIER BFD . . . . . . . . . . . . . 5 64 5. Discriminators and Packet Demultiplexing . . . . . . . . . . 6 65 6. Active Tail in BIER BFD . . . . . . . . . . . . . . . . . . . 6 66 7. Security Considerations . . . . . . . . . . . . . . . . . . . 7 67 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 68 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 69 9.1. BIER OAM Message Type . . . . . . . . . . . . . . . . . . 7 70 9.2. BFD Discriminator TLV . . . . . . . . . . . . . . . . . . 7 71 9.3. BIER BFD Sub-sub-TLV . . . . . . . . . . . . . . . . . . 8 72 9.4. BIER BFD Sub-TLV . . . . . . . . . . . . . . . . . . . . 8 73 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 74 10.1. Normative References . . . . . . . . . . . . . . . . . . 8 75 10.2. Informative References . . . . . . . . . . . . . . . . . 9 76 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 78 1. Introduction 80 Bit Index Explicit Replication (BIER) [RFC8279] provides forwarding 81 of multicast data packets through a multicast domain. It does so 82 without requiring any explicit tree-building protocol and without 83 requiring intermediate nodes to maintain any per-flow state. 85 [RFC8562] defines a method of using Bidirectional Forwarding 86 Detection (BFD) to monitor and detect unicast failures between the 87 sender (head) and one or more receivers (tails) in multipoint or 88 multicast networks. [RFC8563] describes active tail extensions to 89 the BFD protocol for multipoint networks. 91 This document describes the procedures for using such mode of BFD 92 protocol to monitor connectivity between a multipoint sender, Bit- 93 Forwarding Ingress Router (BFIR), and a set of one or more multipoint 94 receivers,Bit-Forwarding Egress Routers (BFERs). The BIER BFD only 95 supports the unidirectional multicast. This document defines the use 96 of P2MP BFD as per [RFC8562], and active tail as per [RFC8563] for 97 BIER-specific domain. 99 2. Conventions used in this document 101 2.1. Terminology 103 This document uses the acronyms defined in [RFC8279] along with the 104 following: 106 BFD: Bidirectional Forwarding Detection. 108 OAM: Operations, Administration, and Maintenance. 110 P2MP: Point to Multi-Point. 112 2.2. Requirements Language 114 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 115 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 116 "OPTIONAL" in this document are to be interpreted as described in BCP 117 14 [RFC2119] [RFC8174] when, and only when, they appear in all 118 capitals, as shown here. 120 3. BIER BFD Encapsulation 122 BIER BFD encapsulation uses the BIER OAM packet format defined in 123 [I-D.ietf-bier-ping]. The value of the Messasge Type field MUST be 124 set to BIER BFD (TBD1 by IANA ). BFD Control Packet, defined in 125 Section 4 [RFC5880] immediately follows the BIER OAM header. The 126 operation of Multipoint BFD with the BFD Control Packet is described 127 in [RFC8562]. 129 4. BIER BFD Session Bootstrapping 131 As defined in [RFC8562], BIER BFD session MAY be established to 132 monitor the state of the multipoint path. The BIER BFD session could 133 be created for each multipoint path and the set of BFERs over which 134 the BFIR wishes to run BIER BFD. The BFIR MUST advertise the BFD 135 Discriminator along with the corresponding multipoint path to the set 136 of BFERs. Bootstrapping a BIER BFD session MAY use BIER OAM message 137 section 4.1 or the control plane section 4.2. 139 The BIER BFD bootstrapping MUST be repeated when the value of this 140 discriminator being changed. 142 4.1. BIER OAM Bootstrapping 144 The BIER OAM could be used for bootstrapping the BIER BFD session. 145 The BFIR sends the BIER OAM Echo request message carrying a BFD 146 discriminator TLV which immediately follows the Target SI-Bitstring 147 TLV (section 3.3.2 [I-D.ietf-bier-ping]). 149 The Target SI-Bitstring TLV MUST be used to carry the set of BFER 150 information (including Sub-domain-id, Set ID, BS Len, Bitstring) for 151 the purpose of session establishment. 153 The BFD discriminator TLV is a new TLV for BIER OAM TLV with the type 154 (TBD2 by IANA) and the length of 4. The value contains the 4-byte 155 local discriminator generated by BFIR for this session. This 156 discriminator MUST subsequently be used as the My Discriminator field 157 in the BIER BFD session packets sent by BFIR. The format is as 158 follows. 160 0 1 2 3 161 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 1 162 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 163 | Type=TBD2 | Length | 164 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 165 | My Discriminator | 166 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 168 Figure 1: BFD discriminator TLV 170 4.2. IGP protocol Bootstrapping 172 An alternative option to bootstrap the BIER BFD is to advertise the 173 BFD information in control plane. This document defines a new BIER 174 BFD Sub-sub-TLV carried in IS-IS and OSPF protocol. 176 The BFIR generates the My Discriminator value for each multicast flow 177 and advertises it to the expecting BFERs which is indicated by the 178 Bitstring which is carried in BIER BFD sub-sub-TLV. The 179 corresponding BFERs SHOULD store the My Discriminator value for 180 packet Demultiplexing. 182 4.2.1. IS-IS extension for BIER BFD 184 The new BIER BFD Sub-sub-TLV is carried within the BIER Info sub-TLV 185 defined in [RFC8401]. The format is as follows. 187 0 1 2 3 188 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 1 189 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 190 | Type | Length | 191 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 192 | My Discriminator | 193 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 194 | RESERVED | BIFT-id | 195 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 196 | BitString (first 32 bits) ~ 197 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 198 ~ ~ 199 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 200 ~ BitString (last 32 bits) | 201 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 203 Figure 2: BIER BFD Sub-sub-TLV for IS-IS extension 205 Type: TBD3 by IANA. 207 Length: Length of the BIER BFD Sub-sub-TLV for IS-IS extension, in 208 bytes. 210 My Discriminator: A unique, nonzero discriminator value generated by 211 BFIR for each multipoint path. 213 The BitString field carries the set of BFR-IDs of BFER(s) that the 214 BFIR expects to establish BIER BFD session. 216 The BIFT-id represents a particular Bit Index Forwarding Table (BIFT) 217 as per [RFC8279]. 219 4.2.2. OSPF extension for BIER BFD 221 The new BIER BFD Sub-TLV is a sub-TLV of the BIER Sub-TLV defined in 222 [RFC8444]. The format is as follows. 224 0 1 2 3 225 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 1 226 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 227 | Type | Length | 228 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 229 | My Discriminator | 230 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 231 | RESERVED | BIFT-id | 232 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 233 | BitString (first 32 bits) ~ 234 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 235 ~ ~ 236 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 237 ~ BitString (last 32 bits) | 238 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 240 Figure 3: BIER BFD Sub-TLV for OSPF extension 242 Type: TBD4 by IANA. 244 Length: Length of the BIER BFD Sub-TLV for OSPF extension, in bytes. 246 Other fields in BIER BFD Sub-TLV is the same with section 4.2.1. 248 5. Discriminators and Packet Demultiplexing 250 As defined in [RFC8562], the BFIR sends BFD Control packets over the 251 multipoint path via the BIER BFD session with My Discriminator set to 252 the value assigned by the BFIR and the value of the Your 253 Discriminator set to zero. The set of BFERs MUST demultiplex BFD 254 packets based on a combination of the source address, My 255 Discriminator value. The source address is BFIR-id and BIER MPLS 256 Label (MPLS network) or BFIR-id and BIFT-id (Non-MPLS network) for 257 BIER BFD. The My Discriminator value is advertised in BIER BFD 258 bootstrapping using one of options described in section 4. 260 6. Active Tail in BIER BFD 262 [RFC8563] defined an extension for Multipoint BFD, which allows the 263 head to discover the state of a multicast distribution tree for any 264 sub-set of tails. For BIER BFD in active tail mode, the BFIR may 265 learn the state and connectivity of the BFERs through allowing the 266 BFERs to notify the BFIR. As per [RFC8563] provides detailed 267 information on how the BFIR can use multipoint Poll sequence message 268 or a combination of multicast and unicast Poll sequence messages to 269 determine the state of multicast tree. Also, [RFC8563] describes 270 that a BFER can transmit an unsolicited unicast Poll sequence message 271 to the BFIR (note that a unicast message must be sent over a path 272 which is disjoint from the multicast distribution tree). 273 [I-D.mirsky-mpls-p2mp-bfd] provides detailed information on using the 274 unsolicited notification method for P2MP MPLS LSP which is also 275 applicable to BIER over MPLS case. 277 7. Security Considerations 279 For BIER OAM packet procssing security considerations, see 280 [I-D.ietf-bier-ping]. 282 For general multipoint BFD security considerations, see [RFC8562]. 284 No additional security issues are raised in this document beyond 285 those that exist in the referenced BFD documents. 287 8. Acknowledgements 289 Authors would like to thank the comments and suggestions from Sandy 290 Zhang, Jeffrey (Zhaohui) Zhang, Donald Eastlake 3rd. 292 9. IANA Considerations 294 9.1. BIER OAM Message Type 296 IANA is requested to assign a new type from the BIER OAM Message Type 297 registry as follows: 299 +--------+--------------+------------------+ 300 | Value | Description | Reference | 301 +--------+--------------+------------------+ 302 | TBD1 | BIER BFD | [this document] | 303 +--------+--------------+------------------+ 305 Table 1 307 9.2. BFD Discriminator TLV 309 IANA is requested to assign a new type from the BIER OAM TLV registry 310 as follows: 312 +--------+-----------------------+------------------+ 313 | Value | Description | Reference | 314 +--------+-----------------------+------------------+ 315 | TBD2 | BFD discriminator TLV | [this document] | 316 +--------+-----------------------+------------------+ 318 Table 2 320 9.3. BIER BFD Sub-sub-TLV 322 IANA is requested to assign a new BIER BFD Sub-sub-TLV within the 323 BIER Info sub-TLV registry defined in [RFC8401] as follows: 325 +--------+----------------------+------------------+ 326 | Value | Description | Reference | 327 +--------+----------------------+------------------+ 328 | TBD3 | BIER BFD Sub-sub-TLV | [this document] | 329 +--------+----------------------+------------------+ 331 Table 3 333 9.4. BIER BFD Sub-TLV 335 IANA is requested to assign a new BIER BFD Sub-TLV from the BIER Sub- 336 TLV registry defined in [RFC8444] as follows: 338 +--------+------------------+------------------+ 339 | Value | Description | Reference | 340 +--------+------------------+------------------+ 341 | TBD4 | BIER BFD Sub-TLV | [this document] | 342 +--------+------------------+------------------+ 344 Table 4 346 10. References 348 10.1. Normative References 350 [I-D.ietf-bier-ping] 351 Kumar, N., Pignataro, C., Akiya, N., Zheng, L., Chen, M., 352 and G. Mirsky, "BIER Ping and Trace", draft-ietf-bier- 353 ping-06 (work in progress), October 2019. 355 [I-D.mirsky-mpls-p2mp-bfd] 356 Mirsky, G., "BFD for Multipoint Networks over Point-to- 357 Multi-Point MPLS LSP", draft-mirsky-mpls-p2mp-bfd-10 (work 358 in progress), April 2020. 360 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 361 Requirement Levels", BCP 14, RFC 2119, 362 DOI 10.17487/RFC2119, March 1997, 363 . 365 [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection 366 (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, 367 . 369 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 370 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 371 May 2017, . 373 [RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., 374 Przygienda, T., and S. Aldrin, "Multicast Using Bit Index 375 Explicit Replication (BIER)", RFC 8279, 376 DOI 10.17487/RFC8279, November 2017, 377 . 379 [RFC8401] Ginsberg, L., Ed., Przygienda, T., Aldrin, S., and Z. 380 Zhang, "Bit Index Explicit Replication (BIER) Support via 381 IS-IS", RFC 8401, DOI 10.17487/RFC8401, June 2018, 382 . 384 [RFC8444] Psenak, P., Ed., Kumar, N., Wijnands, IJ., Dolganow, A., 385 Przygienda, T., Zhang, J., and S. Aldrin, "OSPFv2 386 Extensions for Bit Index Explicit Replication (BIER)", 387 RFC 8444, DOI 10.17487/RFC8444, November 2018, 388 . 390 [RFC8562] Katz, D., Ward, D., Pallagatti, S., Ed., and G. Mirsky, 391 Ed., "Bidirectional Forwarding Detection (BFD) for 392 Multipoint Networks", RFC 8562, DOI 10.17487/RFC8562, 393 April 2019, . 395 [RFC8563] Katz, D., Ward, D., Pallagatti, S., Ed., and G. Mirsky, 396 Ed., "Bidirectional Forwarding Detection (BFD) Multipoint 397 Active Tails", RFC 8563, DOI 10.17487/RFC8563, April 2019, 398 . 400 10.2. Informative References 402 [ISO9577] ISO/IEC TR 9577:1999,, "International Organization for 403 Standardization "Information technology - 404 Telecommunications and Information exchange between 405 systems - Protocol identification in the network layer"", 406 1999. 408 Authors' Addresses 409 Quan Xiong 410 ZTE Corporation 411 No.6 Huashi Park Rd 412 Wuhan, Hubei 430223 413 China 415 Phone: +86 27 83531060 416 Email: xiong.quan@zte.com.cn 418 Greg Mirsky 419 ZTE Corporation 420 USA 422 Email: gregimirsky@gmail.com 424 Fangwei Hu 425 Individual 427 Email: hufwei@gmail.com 429 Chang Liu 430 China Unicom 431 No.9 Shouti Nanlu 432 Beijing 100048 433 China 435 Phone: +86-010-68799999-7294 436 Email: liuc131@chinaunicom.cn