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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 DetNet Working Group G. Mirsky 3 Internet-Draft ZTE Corp. 4 Intended status: Standards Track M. Chen 5 Expires: January 9, 2021 Huawei 6 July 8, 2020 8 Operations, Administration and Maintenance (OAM) for Deterministic 9 Networks (DetNet) with MPLS Data Plane 10 draft-ietf-detnet-mpls-oam-01 12 Abstract 14 This document lists functional requirements for Operations, 15 Administration, and Maintenance (OAM) toolset in Deterministic 16 Networks (DetNet) and, using these requirements; defines format and 17 use principals of the DetNet service Associated Channel over a DetNet 18 network with the MPLS data plane.. 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 January 9, 2021. 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 and Acronyms . . . . . . . . . . . . . . . . 3 57 2.2. Keywords . . . . . . . . . . . . . . . . . . . . . . . . 4 58 3. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 4 59 4. Active OAM for DetNet Networks with MPLS Data Plane . . . . . 5 60 4.1. DetNet Active OAM Encapsulation . . . . . . . . . . . . . 6 61 4.2. DetNet Replication, Elimination, and Ordering Sub- 62 functions Interaction with Active OAM . . . . . . . . . . 8 63 5. Use of Hybrid OAM in DetNet . . . . . . . . . . . . . . . . . 9 64 6. OAM Interworking Models . . . . . . . . . . . . . . . . . . . 9 65 6.1. OAM of DetNet MPLS Interworking with OAM of TSN . . . . . 9 66 6.2. OAM of DetNet MPLS Interworking with OAM of DetNet IP . . 10 67 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 68 8. Security Considerations . . . . . . . . . . . . . . . . . . . 10 69 9. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 11 70 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 71 10.1. Normative References . . . . . . . . . . . . . . . . . . 11 72 10.2. Informational References . . . . . . . . . . . . . . . . 12 73 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 75 1. Introduction 77 [RFC8655] introduces and explains Deterministic Networks (DetNet) 78 architecture and how the Packet Replication and Elimination function 79 (PREF) can be used to ensure low packet drop ratio in DetNet domain. 81 Operations, Administration and Maintenance (OAM) protocols are used 82 to detect, localize defects in the network, and monitor network 83 performance. Some OAM functions, e.g., failure detection, work in 84 the network proactively, while others, e.g., defect localization, 85 usually performed on-demand. These tasks achieved by a combination 86 of active and hybrid, as defined in [RFC7799], OAM methods. 88 This document lists the functional requirements toward OAM for DetNet 89 domain. The list can further be used for gap analysis of available 90 OAM tools to identify possible enhancements of existing or whether 91 new OAM tools are required to support proactive and on-demand path 92 monitoring and service validation. Also, this document defines 93 format and use principals of the DetNet service Associated Channel 94 over a DetNet network with the MPLS data plane 95 [I-D.ietf-detnet-mpls]. 97 2. Conventions used in this document 99 2.1. Terminology and Acronyms 101 The term "DetNet OAM" used in this document interchangeably with 102 longer version "set of OAM protocols, methods and tools for 103 Deterministic Networks". 105 CW Control Word 107 DetNet Deterministic Networks 109 d-ACH DetNet Associated Channel Header 111 d-CW DetNet Control Word 113 DNH DetNet Header 115 GAL Generic Associated Channel Label 117 G-ACh Generic Associated Channel 119 OAM: Operations, Administration and Maintenance 121 PREF Packet Replication and Elimination Function 123 POF Packet Ordering Function 125 PW Pseudowire 127 RDI Remote Defect Indication 129 E2E End-to-end 131 CFM Connectivity Fault Management 133 BFD Bidirectional Forwarding Detection 135 TSN Time-Sensitive Network 137 F-Label A Detnet "forwarding" label that identifies the LSP used to 138 forward a DetNet flow across an MPLS PSN, e.g., a hop-by-hop label 139 used between label switching routers (LSR). 141 S-Label A DetNet "service" label that is used between DetNet nodes 142 that implement also the DetNet service sub-layer functions. An 143 S-Label is also used to identify a DetNet flow at DetNet service sub- 144 layer. 146 Underlay Network or Underlay Layer: The network that provides 147 connectivity between the DetNet nodes. MPLS network providing LSP 148 connectivity between DetNet nodes is an example of the underlay 149 layer. 151 DetNet Node - a node that is an actor in the DetNet domain. DetNet 152 domain edge node and node that performs PREF within the domain are 153 examples of DetNet node. 155 2.2. Keywords 157 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 158 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 159 "OPTIONAL" in this document are to be interpreted as described in BCP 160 14 [RFC2119] [RFC8174] when, and only when, they appear in all 161 capitals, as shown here. 163 3. Requirements 165 This section lists requirements for OAM in DetNet domain with MPLS 166 data plane: 168 1. It MUST be possible to initiate DetNet OAM session from any 169 DetNet node towards another DetNet node(s) within given domain. 171 2. It SHOULD be possible to initialize DetNet OAM session from a 172 centralized controller. 174 3. DetNet OAM MUST support proactive and on-demand OAM monitoring 175 and measurement methods. 177 4. DetNet OAM packets MUST be in-band, i.e., follow precisely the 178 same path as DetNet data plane traffic. 180 5. DetNet OAM MUST support unidirectional OAM methods, continuity 181 check, connectivity verification, and performance measurement. 183 6. DetNet OAM MUST support bi-directional OAM methods. Such OAM 184 methods MAY combine in-band monitoring or measurement in the 185 forward direction and out-of-bound notification in the reverse 186 direction, i.e., from egress to ingress end point of the OAM 187 test session. 189 7. DetNet OAM MUST support proactive monitoring of a DetNet node 190 availability in the given DetNet domain. 192 8. DetNet OAM MUST support Path Maximum Transmission Unit 193 discovery. 195 9. DetNet OAM MUST support Remote Defect Indication (RDI) 196 notification to the DetNet node performing continuity checking. 198 10. DetNet OAM MUST support performance measurement methods. 200 11. DetNet OAM MAY support hybrid performance measurement methods. 202 12. DetNet OAM MUST support unidirectional performance measurement 203 methods. Calculated performance metrics MUST include but are 204 not limited to throughput, packet loss, delay and delay 205 variation metrics. [RFC6374] provides excellent details on 206 performance measurement and performance metrics. 208 13. DetNet OAM MUST support defect notification mechanism, like 209 Alarm Indication Signal. Any DetNet node in the given DetNet 210 domain MAY originate a defect notification addressed to any 211 subset of nodes within the domain. 213 14. DetNet OAM MUST support methods to enable survivability of the 214 DetNet domain. These recovery methods MAY use protection 215 switching and restoration. 217 15. DetNet OAM MUST support the discovery of Packet Replication, 218 Elimination, and Order preservation sub-functions locations in 219 the domain. 221 16. DetNet OAM MUST support testing of Packet Replication, 222 Elimination, and Order preservation sub-functions in the domain. 224 17. DetNet OAM MUST support monitoring any sub-set of paths 225 traversed through the DetNet domain by the DetNet flow. 227 4. Active OAM for DetNet Networks with MPLS Data Plane 229 OAM protocols and mechanisms act within the data plane of the 230 particular networking layer. And thus it is critical that the data 231 plane encapsulation supports OAM mechanisms in such a way to comply 232 with the above-listed requirements. One of such examples that 233 require special consideration is requirement #5: 235 DetNet OAM packets MUST be in-band, i.e., follow precisely the 236 same path as DetNet data plane traffic both for unidirectional and 237 bi-directional DetNet paths. 239 The Det Net data plane encapsulation in transport network with MPLS 240 encapsulation specified in [I-D.ietf-detnet-mpls]. For the MPLS 241 underlay network, DetNet flows to be encapsulated analogous to 242 pseudowires (PW) over MPLS packet switched network, as described in 244 [RFC3985], [RFC4385]. Generic PW MPLS Control Word (CW), defined in 245 [RFC4385], for DetNet displayed in Figure 1. 247 0 1 2 3 248 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 1 249 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 250 |0 0 0 0| Sequence Number | 251 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 253 Figure 1: DetNet Control Word Format 255 PREF in the DetNet domain composed by a combination of nodes that 256 perform replication and elimination sub-functions. The elimination 257 sub-function always uses the S-Label and packet sequencing 258 information, e.g., the value in the Sequence Number field of DetNet 259 CW (d-CW). The replication sub-function uses the S-Label information 260 only. For data packets Figure 2 presents an example of PREF in 261 DetNet domain. 263 1111 11111111 111111 112212 112212 132213 264 CE1----EN1--------R1-------R2-------R3--------EN2----CE2 265 \2 22222/ 3 / 266 \2222222 /----+ 3 / 267 +------R4------------------------+ 268 333333333333333333333333 270 Figure 2: DetNet Data Plane Based on PW 272 4.1. DetNet Active OAM Encapsulation 274 DetNet OAM, like PW OAM, uses PW Associated Channel Header defined in 275 [RFC4385]. Figure 3 displays the encapsulation of a DetNet MPLS 276 [I-D.ietf-detnet-mpls] active OAM packet. 278 +---------------------------------+ 279 | | 280 | DetNet App-Flow | 281 | Payload Packet | 282 | | 283 +---------------------------------+ <--\ 284 | DetNet Associated Channel Header| | 285 +---------------------------------+ +--> DetNet active OAM 286 | S-Label | | MPLS encapsulation 287 +---------------------------------+ | 288 | [ F-Label(s) ] | | 289 +---------------------------------+ <--/ 290 | Data-Link | 291 +---------------------------------+ 292 | Physical | 293 +---------------------------------+ 295 Figure 3: DetNet Active OAM Packet Encapsulation in MPLS Data Plane 297 Figure 4 displays encapsulation of a test packet of an active DetNet 298 OAM protocol in case of MPLS-over-UDP/IP 299 [I-D.ietf-detnet-mpls-over-udp-ip]. 301 +---------------------------------+ 302 | | 303 | DetNet App-Flow | 304 | Payload Packet | 305 | | 306 +---------------------------------+ <--\ 307 | DetNet Associated Channel Header| | 308 +---------------------------------+ +--> DetNet active OAM 309 | S-Label | | MPLS encapsulation 310 +---------------------------------+ | 311 | [ F-label(s) ] | | 312 +---------------------------------+ <--+ 313 | UDP Header | | 314 +---------------------------------+ +--> DetNet data plane 315 | IP Header | | IP encapsulation 316 +---------------------------------+ <--/ 317 | Data-Link | 318 +---------------------------------+ 319 | Physical | 320 +---------------------------------+ 322 Figure 4: DetNet Active OAM Packet Encapsulation in MPLS-over-UDP/IP 323 Figure 5 displays the format of the DetNet Associated Channel Header 324 (d-ACH). 326 0 1 2 3 327 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 1 328 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 329 |0 0 0 1|Version|Sequence Number| Channel Type | 330 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 332 Figure 5: DetNet Associated Channel Header Format 334 The meanings of the fields in the d-ACH are: 336 Bits 0..3 MUST be 0b0001. This value of the first nibble allows 337 the packet to be distinguished from an IP packet [RFC4928] and a 338 DetNet data packet [I-D.ietf-detnet-mpls]. 340 Version: this is the version number of the d-ACH. This 341 specification defines version 0. 343 Sequence Number: this is unsigned eight bits-long field. The 344 originating DetNet node MUST set the value of the Sequence Number 345 field to a non-zero before packet being transmitted. The 346 originating node MUST monotonically increase the value of the 347 Sequence Number field for the every next active OAM packet. 349 Channel Type: the value of DetNet Associated Channel Type is one 350 of values defined in the IANA PW Associated Channel Type registry. 352 The DetNet flow, according to [I-D.ietf-detnet-mpls], is identified 353 by the S-label that MUST be at the bottom of the stack. Active OAM 354 packet MUST have d-ACH immediately following the S-label. 356 4.2. DetNet Replication, Elimination, and Ordering Sub-functions 357 Interaction with Active OAM 359 At the DetNet service layer, special functions MAY be applied to the 360 particular DetNet flow - PREF to potentially lower packet loss, 361 improve the probability of on-time packet delivery and Packet 362 Ordering Function (POF) to ensure in-order packet delivery. As data 363 and the active OAM packets have the same Flow ID, S-label, sub- 364 functions that rely on sequencing information in the DetNet service 365 layer MUST process 28 MSBs of the d-ACH as the source of the 366 sequencing information for the OAM packet. 368 5. Use of Hybrid OAM in DetNet 370 Hybrid OAM methods are used in performance monitoring and defined in 371 [RFC7799] as: 373 Hybrid Methods are Methods of Measurement that use a combination 374 of Active Methods and Passive Methods. 376 A hybrid measurement method may produce metrics as close to passive, 377 but it still alters something in a data packet even if that is the 378 value of a designated field in the packet encapsulation. One example 379 of such a hybrid measurement method is the Alternate Marking method 380 described in [RFC8321]. Reserving the field for the Alternate 381 Marking method in the DetNet Header will enhance available to an 382 operator set of DetNet OAM tools. 384 6. OAM Interworking Models 386 Interworking of two OAM domains that utilize different networking 387 technology can be realized either by a peering or a tunneling model. 388 In a peering model, OAM domains are within the corresponding network 389 domain. When using the peering model, state changes that are 390 detected by a Fault Management OAM protocol can be mapped from one 391 OAM domain into another or a notification, e.g., an alarm, can be 392 sent to a central controller. In the tunneling model of OAM 393 interworking, usually, only one active OAM protocol is used. Its 394 test packets are tunneled through another domain along with the data 395 flow, thus ensuring the fate sharing among test and data packets. 397 6.1. OAM of DetNet MPLS Interworking with OAM of TSN 399 Active DetNet OAM is required to provide the E2E fault management and 400 performance monitoring for a DetNet flow. Interworking of DetNet 401 active OAM with MPLS data plane with the IEEE 802.1 Time-Sensitive 402 Networking (TSN) domain based on [I-D.ietf-detnet-mpls-over-tsn]. 404 In the case of the peering model is used in the fault management OAM, 405 then the node that borders both TSN and DetNet MPLS domains MUST 406 support [RFC7023]. [RFC7023] specified the mapping of defect states 407 between Ethernet Attachment Circuits (ACs) and associated Ethernet 408 PWs that are part of an end-to-end (E2E) emulated Ethernet service. 409 Requirements and mechanisms described in [RFC7023] are equally 410 applicable to using the peering model to achieve E2E FM OAM over 411 DetNet MPLS and TSN domains. The Connectivity Fault Management (CFM) 412 protocol [IEEE.CFM] or in [ITU.Y1731] can provide fast detection of a 413 failure in the TSN segment of the DetNet service. In the DetNet MPLS 414 domain BFD (Bidirectional Forwarding Detection), specified in 415 [RFC5880] and [RFC5885], can be used. To provide E2E failure 416 detection, the TSN segment might be presented as a concatenated with 417 the DetNet MPLS and the Section 6.8.17 [RFC5880] MAY be used to 418 inform the upstream DetNet MPLS node of a failure of the TSN segment. 419 Performance monitoring can be supported by [RFC6374] in the DetNet 420 MPLS and [ITU.Y1731] in the TSN domains, respectively. Performance 421 objectives for each domain should refer to metrics that additive or 422 be defined for each domain separately. 424 The following considerations are to be realized when using the 425 tunneling model of OAM interworking between DetNet MPLS and TSN 426 domains: 428 o Active OAM test packet MUST be mapped to the same TSN Stream ID as 429 the monitored DetNet flow. 431 o Active OAM test packets MUST be treated in the TSN domain based on 432 its S-label and CoS marking (TC field value). 434 Note that the tunneling model of the OAM interworking requires that 435 the remote peer of the E2E OAM domain supports the active OAM 436 protocol selected on the ingress endpoint. For example, if BFD is 437 used for proactive path continuity monitoring in the DetNet MPLS 438 domain, a TSN endpoint of the DetNet service has also support BFD as 439 defined in [RFC5885]. 441 6.2. OAM of DetNet MPLS Interworking with OAM of DetNet IP 443 Interworking between active OAM segments in DetNet MPLS and DetNet IP 444 domains can also be realized using either the peering or the 445 tunneling model, as discussed in Section 6.1. Using the same 446 protocol, e.g., BFD, over both segments, simplifies the mapping of 447 errors in the peering model. To provide the performance monitoring 448 over a DetNet IP domain STAMP [RFC8762] and its extensions 449 [I-D.ietf-ippm-stamp-option-tlv] can be used. 451 7. IANA Considerations 453 TBA 455 8. Security Considerations 457 This document lists the OAM requirements for a DetNet domain and does 458 not raise any security concerns or issues in addition to ones common 459 to networking. Additionally, security considerations discussed in 460 DetNet specifications: [RFC8655], [I-D.ietf-detnet-security], 461 [I-D.ietf-detnet-mpls] are applicable to this document. Security 462 concerns and issues related to MPLS OAM tools like LSP Ping 463 [RFC8029], BFD over PW [RFC5885] also apply to this specification. 465 9. Acknowledgment 467 Authors extend their appreciation to Pascal Thubert for his 468 insightful comments and productive discussion that helped to improve 469 the document. 471 10. References 473 10.1. Normative References 475 [I-D.ietf-detnet-mpls] 476 Varga, B., Farkas, J., Berger, L., Malis, A., Bryant, S., 477 and J. Korhonen, "DetNet Data Plane: MPLS", draft-ietf- 478 detnet-mpls-08 (work in progress), July 2020. 480 [I-D.ietf-detnet-mpls-over-tsn] 481 Varga, B., Farkas, J., Malis, A., and S. Bryant, "DetNet 482 Data Plane: MPLS over IEEE 802.1 Time Sensitive Networking 483 (TSN)", draft-ietf-detnet-mpls-over-tsn-03 (work in 484 progress), June 2020. 486 [I-D.ietf-detnet-mpls-over-udp-ip] 487 Varga, B., Farkas, J., Berger, L., Malis, A., and S. 488 Bryant, "DetNet Data Plane: MPLS over UDP/IP", draft-ietf- 489 detnet-mpls-over-udp-ip-06 (work in progress), May 2020. 491 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 492 Requirement Levels", BCP 14, RFC 2119, 493 DOI 10.17487/RFC2119, March 1997, 494 . 496 [RFC7023] Mohan, D., Ed., Bitar, N., Ed., Sajassi, A., Ed., DeLord, 497 S., Niger, P., and R. Qiu, "MPLS and Ethernet Operations, 498 Administration, and Maintenance (OAM) Interworking", 499 RFC 7023, DOI 10.17487/RFC7023, October 2013, 500 . 502 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 503 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 504 May 2017, . 506 [RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas, 507 "Deterministic Networking Architecture", RFC 8655, 508 DOI 10.17487/RFC8655, October 2019, 509 . 511 10.2. Informational References 513 [I-D.ietf-detnet-security] 514 Mizrahi, T. and E. Grossman, "Deterministic Networking 515 (DetNet) Security Considerations", draft-ietf-detnet- 516 security-10 (work in progress), May 2020. 518 [I-D.ietf-ippm-stamp-option-tlv] 519 Mirsky, G., Min, X., Nydell, H., Foote, R., Masputra, A., 520 and E. Ruffini, "Simple Two-way Active Measurement 521 Protocol Optional Extensions", draft-ietf-ippm-stamp- 522 option-tlv-06 (work in progress), June 2020. 524 [IEEE.CFM] 525 IEEE, "Connectivity Fault Management clause of IEEE 526 802.1Q", IEEE 802.1Q, 2013. 528 [ITU.Y1731] 529 ITU-T, "OAM functions and mechanisms for Ethernet based 530 Networks", ITU-T Recommendation G.8013/Y.1731, November 531 2013. 533 [RFC3985] Bryant, S., Ed. and P. Pate, Ed., "Pseudo Wire Emulation 534 Edge-to-Edge (PWE3) Architecture", RFC 3985, 535 DOI 10.17487/RFC3985, March 2005, 536 . 538 [RFC4385] Bryant, S., Swallow, G., Martini, L., and D. McPherson, 539 "Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for 540 Use over an MPLS PSN", RFC 4385, DOI 10.17487/RFC4385, 541 February 2006, . 543 [RFC4928] Swallow, G., Bryant, S., and L. Andersson, "Avoiding Equal 544 Cost Multipath Treatment in MPLS Networks", BCP 128, 545 RFC 4928, DOI 10.17487/RFC4928, June 2007, 546 . 548 [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection 549 (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, 550 . 552 [RFC5885] Nadeau, T., Ed. and C. Pignataro, Ed., "Bidirectional 553 Forwarding Detection (BFD) for the Pseudowire Virtual 554 Circuit Connectivity Verification (VCCV)", RFC 5885, 555 DOI 10.17487/RFC5885, June 2010, 556 . 558 [RFC6374] Frost, D. and S. Bryant, "Packet Loss and Delay 559 Measurement for MPLS Networks", RFC 6374, 560 DOI 10.17487/RFC6374, September 2011, 561 . 563 [RFC7799] Morton, A., "Active and Passive Metrics and Methods (with 564 Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799, 565 May 2016, . 567 [RFC8029] Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N., 568 Aldrin, S., and M. Chen, "Detecting Multiprotocol Label 569 Switched (MPLS) Data-Plane Failures", RFC 8029, 570 DOI 10.17487/RFC8029, March 2017, 571 . 573 [RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli, 574 L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi, 575 "Alternate-Marking Method for Passive and Hybrid 576 Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321, 577 January 2018, . 579 [RFC8762] Mirsky, G., Jun, G., Nydell, H., and R. Foote, "Simple 580 Two-Way Active Measurement Protocol", RFC 8762, 581 DOI 10.17487/RFC8762, March 2020, 582 . 584 Authors' Addresses 586 Greg Mirsky 587 ZTE Corp. 589 Email: gregimirsky@gmail.com 591 Mach(Guoyi) Chen 592 Huawei 594 Email: mach.chen@huawei.com