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Chen 5 Expires: 21 April 2022 Huawei 6 18 October 2021 8 Operations, Administration and Maintenance (OAM) for Deterministic 9 Networks (DetNet) with MPLS Data Plane 10 draft-ietf-detnet-mpls-oam-05 12 Abstract 14 This document defines format and use principals of the Deterministic 15 Network (DetNet) service Associated Channel (ACH) over a DetNet 16 network with the MPLS data plane. The DetNet service ACH can be used 17 to carry test packets of active Operations, Administration, and 18 Maintenance protocols that are used to detect DetNet failures and 19 measure performance metrics. 21 Status of This Memo 23 This Internet-Draft is submitted in full conformance with the 24 provisions of BCP 78 and BCP 79. 26 Internet-Drafts are working documents of the Internet Engineering 27 Task Force (IETF). Note that other groups may also distribute 28 working documents as Internet-Drafts. The list of current Internet- 29 Drafts is at https://datatracker.ietf.org/drafts/current/. 31 Internet-Drafts are draft documents valid for a maximum of six months 32 and may be updated, replaced, or obsoleted by other documents at any 33 time. It is inappropriate to use Internet-Drafts as reference 34 material or to cite them other than as "work in progress." 36 This Internet-Draft will expire on 21 April 2022. 38 Copyright Notice 40 Copyright (c) 2021 IETF Trust and the persons identified as the 41 document authors. All rights reserved. 43 This document is subject to BCP 78 and the IETF Trust's Legal 44 Provisions Relating to IETF Documents (https://trustee.ietf.org/ 45 license-info) in effect on the date of publication of this document. 46 Please review these documents carefully, as they describe your rights 47 and restrictions with respect to this document. Code Components 48 extracted from this document must include Simplified BSD License text 49 as described in Section 4.e of the Trust Legal Provisions and are 50 provided without warranty as 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. Active OAM for DetNet Networks with MPLS Data Plane . . . . . 4 59 3.1. DetNet Active OAM Encapsulation . . . . . . . . . . . . . 5 60 3.2. DetNet Packet Replication, Elimination, and Ordering 61 Functions Interaction with Active OAM . . . . . . . . . . 7 62 4. Use of Hybrid OAM in DetNet . . . . . . . . . . . . . . . . . 7 63 5. OAM Interworking Models . . . . . . . . . . . . . . . . . . . 7 64 5.1. OAM of DetNet MPLS Interworking with OAM of TSN . . . . . 8 65 5.2. OAM of DetNet MPLS Interworking with OAM of DetNet IP . . 9 66 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 67 7. Security Considerations . . . . . . . . . . . . . . . . . . . 9 68 8. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 9 69 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 70 9.1. Normative References . . . . . . . . . . . . . . . . . . 9 71 9.2. Informational References . . . . . . . . . . . . . . . . 10 72 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 74 1. Introduction 76 [RFC8655] introduces and explains Deterministic Networks (DetNet) 77 architecture and how the Packet Replication, Elimination, and 78 Ordering functions (PREOF) can be used to ensure low packet drop 79 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 Also, this document defines format and use principals of the DetNet 89 service Associated Channel over a DetNet network with the MPLS data 90 plane [RFC8964]. 92 2. Conventions used in this document 94 2.1. Terminology and Acronyms 96 The term "DetNet OAM" used in this document interchangeably with 97 longer version "set of OAM protocols, methods and tools for 98 Deterministic Networks". 100 CW Control Word 102 DetNet Deterministic Networks 104 d-ACH DetNet Associated Channel Header 106 d-CW DetNet Control Word 108 DNH DetNet Header 110 GAL Generic Associated Channel Label 112 G-ACh Generic Associated Channel 114 OAM: Operations, Administration and Maintenance 116 PREOF Packet Replication, Elimination, and Ordering Functions 118 PW Pseudowire 120 RDI Remote Defect Indication 122 E2E End-to-end 124 CFM Connectivity Fault Management 126 BFD Bidirectional Forwarding Detection 128 TSN Time-Sensitive Network 130 F-Label A Detnet "forwarding" label that identifies the LSP used to 131 forward a DetNet flow across an MPLS PSN, e.g., a hop-by-hop label 132 used between label switching routers (LSR). 134 S-Label A DetNet "service" label that is used between DetNet nodes 135 that implement also the DetNet service sub-layer functions. An 136 S-Label is also used to identify a DetNet flow at DetNet service sub- 137 layer. 139 Underlay Network or Underlay Layer: The network that provides 140 connectivity between the DetNet nodes. MPLS network providing LSP 141 connectivity between DetNet nodes is an example of the underlay 142 layer. 144 DetNet Node - a node that is an actor in the DetNet domain. DetNet 145 domain edge node and node that performs PREOF within the domain are 146 examples of DetNet node. 148 2.2. Keywords 150 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 151 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 152 "OPTIONAL" in this document are to be interpreted as described in BCP 153 14 [RFC2119] [RFC8174] when, and only when, they appear in all 154 capitals, as shown here. 156 3. Active OAM for DetNet Networks with MPLS Data Plane 158 OAM protocols and mechanisms act within the data plane of the 159 particular networking layer. And thus it is critical that the data 160 plane encapsulation supports OAM mechanisms in such a way to comply 161 with the OAM requirements listed in [I-D.tpmb-detnet-oam-framework]. 162 One of such examples that require special consideration is 163 requirement #5: 165 DetNet OAM packets MUST be in-band, i.e., follow precisely the 166 same path as DetNet data plane traffic both for unidirectional and 167 bi-directional DetNet paths. 169 The Det Net data plane encapsulation in transport network with MPLS 170 encapsulation specified in [RFC8964]. For the MPLS underlay network, 171 DetNet flows to be encapsulated analogous to pseudowires (PW) over 172 MPLS packet switched network, as described in [RFC3985], [RFC4385]. 173 Generic PW MPLS Control Word (CW), defined in [RFC4385], for DetNet 174 displayed in Figure 1. 176 0 1 2 3 177 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 1 178 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 179 |0 0 0 0| Sequence Number | 180 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 182 Figure 1: DetNet Control Word Format 184 PREOF in the DetNet domain composed by a combination of nodes that 185 perform replication and elimination functions. The elimination 186 function always uses the S-Label and packet sequencing information, 187 e.g., the value in the Sequence Number field of DetNet CW (d-CW). 188 The replication sub-function uses the S-Label information only. For 189 data packets Figure 2 presents an example of PREOF in DetNet domain. 191 1111 11111111 111111 112212 112212 132213 192 CE1----EN1--------R1-------R2-------R3--------EN2----CE2 193 \2 22222/ 3 / 194 \2222222 /----+ 3 / 195 +------R4------------------------+ 196 333333333333333333333333 198 Figure 2: DetNet Data Plane Based on PW 200 3.1. DetNet Active OAM Encapsulation 202 DetNet OAM, like PW OAM, uses PW Associated Channel Header defined in 203 [RFC4385]. Figure 3 displays the encapsulation of a DetNet MPLS 204 [RFC8964] active OAM packet. 206 +---------------------------------+ 207 | | 208 | DetNet OAM Packet | 209 | | 210 +---------------------------------+ <--\ 211 | DetNet Associated Channel Header| | 212 +---------------------------------+ +--> DetNet active OAM 213 | S-Label | | MPLS encapsulation 214 +---------------------------------+ | 215 | [ F-Label(s) ] | | 216 +---------------------------------+ <--/ 217 | Data-Link | 218 +---------------------------------+ 219 | Physical | 220 +---------------------------------+ 222 Figure 3: DetNet Active OAM Packet Encapsulation in MPLS Data Plane 224 Figure 4 displays encapsulation of a test packet of an active DetNet 225 OAM protocol in case of MPLS-over-UDP/IP [RFC9025]. 227 +---------------------------------+ 228 | | 229 | DetNet OAM Packet | 230 | | 231 +---------------------------------+ <--\ 232 | DetNet Associated Channel Header| | 233 +---------------------------------+ +--> DetNet active OAM 234 | S-Label | | MPLS encapsulation 235 +---------------------------------+ | 236 | [ F-label(s) ] | | 237 +---------------------------------+ <--+ 238 | UDP Header | | 239 +---------------------------------+ +--> DetNet data plane 240 | IP Header | | IP encapsulation 241 +---------------------------------+ <--/ 242 | Data-Link | 243 +---------------------------------+ 244 | Physical | 245 +---------------------------------+ 247 Figure 4: DetNet Active OAM Packet Encapsulation in MPLS-over-UDP/IP 249 Figure 5 displays the format of the DetNet Associated Channel Header 250 (d-ACH). 252 0 1 2 3 253 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 1 254 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 255 |0 0 0 1|Version|Sequence Number| Channel Type | 256 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 258 Figure 5: DetNet Associated Channel Header Format 260 The meanings of the fields in the d-ACH are: 262 Bits 0..3 MUST be 0b0001. This value of the first nibble allows 263 the packet to be distinguished from an IP packet [RFC4928] and a 264 DetNet data packet [RFC8964]. 266 Version: this is the version number of the d-ACH. This 267 specification defines version 0. 269 Sequence Number: this is unsigned eight bits-long field. The 270 originating DetNet node MUST set the value of the Sequence Number 271 field before packet being transmitted. The originating node MUST 272 monotonically increase the value of the Sequence Number field for 273 the every next active OAM packet. 275 Channel Type: the value of DetNet Associated Channel Type is one 276 of values defined in the IANA PW Associated Channel Type registry. 278 The DetNet flow, according to [RFC8964], is identified by the S-label 279 that MUST be at the bottom of the stack. Active OAM packet MUST have 280 d-ACH immediately following the S-label. 282 3.2. DetNet Packet Replication, Elimination, and Ordering Functions 283 Interaction with Active OAM 285 At the DetNet service sub-layer, special functions MAY be applied to 286 the particular DetNet flow, PREOF, to potentially lower packet loss, 287 improve the probability of on-time packet delivery and ensure in- 288 order packet delivery. PREOF rely on sequencing information in the 289 DetNet service sub-layer. For a DetNet active OAM packet, 28 MSBs of 290 the d-ACH MUST be used as the source of the sequencing information by 291 PREOF. 293 4. Use of Hybrid OAM in DetNet 295 Hybrid OAM methods are used in performance monitoring and defined in 296 [RFC7799] as: 298 Hybrid Methods are Methods of Measurement that use a combination 299 of Active Methods and Passive Methods. 301 A hybrid measurement method may produce metrics as close to passive, 302 but it still alters something in a data packet even if that is the 303 value of a designated field in the packet encapsulation. One example 304 of such a hybrid measurement method is the Alternate Marking method 305 described in [RFC8321]. Reserving the field for the Alternate 306 Marking method in the DetNet Header will enhance available to an 307 operator set of DetNet OAM tools. 309 5. OAM Interworking Models 311 Interworking of two OAM domains that utilize different networking 312 technology can be realized either by a peering or a tunneling model. 313 In a peering model, OAM domains are within the corresponding network 314 domain. When using the peering model, state changes that are 315 detected by a Fault Management OAM protocol can be mapped from one 316 OAM domain into another or a notification, e.g., an alarm, can be 317 sent to a central controller. In the tunneling model of OAM 318 interworking, usually, only one active OAM protocol is used. Its 319 test packets are tunneled through another domain along with the data 320 flow, thus ensuring the fate sharing among test and data packets. 322 5.1. OAM of DetNet MPLS Interworking with OAM of TSN 324 Active DetNet OAM is required to provide the E2E fault management and 325 performance monitoring for a DetNet flow. Interworking of DetNet 326 active OAM with MPLS data plane with the IEEE 802.1 Time-Sensitive 327 Networking (TSN) domain based on [RFC9037]. 329 In the case of the peering model is used in the fault management OAM, 330 then the node that borders both TSN and DetNet MPLS domains MUST 331 support [RFC7023]. [RFC7023] specified the mapping of defect states 332 between Ethernet Attachment Circuits (ACs) and associated Ethernet 333 PWs that are part of an end-to-end (E2E) emulated Ethernet service. 334 Requirements and mechanisms described in [RFC7023] are equally 335 applicable to using the peering model to achieve E2E FM OAM over 336 DetNet MPLS and TSN domains. The Connectivity Fault Management (CFM) 337 protocol [IEEE.CFM] or in [ITU.Y1731] can provide fast detection of a 338 failure in the TSN segment of the DetNet service. In the DetNet MPLS 339 domain BFD (Bidirectional Forwarding Detection), specified in 340 [RFC5880] and [RFC5885], can be used. To provide E2E failure 341 detection, the TSN segment might be presented as a concatenated with 342 the DetNet MPLS and the Section 6.8.17 [RFC5880] MAY be used to 343 inform the upstream DetNet MPLS node of a failure of the TSN segment. 344 Performance monitoring can be supported by [RFC6374] in the DetNet 345 MPLS and [ITU.Y1731] in the TSN domains, respectively. Performance 346 objectives for each domain should refer to metrics that additive or 347 be defined for each domain separately. 349 The following considerations are to be realized when using the 350 tunneling model of OAM interworking between DetNet MPLS and TSN 351 domains: 353 * Active OAM test packet MUST be mapped to the same TSN Stream ID as 354 the monitored DetNet flow. 356 * Active OAM test packets MUST be treated in the TSN domain based on 357 its S-label and CoS marking (TC field value). 359 Note that the tunneling model of the OAM interworking requires that 360 the remote peer of the E2E OAM domain supports the active OAM 361 protocol selected on the ingress endpoint. For example, if BFD is 362 used for proactive path continuity monitoring in the DetNet MPLS 363 domain, a TSN endpoint of the DetNet service has also support BFD as 364 defined in [RFC5885]. 366 5.2. OAM of DetNet MPLS Interworking with OAM of DetNet IP 368 Interworking between active OAM segments in DetNet MPLS and DetNet IP 369 domains can also be realized using either the peering or the 370 tunneling model, as discussed in Section 5.1. Using the same 371 protocol, e.g., BFD, over both segments, simplifies the mapping of 372 errors in the peering model. To provide the performance monitoring 373 over a DetNet IP domain STAMP [RFC8762] and its extensions [RFC8972] 374 can be used. 376 6. IANA Considerations 378 This document does not have any requests for IANA allocation. This 379 section can be deleted before the publication of the draft. 381 7. Security Considerations 383 Additionally, security considerations discussed in DetNet 384 specifications: [RFC8655], [RFC9055], [RFC8964] are applicable to 385 this document. Security concerns and issues related to MPLS OAM 386 tools like LSP Ping [RFC8029], BFD over PW [RFC5885] also apply to 387 this specification. 389 8. Acknowledgment 391 Authors extend their appreciation to Pascal Thubert for his 392 insightful comments and productive discussion that helped to improve 393 the document. 395 9. References 397 9.1. Normative References 399 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 400 Requirement Levels", BCP 14, RFC 2119, 401 DOI 10.17487/RFC2119, March 1997, 402 . 404 [RFC7023] Mohan, D., Ed., Bitar, N., Ed., Sajassi, A., Ed., DeLord, 405 S., Niger, P., and R. Qiu, "MPLS and Ethernet Operations, 406 Administration, and Maintenance (OAM) Interworking", 407 RFC 7023, DOI 10.17487/RFC7023, October 2013, 408 . 410 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 411 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 412 May 2017, . 414 [RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas, 415 "Deterministic Networking Architecture", RFC 8655, 416 DOI 10.17487/RFC8655, October 2019, 417 . 419 [RFC8964] Varga, B., Ed., Farkas, J., Berger, L., Malis, A., Bryant, 420 S., and J. Korhonen, "Deterministic Networking (DetNet) 421 Data Plane: MPLS", RFC 8964, DOI 10.17487/RFC8964, January 422 2021, . 424 [RFC9025] Varga, B., Ed., Farkas, J., Berger, L., Malis, A., and S. 425 Bryant, "Deterministic Networking (DetNet) Data Plane: 426 MPLS over UDP/IP", RFC 9025, DOI 10.17487/RFC9025, April 427 2021, . 429 9.2. Informational References 431 [I-D.tpmb-detnet-oam-framework] 432 Mirsky, G., Theoleyre, F., Papadopoulos, G. Z., and C. J. 433 Bernardos, "Framework of Operations, Administration and 434 Maintenance (OAM) for Deterministic Networking (DetNet)", 435 Work in Progress, Internet-Draft, draft-tpmb-detnet-oam- 436 framework-01, 30 March 2021, 437 . 440 [IEEE.CFM] IEEE, "Connectivity Fault Management clause of IEEE 441 802.1Q", IEEE 802.1Q, 2013. 443 [ITU.Y1731] 444 ITU-T, "OAM functions and mechanisms for Ethernet based 445 Networks", ITU-T Recommendation G.8013/Y.1731, November 446 2013. 448 [RFC3985] Bryant, S., Ed. and P. Pate, Ed., "Pseudo Wire Emulation 449 Edge-to-Edge (PWE3) Architecture", RFC 3985, 450 DOI 10.17487/RFC3985, March 2005, 451 . 453 [RFC4385] Bryant, S., Swallow, G., Martini, L., and D. McPherson, 454 "Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for 455 Use over an MPLS PSN", RFC 4385, DOI 10.17487/RFC4385, 456 February 2006, . 458 [RFC4928] Swallow, G., Bryant, S., and L. Andersson, "Avoiding Equal 459 Cost Multipath Treatment in MPLS Networks", BCP 128, 460 RFC 4928, DOI 10.17487/RFC4928, June 2007, 461 . 463 [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection 464 (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, 465 . 467 [RFC5885] Nadeau, T., Ed. and C. Pignataro, Ed., "Bidirectional 468 Forwarding Detection (BFD) for the Pseudowire Virtual 469 Circuit Connectivity Verification (VCCV)", RFC 5885, 470 DOI 10.17487/RFC5885, June 2010, 471 . 473 [RFC6374] Frost, D. and S. Bryant, "Packet Loss and Delay 474 Measurement for MPLS Networks", RFC 6374, 475 DOI 10.17487/RFC6374, September 2011, 476 . 478 [RFC7799] Morton, A., "Active and Passive Metrics and Methods (with 479 Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799, 480 May 2016, . 482 [RFC8029] Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N., 483 Aldrin, S., and M. Chen, "Detecting Multiprotocol Label 484 Switched (MPLS) Data-Plane Failures", RFC 8029, 485 DOI 10.17487/RFC8029, March 2017, 486 . 488 [RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli, 489 L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi, 490 "Alternate-Marking Method for Passive and Hybrid 491 Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321, 492 January 2018, . 494 [RFC8762] Mirsky, G., Jun, G., Nydell, H., and R. Foote, "Simple 495 Two-Way Active Measurement Protocol", RFC 8762, 496 DOI 10.17487/RFC8762, March 2020, 497 . 499 [RFC8972] Mirsky, G., Min, X., Nydell, H., Foote, R., Masputra, A., 500 and E. Ruffini, "Simple Two-Way Active Measurement 501 Protocol Optional Extensions", RFC 8972, 502 DOI 10.17487/RFC8972, January 2021, 503 . 505 [RFC9037] Varga, B., Ed., Farkas, J., Malis, A., and S. Bryant, 506 "Deterministic Networking (DetNet) Data Plane: MPLS over 507 IEEE 802.1 Time-Sensitive Networking (TSN)", RFC 9037, 508 DOI 10.17487/RFC9037, June 2021, 509 . 511 [RFC9055] Grossman, E., Ed., Mizrahi, T., and A. Hacker, 512 "Deterministic Networking (DetNet) Security 513 Considerations", RFC 9055, DOI 10.17487/RFC9055, June 514 2021, . 516 Authors' Addresses 518 Greg Mirsky 519 Ericsson 521 Email: gregimirsky@gmail.com 523 Mach(Guoyi) Chen 524 Huawei 526 Email: mach.chen@huawei.com