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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, 2020 Huawei 6 July 8, 2019 8 Operations, Administration and Maintenance (OAM) for Deterministic 9 Networks (DetNet) with MPLS Data Plane 10 draft-mirsky-detnet-mpls-oam-00 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, 2020. 37 Copyright Notice 39 Copyright (c) 2019 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. 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 . . . . . . . . . . 9 63 5. Use of Hybrid OAM in DetNet . . . . . . . . . . . . . . . . . 9 64 6. OAM of DetNet MPLS Interworking with OAM of DetNet IP . . . . 9 65 7. OAM of DetNet MPLS Interworking with OAM of TSN . . . . . . . 9 66 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 67 9. Security Considerations . . . . . . . . . . . . . . . . . . . 9 68 10. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 10 69 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 70 11.1. Normative References . . . . . . . . . . . . . . . . . . 10 71 11.2. Informational References . . . . . . . . . . . . . . . . 10 72 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 74 1. Introduction 76 [I-D.ietf-detnet-architecture] introduces and explains Deterministic 77 Networks (DetNet) architecture and how the Packet Replication and 78 Elimination function (PREF) 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 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 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 TSN Time-Sensitive Network 131 F-Label A Detnet "forwarding" label that identifies the LSP used to 132 forward a DetNet flow across an MPLS PSN, e.g., a hop-by-hop label 133 used between label switching routers (LSR). 135 S-Label A DetNet "service" label that is used between DetNet nodes 136 that implement also the DetNet service sub-layer functions. An 137 S-Label is also used to identify a DetNet flow at DetNet service sub- 138 layer. 140 Underlay Network or Underlay Layer: The network that provides 141 connectivity between the DetNet nodes. MPLS network providing LSP 142 connectivity between DetNet nodes is an example of the underlay 143 layer. 145 DetNet Node - a node that is an actor in the DetNet domain. DetNet 146 domain edge node and node that performs PREF within the domain are 147 examples of DetNet node. 149 2.2. Keywords 151 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 152 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 153 "OPTIONAL" in this document are to be interpreted as described in BCP 154 14 [RFC2119] [RFC8174] when, and only when, they appear in all 155 capitals, as shown here. 157 3. Requirements 159 This section lists requirements for OAM in DetNet domain with MPLS 160 data plane: 162 1. It MUST be possible to initiate DetNet OAM session from any 163 DetNet node towards another DetNet node(s) within given domain. 165 2. It SHOULD be possible to initialize DetNet OAM session from a 166 centralized controller. 168 3. DetNet OAM MUST support proactive and on-demand OAM monitoring 169 and measurement methods. 171 4. DetNet OAM packets MUST be in-band, i.e., follow precisely the 172 same path as DetNet data plane traffic. 174 5. DetNet OAM MUST support unidirectional OAM methods, continuity 175 check, connectivity verification, and performance measurement. 177 6. DetNet OAM MUST support bi-directional OAM methods. Such OAM 178 methods MAY combine in-band monitoring or measurement in the 179 forward direction and out-of-bound notification in the reverse 180 direction, i.e., from egress to ingress end point of the OAM 181 test session. 183 7. DetNet OAM MUST support proactive monitoring of a DetNet node 184 availability in the given DetNet domain. 186 8. DetNet OAM MUST support Path Maximum Transmission Unit 187 discovery. 189 9. DetNet OAM MUST support Remote Defect Indication (RDI) 190 notification to the DetNet node performing continuity checking. 192 10. DetNet OAM MUST support performance measurement methods. 194 11. DetNet OAM MAY support hybrid performance measurement methods. 196 12. DetNet OAM MUST support unidirectional performance measurement 197 methods. Calculated performance metrics MUST include but are 198 not limited to throughput, packet loss, delay and delay 199 variation metrics. [RFC6374] provides excellent details on 200 performance measurement and performance metrics. 202 13. DetNet OAM MUST support defect notification mechanism, like 203 Alarm Indication Signal. Any DetNet node in the given DetNet 204 domain MAY originate a defect notification addressed to any 205 subset of nodes within the domain. 207 14. DetNet OAM MUST support methods to enable survivability of the 208 DetNet domain. These recovery methods MAY use protection 209 switching and restoration. 211 15. DetNet OAM MUST support the discovery of Packet Replication, 212 Elimination, and Order preservation sub-functions locations in 213 the domain. 215 16. DetNet OAM MUST support testing of Packet Replication, 216 Elimination, and Order preservation sub-functions in the domain. 218 17. DetNet OAM MUST support monitoring any sub-set of paths 219 traversed through the DetNet domain by the DetNet flow. 221 4. Active OAM for DetNet Networks with MPLS Data Plane 223 OAM protocols and mechanisms act within the data plane of the 224 particular networking layer. And thus it is critical that the data 225 plane encapsulation supports OAM mechanisms in such a way to comply 226 with the above-listed requirements. One of such examples that 227 require special consideration is requirement #5: 229 DetNet OAM packets MUST be in-band, i.e., follow precisely the 230 same path as DetNet data plane traffic both for unidirectional and 231 bi-directional DetNet paths. 233 The Det Net data plane encapsulation in transport network with MPLS 234 encapsulation specified in [I-D.ietf-detnet-mpls]. For the MPLS 235 underlay network, DetNet flows to be encapsulated analogous to 236 pseudowires (PW) over MPLS packet switched network, as described in 237 [RFC3985], [RFC4385]. Generic PW MPLS Control Word (CW), defined in 238 [RFC4385], for DetNet displayed in Figure 1. 240 0 1 2 3 241 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 1 242 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 243 |0 0 0 0| Sequence Number | 244 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 246 Figure 1: DetNet Control Word Format 248 PREF in the DetNet domain composed by a combination of nodes that 249 perform replication and elimination sub-functions. The elimination 250 sub-function always uses the S-Label and packet sequencing 251 information, e.g., the value in the Sequence Number field of DetNet 252 CW (d-CW). The replication sub-function uses the S-Label information 253 only. For data packets Figure 2 presents an example of PREF in 254 DetNet domain. 256 1111 11111111 111111 112212 112212 132213 257 CE1----EN1--------R1-------R2-------R3--------EN2----CE2 258 \2 22222/ 3 / 259 \2222222 /----+ 3 / 260 +------R4------------------------+ 261 333333333333333333333333 263 Figure 2: DetNet Data Plane Based on PW 265 4.1. DetNet Active OAM Encapsulation 267 DetNet OAM, like PW OAM, uses PW Associated Channel Header defined in 268 [RFC4385]. Figure 3 displays the encapsulation of a DetNet MPLS 269 [I-D.ietf-detnet-mpls] active OAM packet. 271 +---------------------------------+ 272 | | 273 | DetNet App-Flow | 274 | Payload Packet | 275 | | 276 +---------------------------------+ <--\ 277 | DetNet Associated Channel Header| | 278 +---------------------------------+ +--> DetNet active OAM 279 | S-Label | | MPLS encapsulation 280 +---------------------------------+ | 281 | [ F-Label(s) ] | | 282 +---------------------------------+ <--/ 283 | Data-Link | 284 +---------------------------------+ 285 | Physical | 286 +---------------------------------+ 288 Figure 3: DetNet Active OAM Packet Encapsulation in MPLS Data Plane 290 Figure 4 displays encapsulation of a test packet of an active DetNet 291 OAM protocol in case of MPLS-over-UDP/IP 292 [I-D.ietf-detnet-mpls-over-udp-ip]. 294 +---------------------------------+ 295 | | 296 | DetNet App-Flow | 297 | Payload Packet | 298 | | 299 +---------------------------------+ <--\ 300 | DetNet Associated Channel Header| | 301 +---------------------------------+ +--> DetNet active OAM 302 | S-Label | | MPLS encapsulation 303 +---------------------------------+ | 304 | [ F-label(s) ] | | 305 +---------------------------------+ <--+ 306 | UDP Header | | 307 +---------------------------------+ +--> DetNet data plane 308 | IP Header | | IP encapsulation 309 +---------------------------------+ <--/ 310 | Data-Link | 311 +---------------------------------+ 312 | Physical | 313 +---------------------------------+ 315 Figure 4: DetNet Active OAM Packet Encapsulation in MPLS-over-UDP/IP 316 Figure 5 displays the format of the DetNet Associated Channel Header 317 (d-ACH). 319 0 1 2 3 320 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 1 321 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 322 |0 0 0 1|Version|Sequence Number| Channel Type | 323 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 325 Figure 5: DetNet Associated Channel Header Format 327 The meanings of the fields in the d-ACH are: 329 Bits 0..3 MUST be 0b0001. This value of the first nibble allows 330 the packet to be distinguished from an IP packet [RFC4928] and a 331 DetNet data packet [I-D.ietf-detnet-mpls]. 333 Version: this is the version number of the d-ACH. This 334 specification defines version 0. 336 Sequence Number: this is unsigned eight bits-long field. The 337 originating DetNet node MUST set the value of the Sequence Number 338 field to a non-zero before packet being transmitted. The 339 originating node MUST monotonically increase the value of the 340 Sequence Number field for the every next active OAM packet. 342 Channel Type: the value of DetNet Associated Channel Type is one 343 of values defined in the IANA PW Associated Channel Type registry. 345 The DetNet flow, according to [I-D.ietf-detnet-mpls], is identified 346 by the S-label that MUST be at the bottom of the stack. Active OAM 347 packet MUST have d-ACH immediately following the S-label. 349 Special consideration for DetNet active OAM with MPLS data plane 350 interworking with OAM in IEEE 802.1 Time-Sensitive Networking (TSN) 351 domain based on [I-D.ietf-detnet-mpls-over-tsn]: 353 o Active OAM test packet MUST be mapped to the same TSN Stream ID as 354 the monitored DetNet flow . 356 o Active OAM test packets MUST be treated in the TSN domain based on 357 its S-label and CoS marking (TC field value). 359 4.2. DetNet Replication, Elimination, and Ordering Sub-functions 360 Interaction with Active OAM 362 At the DetNet service layer, special functions MAY be applied to the 363 particular DetNet flow - PREF to potentially lower packet loss, 364 improve the probability of on-time packet delivery and Packet 365 Ordering Function (POF) to ensure in-order packet delivery. As data 366 and the active OAM packets have the same Flow ID, S-label, sub- 367 functions that rely on sequencing information in the DetNet service 368 layer MUST process 28 MSBs of the d-ACH as the source of the 369 sequencing information for the OAM packet. 371 5. Use of Hybrid OAM in DetNet 373 Hybrid OAM methods are used in performance monitoring and defined in 374 [RFC7799] as: 376 Hybrid Methods are Methods of Measurement that use a combination 377 of Active Methods and Passive Methods. 379 A hybrid measurement method may produce metrics as close to passive, 380 but it still alters something in a data packet even if that is the 381 value of a designated field in the packet encapsulation. One example 382 of such a hybrid measurement method is the Alternate Marking method 383 described in [RFC8321]. Reserving the field for the Alternate 384 Marking method in the DetNet Header will enhance available to an 385 operator set of DetNet OAM tools. 387 6. OAM of DetNet MPLS Interworking with OAM of DetNet IP 389 TBA 391 7. OAM of DetNet MPLS Interworking with OAM of TSN 393 TBA 395 8. IANA Considerations 397 TBA 399 9. Security Considerations 401 This document lists the OAM requirements for a DetNet domain and does 402 not raise any security concerns or issues in addition to ones common 403 to networking. 405 10. Acknowledgment 407 Authors extend their appreciation to Pascal Thubert for his 408 insightful comments and productive discussion that helped to improve 409 the document. 411 11. References 413 11.1. Normative References 415 [I-D.ietf-detnet-architecture] 416 Finn, N., Thubert, P., Varga, B., and J. Farkas, 417 "Deterministic Networking Architecture", draft-ietf- 418 detnet-architecture-13 (work in progress), May 2019. 420 [I-D.ietf-detnet-mpls] 421 Varga, B., Farkas, J., Berger, L., Fedyk, D., Malis, A., 422 Bryant, S., and J. Korhonen, "DetNet Data Plane: MPLS", 423 draft-ietf-detnet-mpls-01 (work in progress), July 2019. 425 [I-D.ietf-detnet-mpls-over-tsn] 426 Varga, B., Farkas, J., Malis, A., Bryant, S., and J. 427 Korhonen, "DetNet Data Plane: MPLS over IEEE 802.1 Time 428 Sensitive Networking (TSN)", draft-ietf-detnet-mpls-over- 429 tsn-00 (work in progress), May 2019. 431 [I-D.ietf-detnet-mpls-over-udp-ip] 432 Varga, B., Farkas, J., Berger, L., Malis, A., Bryant, S., 433 and J. Korhonen, "DetNet Data Plane: MPLS over UDP/IP", 434 draft-ietf-detnet-mpls-over-udp-ip-01 (work in progress), 435 July 2019. 437 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 438 Requirement Levels", BCP 14, RFC 2119, 439 DOI 10.17487/RFC2119, March 1997, 440 . 442 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 443 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 444 May 2017, . 446 11.2. Informational References 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 [RFC6374] Frost, D. and S. Bryant, "Packet Loss and Delay 464 Measurement for MPLS Networks", RFC 6374, 465 DOI 10.17487/RFC6374, September 2011, 466 . 468 [RFC7799] Morton, A., "Active and Passive Metrics and Methods (with 469 Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799, 470 May 2016, . 472 [RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli, 473 L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi, 474 "Alternate-Marking Method for Passive and Hybrid 475 Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321, 476 January 2018, . 478 Authors' Addresses 480 Greg Mirsky 481 ZTE Corp. 483 Email: gregimirsky@gmail.com 485 Mach(Guoyi) Chen 486 Huawei 488 Email: mach.chen@huawei.com