idnits 2.17.1 draft-ietf-detnet-oam-framework-04.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: ---------------------------------------------------------------------------- == There are 2 instances of lines with non-ascii characters in the document. 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 (14 September 2021) is 955 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- == Outdated reference: A later version (-17) exists of draft-ietf-ippm-ioam-data-14 == Outdated reference: A later version (-11) exists of draft-ietf-ippm-ioam-direct-export-06 == Outdated reference: A later version (-15) exists of draft-mirsky-ippm-hybrid-two-step-11 -- Obsolete informational reference (is this intentional?): RFC 8321 (Obsoleted by RFC 9341) Summary: 0 errors (**), 0 flaws (~~), 5 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 DetNet G. Mirsky 3 Internet-Draft Ericsson 4 Intended status: Informational F. Theoleyre 5 Expires: 18 March 2022 CNRS 6 G.Z. Papadopoulos 7 IMT Atlantique 8 CJ. Bernardos 9 UC3M 10 B. Varga 11 J. Farkas 12 Ericsson 13 14 September 2021 15 Framework of Operations, Administration and Maintenance (OAM) for 16 Deterministic Networking (DetNet) 17 draft-ietf-detnet-oam-framework-04 19 Abstract 21 Deterministic Networking (DetNet), as defined in RFC 8655, is aimed 22 to provide a bounded end-to-end latency on top of the network 23 infrastructure, comprising both Layer 2 bridged and Layer 3 routed 24 segments. This document's primary purpose is to detail the specific 25 requirements of the Operation, Administration, and Maintenance (OAM) 26 recommended to maintain a deterministic network. With the 27 implementation of the OAM framework in DetNet, an operator will have 28 a real-time view of the network infrastructure regarding the 29 network's ability to respect the Service Level Objective, such as 30 packet delay, delay variation, and packet loss ratio, assigned to 31 each DetNet flow. 33 Status of This Memo 35 This Internet-Draft is submitted in full conformance with the 36 provisions of BCP 78 and BCP 79. 38 Internet-Drafts are working documents of the Internet Engineering 39 Task Force (IETF). Note that other groups may also distribute 40 working documents as Internet-Drafts. The list of current Internet- 41 Drafts is at https://datatracker.ietf.org/drafts/current/. 43 Internet-Drafts are draft documents valid for a maximum of six months 44 and may be updated, replaced, or obsoleted by other documents at any 45 time. It is inappropriate to use Internet-Drafts as reference 46 material or to cite them other than as "work in progress." 48 This Internet-Draft will expire on 18 March 2022. 50 Copyright Notice 52 Copyright (c) 2021 IETF Trust and the persons identified as the 53 document authors. All rights reserved. 55 This document is subject to BCP 78 and the IETF Trust's Legal 56 Provisions Relating to IETF Documents (https://trustee.ietf.org/ 57 license-info) in effect on the date of publication of this document. 58 Please review these documents carefully, as they describe your rights 59 and restrictions with respect to this document. Code Components 60 extracted from this document must include Simplified BSD License text 61 as described in Section 4.e of the Trust Legal Provisions and are 62 provided without warranty as described in the Simplified BSD License. 64 Table of Contents 66 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 67 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 68 1.2. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . 4 69 1.3. Requirements Language . . . . . . . . . . . . . . . . . . 5 70 2. Role of OAM in DetNet . . . . . . . . . . . . . . . . . . . . 5 71 3. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 6 72 3.1. Information Collection . . . . . . . . . . . . . . . . . 7 73 3.2. Continuity Check . . . . . . . . . . . . . . . . . . . . 7 74 3.3. Connectivity Verification . . . . . . . . . . . . . . . . 7 75 3.4. Route Tracing . . . . . . . . . . . . . . . . . . . . . . 8 76 3.5. Fault Verification/detection . . . . . . . . . . . . . . 8 77 3.6. Fault Localization and Characterization . . . . . . . . . 8 78 3.7. Use of Hybrid OAM in DetNet . . . . . . . . . . . . . . . 9 79 4. Administration . . . . . . . . . . . . . . . . . . . . . . . 9 80 4.1. Collection of metrics . . . . . . . . . . . . . . . . . . 10 81 4.2. Worst-case metrics . . . . . . . . . . . . . . . . . . . 10 82 5. Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . 10 83 5.1. Replication / Elimination . . . . . . . . . . . . . . . . 10 84 5.2. Resource Reservation . . . . . . . . . . . . . . . . . . 11 85 5.3. Soft transition after reconfiguration . . . . . . . . . . 11 86 6. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 11 87 6.1. Requirements on OAM for DetNet Service Sub-layer . . . . 13 88 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 89 8. Security Considerations . . . . . . . . . . . . . . . . . . . 13 90 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13 91 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 92 10.1. Normative References . . . . . . . . . . . . . . . . . . 14 93 10.2. Informative References . . . . . . . . . . . . . . . . . 14 94 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 96 1. Introduction 98 Deterministic Networking (DetNet) [RFC8655] has proposed to provide a 99 bounded end-to-end latency on top of the network infrastructure, 100 comprising both Layer 2 bridged and Layer 3 routed segments. That 101 work encompasses the data plane, OAM, time synchronization, 102 management, control, and security aspects. 104 Operations, Administration, and Maintenance (OAM) Tools are of 105 primary importance for IP networks [RFC7276]. DetNet OAM should 106 provide a toolset for fault detection, localization, and performance 107 measurement. 109 This document's primary purpose is to detail the specific 110 requirements of the OAM features recommended to maintain a 111 deterministic/reliable network. Specifically, it investigates the 112 requirements for a deterministic network, supporting critical flows. 114 In this document, the term OAM will be used according to its 115 definition specified in [RFC6291]. DetNet expects to implement an 116 OAM framework to maintain a real-time view of the network 117 infrastructure, and its ability to respect the Service Level 118 Objectives (SLO), such as in-order packet delivery, packet delay, 119 delay variation, and packet loss ratio, assigned to each DetNet flow. 121 This document lists the functional requirements toward OAM for DetNet 122 domain. The list can further be used for gap analysis of available 123 OAM tools to identify possible enhancements of existing or whether 124 new OAM tools are required to support proactive and on-demand path 125 monitoring and service validation. 127 1.1. Terminology 129 This document uses definitions, particularly of a DetNet flow, 130 provided in Section 2.1 [RFC8655]. The following terms are used 131 throughout this document as defined below: 133 * DetNet OAM domain: a DetNet network used by the monitored DetNet 134 flow. A DetNet OAM domain (also referred to in this document as 135 "OAM domain") may have MEPs on its edge and MIPs within. 137 * DetNet OAM instance: a function that monitors a DetNet flow for 138 defects and/or measures its performance metrics. Within this 139 document, a shorter version, OAM instance, is used 140 interchangeably. 142 * Maintenance End Point (MEP): an OAM instance that is capable of 143 generating OAM test packets in the particular sub-layer of the 144 DetNet OAM domain. 146 * Maintenance Intermediate endPoint (MIP): an OAM instance along the 147 DetNet flow in the particular sub-layer of the DetNet OAM domain. 148 A MIP MAY respond to an OAM message generated by the MEP at its 149 sub-layer of the same DetNet OAM domain. 151 * Control and management plane: the control and management planes 152 are used to configure and control the network (long-term). 153 Relative to a DetNet flow, the control and/or management plane can 154 be out-of-band. 156 * Active measurement methods (as defined in [RFC7799]) modify a 157 DetNet flow by inserting novel fields, injecting specially 158 constructed test packets [RFC2544]). 160 * Passive measurement methods [RFC7799] infer information by 161 observing unmodified existing flows. 163 * Hybrid measurement methods [RFC7799] is the combination of 164 elements of both active and passive measurement methods. 166 * In-band OAM is an active OAM is considered in-band in the 167 monitored DetNet OAM domain when it traverses the same set of 168 links and interfaces receiving the same QoS and Packet 169 Replication, Elimination, and Ordering Functions (PREOF) treatment 170 as the monitored DetNet flow. 172 * Out-of-band OAM is an active OAM whose path through the DetNet 173 domain is not topologically identical to the path of the monitored 174 DetNet flow, or its test packets receive different QoS and/or 175 PREOF treatment, or both. 177 * On-path telemetry can be realized as a hybrid OAM method. The 178 origination of the telemetry information is inherently in-band as 179 packets in a DetNet flow are used as triggers. Collection of the 180 on-path telemetry information can be performed using in-band or 181 out-of-band OAM methods. 183 1.2. Acronyms 185 OAM: Operations, Administration, and Maintenance 187 DetNet: Deterministic Networking 189 PREOF: Packet Replication, Elimination and Ordering Functions 190 SLO: Service Level Objective 192 1.3. Requirements Language 194 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 195 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 196 "OPTIONAL" in this document are to be interpreted as described in BCP 197 14 [RFC2119] [RFC8174] when, and only when, they appear in all 198 capitals, as shown here. 200 2. Role of OAM in DetNet 202 DetNet networks expect to provide communications with predictable low 203 packet delay and packet loss. Most critical applications will define 204 an SLO to be required for the DetNet flows it generates. 206 To respect strict guarantees, DetNet can use an orchestrator able to 207 monitor and maintain the network. Typically, a Software-Defined 208 Network (SDN) controller places DetNet flows in the deployed network 209 based on their SLO. Thus, resources have to be provisioned a priori 210 for the regular operation of the network. OAM represents the 211 essential elements of the network operation and necessary for OAM 212 resources that need to be accounted for to maintain the network 213 operational. 215 Many legacy OAM tools can be used in DetNet networks, but they are 216 not able to cover all the aspects of deterministic networking. 217 Fulfilling strict guarantees is essential for DetNet flows, resulting 218 in new DetNet specific functionalities that must be covered with OAM. 219 Filling these gaps is inevitable and needs accurate consideration of 220 DetNet specifics. Similar to DetNet flows itself, their OAM needs 221 careful end-to-end engineering as well. 223 For example, appropriate placing of MEPs along the path of a DetNet 224 flow is not always a trivial task and may require proper design 225 together with the design of the service component of a given DetNet 226 flow. 228 There are several DetNet specific challenges for OAM. Bounded 229 network characteristics (e.g., delay, loss) are inseparable service 230 parameters; therefore, PM is a key topic for DetNet. OAM tools are 231 needed to prove the SLO without impacting the DetNet flow 232 characteristics. A further challenge is the strict resource 233 allocation. Resources used by OAM must be considered and allocated 234 to avoid disturbing DetNet flow(s). 236 The DetNet Working Group has defined two sub-layers: 238 DetNet service sub-layer, at which a DetNet service (e.g., service 239 protection) is provided. 241 DetNet forwarding sub-layer, which optionally provides resource 242 allocation for DetNet flows over paths provided by the underlying 243 network. 245 OAM mechanisms exist for the DetNet forwarding sub-layer, 246 nonetheless, OAM for the service sub-layer requires new OAM 247 procedures. These new OAM functions must allow, for example, to 248 recognize/discover DetNet relay nodes, to get information about their 249 configuration, and to check their operation or status. 251 DetNet service sub-layer functions using a sequence number. That 252 creates a challenge for inserting OAM packets in the DetNet flow. 254 Fault tolerance also assumes that multiple paths could be provisioned 255 to maintain an end-to-end circuit by adapting to the existing 256 conditions. The central controller/orchestrator typically controls 257 the PREOF on a node. OAM is expected to support monitoring and 258 troubleshooting PREOF on a particular node and within the domain. 260 Note that distributed controllers can also control PREOF in those 261 scenarios where DetNet solutions involve more than one single central 262 controller. 264 DetNet forwarding sub-layer is based on legacy technologies and has a 265 much better coverage regarding OAM. However, the forwarding sub- 266 layer is terminated at DetNet relay nodes, so the end-to-end OAM 267 state of forwarding may be created only based on the status of 268 multiple forwarding sub-layer segments serving a given DetNet flow 269 (e.g., in case of DetNet MPLS, there may be no end-to-end LSP below 270 the DetNet PW). 272 3. Operation 274 OAM features will enable DetNet with robust operation both for 275 forwarding and routing purposes. 277 It is worth noting that the test and data packets MUST follow the 278 same path, i.e., the connectivity verification has to be conducted 279 in-band without impacting the data traffic. Test packets MUST share 280 fate with the monitored data traffic without introducing congestion 281 in normal network conditions. 283 3.1. Information Collection 285 Information about the state of the network can be collected using 286 several mechanisms. Some protocols, e.g., Simple Network Management 287 Protocol, send queries. Others, e.g., YANG-based data models, 288 generate notifications based on the publish-subscribe method. In 289 either way, information is collected and sent to the controller. 291 Also, we can characterize methods of transporting OAM information 292 relative to the path of data. For instance, OAM information may be 293 transported in-band or out-of-band relative to the DetNet flow. In 294 case of the former, the telemetry information uses resources 295 allocated for the monitored DetNet flow. If an in-band method of 296 transporting telemetry is used, the amount of generated information 297 needs to be carefully analyzed, and additional resources must be 298 reserved. [I-D.ietf-ippm-ioam-data] defines the in-band transport 299 mechanism where telemetry information is collected in the data packet 300 on which information is generated. Two tracing methods are described 301 - end-to-end, i.e., from the ingress and egress nodes, and hop-by- 302 hop, i.e., like end-to-end with additional information from transit 303 nodes. [I-D.ietf-ippm-ioam-direct-export] and 304 [I-D.mirsky-ippm-hybrid-two-step] are examples of out-of-band 305 telemetry transport. In the former case, information is transported 306 by each node traversed by the data packet of the monitored DetNet 307 flow in a specially constructed packet. In the latter, information 308 is collected in a sequence of follow-up packets that traverse the 309 same path as the data packet of the monitored DetNet flow. In both 310 methods, transport of the telemetry can avoid using resources 311 allocated for the DetNet domain. 313 3.2. Continuity Check 315 Continuity check is used to monitor the continuity of a path, i.e., 316 that there exists a way to deliver the packets between two MEP A and 317 MEP B. The continuity check detects a network failure in one 318 direction, from the MEP transmitting test packets to the remote 319 egress MEP. 321 3.3. Connectivity Verification 323 In addition to the Continuity Check, DetNet solutions have to verify 324 the connectivity. This verification considers additional 325 constraints, i.e., the absence of misconnection. The misconnection 326 error state is entered after several consecutive test packets from 327 other DetNet flows are received. The definition of the conditions of 328 entry and exit for misconnection error state is outside the scope of 329 this document. 331 3.4. Route Tracing 333 Ping and traceroute are two ubiquitous tools that help localize and 334 characterize a failure in the network. They help to identify a 335 subset of the list of routers in the route. However, to be 336 predictable, resources are reserved per flow in DetNet. Thus, DetNet 337 needs to define route tracing tools able to track the route for a 338 specific flow. Also, tracing can be used for the discovery of the 339 Path Maximum Transmission Unit or location of elements of PREOF for 340 the particular route in the DetNet domain. 342 DetNet is NOT RECOMMENDED to use multiple paths or links, i.e., 343 Equal-Cost Multipath (ECMP) [RFC8939]. As the result, OAM in ECMP 344 environment is outside the scope of this document. 346 3.5. Fault Verification/detection 348 DetNet expects to operate fault-tolerant networks. Thus, mechanisms 349 able to detect faults before they impact the network performance are 350 needed. 352 The network has to detect when a fault occurred, i.e., the network 353 has deviated from its expected behavior. While the network must 354 report an alarm, the cause may not be identified precisely. For 355 instance, the end-to-end reliability has decreased significantly, or 356 a buffer overflow occurs. 358 DetNet OAM mechanisms SHOULD allow a fault detection in real time. 359 They MAY, when possible, predict faults based on current network 360 conditions. They MAY also identify and report the cause of the 361 actual/predicted network failure. 363 3.6. Fault Localization and Characterization 365 An ability to localize the network defect and provide its 366 characterization are necessary elements of network operation. 368 Fault localization, a process of deducing the location of a 369 network failure from a set of observed failure indications, might 370 be achieved, for example, by tracing the route of the DetNet flow 371 in which the network failure was detected. Another method of 372 fault localization can correlate reports of failures from a set of 373 interleaving sessions monitoring path continuity. 375 Fault characterization is a process of identifying the root cause 376 of the problem. For instance, misconfiguration or malfunction of 377 PREOF elements can be the cause of erroneous packet replication or 378 extra packets being flooded in the DetNet domain. 380 3.7. Use of Hybrid OAM in DetNet 382 Hybrid OAM methods are used in performance monitoring and defined in 383 [RFC7799] as: 385 Hybrid Methods are Methods of Measurement that use a combination 386 of Active Methods and Passive Methods. 388 A hybrid measurement method may produce metrics as close to passive, 389 but it still alters something in a data packet even if that is the 390 value of a designated field in the packet encapsulation. One example 391 of such a hybrid measurement method is the Alternate Marking method 392 (AMM) described in [RFC8321]. As with all on-path telemetry methods, 393 AMM in a DetNet domain with the IP data plane is natively in-band in 394 respect to the monitored DetNet flow. Because the marking is applied 395 to a data flow, measured metrics are directly applicable to the 396 DetNet flow. AMM minimizes the additional load on the DetNet domain 397 by using nodal collection and computation of performance metrics in 398 combination with optionally using out-of-band telemetry collection 399 for further network analysis. 401 4. Administration 403 The network SHOULD expose a collection of metrics to support an 404 operator making proper decisions, including: 406 * Queuing Delay: the time elapsed between a packet enqueued and its 407 transmission to the next hop. 409 * Buffer occupancy: the number of packets present in the buffer, for 410 each of the existing flows. 412 The following metrics SHOULD be collected: 414 * per a DetNet flow to measure the end-to-end performance for a 415 given flow. Each of the paths has to be isolated in multipath 416 routing strategies. 418 * per path to detect misbehaving path when multiple paths are 419 applied. 421 * per device to detect misbehaving device, when it relays the 422 packets of several flows. 424 4.1. Collection of metrics 426 DetNet OAM SHOULD optimize the number of statistics / measurements to 427 collected, frequency of collecting. Distributed and centralized 428 mechanisms MAY be used in combination. Periodic and event-triggered 429 collection information characterizing the state of a network MAY be 430 used. 432 4.2. Worst-case metrics 434 DetNet aims to enable real-time communications on top of a 435 heterogeneous multi-hop architecture. To make correct decisions, the 436 controller needs to know the distribution of packet losses/delays for 437 each flow, and each hop of the paths. In other words, the average 438 end-to-end statistics are not enough. The collected information must 439 be sufficient to allow the controller to predict the worst-case. 441 5. Maintenance 443 In the face of events that impact the network operation (e.g., link 444 up/down, device crash/reboot, flows starting and ending), the DetNet 445 Controller need to perform repair and re-optimization actions in 446 order to permanently ensure the SLO of all active flows with minimal 447 waste of resources The controller MUST be able to continuously 448 retrieve the state of the network, to evaluate conditions and trends 449 about the relevance of a reconfiguration, quantifying: 451 the cost of the sub-optimality: resources may not be used 452 optimally (e.g., a better path exists). 454 the reconfiguration cost: the controller needs to trigger some 455 reconfigurations. For this transient period, resources may be 456 twice reserved, and control packets have to be transmitted. 458 Thus, reconfiguration may only be triggered if the gain is 459 significant. 461 5.1. Replication / Elimination 463 When multiple paths are reserved between two MEPs, packet replication 464 may be used to introduce redundancy and alleviate transmission errors 465 and collisions. For instance, in Figure 1, the source device S is 466 transmitting the packet to both parents, devices A and B. Each MEP 467 will decide to trigger the packet replication, elimination or the 468 ordering process when a set of metrics passes a threshold value. 470 ===> (A) => (C) => (E) === 471 // \\// \\// \\ 472 source (S) //\\ //\\ (R) (root) 473 \\ // \\ // \\ // 474 ===> (B) => (D) => (F) === 476 Figure 1: Packet Replication: S transmits twice the same data 477 packet, to DP(A) and AP (B). 479 5.2. Resource Reservation 481 Because the quality of service criteria associated with a path may 482 degrade, the network has to provision additional resources along the 483 path. We need to provide mechanisms to patch the network 484 configuration. 486 5.3. Soft transition after reconfiguration 488 Since DetNet expects to support real-time flows, DetNet OAM MUST 489 support soft-reconfiguration, where the the additional resources are 490 reserved before the those previously reserved but not in use are 491 released. Some mechanisms have to be proposed so that packets are 492 forwarded through the novel track only when the resources are ready 493 to be used, while maintaining the global state consistent (no packet 494 reordering, duplication, etc.) 496 6. Requirements 498 This section lists requirements for OAM in a DetNet domain: 500 1. It MUST be possible to initiate a DetNet OAM session from a MEP 501 located at a DetNet node towards downstream MEP(s) within the 502 given domain at a particular DetNet sub-layer. [Ed.note: FT: A 503 MEP may be inside the detnet domain: for instance, for PREOF, an 504 OAM session may be maintained between any pair of replicator / 505 eliminator / egress / ingress.] 507 2. It MUST be possible to initialize a DetNet OAM session from a 508 centralized controller. 510 3. DetNet OAM MUST support proactive and on-demand OAM monitoring 511 and measurement methods. 513 4. DetNet OAM MUST support unidirectional OAM methods, continuity 514 check, connectivity verification, and performance measurement. 516 5. OAM methods MAY combine in-band monitoring or measurement in the 517 forward direction and out-of-bound notification in the reverse 518 direction, i.e., towards the ingress MEP. 520 6. DetNet OAM MUST support bi-directional DetNet flows. 522 7. DetNet OAM MAY support bi-directional OAM methods for 523 bidirectional DetNet flows. OAM test packets used for 524 monitoring and measurements MUST be in-band in both directions. 526 8. DetNet OAM MUST support proactive monitoring of a DetNet device 527 reachability for a given DetNet flow. 529 9. DetNet OAM MUST support Path Maximum Transmission Unit 530 discovery. 532 10. DetNet OAM MUST support the discovery of PREOF along a route in 533 the given DetNet domain. 535 11. DetNet OAM MUST support Remote Defect Indication (RDI) 536 notification to the DetNet OAM instance performing continuity 537 checking. 539 12. DetNet OAM MAY support hybrid performance measurement methods. 541 13. DetNet OAM MUST support unidirectional performance measurement 542 methods. Calculated performance metrics MUST include but are 543 not limited to throughput, packet loss, out of order, delay and 544 delay variation metrics. [RFC6374] provides detailed 545 information on performance measurement and performance metrics. 547 14. DetNet OAM MUST be able to measure metrics (e.g. delay) inside a 548 collection of OAM sessions, specially for complex DetNet flows, 549 with PREOF features. 551 15. DetNet OAM MUST support defect notification mechanism, like 552 Alarm Indication Signal. Any DetNet device within the given 553 DetNet flow MAY originate a defect notification addressed to any 554 subset of DetNet devices within that flow. 556 16. DetNet OAM MUST support methods to enable availability of the 557 DetNet domain. These recovery methods MAY use protection 558 switching and restoration. 560 17. DetNet OAM MUST support the discovery of Packet Replication, 561 Elimination, and Order preservation sub-functions locations in 562 the domain. 564 18. DetNet OAM MUST support testing of Packet Replication, 565 Elimination, and Order preservation sub-functions in the domain. 567 19. DetNet OAM MUST support monitoring levels of resources allocated 568 for the particular DetNet flow. Such resources include but not 569 limited to buffer utilization, scheduler transmission calendar. 571 20. DetNet OAM MUST support monitoring any sub-set of paths 572 traversed through the DetNet domain by the DetNet flow. 574 6.1. Requirements on OAM for DetNet Service Sub-layer 576 The OAM functions for the DetNet service sub-layer allow, for 577 example, to recognize/discover DetNet relay nodes, to get information 578 about their configuration, and to check their operation or status. 580 The requirements on OAM for a DetNet relay node are: 582 1. DetNet OAM MUST provide OAM functions for the DetNet service sub- 583 layer. 585 2. DetNet OAM MUST support the discovery of DetNet relay nodes in a 586 DetNet network. 588 3. DetNet OAM MUST support the collection of the DetNet service sub- 589 layer specific (e.g., configuration/operation/status) information 590 from DetNet relay nodes. 592 4. DetNet OAM MUST work for DetNet data planes - MPLS and IP. 594 7. IANA Considerations 596 This document has no actionable requirements for IANA. This section 597 can be removed before the publication. 599 8. Security Considerations 601 This document lists the OAM requirements for a DetNet domain and does 602 not raise any security concerns or issues in addition to ones common 603 to networking and those specific to a DetNet discussed in [RFC9055]. 605 9. Acknowledgments 607 The authors express their appreciation and gratitude to Pascal 608 Thubert for the review, insightful questions, and helpful comments. 610 10. References 611 10.1. Normative References 613 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 614 Requirement Levels", BCP 14, RFC 2119, 615 DOI 10.17487/RFC2119, March 1997, 616 . 618 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 619 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 620 May 2017, . 622 [RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas, 623 "Deterministic Networking Architecture", RFC 8655, 624 DOI 10.17487/RFC8655, October 2019, 625 . 627 10.2. Informative References 629 [I-D.ietf-ippm-ioam-data] 630 Brockners, F., Bhandari, S., and T. Mizrahi, "Data Fields 631 for In-situ OAM", Work in Progress, Internet-Draft, draft- 632 ietf-ippm-ioam-data-14, 24 June 2021, 633 . 636 [I-D.ietf-ippm-ioam-direct-export] 637 Song, H., Gafni, B., Zhou, T., Li, Z., Brockners, F., 638 Bhandari, S., Sivakolundu, R., and T. Mizrahi, "In-situ 639 OAM Direct Exporting", Work in Progress, Internet-Draft, 640 draft-ietf-ippm-ioam-direct-export-06, 8 August 2021, 641 . 644 [I-D.mirsky-ippm-hybrid-two-step] 645 Mirsky, G., Lingqiang, W., Zhui, G., and H. Song, "Hybrid 646 Two-Step Performance Measurement Method", Work in 647 Progress, Internet-Draft, draft-mirsky-ippm-hybrid-two- 648 step-11, 8 July 2021, 649 . 652 [RFC2544] Bradner, S. and J. McQuaid, "Benchmarking Methodology for 653 Network Interconnect Devices", RFC 2544, 654 DOI 10.17487/RFC2544, March 1999, 655 . 657 [RFC6291] Andersson, L., van Helvoort, H., Bonica, R., Romascanu, 658 D., and S. Mansfield, "Guidelines for the Use of the "OAM" 659 Acronym in the IETF", BCP 161, RFC 6291, 660 DOI 10.17487/RFC6291, June 2011, 661 . 663 [RFC6374] Frost, D. and S. Bryant, "Packet Loss and Delay 664 Measurement for MPLS Networks", RFC 6374, 665 DOI 10.17487/RFC6374, September 2011, 666 . 668 [RFC7276] Mizrahi, T., Sprecher, N., Bellagamba, E., and Y. 669 Weingarten, "An Overview of Operations, Administration, 670 and Maintenance (OAM) Tools", RFC 7276, 671 DOI 10.17487/RFC7276, June 2014, 672 . 674 [RFC7799] Morton, A., "Active and Passive Metrics and Methods (with 675 Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799, 676 May 2016, . 678 [RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli, 679 L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi, 680 "Alternate-Marking Method for Passive and Hybrid 681 Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321, 682 January 2018, . 684 [RFC8939] Varga, B., Ed., Farkas, J., Berger, L., Fedyk, D., and S. 685 Bryant, "Deterministic Networking (DetNet) Data Plane: 686 IP", RFC 8939, DOI 10.17487/RFC8939, November 2020, 687 . 689 [RFC9055] Grossman, E., Ed., Mizrahi, T., and A. Hacker, 690 "Deterministic Networking (DetNet) Security 691 Considerations", RFC 9055, DOI 10.17487/RFC9055, June 692 2021, . 694 Authors' Addresses 696 Greg Mirsky 697 Ericsson 699 Email: gregimirsky@gmail.com 701 Fabrice Theoleyre 702 CNRS 703 300 boulevard Sebastien Brant - CS 10413 704 67400 Illkirch - Strasbourg 705 France 707 Phone: +33 368 85 45 33 708 Email: theoleyre@unistra.fr 709 URI: http://www.theoleyre.eu 711 Georgios Z. Papadopoulos 712 IMT Atlantique 713 Office B00 - 102A 714 2 Rue de la Châtaigneraie 715 35510 Cesson-Sévigné - Rennes 716 France 718 Phone: +33 299 12 70 04 719 Email: georgios.papadopoulos@imt-atlantique.fr 721 Carlos J. Bernardos 722 Universidad Carlos III de Madrid 723 Av. Universidad, 30 724 28911 Leganes, Madrid 725 Spain 727 Phone: +34 91624 6236 728 Email: cjbc@it.uc3m.es 729 URI: http://www.it.uc3m.es/cjbc/ 731 Balazs Varga 732 Ericsson 733 Budapest 734 Magyar Tudosok krt. 11. 735 1117 736 Hungary 738 Email: balazs.a.varga@ericsson.com 740 Janos Farkas 741 Ericsson 742 Budapest 743 Magyar Tudosok krt. 11. 744 1117 745 Hungary 747 Email: janos.farkas@ericsson.com