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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Missing Reference: 'Network' is mentioned on line 271, but not defined == Outdated reference: A later version (-09) exists of draft-ietf-detnet-ip-over-mpls-06 == Outdated reference: A later version (-07) exists of draft-ietf-detnet-mpls-over-tsn-03 == Outdated reference: A later version (-16) exists of draft-ietf-detnet-security-10 -- Obsolete informational reference (is this intentional?): RFC 3272 (Obsoleted by RFC 9522) 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 B. Varga, Ed. 3 Internet-Draft J. Farkas 4 Intended status: Standards Track Ericsson 5 Expires: January 7, 2021 L. Berger 6 LabN Consulting, L.L.C. 7 A. Malis 8 Malis Consulting 9 S. Bryant 10 Futurewei Technologies 11 J. Korhonen 12 July 6, 2020 14 DetNet Data Plane: MPLS 15 draft-ietf-detnet-mpls-08 17 Abstract 19 This document specifies the Deterministic Networking data plane when 20 operating over an MPLS Packet Switched Networks. 22 Status of This Memo 24 This Internet-Draft is submitted in full conformance with the 25 provisions of BCP 78 and BCP 79. 27 Internet-Drafts are working documents of the Internet Engineering 28 Task Force (IETF). Note that other groups may also distribute 29 working documents as Internet-Drafts. The list of current Internet- 30 Drafts is at https://datatracker.ietf.org/drafts/current/. 32 Internet-Drafts are draft documents valid for a maximum of six months 33 and may be updated, replaced, or obsoleted by other documents at any 34 time. It is inappropriate to use Internet-Drafts as reference 35 material or to cite them other than as "work in progress." 37 This Internet-Draft will expire on January 7, 2021. 39 Copyright Notice 41 Copyright (c) 2020 IETF Trust and the persons identified as the 42 document authors. All rights reserved. 44 This document is subject to BCP 78 and the IETF Trust's Legal 45 Provisions Relating to IETF Documents 46 (https://trustee.ietf.org/license-info) in effect on the date of 47 publication of this document. Please review these documents 48 carefully, as they describe your rights and restrictions with respect 49 to this document. Code Components extracted from this document must 50 include Simplified BSD License text as described in Section 4.e of 51 the Trust Legal Provisions and are provided without warranty as 52 described in the Simplified BSD License. 54 Table of Contents 56 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 57 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 58 2.1. Terms Used in This Document . . . . . . . . . . . . . . . 3 59 2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 4 60 2.3. Requirements Language . . . . . . . . . . . . . . . . . . 5 61 3. DetNet MPLS Data Plane Overview . . . . . . . . . . . . . . . 5 62 3.1. Layers of DetNet Data Plane . . . . . . . . . . . . . . . 5 63 3.2. DetNet MPLS Data Plane Scenarios . . . . . . . . . . . . 6 64 4. MPLS-Based DetNet Data Plane Solution . . . . . . . . . . . . 8 65 4.1. DetNet Over MPLS Encapsulation Components . . . . . . . . 8 66 4.2. MPLS Data Plane Encapsulation . . . . . . . . . . . . . . 9 67 4.2.1. DetNet Control Word and the DetNet Sequence Number . 10 68 4.2.2. S-Labels . . . . . . . . . . . . . . . . . . . . . . 11 69 4.2.3. F-Labels . . . . . . . . . . . . . . . . . . . . . . 14 70 4.3. OAM Indication . . . . . . . . . . . . . . . . . . . . . 17 71 4.4. Flow Aggregation . . . . . . . . . . . . . . . . . . . . 17 72 4.4.1. Aggregation Via LSP Hierarchy . . . . . . . . . . . . 17 73 4.4.2. Aggregating DetNet Flows as a new DetNet flow . . . . 18 74 4.5. Service Sub-Layer Considerations . . . . . . . . . . . . 19 75 4.5.1. Edge Node Processing . . . . . . . . . . . . . . . . 19 76 4.5.2. Relay Node Processing . . . . . . . . . . . . . . . . 19 77 4.6. Forwarding Sub-Layer Considerations . . . . . . . . . . . 20 78 4.6.1. Class of Service . . . . . . . . . . . . . . . . . . 20 79 4.6.2. Quality of Service . . . . . . . . . . . . . . . . . 21 80 5. Management and Control Information Summary . . . . . . . . . 21 81 5.1. Service Sub-Layer Information Summary . . . . . . . . . . 22 82 5.1.1. Service Aggregation Information Summary . . . . . . . 23 83 5.2. Forwarding Sub-Layer Information Summary . . . . . . . . 23 84 6. Security Considerations . . . . . . . . . . . . . . . . . . . 24 85 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25 86 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 25 87 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 25 88 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 25 89 10.1. Normative References . . . . . . . . . . . . . . . . . . 25 90 10.2. Informative References . . . . . . . . . . . . . . . . . 27 91 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 30 93 1. Introduction 95 Deterministic Networking (DetNet) is a service that can be offered by 96 a network to DetNet flows. DetNet provides these flows extremely low 97 packet loss rates and assured maximum end-to-end delivery latency. 98 General background and concepts of DetNet can be found in [RFC8655]. 100 The DetNet Architecture models the DetNet related data plane 101 functions decomposed into two sub-layers: a service sub-layer and a 102 forwarding sub-layer. The service sub-layer is used to provide 103 DetNet service functions such as protection and reordering. The 104 forwarding sub-layer is used to provide forwarding assurance (low 105 loss, assured latency, and limited reordering). 107 This document specifies the DetNet data plane operation and the on- 108 wire encapsulation of DetNet flows over an MPLS-based Packet Switched 109 Network (PSN) using the service sub-layer reference model. MPLS 110 encapsulation already provides a solid foundation of building blocks 111 to enable the DetNet service and forwarding sub-layer functions. 112 MPLS encapsulated DetNet can be carried over a variety of different 113 network technologies that can provide the DetNet required level of 114 service. However, the specific details of how DetNet MPLS is carried 115 over different network technologies is out of scope of this document. 117 MPLS encapsulated DetNet flows can carry different types of traffic. 118 The details of the types of traffic that are carried in DetNet are 119 also out of scope of this document. An example of IP using DetNet 120 MPLS sub-networks can be found in [I-D.ietf-detnet-ip]. DetNet MPLS 121 may use an associated controller and Operations, Administration, and 122 Maintenance (OAM) functions that are defined outside of this 123 document. 125 Background information common to all data planes for DetNet can be 126 found in the DetNet Data Plane Framework 127 [I-D.ietf-detnet-data-plane-framework]. 129 2. Terminology 131 2.1. Terms Used in This Document 133 This document uses the terminology established in the DetNet 134 architecture [RFC8655] and the DetNet Data Plane Framework 135 [I-D.ietf-detnet-data-plane-framework]. The reader is assumed to be 136 familiar with these documents, any terminology defined therein and 137 basic MPLS related terminologies in [RFC3031]. 139 The following terminology is introduced in this document: 141 F-Label A Detnet "forwarding" label that identifies the LSP 142 used to forward a DetNet flow across an MPLS PSN, e.g., 143 a hop-by-hop label used between label switching routers 144 (LSR). 146 S-Label A DetNet "service" label that is used between DetNet 147 nodes that implement also the DetNet service sub-layer 148 functions. An S-Label is also used to identify a 149 DetNet flow at DetNet service sub-layer at a receiving 150 DetNet node. 152 A-Label A special case of an S-Label, whose aggregation 153 properties are known only at the aggregation and 154 deaggregation end-points. 156 d-CW A DetNet Control Word (d-CW) is used for sequencing 157 information of a DetNet flow at the DetNet service sub- 158 layer. 160 2.2. Abbreviations 162 The following abbreviations are used in this document: 164 CoS Class of Service. 166 CW Control Word. 168 DetNet Deterministic Networking. 170 LSR Label Switching Router. 172 MPLS Multiprotocol Label Switching. 174 MPLS-TE Multiprotocol Label Switching - Traffic Engineering. 176 MPLS-TP Multiprotocol Label Switching - Transport Profile. 178 OAM Operations, Administration, and Maintenance. 180 PE Provider Edge. 182 PEF Packet Elimination Function. 184 PRF Packet Replication Function. 186 PREOF Packet Replication, Elimination and Ordering Functions. 188 POF Packet Ordering Function. 190 PSN Packet Switched Network. 192 PW PseudoWire. 194 QoS Quality of Service. 196 S-PE Switching Provider Edge. 198 T-PE Terminating Provider Edge. 200 TSN Time-Sensitive Network. 202 2.3. Requirements Language 204 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 205 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 206 "OPTIONAL" in this document are to be interpreted as described in BCP 207 14 [RFC2119] [RFC8174] when, and only when, they appear in all 208 capitals, as shown here. 210 3. DetNet MPLS Data Plane Overview 212 3.1. Layers of DetNet Data Plane 214 MPLS provides a wide range of capabilities that can be utilised by 215 DetNet. A straight forward approach utilizing MPLS for a DetNet 216 service sub-layer is based on the existing pseudowire (PW) 217 encapsulations and by utilizing existing MPLS Traffic Engineering 218 encapsulations and mechanisms. Background on PWs can be found in 219 [RFC3985] and [RFC3031]. Background on MPLS Traffic Engineering can 220 be found in [RFC3272] and [RFC3209]. 222 DetNet MPLS 223 . 224 Bottom of Stack . 225 (inner label) +------------+ 226 | Service | d-CW, S-Label (A-Label) 227 +------------+ 228 | Forwarding | F-Label(s) 229 +------------+ 230 Top of Stack . 231 (outer label) . 233 Figure 1: DetNet Adaptation to MPLS Data Plane 235 The DetNet MPLS data plane representation is illustrated in Figure 1. 236 The service sub-layer includes a DetNet control word (d-CW) and an 237 identifying service label (S-Label). The DetNet control word (d-CW) 238 conforms to the Generic PW MPLS Control Word (PWMCW) defined in 239 [RFC4385]. An aggregation label (A-Label) is a special case of 240 S-Label used for aggregation. 242 A node operating on a received DetNet flow at the Detnet service sub- 243 layer uses the local context associated with a received S-Label, 244 i.e., a received F-Label, to determine which local DetNet 245 operation(s) are applied to that packet. An S-Label may be taken 246 from the platform label space [RFC3031], making it unique, enabling 247 DetNet flow identification regardless of which input interface or LSP 248 the packet arrives on. It is important to note that S-Label values 249 are driven by the receiver, not the sender. 251 The DetNet forwarding sub-layer is supported by zero or more 252 forwarding labels (F-Labels). MPLS Traffic Engineering 253 encapsulations and mechanisms can be utilized to provide a forwarding 254 sub-layer that is responsible for providing resource allocation and 255 explicit routes. 257 3.2. DetNet MPLS Data Plane Scenarios 259 DetNet MPLS Relay Transit Relay DetNet MPLS 260 End System Node Node Node End System 261 (T-PE) (S-PE) (LSR) (S-PE) (T-PE) 262 +----------+ +----------+ 263 | Appl. |<------------ End to End Service ----------->| Appl. | 264 +----------+ +---------+ +---------+ +----------+ 265 | Service |<--| Service |-- DetNet flow --| Service |-->| Service | 266 +----------+ +---------+ +----------+ +---------+ +----------+ 267 |Forwarding| |Fwd| |Fwd| |Forwarding| |Fwd| |Fwd| |Forwarding| 268 +-------.--+ +-.-+ +-.-+ +----.---.-+ +-.-+ +-.-+ +---.------+ 269 : Link : / ,-----. \ : Link : / ,-----. \ 270 +........+ +-[ Sub ]-+ +......+ +-[ Sub ]-+ 271 [Network] [Network] 272 `-----' `-----' 273 |<- LSP -->| |<-------- LSP -----------| |<--- LSP -->| 275 |<----------------- DetNet MPLS --------------------->| 277 Figure 2: A DetNet MPLS Network 279 Figure 2 illustrates a hypothetical DetNet MPLS-only network composed 280 of DetNet aware MPLS enabled end systems, operating over a DetNet 281 aware MPLS network. In this figure, the relay nodes are PE devices 282 that define the MPLS LSP boundaries and the transit nodes are LSRs. 284 DetNet end systems and relay nodes understand the particular needs of 285 DetNet flows and provide both DetNet service and forwarding sub-layer 286 functions. In the case of MPLS, DetNet service-aware nodes add, 287 remove and process d-CWs, S-Labels and F-labels as needed. DetNet 288 MPLS nodes provide functionality analogous to T-PEs when they sit at 289 the edge of an MPLS domain, and S-PEs when they are in the middle of 290 an MPLS domain, see [RFC6073]. 292 In a DetNet MPLS network, transit nodes may be DetNet service aware 293 or may be DetNet unaware MPLS Label Switching Routers (LSRs). In 294 this latter case, such LSRs would be unaware of the special 295 requirements of the DetNet service sub-layer, but would still provide 296 traffic engineering functions and the QoS capabilities needed to 297 ensure that the (TE) LSPs meet the service requirements of the 298 carried DetNet flows. 300 The application of DetNet using MPLS supports a number of control 301 plane/management plane types. These types support certain MPLS data 302 plane deployments. For example RSVP-TE, MPLS-TP, or MPLS Segment 303 Routing (when extended to support resource allocation) are all valid 304 MPLS deployment cases. 306 Figure 3 illustrates how an end-to-end MPLS-based DetNet service is 307 provided in a more detail. In this figure, the customer end systems, 308 CE1 and CE2, are able to send and receive MPLS encapsulated DetNet 309 flows, and R1, R2 and R3 are relay nodes in the middle of a DetNet 310 network. The 'X' in the end systems, and relay nodes represents 311 potential DetNet compound flow packet replication and elimination 312 points. In this example, service protection is supported utilizing 313 at least two DetNet member flows and TE LSPs. For a unidirectional 314 flow, R1 supports PRF and R3 supports PEF and POF. Note that the 315 relay nodes may change the underlying forwarding sub-layer, for 316 example tunneling MPLS over IEEE 802.1 TSN 317 [I-D.ietf-detnet-mpls-over-tsn], or simply over interconnect network 318 links. 320 DetNet DetNet 321 MPLS Service Transit Transit Service MPLS 322 DetNet | |<-Tnl->| |<-Tnl->| | DetNet 323 End | V 1 V V 2 V | End 324 System | +--------+ +--------+ +--------+ | System 325 +---+ | | R1 |=======| R2 |=======| R3 | | +---+ 326 | X...DFa...|._X_....|..DF1..|.__ ___.|..DF3..|...._X_.|.DFa..|.X | 327 |CE1|========| \ | | X | | / |======|CE2| 328 | | | | \_.|..DF2..|._/ \__.|..DF4..|._/ | | | | 329 +---+ | |=======| |=======| | +---+ 330 ^ +--------+ +--------+ +--------+ ^ 331 | Relay Node Relay Node Relay Node | 332 | (S-PE) (S-PE) (S-PE) | 333 | | 334 |<---------------------- DetNet MPLS --------------------->| 335 | | 336 |<--------------- End to End DetNet Service -------------->| 338 -------------------------- Data Flow -------------------------> 340 X = Optional service protection (none, PRF, PREOF, PEF/POF) 341 DFx = DetNet member flow x over a TE LSP 343 Figure 3: MPLS-Based Native DetNet 345 4. MPLS-Based DetNet Data Plane Solution 347 4.1. DetNet Over MPLS Encapsulation Components 349 To carry DetNet over MPLS the following is required: 351 1. A method of identifying the MPLS payload type. 353 2. A method of identifying the DetNet flow group to the processing 354 element. 356 3. A method of distinguishing DetNet OAM packets from DetNet data 357 packets. 359 4. A method of carrying the DetNet sequence number. 361 5. A suitable LSP to deliver the packet to the egress PE. 363 6. A method of carrying queuing and forwarding indication. 365 In this design an MPLS service label (the S-Label), is similar to a 366 pseudowire (PW) label [RFC3985], and is used to identify both the 367 DetNet flow identity and the payload MPLS payload type satisfying (1) 368 and (2) in the list above. OAM traffic discrimination happens 369 through the use of the Associated Channel method described in 370 [RFC4385]. The DetNet sequence number is carried in the DetNet 371 Control word which carries the Data/OAM discriminator. To simplify 372 implementation and to maximize interoperability two sequence number 373 sizes are supported: a 16 bit sequence number and a 28 bit sequence 374 number. The 16 bit sequence number is needed to support some types 375 of legacy clients. The 28 bit sequence number is used in situations 376 where it is necessary ensure that in high speed networks the sequence 377 number space does not wrap whilst packets are in flight. 379 The LSP used to forward the DetNet packet is not restricted regarding 380 any method used for establishing that LSP (for example, MPLS-LDP, 381 MPLS-TE, MPLS-TP [RFC5921], MPLS-SR [RFC8660], etc.). The LSP 382 (F-Label) label(s) and/or the S-Label may be used to indicate the 383 required queue processing as well as the forwarding parameters. Note 384 that the possible use of Penultimate Hop Popping (PHP) means that the 385 S-Label may be the only label received at the terminating DetNet 386 service. 388 4.2. MPLS Data Plane Encapsulation 390 Figure 4 illustrates a DetNet data plane MPLS encapsulation. The 391 MPLS-based encapsulation of the DetNet flows is well suited for the 392 scenarios described in [I-D.ietf-detnet-data-plane-framework]. 393 Furthermore, an end to end DetNet service i.e., native DetNet 394 deployment (see Section 3.2) is also possible if DetNet end systems 395 are capable of initiating and termination MPLS encapsulated packets. 397 The MPLS-based DetNet data plane encapsulation consists of: 399 o DetNet control word (d-CW) containing sequencing information for 400 packet replication and duplicate elimination purposes, and the OAM 401 indicator. 403 o DetNet service Label (S-Label) that identifies a DetNet flow at 404 the receiving DetNet service sub-layer processing node. 406 o Zero or more Detnet MPLS Forwarding label(s) (F-Label) used to 407 direct the packet along the label switched path (LSP) to the next 408 DetNet service sub-layer processing node along the path. When 409 Penultimate Hop Popping is in use there may be no label F-Label in 410 the protocol stack on the final hop. 412 o The necessary data-link encapsulation is then applied prior to 413 transmission over the physical media. 415 DetNet MPLS-based encapsulation 417 +---------------------------------+ 418 | | 419 | DetNet App-Flow | 420 | Payload Packet | 421 | | 422 +---------------------------------+ <--\ 423 | DetNet Control Word | | 424 +---------------------------------+ +--> DetNet data plane 425 | S-Label | | MPLS encapsulation 426 +---------------------------------+ | 427 | [ F-Label(s) ] | | 428 +---------------------------------+ <--/ 429 | Data-Link | 430 +---------------------------------+ 431 | Physical | 432 +---------------------------------+ 434 Figure 4: Encapsulation of a DetNet App-Flow in an MPLS PSN 436 4.2.1. DetNet Control Word and the DetNet Sequence Number 438 A DetNet control word (d-CW) conforms to the Generic PW MPLS Control 439 Word (PWMCW) defined in [RFC4385]. The d-CW formatted as shown in 440 Figure 5 MUST be present in all DetNet packets containing app-flow 441 data. This format of the d-CW was created in order (1) to allow 442 larger S/N space to avoid S/N rollover frequency in some applications 443 and (2) to allow non-skip zero S/N what simplifies implementation. 445 0 1 2 3 446 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 1 447 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 448 |0 0 0 0| Sequence Number | 449 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 451 Figure 5: DetNet Control Word 453 (bits 0 to 3) 455 Per [RFC4385], MUST be set to zero (0). 457 Sequence Number (bits 4 to 31) 459 An unsigned value implementing the DetNet sequence number. The 460 sequence number space is a circular one. 462 A separate sequence number space MUST be maintained by the node that 463 adds the d-CW for each DetNet app-flow, i.e., DetNet service. The 464 following sequence number field lengths MUST be supported: 466 0 bits 468 16 bits 470 28 bits 472 The sequence number length MUST be provisioned on a per Detnet 473 service basis via configuration, i.e., via the controller plane 474 described in [I-D.ietf-detnet-data-plane-framework]. 476 A 0 bit sequence number field length indicates that there is no 477 DetNet sequence number used for the flow. When the length is zero, 478 the sequence number field MUST be set to zero (0) on all packets sent 479 for the flow. 481 When the sequence number field length is 16 or 28 bits for a flow, 482 the sequence number MUST be incremented by one for each new app-flow 483 packet sent. When the field length is 16 bits, d-CW bits 4 to 15 484 MUST be set to zero (0). The values carried in this field can wrap 485 and it is important to note that zero (0) is a valid field value. 486 For example, were the sequence number size is 16 bits, the sequence 487 will contain: 65535, 0, 1, where zero (0) is an ordinary sequence 488 number. 490 It is important to note that this document differs from [RFC4448] 491 where a sequence number of zero (0) is used to indicate that the 492 sequence number check algorithm is not used. 494 The sequence number is optionally used during receive processing as 495 described below in Section 4.2.2.2 and Section 4.2.2.3. 497 4.2.2. S-Labels 499 A DetNet flow at the DetNet service sub-layer is identified by an 500 S-Label. MPLS-aware DetNet end systems and edge nodes, which are by 501 definition MPLS ingress and egress nodes, MUST add (push) and remove 502 (pop) a DetNet service-specific d-CW and S-Label. Relay nodes MAY 503 swap S-Label values when processing a DetNet flow, i.e., incoming and 504 outgoing S-Labels of a DetNet flow can be different. 506 S-Label values MUST be provisioned per DetNet service via 507 configuration, e.g., via the controller plane described in 508 [I-D.ietf-detnet-data-plane-framework]. Note that S-Labels provide 509 identification at the downstream DetNet service sub-layer receiver, 510 not the sender. As such, S-Labels MUST be allocated by the entity 511 that controls the service sub-layer receiving node's label space, and 512 MAY be allocated from the platform label space [RFC3031]. Because 513 S-Labels are local to each node rather than being a global identifier 514 within a domain, they must be advertised to their upstream DetNet 515 service-aware peer nodes (e.g., a DetNet MPLS End System or a DetNet 516 Relay or Edge Node) and interpreted in the context of their received 517 F-Label(s). 519 An S-Label will normally be at the bottom of the label stack once the 520 last F-Label is removed, immediately preceding the d-CW. To support 521 service sub-layer level OAM, an OAM Associated Channel Header (ACH) 522 [RFC4385] together with a Generic Associated Channel Label (GAL) 523 [RFC5586] MAY be used in place of a d-CW. 525 Similarly, an Entropy Label Indicator/Entropy Label (ELI/EL) 526 [RFC6790] MAY be carried below the S-Label in the label stack in 527 networks where DetNet flows would otherwise received ECMP treatment. 528 When ELs are used, the same EL value SHOULD be used for all of the 529 packets sent using a specific S-Label to force the flow to follow the 530 same path. However, as outlines in 531 [I-D.ietf-detnet-data-plane-framework] the use of ECMP for DetNet 532 flows is NOT RECOMMENDED. ECMP MAY be used for non-DetNet flows 533 within a DetNet domain. 535 When receiving a DetNet MPLS packet, an implementation MUST identify 536 the DetNet service associated with the incoming packet based on the 537 S-Label. When a node is using platform labels for S-Labels, no 538 additional information is needed as the S-label uniquely identifies 539 the DetNet service. In the case where platform labels are not used, 540 zero or more F-Labels and optionally, the incoming interface, 541 proceeding the S-Label MUST be used together with the S-Label to 542 uniquely identify the DetNet service associated with a received 543 packet. The incoming interface MAY also be used together with any 544 present F-Label(s) and the S-Label to uniquely identify an incoming 545 DetNet service, for example, in the case where PHP is used. Note 546 that choice to use platform label space for S-Label or S-Label plus 547 one or more F-Labels to identify DetNet services is a local 548 implementation choice, with one caveat. When one or more F-labels, 549 or incoming interface, is needed together with an S-Label to uniquely 550 identify a service, the controller plane must ensure that incoming 551 DetNet MPLS packets arrive with the needed information (F-label(s) 552 and/or incoming interface) and provision the needed information. The 553 provisioned information MUST then be used to identify incoming DetNet 554 service based on the combination of S-Label and F-Label(s) or 555 incoming interface. 557 The use of platform labels for S-Labels matches other pseudowire 558 encapsulations for consistency but there is no hard requirement in 559 this regard. 561 4.2.2.1. Packet Replication Function Processing 563 The Packet Replication Function (PRF) function MAY be supported by an 564 implementation for outgoing DetNet flows. The use of the PRF for a 565 particular DetNet service MUST be provisioned via configuration, 566 e.g., via the controller plane described in 567 [I-D.ietf-detnet-data-plane-framework]. When replication is 568 configure, the same app-flow data will be sent over multiple outgoing 569 DetNet member flows using forwarding sub-layer LSPs. The same d-CW 570 field value MUST be used on all outgoing member flows for each 571 replicated MPLS packet. 573 4.2.2.2. Packet Elimination Function Processing 575 Implementations MAY support the Packet Elimination Function (PEF) for 576 received DetNet MPLS flows. When supported, use of the PEF for a 577 particular DetNet service MUST be provisioned via configuration, 578 e.g., via the controller plane described in 579 [I-D.ietf-detnet-data-plane-framework]. 581 After a DetNet service is identified for a received DetNet MPLS 582 packet, as described above, an implementation MUST check if PEF is 583 configured for that DetNet service. When configured, the 584 implementation MUST track the sequence number contained in received 585 d-CWs and MUST ensure that duplicate (replicated) instances of a 586 particular sequence number are discarded. The specific mechanisms 587 used for an implementation to identify which received packets are 588 duplicates and which are new is an implementation choice. Note that 589 per Section 4.2.1 the sequence number field length may be 16 or 28 590 bits, and the field value can wrap. PEF MUST NOT be used with DetNet 591 flows configured with a d-CW sequence number field length of 0 bits. 593 Note that an implementation MAY wish to constrain the maximum number 594 sequence numbers that are tracked, on platform-wide or per flow 595 basis. Some implementations MAY support the provisioning of the 596 maximum number sequence numbers that are tracked number on either a 597 platform-wide or per flow basis. 599 4.2.2.3. Packet Ordering Function Processing 601 A function that is related to in-order delivery is the Packet 602 Ordering Function (POF). Implementations MAY support POF. When 603 supported, use of the POF for a particular DetNet service MUST be 604 provisioned via configuration, e.g., via the controller plane 605 described by [I-D.ietf-detnet-data-plane-framework]. Implementations 606 MAY required that PEF and POF be used in combination. There is no 607 requirement related to the order of execution of the Packet 608 Elimination and Ordering Functions in an implementation. 610 After a DetNet service is identified for a received DetNet MPLS 611 packet, as described above, an implementation MUST check if POF is 612 configured for that DetNet service. When configured, the 613 implementation MUST track the sequence number contained in received 614 d-CWs and MUST ensure that packets are processed in the order 615 indicated in the received d-CW sequence number field, which may not 616 be in the order the packets are received. As defined in 617 Section 4.2.1 the sequence number field length may be 16 or 28 bits, 618 is incremented by one (1) for each new MPLS packet sent for a 619 particular DetNet service, and the field value can wrap. The 620 specific mechanisms used for an implementation to identify the order 621 of received packets is an implementation choice. 623 Note that an implementation MAY wish to constrain the maximum number 624 of out of order packets that can be processed, on platform-wide or 625 per flow basis. Some implementations MAY support the provisioning of 626 this number on either a platform-wide or per flow basis. The number 627 of out of order packets that can be processed also impacts the 628 latency of a flow. 630 4.2.3. F-Labels 632 F-Labels are supported the DetNet forwarding sub-layer. F-Labels are 633 used to provide LSP-based connectivity between DetNet service sub- 634 layer processing nodes. 636 4.2.3.1. Service Sub-Layer Related Processing 638 DetNet MPLS end systems, edge nodes and relay nodes may operate at 639 the DetNet service sub-layer with understanding of DetNet services 640 and their requirements. As mentioned earlier, when operating at this 641 layer such nodes can push, pop or swap (pop then push) S-Labels. In 642 all cases, the F-Label(s) used for a DetNet service are always 643 replaced and the following procedures apply. 645 When sending a DetNet flow, zero or more F-Labels MAY be pushed on 646 top of an S-Label by the node pushing an S-Label. The F-Label(s) to 647 be pushed when sending a particular DetNet service MUST be 648 provisioned per DetNet service via configuration, e.g., via the 649 controller plane discussed in [I-D.ietf-detnet-data-plane-framework]. 650 F-Label(s) can also provide context for an S-Label. To allow for the 651 omission of F-Label(s), an implementation SHOULD also allow an 652 outgoing interface to be configured. 654 When PRF is supported, the same app-flow data will be sent over 655 multiple outgoing DetNet member flows using forwarding sub-layer 656 LSPs. To support PRF an implementation MUST support the setting of 657 different sets of F-Labels per DetNet member flow. To allow for the 658 omission of F-Labels, an implementation SHOULD also allow multiple 659 outgoing interfaces to be provisioned. 661 When a single set of F-Labels is provisioned for a particular 662 outgoing S-Label, that set of F-labels MUST be pushed after the 663 S-Label is pushed. The outgoing packet is then forwarded as 664 described below in Section 4.2.3.2. When a single outgoing interface 665 is provisioned, the outgoing packet is then forwarded as described 666 below in Section 4.2.3.2. 668 When multiple sets of outgoing F-Labels or interfaces are provisioned 669 for a particular DetNet service, a copy of the outgoing packet, 670 including the pushed S-Label, MUST be made per F-label set and 671 outgoing interface. Each set of provisioned F-Labels are then pushed 672 onto a copy of the packet. Each copy is then forwarded as described 673 below in Section 4.2.3.2. 675 As described in the previous section, when receiving a DetNet MPLS 676 flow, an implementation identifies the DetNet service associated with 677 the incoming packet based on the S-Label. When a node is using 678 platform labels for S-Labels, any F-Labels can be popped and the 679 S-label uniquely identifies the DetNet service. In the case where 680 platform labels are not used, incoming F-Label(s) and, optionally, 681 the incoming interface MUST also be provisioned for a DetNet service. 683 4.2.3.2. Common F-Label Processing 685 All DetNet aware MPLS nodes process F-Labels as needed to meet the 686 service requirements of the DetNet flow or flows carried in the LSPs 687 represented by the F-Labels. This includes normal push, pop and swap 688 operations. Such processing is essentially the same type of 689 processing provided for TE LSPs, although the specific service 690 parameters, or traffic specification, can differ. When the DetNet 691 service parameters of the DetNet flow or flows carried in an LSP 692 represented by an F-Label can be met by an existing TE mechanism, the 693 forwarding sub-layer processing node MAY be a DetNet unaware, i.e., 694 standard, MPLS LSR. Such TE LSPs may provide LSP forwarding service 695 as defined in, but not limited to, [RFC3209], [RFC3270], [RFC3272], 696 [RFC3473], [RFC4875], [RFC5440], and [RFC8306]. 698 More specifically, as mentioned above, the DetNet forwarding sub- 699 layer provides explicit routes and allocated resources, and F-Labels 700 are used to map to each. Explicit routes are supported based on the 701 topmost (outermost) F-Label that is pushed or swapped and the LSP 702 that corresponds to this label. This topmost (outgoing) label MUST 703 be associated with a provisioned outgoing interface and, for non- 704 point-to-point outgoing interfaces, a next hop LSR. Note that this 705 information MUST be provisioned via configuration or the controller 706 plane. In the previously mentioned special case where there are no 707 added F-labels and the outgoing interface is not a point-to-point 708 interface, the outgoing interface MUST also be associated with a next 709 hop LSR. 711 Resources may be allocated in a hierarchical fashion per LSP that is 712 represented by each F-Label. Each LSP MAY be provisioned with a 713 service parameters that dictates the specific traffic treatment to be 714 received by the traffic carried over that LSP. Implementations of 715 this document MUST ensure that traffic carried over each LSP 716 represented by one or more F-Labels receives the traffic treatment 717 provisioned for that LSP. Typical mechanisms used to provide 718 different treatment to different flows includes the allocation of 719 system resources (such as queues and buffers) and provisioning or 720 related parameters (such as shaping, and policing). Support can also 721 be provided via an underlying network technology such IEEE802.1 TSN 722 [I-D.ietf-detnet-mpls-over-tsn]. The specific mechanisms used by a 723 DetNet node to ensure DetNet service delivery requirements are met 724 for supported DetNet flows is outside the scope of this document. 726 Packets that are marked in a way that do not correspond to allocated 727 resources, e.g., lack a provisioned F-Label, can disrupt the QoS 728 offered to properly reserved DetNet flows by using resources 729 allocated to the reserved flows. Therefore, the network nodes of a 730 DetNet network: 732 o MUST defend the DetNet QoS by discarding or remarking (to an 733 allocated DetNet flow or non-competing non-DetNet flow) packets 734 received that are not associated with a completed resource 735 allocation. 737 o MUST NOT use a DetNet allocated resource, e.g. a queue or shaper 738 reserved for DetNet flows, for any packet that does match the 739 corresponding DetNet flow. 741 o MUST ensure a QoS flow does not exceed its allocated resources or 742 provisioned service level, 744 o MUST ensure a CoS flow or service class does not impact the 745 service delivered to other flows. This requirement is similar to 746 requirement for MPLS LSRs to that CoS LSPs do not impact the 747 resources allocated to TE LSPs, e.g., via [RFC3473]. 749 Subsequent sections provide additional considerations related to CoS 750 (Section 4.6.1), QoS (Section 4.6.2) and aggregation (Section 4.4). 752 4.3. OAM Indication 754 OAM follows the procedures set out in [RFC5085] with the restriction 755 that only Virtual Circuit Connectivity Verification (VCCV) type 1 is 756 supported. 758 As shown in Figure 3 of [RFC5085] when the first nibble of the d-CW 759 is 0x0 the payload following the d-CW is normal user data. However, 760 when the first nibble of the d-CW is 0X1, the payload that follows 761 the d-CW is an OAM payload with the OAM type indicated by the value 762 in the d-CW Channel Type field. 764 The reader is referred to [RFC5085] for a more detailed description 765 of the Associated Channel mechanism, and to the DetNet work on OAM 766 for more information DetNet OAM. 768 Additional considerations on DetNet-specific OAM are subjects for 769 further study. 771 4.4. Flow Aggregation 773 The ability to aggregate individual flows, and their associated 774 resource control, into a larger aggregate is an important technique 775 for improving scaling of control in the data, management and control 776 planes. The DetNet data plane allows for the aggregation of DetNet 777 flows, to improved scaling. There are two methods of supporting flow 778 aggregation covered in this section. 780 The resource control and management aspects of aggregation (including 781 the configuration of queuing, shaping, and policing) are the 782 responsibility of the DetNet controller plane and is out of scope of 783 this documents. It is also the responsibility of the controller 784 plane to ensure that consistent aggregation methods are used. 786 4.4.1. Aggregation Via LSP Hierarchy 788 DetNet flows forwarded via MPLS can leverage MPLS-TE's existing 789 support for hierarchical LSPs (H-LSPs), see [RFC4206]. H-LSPs are 790 typically used to aggregate control and resources, they may also be 791 used to provide OAM or protection for the aggregated LSPs. Arbitrary 792 levels of aggregation naturally falls out of the definition for 793 hierarchy and the MPLS label stack [RFC3032]. DetNet nodes which 794 support aggregation (LSP hierarchy) map one or more LSPs (labels) 795 into and from an H-LSP. Both carried LSPs and H-LSPs may or may not 796 use the TC field, i.e., L-LSPs or E-LSPs. Such nodes will need to 797 ensure that individual LSPs and H-LSPs receive the traffic treatment 798 required to ensure the required DetNet service is preserved. 800 Additional details of the traffic control capabilities needed at a 801 DetNet-aware node may be covered in the new service definitions 802 mentioned above or in separate future documents. Controller plane 803 mechanisms will also need to ensure that the service required on the 804 aggregate flow are provided, which may include the discarding or 805 remarking mentioned in the previous sections. 807 4.4.2. Aggregating DetNet Flows as a new DetNet flow 809 An aggregate can be built by layering DetNet flows, including both 810 their S-Label and, when present, F-Labels as shown below: 812 +---------------------------------+ 813 | | 814 | DetNet Flow | 815 | Payload Packet | 816 | | 817 +---------------------------------+ <--\ 818 | DetNet Control Word | | 819 +=================================+ | 820 | S-Label | | 821 +---------------------------------+ | 822 | [ F-Label(s) ] | +----DetNet data plane 823 +---------------------------------+ | 824 | DetNet Control Word | | 825 +=================================+ | 826 | A-Label | | 827 +---------------------------------+ | 828 | F-Label(s) | <--/ 829 +---------------------------------+ 830 | Data-Link | 831 +---------------------------------+ 832 | Physical | 833 +---------------------------------+ 835 Figure 6: DetNet Aggregation as a new DetNet Flow 837 Both the aggregation label, which is referred to as an A-Label, and 838 the individual flow's S-Label have their MPLS S bit set indicating 839 bottom of stack, and the d-CW allows the PREOF to work. An A-Label 840 is a special case of an S-Label, whose properties are known only at 841 the aggregation and deaggregation end-points. 843 It is a property of the A-Label that what follows is a d-CW followed 844 by an MPLS label stack. A relay node processing the A-Label would 845 not know the underlying payload type, and the A-Label would be 846 processed as a normal S-Label. This would only be known to a node 847 that was a peer of the node imposing the S-Label. However there is 848 no real need for it to know the payload type during aggregation 849 processing. 851 As in the previous section, nodes supporting this type of aggregation 852 will need to ensure that individual and aggregated flows receive the 853 traffic treatment required to ensure the required DetNet service is 854 preserved. Also, it is the controller plane's responsibility to to 855 ensure that the service required on the aggregate flow are properly 856 provisioned. 858 4.5. Service Sub-Layer Considerations 860 The edge and relay node internal procedures related to PREOF are 861 implementation specific. The order of a packet elimination or 862 replication is out of scope in this specification. 864 It is important that the DetNet layer is configured such that a 865 DetNet node never receives its own replicated packets. If it were to 866 receive such packets the replication function would make the loop 867 more destructive of bandwidth than a conventional unicast loop. 868 Ultimately the TTL in the S-Label will cause the packet to die during 869 a transient loop, but given the sensitivity of applications to packet 870 latency the impact on the DetNet application would be severe. To 871 avoid the problem of a transient forwarding loop, changes to an LSP 872 supporting DetNet MUST be loop-free. 874 4.5.1. Edge Node Processing 876 A DetNet Edge node operates in the DetNet forwarding sub-layer and 877 service sub-layer. An edge node is responsible for matching incoming 878 packets to the service they require and encapsulating them 879 accordingly. An edge node may perform PRF, PEF, and or POF. Details 880 on encapsulation can be found in Section 4.2; details on PRF can be 881 found in Section 4.2.2.1; details on PEF can be found in 882 Section 4.2.2.2; and details on POF can be found in Section 4.2.2.3. 884 4.5.2. Relay Node Processing 886 A DetNet Relay node operates in the DetNet forwarding sub-layer and 887 service sub-layer. For DetNet using MPLS forwarding related 888 processing is performed on the F-Label. This processing is done 889 within an extended forwarder function. Whether an incoming DetNet 890 flow receives DetNet specific processing depends on how the 891 forwarding is programmed. Some relay nodes may be DetNet service 892 aware for certain DetNet services, while for other DetNet services 893 these nodes may perform as unmodified LSRs that only understand how 894 to switch MPLS-TE LSPs, i.e., as a transit node, see Section 4.4. 895 Again, this is entirely up to how the forwarding has been programmed. 897 During the elimination and replication process the sequence number of 898 an incoming DetNet packet MUST be preserved and carried in the 899 corresponding outgoing DetNet packet. For example, a relay node that 900 performs both PEF and PRF first performs PEF on incoming packets to 901 create a compound flow. It then performs PRF and copies the app-flow 902 data and the d-CW into packets for each outgoing DetNet member flow. 904 The internal design of a relay node is out of scope of this document. 905 However the reader's attention is drawn to the need to make any PREOF 906 state available to the packet processor(s) dealing with packets to 907 which the PREOF functions must be applied, and to maintain that state 908 is such a way that it is available to the packet processor operation 909 on the next packet in the DetNet flow (which may be a duplicate, a 910 late packet, or the next packet in sequence). 912 4.6. Forwarding Sub-Layer Considerations 914 4.6.1. Class of Service 916 Class and quality of service, i.e., CoS and QoS, are terms that are 917 often used interchangeably and confused with each other. In the 918 context of DetNet, CoS is used to refer to mechanisms that provide 919 traffic forwarding treatment based on aggregate group basis and QoS 920 is used to refer to mechanisms that provide traffic forwarding 921 treatment based on a specific DetNet flow basis. Examples of 922 existing network level CoS mechanisms include DiffServ which is 923 enabled by IP header differentiated services code point (DSCP) field 924 [RFC2474] and MPLS label traffic class field [RFC5462], and at Layer- 925 2, by IEEE 802.1p priority code point (PCP). 927 CoS for DetNet flows carried in PWs and MPLS is provided using the 928 existing MPLS Differentiated Services (DiffServ) architecture 929 [RFC3270]. Both E-LSP and L-LSP MPLS DiffServ modes MAY be used to 930 support DetNet flows. The Traffic Class field (formerly the EXP 931 field) of an MPLS label follows the definition of [RFC5462] and 932 [RFC3270]. The Uniform, Pipe, and Short Pipe DiffServ tunneling and 933 TTL processing models are described in [RFC3270] and [RFC3443] and 934 MAY be used for MPLS LSPs supporting DetNet flows. MPLS ECN MAY also 935 be used as defined in ECN [RFC5129] and updated by [RFC5462]. 937 4.6.2. Quality of Service 939 In addition to explicit routes, and packet replication and 940 elimination, described in Section 4 above, DetNet provides zero 941 congestion loss and bounded latency and jitter. As described in 942 [RFC8655], there are different mechanisms that maybe used separately 943 or in combination to deliver a zero congestion loss service. This 944 includes Quality of Service (QoS) mechanisms at the MPLS layer, that 945 may be combined with the mechanisms defined by the underlying network 946 layer such as 802.1TSN. 948 Quality of Service (QoS) mechanisms for flow specific traffic 949 treatment typically includes a guarantee/agreement for the service, 950 and allocation of resources to support the service. Example QoS 951 mechanisms include discrete resource allocation, admission control, 952 flow identification and isolation, and sometimes path control, 953 traffic protection, shaping, policing and remarking. Example 954 protocols that support QoS control include Resource ReSerVation 955 Protocol (RSVP) [RFC2205] (RSVP) and RSVP-TE [RFC3209] and [RFC3473]. 956 The existing MPLS mechanisms defined to support CoS [RFC3270] can 957 also be used to reserve resources for specific traffic classes. 959 A baseline set of QoS capabilities for DetNet flows carried in PWs 960 and MPLS can provided by MPLS with Traffic Engineering (MPLS-TE) 961 [RFC3209] and [RFC3473]. TE LSPs can also support explicit routes 962 (path pinning). Current service definitions for packet TE LSPs can 963 be found in "Specification of the Controlled Load Quality of 964 Service", [RFC2211], "Specification of Guaranteed Quality of 965 Service", [RFC2212], and "Ethernet Traffic Parameters", [RFC6003]. 966 Additional service definitions are expected in future documents to 967 support the full range of DetNet services. In all cases, the 968 existing label-based marking mechanisms defined for TE-LSPs and even 969 E-LSPs are use to support the identification of flows requiring 970 DetNet QoS. 972 5. Management and Control Information Summary 974 The specific information needed for the processing of each DetNet 975 service depends on the DetNet node type and the functions being 976 provided on the node. This section summarizes based on the DetNet 977 sub-layer and if the DetNet traffic is being sent or received. All 978 DetNet node types are DetNet forwarding sub-layer aware, while all 979 but transit nodes are service sub-layer aware. This is shown in 980 Figure 2. 982 Much like other MPLS labels, there are a number of alternatives 983 available for DetNet S-Label and F-Label advertisement to an upstream 984 peer node. These include distributed signaling protocols such as 985 RSVP-TE, centralized label distribution via a controller that manages 986 both the sender and the receiver using NETCONF/YANG, BGP, PCEP, etc., 987 and hybrid combinations of the two. The details of the controller 988 plane solution required for the label distribution and the management 989 of the label number space are out of scope of this document. There 990 are particular DetNet considerations and requirements that are 991 discussed in [I-D.ietf-detnet-data-plane-framework]. 993 5.1. Service Sub-Layer Information Summary 995 The following summarizes the information that is needed on service 996 sub-layer aware nodes that transmit DetNet MPLS traffic, on a per 997 service basis: 999 o App-Flow identification information, e.g., IP information as 1000 defined in [I-D.ietf-detnet-ip-over-mpls]. Note, this information 1001 is not needed on DetNet relay nodes. 1003 o The sequence number length to be used for the service. Valid 1004 values included 0, 16 and 28 bits. 0 bits cannot be used when PEF 1005 or POF is configured for the service. 1007 o The outgoing S-Label for the service. 1009 o If PRF is to be provided for the service. 1011 o The forwarding sub-layer information associated with the output of 1012 the service sub-layer. Note that when the PRF function is 1013 provisioned, this information is per DetNet member flow. 1014 Logically the forwarding sub-layer information is a pointer to 1015 further details of transmission of Detnet flows at the forwarding 1016 sub-layer. 1018 The following summarizes the information that is needed on service 1019 sub-layer aware nodes that receive DetNet MPLS traffic, on a per 1020 service basis: 1022 o The forwarding sub-layer information associated with the input of 1023 the service sub-layer. Note that when the PEF function is 1024 provisioned, this information is per DetNet member flow. 1025 Logically the forwarding sub-layer information is a pointer to 1026 further details of the reception of Detnet flows at the forwarding 1027 sub-layer or A-Label. 1029 o The incoming S-Label for the service. 1031 o If PEF or POF is to be provided for the service. 1033 o The sequence number length to be used for the service. Valid 1034 values included 0, 16 and 28 bits. 0 bits cannot be used when PEF 1035 or POF are configured for the service. 1037 o App-Flow identification information, e.g., IP information as 1038 defined in [I-D.ietf-detnet-ip-over-mpls]. Note, this information 1039 is not needed on DetNet relay nodes. 1041 5.1.1. Service Aggregation Information Summary 1043 Nodes performing aggregation using A-Labels, per 1044 Section Section 4.4.2, require the additional information summarized 1045 in this section. 1047 The following summarizes the additional information that is needed on 1048 a node that sends aggregated flows using A-Labels: 1050 o The S-Labels or F-Labels that are to be carried over each 1051 aggregated service. 1053 o The A-Label associated with each aggregated service. 1055 o The other S-Label information summarized above. 1057 On the receiving node, the A-Label provides the forwarding context of 1058 an incoming interface or an F-Label and is used in subsequent service 1059 or forwarding sub-layer receive processing, as appropriated. The 1060 related addition configuration that may be provided discussed 1061 elsewhere in this section. 1063 5.2. Forwarding Sub-Layer Information Summary 1065 The following summarizes the information that is needed on forwarding 1066 sub-layer aware nodes that send DetNet MPLS traffic, on a per 1067 forwarding sub-layer flow basis: 1069 o The outgoing F-Label stack to be pushed. The stack may include 1070 H-LSP labels. 1072 o The traffic parameters associated with a specific label in the 1073 stack. Note that there may be multiple sets of traffic paramters 1074 associated with specific labels in the stack, e.g., when H-LSPs 1075 are used. 1077 o Outgoing interface and, for unicast traffic, the next hop 1078 information. 1080 o Sub-network specific parameters on a technology specific basis. 1081 For example, see [I-D.ietf-detnet-mpls-over-tsn]. 1083 The following summarizes the information that is needed on forwarding 1084 sub-layer aware nodes that receive DetNet MPLS traffic, on a per 1085 forwarding sub-layer flow basis: 1087 o The incoming interface. For some implementations and deployment 1088 scenarios, this information may not be needed. 1090 o The incoming F-Label stack to be popped. The stack may include 1091 H-LSP labels. 1093 o How the incoming forwarding sub-layer flow is to be handled, i.e., 1094 forwarded as a transit node, or provided to the service sub-layer. 1096 It is the responsibility of the DetNet controller plane to properly 1097 provision both flow identification information and the flow specific 1098 resources needed to provided the traffic treatment needed to meet 1099 each flow's service requirements. This applies for aggregated and 1100 individual flows. 1102 6. Security Considerations 1104 General security considerations are described in [RFC8655]. 1105 Additionally, security considerations and a threat analysis are 1106 described in [I-D.ietf-detnet-security]. This section considers 1107 security considerations which are specific to the DetNet MPLS data 1108 plane. The considerations raised related to MPLS networks in general 1109 in [RFC5920] are equally applicable to the the DetNet MPLS data 1110 plane. 1112 Security aspects which are unique to DetNet are those whose aim is to 1113 provide the specific quality of service aspects of DetNet, which are 1114 primarily to deliver data flows with extremely low packet loss rates 1115 and bounded end-to-end delivery latency. 1117 The primary considerations for the data plane is to maintain 1118 integrity of data and delivery of the associated DetNet service 1119 traversing the DetNet network. Application flows can be protected 1120 through whatever means is provided by the underlying technology. For 1121 example, encryption may be used, such as that provided by IPSec 1122 [RFC4301] for IP flows and/or by an underlying sub-net using MACSec 1123 [IEEE802.1AE-2018] for IP over Ethernet (Layer-2) flows. 1125 From a data plane perspective this document does not add or modify 1126 any header information. 1128 At the management and control level DetNet flows are identified on a 1129 per-flow basis, which may provide controller plane attackers with 1130 additional information about the data flows (when compared to 1131 controller planes that do not include per-flow identification). This 1132 is an inherent property of DetNet which has security implications 1133 that should be considered when determining if DetNet is a suitable 1134 technology for any given use case. 1136 To provide uninterrupted availability of the DetNet service, 1137 provisions can be made against DOS attacks and delay attacks. To 1138 protect against DOS attacks, excess traffic due to malicious or 1139 malfunctioning devices is prevented or mitigated through the use of 1140 existing mechanisms, for example by policing and shaping incoming 1141 traffic. To prevent DetNet packets from being delayed by an entity 1142 external to a DetNet domain, DetNet technology definition can allow 1143 for the mitigation of Man-In-The-Middle attacks, for example through 1144 use of authentication and authorization of devices within the DetNet 1145 domain. 1147 7. IANA Considerations 1149 This document makes no IANA requests. 1151 8. Acknowledgements 1153 The authors wish to thank Pat Thaler, Norman Finn, Loa Anderson, 1154 David Black, Rodney Cummings, Ethan Grossman, Tal Mizrahi, David 1155 Mozes, Craig Gunther, George Swallow, Yuanlong Jiang, Jeong-dong Ryoo 1156 and Carlos J. Bernardos for their various contributions to this 1157 work. 1159 9. Contributors 1161 RFC7322 limits the number of authors listed on the front page of a 1162 draft to a maximum of 5. The editor wishes to thank and acknowledge 1163 the follow author for contributing text to this draft. 1165 Don Fedyk 1166 LabN Consulting, L.L.C. 1167 Email: dfedyk@labn.net 1169 10. References 1171 10.1. Normative References 1173 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1174 Requirement Levels", BCP 14, RFC 2119, 1175 DOI 10.17487/RFC2119, March 1997, 1176 . 1178 [RFC2211] Wroclawski, J., "Specification of the Controlled-Load 1179 Network Element Service", RFC 2211, DOI 10.17487/RFC2211, 1180 September 1997, . 1182 [RFC2212] Shenker, S., Partridge, C., and R. Guerin, "Specification 1183 of Guaranteed Quality of Service", RFC 2212, 1184 DOI 10.17487/RFC2212, September 1997, 1185 . 1187 [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol 1188 Label Switching Architecture", RFC 3031, 1189 DOI 10.17487/RFC3031, January 2001, 1190 . 1192 [RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y., 1193 Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack 1194 Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001, 1195 . 1197 [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., 1198 and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP 1199 Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, 1200 . 1202 [RFC3270] Le Faucheur, F., Wu, L., Davie, B., Davari, S., Vaananen, 1203 P., Krishnan, R., Cheval, P., and J. Heinanen, "Multi- 1204 Protocol Label Switching (MPLS) Support of Differentiated 1205 Services", RFC 3270, DOI 10.17487/RFC3270, May 2002, 1206 . 1208 [RFC3443] Agarwal, P. and B. Akyol, "Time To Live (TTL) Processing 1209 in Multi-Protocol Label Switching (MPLS) Networks", 1210 RFC 3443, DOI 10.17487/RFC3443, January 2003, 1211 . 1213 [RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label 1214 Switching (GMPLS) Signaling Resource ReserVation Protocol- 1215 Traffic Engineering (RSVP-TE) Extensions", RFC 3473, 1216 DOI 10.17487/RFC3473, January 2003, 1217 . 1219 [RFC4206] Kompella, K. and Y. Rekhter, "Label Switched Paths (LSP) 1220 Hierarchy with Generalized Multi-Protocol Label Switching 1221 (GMPLS) Traffic Engineering (TE)", RFC 4206, 1222 DOI 10.17487/RFC4206, October 2005, 1223 . 1225 [RFC4385] Bryant, S., Swallow, G., Martini, L., and D. McPherson, 1226 "Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for 1227 Use over an MPLS PSN", RFC 4385, DOI 10.17487/RFC4385, 1228 February 2006, . 1230 [RFC5085] Nadeau, T., Ed. and C. Pignataro, Ed., "Pseudowire Virtual 1231 Circuit Connectivity Verification (VCCV): A Control 1232 Channel for Pseudowires", RFC 5085, DOI 10.17487/RFC5085, 1233 December 2007, . 1235 [RFC5129] Davie, B., Briscoe, B., and J. Tay, "Explicit Congestion 1236 Marking in MPLS", RFC 5129, DOI 10.17487/RFC5129, January 1237 2008, . 1239 [RFC5462] Andersson, L. and R. Asati, "Multiprotocol Label Switching 1240 (MPLS) Label Stack Entry: "EXP" Field Renamed to "Traffic 1241 Class" Field", RFC 5462, DOI 10.17487/RFC5462, February 1242 2009, . 1244 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1245 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 1246 May 2017, . 1248 [RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas, 1249 "Deterministic Networking Architecture", RFC 8655, 1250 DOI 10.17487/RFC8655, October 2019, 1251 . 1253 10.2. Informative References 1255 [I-D.ietf-detnet-data-plane-framework] 1256 Varga, B., Farkas, J., Berger, L., Malis, A., and S. 1257 Bryant, "DetNet Data Plane Framework", draft-ietf-detnet- 1258 data-plane-framework-06 (work in progress), May 2020. 1260 [I-D.ietf-detnet-ip] 1261 Varga, B., Farkas, J., Berger, L., Fedyk, D., and S. 1262 Bryant, "DetNet Data Plane: IP", draft-ietf-detnet-ip-07 1263 (work in progress), July 2020. 1265 [I-D.ietf-detnet-ip-over-mpls] 1266 Varga, B., Berger, L., Fedyk, D., Bryant, S., and J. 1267 Korhonen, "DetNet Data Plane: IP over MPLS", draft-ietf- 1268 detnet-ip-over-mpls-06 (work in progress), May 2020. 1270 [I-D.ietf-detnet-mpls-over-tsn] 1271 Varga, B., Farkas, J., Malis, A., and S. Bryant, "DetNet 1272 Data Plane: MPLS over IEEE 802.1 Time Sensitive Networking 1273 (TSN)", draft-ietf-detnet-mpls-over-tsn-03 (work in 1274 progress), June 2020. 1276 [I-D.ietf-detnet-security] 1277 Mizrahi, T. and E. Grossman, "Deterministic Networking 1278 (DetNet) Security Considerations", draft-ietf-detnet- 1279 security-10 (work in progress), May 2020. 1281 [IEEE802.1AE-2018] 1282 IEEE Standards Association, "IEEE Std 802.1AE-2018 MAC 1283 Security (MACsec)", 2018, 1284 . 1286 [RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S. 1287 Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 1288 Functional Specification", RFC 2205, DOI 10.17487/RFC2205, 1289 September 1997, . 1291 [RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, 1292 "Definition of the Differentiated Services Field (DS 1293 Field) in the IPv4 and IPv6 Headers", RFC 2474, 1294 DOI 10.17487/RFC2474, December 1998, 1295 . 1297 [RFC3272] Awduche, D., Chiu, A., Elwalid, A., Widjaja, I., and X. 1298 Xiao, "Overview and Principles of Internet Traffic 1299 Engineering", RFC 3272, DOI 10.17487/RFC3272, May 2002, 1300 . 1302 [RFC3985] Bryant, S., Ed. and P. Pate, Ed., "Pseudo Wire Emulation 1303 Edge-to-Edge (PWE3) Architecture", RFC 3985, 1304 DOI 10.17487/RFC3985, March 2005, 1305 . 1307 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 1308 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 1309 December 2005, . 1311 [RFC4448] Martini, L., Ed., Rosen, E., El-Aawar, N., and G. Heron, 1312 "Encapsulation Methods for Transport of Ethernet over MPLS 1313 Networks", RFC 4448, DOI 10.17487/RFC4448, April 2006, 1314 . 1316 [RFC4875] Aggarwal, R., Ed., Papadimitriou, D., Ed., and S. 1317 Yasukawa, Ed., "Extensions to Resource Reservation 1318 Protocol - Traffic Engineering (RSVP-TE) for Point-to- 1319 Multipoint TE Label Switched Paths (LSPs)", RFC 4875, 1320 DOI 10.17487/RFC4875, May 2007, 1321 . 1323 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation 1324 Element (PCE) Communication Protocol (PCEP)", RFC 5440, 1325 DOI 10.17487/RFC5440, March 2009, 1326 . 1328 [RFC5586] Bocci, M., Ed., Vigoureux, M., Ed., and S. Bryant, Ed., 1329 "MPLS Generic Associated Channel", RFC 5586, 1330 DOI 10.17487/RFC5586, June 2009, 1331 . 1333 [RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS 1334 Networks", RFC 5920, DOI 10.17487/RFC5920, July 2010, 1335 . 1337 [RFC5921] Bocci, M., Ed., Bryant, S., Ed., Frost, D., Ed., Levrau, 1338 L., and L. Berger, "A Framework for MPLS in Transport 1339 Networks", RFC 5921, DOI 10.17487/RFC5921, July 2010, 1340 . 1342 [RFC6003] Papadimitriou, D., "Ethernet Traffic Parameters", 1343 RFC 6003, DOI 10.17487/RFC6003, October 2010, 1344 . 1346 [RFC6073] Martini, L., Metz, C., Nadeau, T., Bocci, M., and M. 1347 Aissaoui, "Segmented Pseudowire", RFC 6073, 1348 DOI 10.17487/RFC6073, January 2011, 1349 . 1351 [RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and 1352 L. Yong, "The Use of Entropy Labels in MPLS Forwarding", 1353 RFC 6790, DOI 10.17487/RFC6790, November 2012, 1354 . 1356 [RFC8306] Zhao, Q., Dhody, D., Ed., Palleti, R., and D. King, 1357 "Extensions to the Path Computation Element Communication 1358 Protocol (PCEP) for Point-to-Multipoint Traffic 1359 Engineering Label Switched Paths", RFC 8306, 1360 DOI 10.17487/RFC8306, November 2017, 1361 . 1363 [RFC8660] Bashandy, A., Ed., Filsfils, C., Ed., Previdi, S., 1364 Decraene, B., Litkowski, S., and R. Shakir, "Segment 1365 Routing with the MPLS Data Plane", RFC 8660, 1366 DOI 10.17487/RFC8660, December 2019, 1367 . 1369 Authors' Addresses 1371 Balazs Varga (editor) 1372 Ericsson 1373 Magyar Tudosok krt. 11. 1374 Budapest 1117 1375 Hungary 1377 Email: balazs.a.varga@ericsson.com 1379 Janos Farkas 1380 Ericsson 1381 Magyar Tudosok krt. 11. 1382 Budapest 1117 1383 Hungary 1385 Email: janos.farkas@ericsson.com 1387 Lou Berger 1388 LabN Consulting, L.L.C. 1390 Email: lberger@labn.net 1392 Andrew G. Malis 1393 Malis Consulting 1395 Email: agmalis@gmail.com 1396 Stewart Bryant 1397 Futurewei Technologies 1399 Email: stewart.bryant@gmail.com 1401 Jouni Korhonen 1403 Email: jouni.nospam@gmail.com