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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: April 29, 2020 A. Malis 6 Independent 7 S. Bryant 8 Futurewei Technologies 9 October 27, 2019 11 DetNet Data Plane: IP over IEEE 802.1 Time Sensitive Networking (TSN) 12 draft-ietf-detnet-ip-over-tsn-01 14 Abstract 16 This document specifies the Deterministic Networking IP data plane 17 when operating over a TSN sub-network. 19 Status of This Memo 21 This Internet-Draft is submitted in full conformance with the 22 provisions of BCP 78 and BCP 79. 24 Internet-Drafts are working documents of the Internet Engineering 25 Task Force (IETF). Note that other groups may also distribute 26 working documents as Internet-Drafts. The list of current Internet- 27 Drafts is at https://datatracker.ietf.org/drafts/current/. 29 Internet-Drafts are draft documents valid for a maximum of six months 30 and may be updated, replaced, or obsoleted by other documents at any 31 time. It is inappropriate to use Internet-Drafts as reference 32 material or to cite them other than as "work in progress." 34 This Internet-Draft will expire on April 29, 2020. 36 Copyright Notice 38 Copyright (c) 2019 IETF Trust and the persons identified as the 39 document authors. All rights reserved. 41 This document is subject to BCP 78 and the IETF Trust's Legal 42 Provisions Relating to IETF Documents 43 (https://trustee.ietf.org/license-info) in effect on the date of 44 publication of this document. Please review these documents 45 carefully, as they describe your rights and restrictions with respect 46 to this document. Code Components extracted from this document must 47 include Simplified BSD License text as described in Section 4.e of 48 the Trust Legal Provisions and are provided without warranty as 49 described in the Simplified BSD License. 51 Table of Contents 53 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 54 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 55 2.1. Terms Used In This Document . . . . . . . . . . . . . . . 3 56 2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 3 57 2.3. Requirements Language . . . . . . . . . . . . . . . . . . 3 58 3. DetNet IP Data Plane Overview . . . . . . . . . . . . . . . . 3 59 4. DetNet IP Flows over an IEEE 802.1 TSN sub-network . . . . 5 60 4.1. Functions for DetNet Flow to TSN Stream Mapping . . . . . 6 61 4.2. TSN requirements of IP DetNet nodes . . . . . . . . . . . 6 62 4.3. Service protection within the TSN sub-network . . . . . . 8 63 4.4. Aggregation during DetNet flow to TSN Stream mapping . . 8 64 5. Management and Control Implications . . . . . . . . . . . . . 8 65 6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 66 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 67 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10 68 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 69 9.1. Normative references . . . . . . . . . . . . . . . . . . 10 70 9.2. Informative references . . . . . . . . . . . . . . . . . 10 71 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 73 1. Introduction 75 Deterministic Networking (DetNet) is a service that can be offered by 76 a network to DetNet flows. DetNet provides these flows extremely low 77 packet loss rates and assured maximum end-to-end delivery latency. 78 General background and concepts of DetNet can be found in the DetNet 79 Architecture [I-D.ietf-detnet-architecture]. 81 [I-D.ietf-detnet-ip] specifies the DetNet data plane operation for IP 82 hosts and routers that provide DetNet service to IP encapsulated 83 data. This document focuses on the scenario where DetNet IP nodes 84 are interconnected by a TSN sub-network. 86 The DetNet Architecture decomposes the DetNet related data plane 87 functions into two sub-layers: a service sub-layer and a forwarding 88 sub-layer. The service sub-layer is used to provide DetNet service 89 protection and reordering. The forwarding sub-layer is used to 90 provides congestion protection (low loss, assured latency, and 91 limited reordering). As described in [I-D.ietf-detnet-ip] no DetNet 92 specific headers are added to support DetNet IP flows, only the 93 forwarding sub-layer functions are supported inside the DetNet 94 domain. Service protection can be provided on a per sub-network 95 basis as shown here for the IEEE802.1 TSN sub-network scenario. 97 2. Terminology 99 [Editor's note: Needs clean up.]. 101 2.1. Terms Used In This Document 103 This document uses the terminology and concepts established in the 104 DetNet architecture [I-D.ietf-detnet-architecture], and the reader is 105 assumed to be familiar with that document and its terminology. 107 2.2. Abbreviations 109 The following abbreviations used in this document: 111 DetNet Deterministic Networking. 113 DF DetNet Flow. 115 L2 Layer-2. 117 L3 Layer-3. 119 PREOF Packet Replication, Ordering and Elimination Function. 121 TSN Time-Sensitive Networking, TSN is a Task Group of the 122 IEEE 802.1 Working Group. 124 2.3. Requirements Language 126 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 127 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 128 "OPTIONAL" in this document are to be interpreted as described in BCP 129 14 [RFC2119] [RFC8174] when, and only when, they appear in all 130 capitals, as shown here. 132 3. DetNet IP Data Plane Overview 134 [Editor's note: this section and highlights that DetNet IP over 135 subnets scenario being the focus in the remaining part of the 136 document.]. 138 [I-D.ietf-detnet-ip] describes how IP is used by DetNet nodes, i.e., 139 hosts and routers, to identify DetNet flows and provide a DetNet 140 service. From a data plane perspective, an end-to-end IP model is 141 followed. DetNet uses "6-tuple" based flow identification, where 142 "6-tuple" refers to information carried in IP and higher layer 143 protocol headers. 145 DetNet flow aggregation may be enabled via the use of wildcards, 146 masks, prefixes and ranges. IP tunnels may also be used to support 147 flow aggregation. In these cases, it is expected that DetNet aware 148 intermediate nodes will provide DetNet service assurance on the 149 aggregate through resource allocation and congestion control 150 mechanisms. 152 Congestion protection, latency control and the resource allocation 153 (queuing, policing, shaping) are supported using the underlying link 154 / sub-net specific mechanisms. Service protections (packet 155 replication and packet elimination functions) are not provided at the 156 DetNet layer end to end due the lack of a unified end to end 157 sequencing information that would be available for intermediate 158 nodes. However, such service protection can be provided on a per 159 underlying L2 link and sub-network basis. 161 Edge Transit Relay 162 Node Node Node 164 +.........+ 165 <--:Svc Proxy:-- End to End Service -----------> 166 +-----....+ +..........+ 167 |IP | :Svc:<-- DetNet flow ---: Service :---> 168 +---+ +---+ +---------+ +---------+ 169 |Fwd| |Fwd| | Fwd | |Fwd| |Fwd| 170 +-.-+ +-.-+ +--.----.-+ +-.-+ +-.-+ 171 : / ,-----. \ : Link : : 172 .....+ +-[TSN Sub]-+ +........+ +..... 173 [Network] 174 `-----' 175 <------------- DetNet IP ------------- 177 Figure 1: Part of a Simple DetNet (DN) Enabled IP Network using a TSN 178 sub-net 180 Figure 1 illustrates an extract of a DetNet enabled IP network, that 181 uses a TSN sub-network as interconnection between two DetNet Nodes. 182 In this figure, an Edge Node sits at the boundary of the DetNet 183 domain and provide DetNet service proxies for the end applications by 184 initiating and terminating DetNet service for the application's IP 185 flows. Node and interface resources are allocated to ensure DetNet 186 service requirements. Dotted lines around the Service components of 187 the Edge and Relay Nodes indicate that they are DetNet service aware 188 but do not perform any DetNet service sub-layer function, e.g., PREOF 189 (Packet Replication, Elimination, and Ordering Functions). In this 190 example the Edge Node and the Transit Node are interconnected by a 191 TSN sub-network, being the primary focus of this document. 193 DetNet routers ensure that detnet service requirements are met per 194 hop by allocating local resources, both receive and transmit, and by 195 mapping the service requirements of each flow to appropriate sub- 196 network mechanisms. Such mappings are sub-network technology 197 specific. The mapping of DetNet IP flows to TSN streams and TSN 198 protection mechanisms are covered in Section 4. 200 4. DetNet IP Flows over an IEEE 802.1 TSN sub-network 202 [Authors note: how do we handle control protocols such as ICMP, 203 IPsec, etc.? If such protocols are part of the DetNet flow they can 204 be identified by the Mask-and-match Stream identification function of 205 P802.1CBdb.] 207 This section covers how DetNet IP flows operate over an IEEE 802.1 208 TSN sub-network. Figure 2 illustrates such a scenario, where two IP 209 (DetNet) nodes are interconnected by a TSN sub-network. Node-1 is 210 single homed and Node-2 is dual-homed to the TSN sub-network. 212 IP (DetNet) IP (DetNet) 213 Node-1 Node-2 215 ............ ............ 216 <--: Service :-- DetNet flow ---: Service :--> 217 +----------+ +----------+ 218 |Forwarding| |Forwarding| 219 +--------.-+ <-TSN Str-> +-.-----.--+ 220 \ ,-------. / / 221 +----[ TSN-Sub ]---+ / 222 [ Network ]--------+ 223 `-------' 224 <----------------- DetNet IP -----------------> 226 Figure 2: DetNet (DN) Enabled IP Network over a TSN sub-network 228 The Time-Sensitive Networking (TSN) Task Group of the IEEE 802.1 229 Working Group have defined (and are defining) a number of amendments 230 to IEEE 802.1Q [IEEE8021Q] that provide zero congestion loss and 231 bounded latency in bridged networks. Furthermore IEEE 802.1CB 232 [IEEE8021CB] defines frame replication and elimination functions for 233 reliability that should prove both compatible with and useful to 234 DetNet networks. All these functions have to identify flows that 235 require TSN treatment. 237 TSN capabilities of the TSN sub-network are made available for IP 238 (DetNet) flows via the protocol interworking function defined in IEEE 239 802.1CB [IEEE8021CB]. For example, applied on the TSN edge port it 240 can convert an ingress unicast IP (DetNet) flow to use a specific 241 Layer-2 multicast destination MAC address and a VLAN, in order to 242 direct the packet through a specific path inside the bridged network. 243 A similar interworking function pair at the other end of the TSN sub- 244 network would restore the packet to its original Layer-2 destination 245 MAC address and VLAN. 247 Placement of TSN functions depends on the TSN capabilities of nodes. 248 IP (DetNet) Nodes may or may not support TSN functions. For a given 249 TSN Stream (i.e., DetNet flow) an IP (DetNet) node is treated as a 250 Talker or a Listener inside the TSN sub-network. 252 4.1. Functions for DetNet Flow to TSN Stream Mapping 254 Mapping of a DetNet IP flow to a TSN Stream is provided via the 255 combination of a passive and an active stream identification function 256 that operate at the frame level. The passive stream identification 257 function is used to catch the 6-tuple of a DetNet IP flow and the 258 active stream identification function is used to modify the Ethernet 259 header according to ID of the mapped TSN Stream. 261 IEEE 802.1CB [IEEE8021CB] defines an IP Stream identification 262 function that can be used as a passive function for IP DetNet flows 263 using UDP or TCP. IEEE P802.1CBdb [IEEEP8021CBdb] defines a Mask- 264 and-Match Stream identification function that can be used as a 265 passive function for any IP DetNet flows. 267 IEEE 802.1CB [IEEE8021CB] defines an Active Destination MAC and VLAN 268 Stream identification function, what can replace some Ethernet header 269 fields namely (1) the destination MAC-address, (2) the VLAN-ID and 270 (3) priority parameters with alternate values. Replacement is 271 provided for the frame passed down the stack from the upper layers or 272 up the stack from the lower layers. 274 Active Destination MAC and VLAN Stream identification can be used 275 within a Talker to set flow identity or a Listener to recover the 276 original addressing information. It can be used also in a TSN bridge 277 that is providing translation as a proxy service for an End System. 279 4.2. TSN requirements of IP DetNet nodes 281 This section covers required behavior of a TSN-aware DetNet node 282 using a TSN sub-network. 284 From the TSN sub-network perspective DetNet IP nodes are treated as 285 Talker or Listener, that may be (1) TSN-unaware or (2) TSN-aware. 287 In cases of TSN-unaware IP DetNet nodes the TSN relay nodes within 288 the TSN sub-network must modify the Ethernet encapsulation of the 289 DetNet IP flow (e.g., MAC translation, VLAN-ID setting, Sequence 290 number addition, etc.) to allow proper TSN specific handling inside 291 the sub-network. There are no requirements defined for TSN-unaware 292 IP DetNet nodes in this document. 294 IP (DetNet) nodes being TSN-aware can be treated as a combination of 295 a TSN-unaware Talker/Listener and a TSN-Relay, as shown in Figure 3. 296 In such cases the IP (DetNet) node must provide the TSN sub-network 297 specific Ethernet encapsulation over the link(s) towards the sub- 298 network. 300 IP (DetNet) 301 Node 302 <----------------------------------> 304 ............ 305 <--: Service :-- DetNet flow ------------------ 306 +----------+ 307 |Forwarding| 308 +----------+ +---------------+ 309 | L2 | | L2 Relay with |<--- TSN --- 310 | | | TSN function | Stream 311 +-----.----+ +--.------.---.-+ 312 \__________/ \ \______ 313 \_________ 314 TSN-unaware 315 Talker / TSN-Bridge 316 Listener Relay 317 <----- TSN Sub-network ----- 318 <------- TSN-aware Tlk/Lstn -------> 320 Figure 3: IP (DetNet) node with TSN functions 322 A TSN-aware IP (DetNet) node impementations MUST support the Stream 323 Identification TSN component for recognizing flows. 325 A Stream identification component MUST be able to instantiate the 326 following functions (1) Active Destination MAC and VLAN Stream 327 identification function, (2) IP Stream identification function, (3) 328 Mask-and-Match Stream identification function and (4) the related 329 managed objects in Clause 9 of IEEE 802.1CB [IEEE8021CB] and IEEE 330 P802.1CBdb [IEEEP8021CBdb]. 332 A TSN-aware IP (DetNet) node implementations MUST support the 333 Sequencing function and the Sequence encode/decode function as 334 defined in IEEE 802.1CB [IEEE8021CB] if FRER is used inside the TSN 335 sub-network. 337 The Sequence encode/decode function MUST support the Redundancy tag 338 (R-TAG) format as per Clause 7.8 of IEEE 802.1CB [IEEE8021CB]. 340 A TSN-aware IP (DetNet) node implementations MUST support the Stream 341 splitting function and the Individual recovery function as defined in 342 IEEE 802.1CB [IEEE8021CB] when the node is a replication or 343 elimination point for FRER. 345 4.3. Service protection within the TSN sub-network 347 TSN Streams supporting DetNet flows may use Frame Replication and 348 Elimination for Redundancy (FRER) as defined in IEEE 802.1CB 349 [IEEE8021CB] based on the loss service requirements of the TSN 350 Stream, which is derived from the DetNet service requirements of the 351 DetNet mapped flow. The specific operation of FRER is not modified 352 by the use of DetNet and follows IEEE 802.1CB [IEEE8021CB]. 354 FRER function and the provided service recovery is available only 355 within the TSN sub-network as the TSN Stream-ID and the TSN sequence 356 number are not valid outside the sub-network. An IP (DetNet) node 357 represents a L3 border and as such it terminates all related 358 information elements encoded in the L2 frames. 360 4.4. Aggregation during DetNet flow to TSN Stream mapping 362 Implementations of this document SHALL use management and control 363 information to map a DetNet flow to a TSN Stream. N:1 mapping 364 (aggregating DetNet flows in a single TSN Stream) SHALL be supported. 365 The management or control function that provisions flow mapping SHALL 366 ensure that adequate resources are allocated and configured to 367 provide proper service requirements of the mapped flows. 369 5. Management and Control Implications 371 [Editor's note: This section covers management/control plane related 372 implications of creation, mapping, removal of TSN Stream IDs, their 373 related parameters and, when needed, the configuration of FRER.] 375 DetNet flow and TSN Stream mapping related information are required 376 only for TSN-aware IP (DetNet) nodes. From the Data Plane 377 perspective there is no practical difference based on the origin of 378 flow mapping related information (management plane or control plane). 380 TSN-aware IP DetNet nodes are member of both the DetNet domain and 381 the TSN sub-network. Within the TSN sub-network the TSN-aware IP 382 (DetNet) node has a TSN-aware Talker/Listener role, so TSN specific 383 management and control plane functionalities must be implemented. 384 There are many similarities in the management plane techniques used 385 in DetNet and TSN, but that is not the case for the control plane 386 protocols. For example, RSVP-TE and MSRP behaves differently. 387 Therefore management and control plane design is an important aspect 388 of scenarios, where mapping between DetNet and TSN is required. 390 In order to use a TSN sub-network between DetNet nodes, DetNet 391 specific information must be converted to TSN sub-network specific 392 ones. DetNet flow ID and flow related parameters/requirements must 393 be converted to a TSN Stream ID and stream related parameters/ 394 requirements. Note that, as the TSN sub-network is just a portion of 395 the end2end DetNet path (i.e., single hop from IP perspective), some 396 parameters (e.g., delay) may differ significantly. Other parameters 397 (like bandwidth) also may have to be tuned due to the L2 398 encapsulation used within the TSN sub-network. 400 In some case it may be challenging to determine some TSN Stream 401 related information. For example, on a TSN-aware IP (DetNet) node 402 that acts as a Talker, it is quite obvious which DetNet node is the 403 Listener of the mapped TSN stream (i.e., the IP Next-Hop). However 404 it may be not trivial to locate the point/interface where that 405 Listener is connected to the TSN sub-network. Such attributes may 406 require interaction between control and management plane functions 407 and between DetNet and TSN domains. 409 Mapping between DetNet flow identifiers and TSN Stream identifiers, 410 if not provided explicitly, can be done by a TSN-aware IP (DetNet) 411 node locally based on information provided for configuration of the 412 TSN Stream identification functions (IP Stream identification, Mask- 413 and-match Stream identification and active Stream identification 414 function). 416 Triggering the setup/modification of a TSN Stream in the TSN sub- 417 network is an example where management and/or control plane 418 interactions are required between the DetNet and TSN sub-network. 419 TSN-unaware IP (DetNet) nodes make such a triggering even more 420 complicated as they are fully unaware of the sub-network and run 421 independently. 423 Configuration of TSN specific functions (e.g., FRER) inside the TSN 424 sub-network is a TSN domain specific decision and may not be visible 425 in the DetNet domain. 427 6. Security Considerations 429 The security considerations of DetNet in general are discussed in 430 [I-D.ietf-detnet-architecture] and [I-D.ietf-detnet-security]. 431 DetNet IP data plane specific considerations are summarized in 433 [I-D.ietf-detnet-ip]. Encryption may provided by an underlying sub- 434 net using MACSec [IEEE802.1AE-2018] for DetNet IP over TSN flows. 436 7. IANA Considerations 438 None. 440 8. Acknowledgements 442 The authors wish to thank Norman Finn, Lou Berger, Craig Gunther, 443 Christophe Mangin and Jouni Korhonen for their various contributions 444 to this work. 446 9. References 448 9.1. Normative references 450 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 451 Requirement Levels", BCP 14, RFC 2119, 452 DOI 10.17487/RFC2119, March 1997, 453 . 455 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 456 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 457 May 2017, . 459 9.2. Informative references 461 [G.8275.1] 462 International Telecommunication Union, "Precision time 463 protocol telecom profile for phase/time synchronization 464 with full timing support from the network", ITU-T 465 G.8275.1/Y.1369.1 G.8275.1, June 2016, 466 . 468 [G.8275.2] 469 International Telecommunication Union, "Precision time 470 protocol telecom profile for phase/time synchronization 471 with partial timing support from the network", ITU-T 472 G.8275.2/Y.1369.2 G.8275.2, June 2016, 473 . 475 [I-D.ietf-detnet-architecture] 476 Finn, N., Thubert, P., Varga, B., and J. Farkas, 477 "Deterministic Networking Architecture", draft-ietf- 478 detnet-architecture-13 (work in progress), May 2019. 480 [I-D.ietf-detnet-flow-information-model] 481 Farkas, J., Varga, B., Cummings, R., Jiang, Y., and D. 482 Fedyk, "DetNet Flow Information Model", draft-ietf-detnet- 483 flow-information-model-05 (work in progress), September 484 2019. 486 [I-D.ietf-detnet-ip] 487 Varga, B., Farkas, J., Berger, L., Fedyk, D., Malis, A., 488 Bryant, S., and J. Korhonen, "DetNet Data Plane: IP", 489 draft-ietf-detnet-ip-01 (work in progress), July 2019. 491 [I-D.ietf-detnet-security] 492 Mizrahi, T., Grossman, E., Hacker, A., Das, S., Dowdell, 493 J., Austad, H., Stanton, K., and N. Finn, "Deterministic 494 Networking (DetNet) Security Considerations", draft-ietf- 495 detnet-security-05 (work in progress), August 2019. 497 [IEEE1588] 498 IEEE, "IEEE 1588 Standard for a Precision Clock 499 Synchronization Protocol for Networked Measurement and 500 Control Systems Version 2", 2008. 502 [IEEE802.1AE-2018] 503 IEEE Standards Association, "IEEE Std 802.1AE-2018 MAC 504 Security (MACsec)", 2018, 505 . 507 [IEEE8021CB] 508 Finn, N., "Draft Standard for Local and metropolitan area 509 networks - Seamless Redundancy", IEEE P802.1CB 510 /D2.1 P802.1CB, December 2015, 511 . 514 [IEEE8021Q] 515 IEEE 802.1, "Standard for Local and metropolitan area 516 networks--Bridges and Bridged Networks (IEEE Std 802.1Q- 517 2014)", 2014, . 519 [IEEEP8021CBdb] 520 Mangin, C., "Extended Stream identification functions", 521 IEEE P802.1CBdb /D0.2 P802.1CBdb, August 2019, 522 . 525 Authors' Addresses 527 Balazs Varga (editor) 528 Ericsson 529 Magyar Tudosok krt. 11. 530 Budapest 1117 531 Hungary 533 Email: balazs.a.varga@ericsson.com 535 Janos Farkas 536 Ericsson 537 Magyar Tudosok krt. 11. 538 Budapest 1117 539 Hungary 541 Email: janos.farkas@ericsson.com 543 Andrew G. Malis 544 Independent 546 Email: agmalis@gmail.com 548 Stewart Bryant 549 Futurewei Technologies 551 Email: stewart.bryant@gmail.com