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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 DetNet H. Wang 2 Internet Draft P. Wang 3 Interned status: Standards Track C. Zhang 4 Expires: June 22, 2017 Y. Yang 5 Chongqing University of 6 Posts and Telecommunications 7 December 19, 2016 9 Joint Scheduling Architecture for Deterministic Industrial 10 Field/Backhaul Networks 11 draft-wang-detnet-backhaul-architecture-00 13 Abstract 15 Joint scheduling of industrial field network and backhaul network is 16 significant for end-to-end deterministic delay requirements of data 17 flows in factories. This document describes a joint scheduling 18 architecture for deterministic industrial field and backhaul 19 networks. Taking WIA-PA wireless field network and IPv6-based 20 backhaul network as an example, this document shows how the joint 21 scheduling architecture works. 23 Status of this Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF), its areas, and its working groups. Note that 30 other groups may also distribute working documents as Internet- 31 Drafts. 33 Internet-Drafts are draft documents valid for a maximum of six 34 months and may be updated, replaced, or obsoleted by other documents 35 at any time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 The list of current Internet-Drafts can be accessed at 39 http://www.ietf.org/ietf/1id-abstracts.txt 41 The list of Internet-Draft Shadow Directories can be accessed at 42 http://www.ietf.org/shadow.html 44 This Internet-Draft will expire on June 22, 2017. 46 Copyright Notice 48 Copyright (c) 2016 IETF Trust and the persons identified as the 49 document authors. All rights reserved. 51 This document is subject to BCP 78 and the IETF Trust's Legal 52 Provisions Relating to IETF Documents 53 (http://trustee.ietf.org/license-info) in effect on the date of 54 publication of this document. Please review these documents 55 carefully, as they describe your rights and restrictions with 56 respect to this document. Code Components extracted from this 57 document must include Simplified BSD License text as described in 58 Section 4.e of the Trust Legal Provisions and are provided without 59 warranty as described in the Simplified BSD License. 61 Table of Contents 63 1. Introduction ................................................ 2 64 2. Joint Scheduling Architecture................................ 3 65 2.1. Distributed Architecture................................ 4 66 2.2. Centralized Architecture................................ 5 67 2.3. Joint Scheduling Architecture........................... 6 68 3. Joint Scheduling Scheme...................................... 8 69 3.1. WIA-PA Network Joint Scheduling ........................ 9 70 3.2. Protocol Conversion..................................... 9 71 3.3. Industrial Backhaul Network Scheduling ................ 11 72 4. Security Considerations..................................... 13 73 5. IANA Considerations ........................................ 13 74 6. References ................................................. 13 75 6.1. Normative References................................... 13 76 6.2. Informative References................................. 13 78 1. Introduction 80 Deterministic network is an essential element of the industrial 81 network. Using deterministic network in the industrial field can 82 enhance the network performance and greatly reduce the network 83 packet loss. Thus, it is the future development direction of 84 industrial network technology to use deterministic networks in the 85 whole industrial network. Deterministic networks in industrial 86 networks are mainly concentrated on the industrial field networks, 87 such as ISA100.11a[IEC62734], WirelessHART[IEC62591] and WIA- 88 PA[IEC62601], and there is little joint scheduling scheme that can 89 be applied to industrial networks. 91 Nowadays, in the use case document[draft-bas-usecase-detnet] and 92 architecture document[draft-finn-detnet-architecture] submitted by 93 the IETF DetNet working group, a deterministic network based on 94 Ethernet has already been researched. The document proposes a 95 network architecture based on SDN technology, which can accurately 96 control the transmission of data streams. However, the document does 97 not consider the characteristics of the industrial backhaul networks 98 and the actual situation of other industrial field deterministic 99 networks. First of all, the data flow of industrial backhaul network 100 is highly sensitive to the uncertainty of time. Therefore, it is 101 very important that how to apply the deterministic networks based on 102 Ethernet to industrial backhaul networks. Secondly, the existing 103 deterministic networks in the industrial field have been widely 104 deployed in the factory, and Deterministic network technology is 105 already very mature, and direct replacement will consume a lot of 106 manpower and material resources. 108 Based on existing work in the architecture document[draft-finn- 109 detnet-architecture], this document proposes a joint scheduling 110 architecture for deterministic industrial field networks. This 111 framework will firstly replace the industrial backhaul networks and 112 other non-deterministic networks of industrial networks into 113 deterministic Ethernet-based network, and then on the basis of SDN 114 technology, this document proposes a joint scheduler, which can be 115 used for joint scheduling on other deterministic networks in 116 deterministic Ethernet-based network and industrial field network. 117 Through deploying the deterministic network throughout the 118 industrial network based on the joint scheduling architecture, it 119 can realize the end-to-end deterministic scheduling between 120 different industrial field networks, and ensure data stream 121 indicators as well as save manpower and material resources. 123 2. Joint Scheduling Architecture 125 For industrial networks, there are many network controllers in the 126 network, which together constitute the control plane for the whole 127 industrial network. The control plane is very important in the 128 entire network, especially when it comes to cross domain transfer of 129 time-sensitive data. So the control plane architecture will greatly 130 affect the performance of the network, therefore it is becoming a 131 research hotspot on how to give full play to the performance of 132 their respective networks when the multiple controllers are in the 133 joint cooperation. However, there is not a unified standard of joint 134 architecture of multiple controllers in the industry at present. The 135 main frameworks are the following two kinds: the distributed 136 architecture and the centralized architecture. The WIA-PA network, 137 which is the typical of WSNs standards which has become an 138 international standard for industrial field networks approved by IEC, 139 is used as an example to illustrate these architectures. 141 2.1. Distributed Architecture 143 Distributed architecture is also known as East-West architecture. In 144 the architecture, the status of all network controller is equal, 145 these controllers are connected to each other to form an 146 unstructured network, and achieve cross domain transfer task 147 deployment through the mutual transmission of information, as shown 148 in Figure 1. 150 In the distributed architecture, the controller can exchange 151 different network topologies and the accessibility of information 152 through the east-west interface, and each controller can build a 153 global network topology. In the access to the global network 154 topology, since each controller is equal, it can serve as a server 155 role at the same time, as well as has the service capacity of 156 starting deterministic cross-network transmission. 158 +-------------------------------------------------------------+ 159 | | 160 Application | +--------+ +--------+ +-------+ | 161 Plane | | APP | | APP | | APP | | 162 | +----+---+ +----+---+ +---+---+ | 163 | | | | | 164 +----------+------------------+------------------+------------+ 165 | | | 166 --------------------------------------------------------------------------------- 167 | | | 168 +----------+------------------+------------------+------------+ 169 | | | | | 170 Control | +----+-----+ +----+-----+ +----+-----+ | 171 Plane | |Controller|------>|Controller|------>|Controller| | 172 | | |<------| |<------| | | 173 | +----------+ +----------+ +----------+ | 174 | | | | | 175 +----------+------------------+------------------+------------+ 176 | | | 177 --------------------------------------------------------------------------------- 178 | | | 179 +----+-----+ +----+-----+ +----+-----+ 180 Forwarding | WIA-PA |------>| backhaul |------>| WIA-PA | 181 Plane | network |<------| network |<------| network | 182 +----------+ +----------+ +----------+ 183 Figure 1. Distributed Architecture 185 2.2. Centralized Architecture 187 Centralized architecture is also known as vertical multi-level 188 architecture. In this architecture, the control plane is divided 189 into two parts, one is the basic control plane composed of a variety 190 of network controllers; another part is a network controller 191 composed of the main controller, which is responsible for 192 controlling the basic control plane, as shown in Figure 2. 194 +-------------------------------------------------------------+ 195 | | 196 Application | +--------+ +--------+ +-------+ | 197 Plane | | APP | | APP | | APP | | 198 | +--------+ +----+---+ +-------+ | 199 | | | 200 +-----------------------------+-------------------------------+ 201 | 202 -------------------------------------------------------------------------------- 203 | 204 +-----------------------------+-------------------------------+ 205 | | | 206 | +------+-----+ | 207 | +-----------| Main |------------+ | 208 | | | Controller | | | 209 Control | | +------+-----+ | | 210 Plane | | | | | 211 | +----+-----+ +----+-----+ +----+-----+ | 212 | |Controller| |Controller| |Controller| | 213 | +----+-----+ +----+-----+ +----+-----+ | 214 | | | | | 215 +----------+------------------+------------------+------------+ 216 | | | 217 -------------------------------------------------------------------------------- 218 | | | 219 +----+-----+ +----+-----+ +----+-----+ 220 Forwarding | WIA-PA |------>| backhaul |------>| WIA-PA | 221 Plane | network |<------| network |<------| network | 222 +----------+ +----------+ +----------+ 224 Figure 2. Centralized Architecture 226 The centralized architecture needn't to expand the east-west 227 interface. It only needs to establish a connection with the basic 228 controllers through the southbound interface. After the connection 229 is established, the main controller obtains the every domain network 230 topology through the API interface provided by the basic controllers, 231 and storages global network topology on its own. It can also assign 232 tasks to basic controllers through the API interface. 234 2.3. Joint Scheduling Architecture 236 In the practical application, distributed architecture not only 237 needs to extend the east-west interface, but also maintains a global 238 network topology in each controller. Only each controller maintains 239 such a global network topology, it can ensure the deterministic 240 control of the control plane for the whole network. 242 Though the centralized architecture does not have the above 243 requirements, for the deterministic industrial network, the scale of 244 the network is not very large, in the industrial backhaul network, a 245 single SDN controller is sufficient to meet the control demands of 246 industrial backhaul network. If centralized architecture is directly 247 applied to an industrial network, it will not only be unable to give 248 full play to the advantages of the architecture in multi controllers 249 collaboration, but also cause meaningless information interaction 250 between the controllers, which will waste network resource. 252 In view of the problems existing in these two architectures, this 253 document takes the WIA-PA network as an example and proposes a joint 254 scheduling architecture based on the architecture document[draft- 255 finn-detnet-architecture]. The architecture is optimized according 256 to the characteristics of deterministic industrial network, so that 257 a single SDN controller can unite the WIA-PA network systems manager 258 to manage the entire industrial network, and provide support for the 259 deterministic scheduling of data streams across network transmission 260 through industrial backhaul network located in different domains of 261 WIA-PA network. 263 +-------------------------------------------------------------+ 264 | | 265 Application | +--------+ +--------+ +-------+ | 266 Plane | | APP | | APP | | APP | | 267 | +--------+ +----+---+ +-------+ | 268 | | | 269 +-----------------------------+-------------------------------+ 270 | 271 --------------------------------------------------------------------------------------- 272 | 273 +-----------------------------+-------------------------------+ 274 | | | 275 Control | +--------------+ +----+-----+ +--------------+ | 276 Plane | | WIA-PA |------| SDN |------| WIA-PA | | 277 | |System Manager| |Controller| |System Manager| | 278 | +------+-------+ +----+-----+ +-------+------+ | 279 | | | | | 280 +---------+-------------------+--------------------+----------+ 281 | | | 282 --------------------------------------------------------------------------------------- 283 | | | 284 +----+-----+ +----+-----+ +-----+----+ 285 Forwarding | WIA-PA |------->| backhaul |------->| WIA-PA | 286 Plane | network |<-------| network |<-------| network | 287 +----------+ +----------+ +----------+ 289 Figure 3. Joint scheduling architecture 291 As shown in Figure 3, joint scheduling architecture can be mainly 292 classified into three planes: 294 o Forwarding plane: this plane contains various types of network 295 equipment in different networks. It is the physical entities of 296 the network transmission. In general, to achieve the desired 297 network functions for the network manager, these devices are 298 specific factors of management control operation, which makes 299 their own resources abstract for their own control elements to 300 manage and configure. 302 o Control plane: this plane is formed by the WIA-PA System Manager 303 and the SDN controller. Joint scheduler is integrated into the 304 SDN controller in the form of plugin, and other WIA-PA System 305 Managers accept joint management scheduler by establishing a 306 connection with the SDN controller. Meanwhile, inside the SDN 307 controller, joint scheduler achieves the management of industrial 308 backhaul network by directly calling the corresponding module of 309 SDN controller. 311 o Application plane: this plane provides users with a unified 312 interface about a variety of resources for the whole network. At 313 the same time, it also provides users with an intuitive, user- 314 friendly interface, which can shield the complex network 315 information of the original. 317 Joint Scheduling Architecture defines an architecture that when 318 industrial networks contain other deterministic networks, these 319 deterministic networks and deterministic Ethernet-based networks are 320 jointly scheduling. On the basis of this architecture, control and 321 scheduling for the entire industrial network can be realized by 322 joint scheduler, so as to provide a real-time protection for each 323 data stream. 325 3. Joint Scheduling Scheme 327 Taking WIA-PA wireless field network and IPv6-based backhaul network 328 as an example, this section shows how the joint scheduling 329 architecture works. Existing WIA-PA scheduling scheme only applies 330 to WIA-PA field network. Scheduling scheme will fail once the data 331 is transferred to backhaul networks. Joint scheduling scheme is 332 innovation and expansion of WIA-PA scheduling scheme. 334 Firstly, scheduling scheme based on SDN in industry backhaul network 335 is added to the original scheduling scheme, so that data can flow in 336 the industrial backhaul network, and the data can be identified and 337 assigned existing backhaul network resource according to their 338 requirements for the network resources. 340 Secondly, conducting an optimization for original WIA-PA scheduling 341 scheme enables scheduling scheme based on WIA-PA networks plays 342 together joint scheduler, and scheduling scheme can simultaneously 343 apply to two non-adjacent domains so that it can be adapt to the 344 cross-border joint operation based on SDN. 346 Thirdly, due to the specificity of cross-border transmission 347 services, the joint scheduling scheme for WIA-PA network VCR_ID and 348 Route ID is reclassified. 350 Finally, since the system manager allocates a short address to the 351 field device on the basis of the network address information about 352 its own domain in WIA-PA networks. Thus resulting in the entire 353 network short address field device is uncertain. In order to 354 identify the field device on different network domains and domain, 355 the network identifier (PAN_ID) is applied to the joint scheduling 356 scheme to identify WIA-PA network. 358 After the SDN controller initiates joint scheduling module, WIA-PA 359 system manager will actively establish a connection with the united 360 scheduler. After the scheduler receives a cross-border transmission 361 request, joint scheduler will send a request for obtaining topology 362 information and node information to WIA-PA System Manager. Then, the 363 scheduler will assign paths and network resources according to this 364 information by pre-defined scheduling algorithm. 366 After the routing and network resources have been calculated, joint 367 scheduler will configure and deploy networks by the corresponding 368 network controller. 370 3.1. WIA-PA Network Joint Scheduling 372 In the united scheduling process, path deployment and resource 373 allocation for WIA-PA network are performed by calling the WIA-PA 374 network system manager API interface. System manager will query the 375 corresponding information of the field device in the network upon 376 receiving the acquisition command of joint operation for the network 377 information, and then return the received information to the united 378 scheduler. The system manager will configure communication resources 379 for the corresponding gateway device, routing equipment and field 380 equipment if the system manager receives configuration commands from 381 joint scheduler. After receiving a successful response, it will send 382 a successful reply to the united scheduler. 384 3.2. Protocol Conversion 386 In the process of cross-border transmission, since industrial 387 backhaul network is different from WIA-PA network, which is not an 388 IP-based Ethernet. Protocol conversion of gateway for WIA-PA packet 389 is needed when the data of WIA-PA network needs to transmit to 390 another network through cross-border industrial backhaul. Meanwhile, 391 according to the joint scheduling scheme, SDN controller is able to 392 identify the WIA-PA Ethernet data stream, and allocate resources 393 according to the data stream type and level of the data stream. 394 Therefore, in the protocol conversion process of gateway, scheduling 395 and control of WIA-PA data flow can be realized by SDN controller 396 unless the VCR of WIA-PA data stream and the priority are filled in 397 the IPv6 header. 399 +-------+ 400 | Start | 401 +-------+ 402 | 403 +-------------+ 404 | Receiving | 405 |data packets | 406 +-------------+ 407 | 408 /-------------\ +--------------+ 409 /Whether is the \ | Forwarded to | 410 | management |-- Yes -->| the system | 411 \ data / | manager | 412 \-------------/ +--------------+ 413 | 414 No 415 | 416 +-----------+ 417 | Resolution| 418 | Packet | 419 +-----------+ 420 | 421 /------------\ /------------\ +-------------+ 422 / Find the \ / Find the \ | Encapsulate | 423 |corresponding |-- Yes -->| corresponding |-- Yes-->| and sent | 424 \ VCR / \ IPv6 address / | IPv6 packet| 425 \------------/ \------------/ +-------------+ 426 | | | 427 No No | 428 | | | 429 +--------+ | | 430 | End |<---------------------+------------------------+ 431 +--------+ 433 Figure 4. The conversion process of gateway protocol 435 As shown in Figure 4, according to the above section, the gateway 436 will receive the address mapping of joint scheduler configure when 437 configuration WIA-PA network. After that, VCR tables and IPv6 438 address-mapping tables will be formed according to this information. 439 When the gateway receives WIA-PA packets, it will firstly parse out 440 Route ID, Object ID and Instance ID, and find corresponding VCR from 441 VCR tables. Meanwhile, the gateway finds the corresponding IPv6 442 address according to Route ID in IPv6 address mapping table. Then, 443 the gateway begins to encapsulate WIA-PA packets based on IPv6 444 format, fill VCR_ID in IPv6 header flow label field, and fill the 445 priority of WIA-PA packet in communication category of IPv6 header 446 fields, zero is used to fill up insufficient bytes. Then, the 447 protocol conversion for WIA-PA data is completed. 449 When the gateway receives IPv6 packets from the industrial backhaul 450 networks, the gateway will make out VCR_ID from IPv6 packet header, 451 and find packets VCR in the domain WIA-PA network according to the 452 VCR ID in its own maintenance VCR table, and replace it with the 453 information of original packet. Then, the protocol conversion for 454 IPv6 packet is completed. 456 3.3. Industrial Backhaul Network Scheduling 458 In deterministic network based on SDN, joint scheduler can recognize 459 WIA-PA data stream through matching on IPv6 flow label field. 460 According to priority of IPv6 and VCR_ID type, joint scheduling can 461 allocate the necessary resources to communication, and ensure that 462 the key data flow is not affected when adding new data flow in the 463 existing network. It can also monitor the real-time data flow of the 464 network. To protect critical data flows from affected, switching 465 paths is also considered when necessary. The scheduling process of 466 industrial backhaul network is shown in Figure 5. 468 +-------+ 469 | Start | 470 +-------+ 471 | 472 +--------------+ 473 |Obtain network| 474 | topology | 475 +--------------+ 476 | 477 +-------------------+ 478 | Calculate the | 479 | path and allocates|<----------------+ 480 | resources | | 481 +-------------------+ | 482 | | 483 +----------+ | 484 |Query path| | 485 +----------+ | 486 | | 487 /---------------\ +----------------+ 488 /whether the path \ | Calculate the | 489 |meets the resource|- No ->| weight and | 490 \ requirements / | adjustment path| 491 \---------------/ +----------------+ 492 | 493 Yes 494 | 495 +------------+ 496 | Deployment | 497 | flow table | 498 +------------+ 499 | 500 +-----+ 501 | End | 502 +-----+ 504 Figure 5. The scheduling process of Industrial backhaul network 506 After receiving the request for service, the joint scheduler will 507 calculate the route information and network resource allocation. 508 Once the path information and resource allocation are determined, 509 joint dispatcher will confirm whether the resource path is capable 510 of meeting business requirements through the inside module of SDN 511 controller. If it meets business requirements, then the flow table 512 is deployed by SDN controller. Otherwise, the path information and 513 resource allocation are recalculated to choose the other paths to 514 transmit data flow. 516 4. Security Considerations 518 5. IANA Considerations 520 This memo includes no request to IANA. 522 6. References 524 6.1. Normative References 526 6.2. Informative References 528 [IEC62734] 529 ISA/IEC, "ISA100.11a, Wireless Systems for Automation, 530 also IEC 62734", 2011, . 534 [IEC62591] 535 IEC, "Industrial Communication Networks - 536 Wireless Communication Network and Communication Profiles 537 - WirelessHART - IEC 62591", 2010, 538 541 [IEC62601] 542 IEC, "Industrial networks - Wireless communication network 543 and communication profiles - WIA-PA - IEC 62601", 2015, < 544 https://webstore.iec.ch/preview/info_iec62601%7Bed2.0%7Db.pdf> 546 [I-D.finn-detnet-problem-statement] 547 Finn, N. and P. Thubert, "Deterministic Networking Problem 548 Statement", draft-finn-detnet-problem-statement-04 (work in 549 progress), October 2015. 551 [I-D.finn-detnet-architecture] 552 Finn, N., Thubert, P., and M. Teener, "Deterministic 553 Networking Architecture", draft-finn-detnetarchitecture-03 554 (work in progress), March 2016. 556 [I-D.bas-usecase-detnet] 557 Kaneko, Y., Toshiba and Das, S, "Building Automation Use 558 Cases and Requirements for Deterministic Networking", draft- 559 bas-usecase-detnet-00 (work in progress), April 2016. 561 Authors' Addresses 563 Heng Wang 564 Chongqing University of Posts and Telecommunications 565 2 Chongwen Road 566 Chongqing, 400065 567 China 569 Phone: (86)-23-6248-7845 570 Email: wangheng@cqupt.edu.cn 572 Ping Wang 573 Chongqing University of Posts and Telecommunications 574 2 Chongwen Road 575 Chongqing, 400065 576 China 578 Phone: (86)-23-6246-1061 579 Email: wangping@cqupt.edu.cn 581 Chang Zhang 582 Chongqing University of Posts and Telecommunications 583 2 Chongwen Road 584 Chongqing, 400065 585 China 587 Phone: (86)-23-6246-1061 588 Email: zc910522@126.com 590 Yi Yang 591 Chongqing University of Posts and Telecommunications 592 2 Chongwen Road 593 Chongqing, 400065 594 China 596 Phone: (86)-23-6246-1061 597 Email: 15023705316@163.com