idnits 2.17.1 draft-zhou-netconf-multi-stream-originators-08.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (October 26, 2019) is 1634 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 5246 (Obsoleted by RFC 8446) ** Obsolete normative reference: RFC 6536 (Obsoleted by RFC 8341) == Outdated reference: A later version (-15) exists of draft-ietf-netconf-https-notif-00 == Outdated reference: A later version (-08) exists of draft-ietf-netconf-notification-messages-07 Summary: 2 errors (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 NETCONF T. Zhou 3 Internet-Draft G. Zheng 4 Intended status: Standards Track Huawei 5 Expires: April 28, 2020 E. Voit 6 Cisco Systems 7 A. Clemm 8 Futurewai 9 A. Bierman 10 YumaWorks 11 October 26, 2019 13 Subscription to Multiple Stream Originators 14 draft-zhou-netconf-multi-stream-originators-08 16 Abstract 18 This document describes the distributed data export mechanism that 19 allows multiple data streams to be managed using a single 20 subscription. Specifically, multiple data streams are pushed 21 directly to the collector without passing through a broker for 22 internal consolidation. 24 Requirements Language 26 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 27 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 28 document are to be interpreted as described in RFC 2119 [RFC2119]. 30 Status of This Memo 32 This Internet-Draft is submitted in full conformance with the 33 provisions of BCP 78 and BCP 79. 35 Internet-Drafts are working documents of the Internet Engineering 36 Task Force (IETF). Note that other groups may also distribute 37 working documents as Internet-Drafts. The list of current Internet- 38 Drafts is at https://datatracker.ietf.org/drafts/current/. 40 Internet-Drafts are draft documents valid for a maximum of six months 41 and may be updated, replaced, or obsoleted by other documents at any 42 time. It is inappropriate to use Internet-Drafts as reference 43 material or to cite them other than as "work in progress." 45 This Internet-Draft will expire on April 28, 2020. 47 Copyright Notice 49 Copyright (c) 2019 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents 54 (https://trustee.ietf.org/license-info) in effect on the date of 55 publication of this document. Please review these documents 56 carefully, as they describe your rights and restrictions with respect 57 to this document. Code Components extracted from this document must 58 include Simplified BSD License text as described in Section 4.e of 59 the Trust Legal Provisions and are provided without warranty as 60 described in the Simplified BSD License. 62 Table of Contents 64 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 65 2. Data Collection from Devices with Main-board and Line-cards . 3 66 3. Terminologies . . . . . . . . . . . . . . . . . . . . . . . . 4 67 4. Solution Overview . . . . . . . . . . . . . . . . . . . . . . 5 68 5. Subscription Decomposition . . . . . . . . . . . . . . . . . 7 69 6. Publication Composition . . . . . . . . . . . . . . . . . . . 8 70 7. Subscription State Change Notifications . . . . . . . . . . . 9 71 8. Publisher Configurations . . . . . . . . . . . . . . . . . . 9 72 9. YANG Tree . . . . . . . . . . . . . . . . . . . . . . . . . . 9 73 10. YANG Module . . . . . . . . . . . . . . . . . . . . . . . . . 10 74 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 75 12. Transport Considerations . . . . . . . . . . . . . . . . . . 12 76 13. Security Considerations . . . . . . . . . . . . . . . . . . . 12 77 14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 78 15. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 79 15.1. Normative References . . . . . . . . . . . . . . . . . . 13 80 15.2. Informative References . . . . . . . . . . . . . . . . . 14 81 Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 14 82 A.1. Dynamic Subscription . . . . . . . . . . . . . . . . . . 14 83 A.2. Configured Subscription . . . . . . . . . . . . . . . . . 18 84 Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 20 85 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22 87 1. Introduction 89 Streaming telemetry refers to sending a continuous stream of 90 operational data from a device to a remote receiver. This provides 91 an ability to monitor a network from remote and to provide network 92 analytics. Devices generate telemetry data and push that data to a 93 collector for further analysis. By streaming the data, much better 94 performance, finer-grained sampling, monitoring accuracy, and 95 bandwidth utilization can be achieved than with polling-based 96 alternatives. 98 Mechanisms to support subscription to event notifications have been 99 defined in[RFC8639] and [RFC8641]. The current design involves 100 subscription to a single push server. This conceptually centralized 101 model encounters efficiency limitations in cases where the data 102 sources are themselves distributed, such as line cards in a piece of 103 network equipment. In such cases, it will be a lot more efficient to 104 have each data source (e.g., each line card) originate its own stream 105 of updates, rather than requiring updates to be tunneled through a 106 central server where they are combined. What is needed is a 107 distributed mechanism that allows to directly push multiple 108 individual data substreams, without needing to first pass them 109 through an additional processing stage for internal consolidation, 110 but still allowing those substreams to be managed and controlled via 111 a single subscription. 113 This document will describe such distributed data collection 114 mechanism and how it can work by extending existing push mechanism. 115 The proposal will focus on the scenario when data collection from 116 devices with main-board and line-cards. It could be generalized to 117 other distributed data export scenarios. 119 2. Data Collection from Devices with Main-board and Line-cards 121 For data collection from devices with main-board and line-cards, 122 existing push solutions consider only one push server typically 123 reside in the main board. As shown in the following figure, data are 124 collected from line cards and aggregate to the main board as one 125 consolidated stream. So the main board can easily become the 126 performance bottle-neck. The optimization is to apply the 127 distributed data export mechanism which can directly push data from 128 line cards to a collector. On one hand, this will reduce the cost of 129 scarce compute and memory resources on the main board for data 130 processing and assembling. On the other hand, distributed data push 131 can off-load the streaming traffic to multiple interfaces. 133 +-------------------------------------+ 134 | collector | 135 +------^-----------^-----------^------+ 136 | | | 137 | | | 138 +-------------------------------------+ 139 | | | | | 140 | | +-----+------+ | | 141 | | | main board | | | 142 | | +--^-----^---+ | | 143 | | | | | | 144 | | +---+ +---+ | | 145 | | | | | | 146 | +----+----+---+ +---+----+----+ | 147 | | line card 1 | | line card 2 | | 148 | +-------------+ +-------------+ | 149 | device | 150 +-------------------------------------+ 152 Fig. 1 Data Collection from Devices with Main-board and Line-cards 154 3. Terminologies 156 The following terms are defined in [RFC8639] and are not redefined 157 here: 159 Subscriber 161 Publisher 163 Receiver 165 Subscription 167 In addition, this document defines the following terms: 169 Global Subscription: the Subscription requested by the subscriber. 170 It may be decomposed into multiple Component Subscriptions. 172 Component Subscription: is the Subscription that defines the data 173 from each individual telemetry source which is managed and controlled 174 by a single Publisher. 176 Global Capability: is the overall subscription capability that the 177 group of Publishers can expose to the Subscriber. 179 Component Capability: is the subscription capability that each 180 Publisher can expose to the Subscriber. 182 Master: is the Publisher that interacts with the Subscriber to deal 183 with the Global Subscription. It decomposes the Global Subscription 184 to multiple Component Subscriptions and interacts with the Agents. 186 Agent: is the Publisher that interacts with the Master to deal with 187 the Component Subscription. 189 4. Solution Overview 191 Figure 2 below shows the distributed data export framework. 193 A collector usually includes two components, 195 o the Subscriber generates the subscription instructions to express 196 what and how the collector want to receive the data; 198 o the Receiver is the target for the data publication. 200 For one subscription, there may be one to many Receivers. And the 201 Subscriber does not necessarily share the same address with the 202 Receivers. 204 In this framework, the Publisher pushes data to the Receiver 205 according to the subscription information. The Publisher has the 206 Master role and the Agent role. The Master knows all the 207 capabilities that the attached Agents and itself can provide, and 208 exposes the Global Capability to the collector. The collector cannot 209 see the Agents directly, so it will only send the Global Subscription 210 information to the Master. The Master disassembles the Global 211 Subscription to multiple Component Subscriptions, each involving data 212 from a separate telemetry source. The Component Subscriptions are 213 then distributed to the corresponding Agents. 215 When data streaming, the Publisher collects and encapsulates the 216 packets per the Component Subscription, and pushes the piece of data 217 which can serve directly to the designated data collector. The 218 collector is able to assemble many pieces of data associated with one 219 Global Subscription, and can also deduce the missing pieces of data. 221 +-----------------------------------------+ 222 | Collector |-------------+ | 223 | +------------+ | | 224 | +------------+ || Receiver | | | 225 | | Subscriber | |--------------+ | 226 | +-----^-+----+ +-----^------^ | 227 | | | | | | 228 +-----------------------------------------+ 229 Global | | Global | | 230 Capability| | Subscription | | 231 +-----------------------------------------+ 232 | | | Push | | | 233 | +--------+-v---------------+---+ | | 234 | | Publisher(Master) | | | 235 | +--------^-+-------------------+ | | 236 | | | | | 237 | | | | | 238 | Component | | Component Push | | 239 | Capability| | Subscription | | 240 | +--------+-v-------------------+ | | 241 | | Publisher(Agent) +--+ | 242 | +------------------------------+ | 243 | | 244 | Device | 245 +-----------------------------------------+ 247 Fig. 2 The Distributed Data Export Framework 249 Master and Agents may interact with each other in several ways: 251 o Agents need to have a registration or announcement handshake with 252 the Master, so the Master is aware of them and of life-cycle 253 events (such as Agent appearing and disappearing). 255 o Contracts are needed between the Master and each Agent on the 256 Component Capability, and the format for streaming data structure. 258 o The Master relays the component subscriptions to the Agents. 260 o The Agents indicate status of Component Subscriptions to the 261 Master. The status of the overall subscription is maintained by 262 the Master. The Master is also responsible for notifying the 263 subscriber in case of any problems of Component Subscriptions. 265 Any technical mechanisms or protocols used for the coordination of 266 operational information between Master and Agent is out-of-scope of 267 this document. We will need to instrument the results of this 268 coordination on the Master. 270 5. Subscription Decomposition 272 The Collector can only subscribe to the Master. This requires the 273 Master to: 275 1. expose the Global Capability that can be served by multiple 276 Publishers; 278 2. disassemble the Global Subscription to multiple Component 279 Subscriptions, and distribute them to the corresponding telemetry 280 sources; 282 3. notify on changes when portions of a subscription moving between 283 different Agents over time. 285 The Master can keep track of the mapping between the resource and the 286 corresponding location of the Publisher which commits to serve the 287 data. In some implementations, the Global Subscription can be 288 disassembled into multiple Component Subscriptions according to the 289 Resource-Location Table, and the corresponding location can be 290 associated. The decision whether to decompose a Global Subscription 291 into multiple Component Subscriptions rests with the Resource- 292 Location Table. A Master can decide to not decompose a Global 293 Subscription at all and push a single stream to the receiver, because 294 the location information indicates the Global Subscription can be 295 served locally by the Master. Similarly, it can decide to entirely 296 decompose a Global Subscription into multiple Component Subscriptions 297 that each push their own streams, but not from the Master. It can 298 also decide to decompose the Global Subscription into several 299 Component Subscriptions and retain some aspects of the Global 300 Subscription itself, also pushing its own stream. 302 Component Subscriptions belonging to the same Global Subscription 303 MUST NOT overlap. The combination of all Component Subscriptions 304 MUST cover the same range of nodes as the Global Subscription. Also, 305 the same subscription settings apply to each Component Subscription, 306 i.e., the same receivers, the same time periods, the same encodings 307 are applied to each Component Subscription per the settings of the 308 Global Subscription. 310 Each Component Subscription in effect constitutes a full-fledged 311 subscription, with the following constraints: 313 o Component subscriptions are system-controlled, i.e. managed by the 314 Master, not by the subscriber. 316 o Component subscription settings such as time periods, dampening 317 periods, encodings, receivers adopt the settings of their Global 318 Subscription. 320 o The life-cycle of the Component Subscription is tied to the life- 321 cycle of the Global Subscription. Specifically, terminating/ 322 removing the Global Subscription results in termination/removal of 323 Component Subscriptions. 325 o The Component Subscriptions share the same Subscription ID as the 326 Global Subscription. 328 6. Publication Composition 330 The Publisher collects data and encapsulates the packets per the 331 Component Subscription. There are several potential encodings, 332 including XML, JSON, CBOR and GPB. The format and structure of the 333 data records are defined by the YANG schema, so that the composition 334 at the Receiver can benefit from the structured and hierarchical data 335 instance. 337 The Receiver is able to assemble many pieces of data associated with 338 one subscription, and can also deduce the missing pieces of data. 339 The Receiver recognizes data records associated with one subscription 340 according the Subscription ID [RFC8639]. Data records generated per 341 one subscription are assigned with the same Subscription ID. 343 For the periodic updates, records are produced periodically from each 344 Publisher. The message arrival time varies because of the 345 distributed nature of the publication. The Receiver assembles data 346 generated at the same time period based on the recording time 347 consisted in each data record. In this case, time synchronization is 348 required for all the Publishers. 350 Message Generator ID [I-D.ietf-netconf-notification-messages] is the 351 identifier for the process which created the notification message. 352 It's contained in every notification messages. In this document, 353 it's the identifier for the Publisher, and allows disambiguation of 354 different line cards sending the messages. If the collector knows 355 the set of Message Generator IDs standing for the Publishers serving 356 for one Global Subscription, it can easily check the integrity of the 357 data collected from different Publishers at the same time period. 358 And the collector can deduce the Publishers which are responsible for 359 the missing pieces of data. 361 For the dynamic subscription, the output of the "establish- 362 subscription" RPC defined in [RFC8639] MUST include a list of Message 363 Generator IDs to indicate how the Global Subscription is decomposed 364 into several Component Subscriptions. 366 The "subscription-started" and "subscription-modified" notification 367 defined in [RFC8639] MUST also include a list of Message Generator 368 IDs to notify the current Publishers for the corresponding Global 369 Subscription. 371 7. Subscription State Change Notifications 373 In addition to sending event records to receivers, the Master MUST 374 also send subscription state change notifications [RFC8639] when 375 events related to subscription management have occurred. All the 376 subscription state change notifications MUST be delivered by the 377 Master. 379 When the subscription decomposition result changed, the 380 "subscription-modified" notification MUST be sent to indicate the new 381 list of Publishers. 383 8. Publisher Configurations 385 This document assumes all the Publishers are preconfigured to be able 386 to push data. The actual working Publishers are selected dynamically 387 based on the subscription decomposition result. For UDP Publishers, 388 the virtual IP address could be assigned for the publication. So all 389 the UDP Publishers on the device can use the same source IP address 390 configured, which may even not routeable. For connection based 391 Publishers, e.g., HTTPS-based transport 392 [I-D.ietf-netconf-https-notif], each Publisher MUST be able to 393 receive packets from the receivers. This document does not restrict 394 the way how the Publishers are accessible. 396 The specific configuration on transports is out of the scope of this 397 document. 399 9. YANG Tree 401 module: ietf-multiple-stream-originators 402 augment /sn:subscriptions/sn:subscription: 403 +--ro message-generator-id* string 404 augment /sn:subscription-started: 405 +--ro message-generator-id* string 406 augment /sn:subscription-modified: 407 +--ro message-generator-id* string 408 augment /sn:establish-subscription/sn:output: 409 +--ro message-generator-id* string 411 10. YANG Module 413 file "ietf-multiple-stream-originators@2019-10-12.yang" 414 module ietf-multiple-stream-originators { 415 yang-version 1.1; 416 namespace 417 "urn:ietf:params:xml:ns:yang:ietf-multiple-stream-originators"; 418 prefix mso; 419 import ietf-subscribed-notifications { 420 prefix sn; 421 } 423 organization "IETF NETCONF (Network Configuration) Working Group"; 424 contact 425 "WG Web: 426 WG List: 428 Editor: Tianran Zhou 429 431 Editor: Guangying Zheng 432 "; 434 description 435 "Defines augmentation for ietf-subscribed-notifications to enable 436 the distributed publication with single subscription. 438 Copyright (c) 2018 IETF Trust and the persons identified as authors 439 of the code. All rights reserved. 441 Redistribution and use in source and binary forms, with or without 442 modification, is permitted pursuant to, and subject to the license 443 terms contained in, the Simplified BSD License set forth in Section 444 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents 445 (https://trustee.ietf.org/license-info). 447 This version of this YANG module is part of RFC XXXX; see the RFC 449 itself for full legal notices."; 451 revision 2019-10-12 { 452 description 453 "Initial version"; 454 reference 455 "RFC XXXX: Subscription to Multiple Stream Originators"; 456 } 457 grouping message-generator-ids { 458 description 459 "Provides a reusable list of message-generator-ids."; 461 leaf-list message-generator-id { 462 type string; 463 config false; 464 ordered-by user; 465 description 466 "Software entity which created the message (e.g., 467 linecard 1). This field is used to notify the 468 collector the working originator."; 469 } 470 } 472 augment "/sn:subscriptions/sn:subscription" { 473 description 474 "This augmentation allows the message generators to be exposed 475 for a subscription."; 477 uses message-generator-ids; 478 } 480 augment "/sn:subscription-started" { 481 description 482 "This augmentation allows MSO specific parameters to be 483 exposed for a subscription."; 485 uses message-generator-ids; 486 } 488 augment "/sn:subscription-modified" { 489 description 490 "This augmentation allows MSO specific parameters to be 491 exposed for a subscription."; 493 uses message-generator-ids; 494 } 496 augment "/sn:establish-subscription/sn:output" { 497 description 498 "This augmentation allows MSO specific parameters to be 499 exposed for a subscription."; 501 uses message-generator-ids; 502 } 503 } 504 506 11. IANA Considerations 508 This document registers the following namespace URI in the IETF XML 509 Registry [RFC3688]: 511 URI: urn:ietf:params:xml:ns:yang:ietf-multiple-stream-originators 513 Registrant Contact: The IESG. 515 XML: N/A; the requested URI is an XML namespace. 517 This document registers the following YANG module in the YANG Module 518 Names registry [RFC3688]: 520 Name: ietf-multiple-stream-originators 522 Namespace: urn:ietf:params:xml:ns:yang:ietf-multiple-stream- 523 originators 525 Prefix: mso 527 Reference: RFC XXXX 529 12. Transport Considerations 531 The distributed data export mechanism enabled by this draft is 532 expected to generate more data than YANG-Push [RFC8641]. The large 533 amount of data may congest the network and impact other network 534 business. In this case, the collector may also not be able to accept 535 all the data. So the congestion control method is required for any 536 transport that is going to implement the solution proposed in this 537 document. 539 13. Security Considerations 541 The YANG module specified in this document defines a schema for data 542 that is designed to be accessed via network management protocols such 543 as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer 544 is the secure transport layer, and the mandatory-to-implement secure 545 transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer 546 is HTTPS, and the mandatory-to-implement secure transport is TLS 547 [RFC5246]. 549 The NETCONF Access Control Model (NACM) [RFC6536] provides the means 550 to restrict access for particular NETCONF or RESTCONF users to a 551 preconfigured subset of all available NETCONF or RESTCONF protocol 552 operations and content. 554 The new data nodes introduced in this YANG module may be considered 555 sensitive or vulnerable in some network environments. It is thus 556 important to control read access (e.g., via get-config or 557 notification) to this data nodes. These are the subtrees and data 558 nodes and their sensitivity/vulnerability: 560 o /subscriptions/subscription/message-generator-ids 562 The entries in the two lists above will show where subscribed 563 resources might be located on the publishers. Access control MUST be 564 set so that only someone with proper access permissions has the 565 ability to access this resource. 567 Other Security Considerations is the same as those discussed in YANG- 568 Push [RFC8641]. 570 14. Acknowledgements 572 We thank Kent Watsen, Mahesh Jethanandani, Martin Bjorklund, Tim 573 Carey and Qin Wu for their constructive suggestions for improving 574 this document. 576 15. References 578 15.1. Normative References 580 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 581 Requirement Levels", BCP 14, RFC 2119, 582 DOI 10.17487/RFC2119, March 1997, 583 . 585 [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, 586 DOI 10.17487/RFC3688, January 2004, 587 . 589 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security 590 (TLS) Protocol Version 1.2", RFC 5246, 591 DOI 10.17487/RFC5246, August 2008, 592 . 594 [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., 595 and A. Bierman, Ed., "Network Configuration Protocol 596 (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, 597 . 599 [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure 600 Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011, 601 . 603 [RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration 604 Protocol (NETCONF) Access Control Model", RFC 6536, 605 DOI 10.17487/RFC6536, March 2012, 606 . 608 [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF 609 Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, 610 . 612 [RFC8639] Voit, E., Clemm, A., Gonzalez Prieto, A., Nilsen-Nygaard, 613 E., and A. Tripathy, "Subscription to YANG Notifications", 614 RFC 8639, DOI 10.17487/RFC8639, September 2019, 615 . 617 [RFC8641] Clemm, A. and E. Voit, "Subscription to YANG Notifications 618 for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641, 619 September 2019, . 621 15.2. Informative References 623 [I-D.ietf-netconf-https-notif] 624 Jethanandani, M. and K. Watsen, "An HTTPS-based Transport 625 for Configured Subscriptions", draft-ietf-netconf-https- 626 notif-00 (work in progress), September 2019. 628 [I-D.ietf-netconf-notification-messages] 629 Voit, E., Birkholz, H., Bierman, A., Clemm, A., and T. 630 Jenkins, "Notification Message Headers and Bundles", 631 draft-ietf-netconf-notification-messages-07 (work in 632 progress), August 2019. 634 Appendix A. Examples 636 This appendix is non-normative. 638 A.1. Dynamic Subscription 640 Figure 3 shows a typical dynamic subscription to the device with 641 distributed data export capability. 643 +-------------+ +-------------+ +-------------+ 644 | Subscriber/ | | Publisher | | Publisher | 645 | Receiver | | (Master) | | (Agent) | 646 +-------------+ +------+------+ +------+------+ 647 | | | 648 | establish-subscription | | 649 +------------------------------>+ component | 650 | | subscription | 651 | RPC Reply: OK, id #22 +-------------->+ 652 | message generator ID [#1, #2] | | 653 +<------------------------------+ | 654 | | | 655 | notif-mesg, id #22 | | 656 | message generator ID #1 | | 657 +<------------------------------+ | 658 | | | 659 | notif-mesg, id#22 | | 660 | message generator ID #2 | | 661 +<----------------------------------------------+ 662 | | | 663 | modify-subscription (id#22) | | 664 +------------------------------>+ component | 665 | | subscription | 666 | RPC Reply: OK, id #22 +-------------->+ 667 +<------------------------------+ | 668 | | | 669 | subscription-modified, id#22 | | 670 | message generator ID [#1] | | 671 +<------------------------------+ | 672 | | | 673 | notif-mesg, id #22 | | 674 | message generator ID #1 | | 675 +<------------------------------+ | 676 | | | 677 | | | 678 + + + 680 Fig. 3 Call Flow for Dynamic Subscription 682 A "establish-subscription" RPC request as per [RFC8641] is sent to 683 the Master with a successful response. An example of using NETCONF 684 might look like: 686 688 691 693 ds:operational 694 695 697 /ex:foo 698 699 700 500 701 702 703 705 Fig. 4 "establish-subscription" Request 707 As the device is able to fully satisfy the request, the request is 708 given a subscription ID of 22. The response as in Figure 5 indicates 709 that the subscription is decomposed into two component subscriptions 710 which will be published by two message generators: #1 and #2. 712 714 716 22 717 718 724 2 725 726 728 Fig. 5 "establish-subscription" Positive RPC Response 730 Then, both Publishers send notifications with the corresponding piece 731 of data to the receiver. 733 The subscriber may invoke the "modify-subscription" RPC for a 734 subscription it previously established. The RPC has no difference to 735 the single publisher case as in [RFC8641]. Figure 6 provides an 736 example where a subscriber attempts to modify the period and 737 datastore XPath filter of a subscription using NETCONF. 739 741 745 22 746 748 ds:operational 749 750 752 /ex:bar 753 754 755 250 756 757 758 760 Fig. 6 "modify-subscription" Request 762 If the modification is successfully accepted, the "subscription- 763 modified" subscription state notification is sent to the subscriber 764 by the Master. The notification, Figure 7 for example, indicates the 765 modified subscription is decomposed into one component subscription 766 which will be published by message generator #1. 768 769 2007-09-01T10:00:00Z 770 773 22 774 776 ds:operational 777 778 780 /ex:bar 781 782 783 250 784 785 829 2007-09-01T10:00:00Z 830 833 39 834 836 ds:operational 837 838 840 /ex:foo 841 842 843 250 844 845 851 2 852 853 854 856 Fig. 9 "subscription-started" Subscription State Notification 858 Then, both Publishers send notifications with the corresponding piece 859 of data to the receiver. 861 Appendix B. Change Log 863 (To be removed by RFC editor prior to publication) 865 v01 867 o Minor revision on Subscription Decomposition 869 o Revised terminologies 871 o Removed most implementation related text 873 o Place holder of two sections: Subscription Management, and 874 Notifications on Subscription State Changes 876 v02 878 o Revised section 4 and 5. Moved them from apendix to the main 879 text. 881 v03 883 o Added a section for Terminologies. 885 o Added a section for Subscription State Change Notifications. 887 o Improved the Publication Composition section by adding a method to 888 check the integrity of the data generated from different 889 Publishers at the same time period. 891 o Revised the solution overview for a more clear description. 893 v04 895 o Added the YANG data model for the proposed augment. 897 v05 899 o Added the IANA considerations, transport considerations and 900 security considerations. 902 v06 904 o Added examples. 906 v07 908 o Removed the IoT use case. 910 o Revised examples. 912 o Add discussion on Publisher Configurations in section 8. 914 v08 916 o Cleared up the document to fix Terms, nits. 918 o Reduced internal implementation descriptions. 920 o Clarified Message Generator ID. 922 Authors' Addresses 924 Tianran Zhou 925 Huawei 926 156 Beiqing Rd., Haidian District 927 Beijing 928 China 930 Email: zhoutianran@huawei.com 932 Guangying Zheng 933 Huawei 934 101 Yu-Hua-Tai Software Road 935 Nanjing, Jiangsu 936 China 938 Email: zhengguangying@huawei.com 940 Eric Voit 941 Cisco Systems 942 United States of America 944 Email: evoit@cisco.com 946 Alexander Clemm 947 Futurewai 948 2330 Central Expressway 949 Santa Clara, California 950 United States of America 952 Email: ludwig@clemm.org 954 Andy Bierman 955 YumaWorks 956 United States of America 958 Email: andy@yumaworks.com