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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to lower-maturity documents in RFCs) == Missing Reference: 'RFC8341' is mentioned on line 598, but not defined == Outdated reference: A later version (-21) exists of draft-ietf-netmod-yang-instance-file-format-06 Summary: 0 errors (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 NETCONF B. Lengyel 3 Internet-Draft Ericsson 4 Intended status: Standards Track A. Clemm 5 Expires: June 11, 2020 Futurewei 6 B. Claise 7 Cisco Systems, Inc. 8 December 9, 2019 10 YANG-Push Notification Capabilities 11 draft-ietf-netconf-notification-capabilities-08 13 Abstract 15 This document proposes a YANG module that allows a publisher to 16 specify capabilities related to "Subscription to YANG Datastores" 17 (YANG-Push). It proposes to use YANG Instance Data to document this 18 information and make it already available at implementation-time, but 19 also allow it to be reported at run-time. 21 The YANG module is also prepared to contain other system 22 capabilities, for future augmentations. 24 Status of This Memo 26 This Internet-Draft is submitted in full conformance with the 27 provisions of BCP 78 and BCP 79. 29 Internet-Drafts are working documents of the Internet Engineering 30 Task Force (IETF). Note that other groups may also distribute 31 working documents as Internet-Drafts. The list of current Internet- 32 Drafts is at https://datatracker.ietf.org/drafts/current/. 34 Internet-Drafts are draft documents valid for a maximum of six months 35 and may be updated, replaced, or obsoleted by other documents at any 36 time. It is inappropriate to use Internet-Drafts as reference 37 material or to cite them other than as "work in progress." 39 This Internet-Draft will expire on June 11, 2020. 41 Copyright Notice 43 Copyright (c) 2019 IETF Trust and the persons identified as the 44 document authors. All rights reserved. 46 This document is subject to BCP 78 and the IETF Trust's Legal 47 Provisions Relating to IETF Documents 48 (https://trustee.ietf.org/license-info) in effect on the date of 49 publication of this document. Please review these documents 50 carefully, as they describe your rights and restrictions with respect 51 to this document. Code Components extracted from this document must 52 include Simplified BSD License text as described in Section 4.e of 53 the Trust Legal Provisions and are provided without warranty as 54 described in the Simplified BSD License. 56 Table of Contents 58 1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 59 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 60 3. Notification Capability Model . . . . . . . . . . . . . . . . 5 61 3.1. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 6 62 3.2. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 7 63 3.3. Other System Capabilities . . . . . . . . . . . . . . . . 13 64 4. Security Considerations . . . . . . . . . . . . . . . . . . . 13 65 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 66 5.1. The IETF XML Registry . . . . . . . . . . . . . . . . . . 13 67 5.2. The YANG Module Names Registry . . . . . . . . . . . . . 14 68 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 69 6.1. Normative References . . . . . . . . . . . . . . . . . . 14 70 6.2. Informative References . . . . . . . . . . . . . . . . . 15 71 Appendix A. Instance data examples . . . . . . . . . . . . . . . 15 72 Appendix B. Changes between revisions . . . . . . . . . . . . . 19 73 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20 75 1. Terminology 77 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 78 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 79 "OPTIONAL" in this document are to be interpreted as described in BCP 80 14 [RFC2119] [RFC8174] when, and only when, they appear in all 81 capitals, as shown here. 83 The terms YANG-Push, On-change subscription and Periodic subscription 84 are used as defined in [RFC8641] 86 The terms Subscriber, Publisher and Receiver are used as defined in 87 [RFC8639] 89 The term Server is used as defined in [RFC8342] 91 On-change Notification Capability: The capability of the publisher to 92 send on-change notifications for a specific datastore or a specific 93 data node. 95 Implementation-time information: Information about the publisher's 96 behavior that is made available during the implementation of the 97 publisher, available from a source other then a running server 98 implementing the publisher. 100 Run-time information: Information about the publisher's behavior that 101 is available from the running server (implementing the publisher) via 102 management protocols such as NETCONF [RFC6241] or RESTCONF [RFC8040]. 104 2. Introduction 106 As defined in [RFC8641] a publisher may allow subscribers to 107 subscribe to updates from a datastore and subsequently push such 108 update notifications to the receiver. Notifications may be sent 109 periodically or on-change (more or less immediately after each 110 change). 112 A publisher supporting YANG-Push has a number of capabilities defined 113 in [RFC8641] that are often determined during the implementation of 114 the publisher. These include: 116 o Supported (reporting) periods for periodic subscriptions 118 o Maximum number of objects that can be sent in an update 120 o The set of datastores or data nodes for which periodic 121 notification is supported 123 If the optional on-change feature is supported, additionally: 125 o Supported dampening periods for on-change subscriptions 127 o The set of datastores or data nodes for which on-change 128 notification is supported 130 Publishers have limitations in how many update notifications and how 131 many datastore node updates they can send out in a certain time- 132 period. 134 Publishers might not support periodic subscriptions to all 135 datastores. 137 In some cases, a publisher supporting on-change notifications will 138 not be able to push updates for some object types on-change. Reasons 139 for this might be that the value of the datastore node changes 140 frequently (e.g. in-octets counter), that small object changes are 141 frequent and irrelevant to the receiver (e.g., a temperature gauge 142 changing 0.1 degrees within a predetermined and acceptable range), or 143 that the implementation is not capable of on-change notification for 144 a particular object. In those cases, it will be important for 145 subscriber applications to have a way to identify which objects on- 146 change notifications are supported and for which ones not. 148 Faced with the reality that support for on-change notification does 149 not mean that such notifications will be sent for any specific data 150 node, subscriber/management applications can not rely on the on- 151 change functionality unless the subscriber has some means to identify 152 which objects on-change notifications are supported. YANG models are 153 meant to be used as an interface contract. Without identification of 154 the data nodes actually supporting on-change, this contract would be 155 incomplete. 157 This document proposes a YANG module that allows a subscriber to 158 discover YANG-Push related capabilities both at implementation-time 159 and run-time. 161 Implementation-time information is needed by Network Management 162 System (NMS) implementers. A NMS implementation that wants to 163 support notifications, needs the information about on-change 164 notification capability. If the information is not documented in a 165 way available to the NMS designer, but only as instance data from the 166 network node once it is deployed, the NMS implementation will be 167 delayed, because it has to wait for the network node to be ready. In 168 addition, the assumption that all NMS implementers will have a 169 correctly configured network node available to retrieve data from is 170 an expensive proposition and may not always hold. (An NMS may need 171 to be able to handle many dozens of network node types.) Often a 172 fully functional NMS is a requirement for introducing a new network 173 node type into a network, so delaying NMS readiness effectively also 174 delays the time at which a new network node type can be introduced 175 into the network. 177 Implementation-time information is needed by system integrators. 178 When introducing a network node type into their network, operators 179 often need to integrate the node type into their own management 180 system. The NMS may have management functions that depend on on- 181 change notifications. The network operator needs to plan his 182 management practices and NMS implementation before he even decides to 183 buy the specific network node type. Moreover the decision to buy the 184 node type sometimes depends on these management possibilities. 186 Run-time information is needed: 188 o for any "purely model driven" application, e.g. a NETCONF-browser. 189 Such applications depend on reading models, capabilities in run- 190 time to support all the publisher's available functionality. 192 o in case the capability might change during run-time e.g. due to 193 licensing, HW constraints etc. 195 o to check that capability information provided early, already in 196 implementation-time is indeed what the publisher implements (is 197 the supplied documentation correct?) 199 The proposed YANG module is also intended as a base model to be 200 augmented by other YANG modules defining system-capabilities not 201 related to YANG-Push. Other capability defining YANG modules MAY 202 augment the data nodes specifying these capabilites into this model. 204 3. Notification Capability Model 206 It is a goal to provide YANG-Push notification capability information 207 in a format that is: 209 o vendor independent 211 o machine readable 213 o identical for implementation-time and run-time 215 The YANG module ietf-notification-capabilities is defined to provide 216 the information. It contains: 218 o a set of capabilities related to the throughput of notification 219 data the publisher can send out. 221 o specification of which data nodes support on-change notifications. 223 Capability values can be specified on system/publisher level, 224 datastore level or on specific data nodes (and their contained sub- 225 tree) of a specific datastore. Capability values on a smaller, more 226 specific part of the publisher's data always override more generic 227 values. 229 Note: The solution is usable for both NMDA and non-NMDA systems. For 230 non-NMDA servers/publishers the config=false data is considered as if 231 it was part of the running datastore. 233 The information SHOULD be provided in two ways both following the 234 ietf-notification-capabilities module: 236 o For the implementation-time use-case: It SHOULD be provided by the 237 implementer as YANG instance data file complying to 238 [I-D.ietf-netmod-yang-instance-file-format]. The file SHALL be 239 available already in implementation-time retrievable in a way that 240 does not depend on a live network node. E.g. download from 241 product website. 243 o For the run-time use-case: It SHOULD be available via NETCONF 244 [RFC6241] or RESTCONF [RFC8040] from the live server (implementing 245 the publisher) during run-time. Implementations which support 246 changing these capabilities at run-time SHOULD support on-change 247 notifications about the system-capabilities container. 249 3.1. Tree Diagram 251 The following tree diagram [RFC8340] provides an overview of the data 252 model. 254 module: ietf-notification-capabilities 255 +--ro system-capabilities 256 +--ro subscription-capabilities 257 | +--ro (update-period)? 258 | | +--:(minimum-update-period) 259 | | | +--ro minimum-update-period? uint32 260 | | +--:(supported-update-period) 261 | | +--ro supported-update-period* uint32 262 | +--ro max-objects-per-update? uint32 263 | +--ro minimum-dampening-period? uint32 {yp:on-change}? 264 | +--ro on-change-supported? notification-support 265 | | {yp:on-change}? 266 | +--ro periodic-notifications-supported? notification-support 267 | +--ro supported-excluded-change-type* union {yp:on-change}? 268 +--ro datastore-capabilities* [datastore] 269 +--ro datastore -> /yanglib:yang-library/datastore/name 270 +--ro per-node-capabilities* [node-selector] 271 +--ro node-selector nacm:node-instance-identifier 272 +--ro subscription-capabilities 273 +--ro (update-period)? 274 | +--:(minimum-update-period) 275 | | +--ro minimum-update-period? uint32 276 | +--:(supported-update-period) 277 | +--ro supported-update-period* uint32 278 +--ro max-objects-per-update? uint32 279 +--ro minimum-dampening-period? uint32 280 | {yp:on-change}? 281 +--ro on-change-supported? notification-support 282 | {yp:on-change}? 283 +--ro periodic-notifications-supported? 284 | notification-support 285 +--ro supported-excluded-change-type* union 286 {yp:on-change}? 288 3.2. YANG Module 290 file "ietf-notification-capabilities@2019-12-09.yang" 292 module ietf-notification-capabilities { 293 yang-version 1.1; 294 namespace 295 "urn:ietf:params:xml:ns:yang:ietf-notification-capabilities"; 296 prefix inc; 298 import ietf-netconf-acm { 299 prefix nacm; 300 description 301 "This module does not require NACM to be implemented, as 302 only a NACM typedef is used"; 303 } 305 import ietf-yang-push { 306 prefix yp; 307 description 308 "This module requires ietf-yang-push to be implemented for the 309 two subscription-capabilities containers."; 310 } 311 import ietf-yang-library { 312 prefix yanglib; 313 description "This module requires ietf-yang-library to 314 be implemented. Revision 2019-01-04 or a 315 revision derived from it is required."; 316 } 318 organization 319 "IETF NETCONF (Network Configuration) Working Group"; 320 contact 321 "WG Web: 322 WG List: 324 Editor: Balazs Lengyel 325 "; 326 description 327 "This module specifies YANG-Push related publisher 328 capabilities. 330 The module contains 331 - capabilities related to the throughput of notification data the 332 publisher can support. (Note that for a specific subscription 333 the publisher MAY still allow only longer periods or smaller 334 updates depending on e.g. actual load conditions.) 335 - specification of which data nodes support on-change or periodic 336 notifications. 338 Capability values can be specified on system/publisher level, 339 datastore level or on specific data nodes (and their contained 340 sub-tree) of a specific datastore. 341 If a capability is specified on multiple levels, the 342 specification on a more specific level overrides more 343 generic capability specifications; thus 344 - a system/publisher level specification is overridden by any 345 other specification 346 - a datastore level specification (with a node-selector '/') is 347 overridden by a specification with a more specific node-selector. 348 - a specification for a specific datastore and node-selector 349 is overridden by a specification for the same datastore with 350 a node-slector that describes more levels of containing lists 351 and containers. 353 If, different data nodes covered by a single subscription 354 have different values for a specific capability, then using values 355 that are only acceptable for some of these data nodes, but not for 356 others, may result in the rejection of the subscription. 358 To find a capability value for a specific node in a 359 specific datastore the user SHALL 360 1) consider the system/publisher level capabilities under the 361 system-capabilities container if the 362 capability value is specified. 363 2) search for a datastore-capabilities list entry for 364 the specific datastore. 365 3) within that datastore entry search for a 366 per-node-capabilities entry that specifies the specific 367 capability and that has the node-selector selecting the 368 specific data node and that specifies the most levels of 369 containing containers and lists. 370 4) If no entries are found in the previous steps the 371 publisher is not capable of providing a value because 372 it is unknown, the capability is changing for some reason, 373 there is no specified limit etc. In this case the 374 publisher's behavior is unspecified. 376 The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 377 'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 378 'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this document 379 are to be interpreted as described in BCP 14 (RFC 2119) 380 (RFC 8174) when, and only when, they appear in all 381 capitals, as shown here. 383 Copyright (c) 2019 IETF Trust and the persons identified as 384 authors of the code. All rights reserved. 386 Redistribution and use in source and binary forms, with or 387 without modification, is permitted pursuant to, and subject 388 to the license terms contained in, the Simplified BSD License 389 set forth in Section 4.c of the IETF Trust's Legal Provisions 390 Relating to IETF Documents 391 (http://trustee.ietf.org/license-info). 393 This version of this YANG module is part of RFC XXXX; see 394 the RFC itself for full legal notices."; 396 revision 2019-12-09 { 397 description 398 "Initial version"; 399 reference 400 "RFC XXX: YANG-Push Notification Capabilities"; 401 } 403 grouping subscription-capabilities { 404 description "Capabilities related to Yang-Push notifications"; 405 container subscription-capabilities { 406 description "Capabilities related to Yang-Push notifications"; 408 typedef notification-support { 409 type enumeration { 410 enum no-notifications-supported { 411 description "The publisher is not capable of sending any 412 notifications for the relevant scope and subscription 413 type." ; 414 } 415 enum notifications-for-config-changes-supported { 416 description "The publisher is capable of sending 417 notifications for config=true nodes, but not 418 for config=false nodes for the relevant scope 419 and subscription type." ; 420 } 421 enum notifications-for-state-changes-supported { 422 description "The publisher is capable of sending 423 notifications for config=false nodes, but not 424 for config=true nodes for the relevant scope 425 and subscription type." ; 426 } 427 enum notifications-for-all-changes-supported { 428 description "The publisher is capable of sending 429 notifications for both config=false and config=true 430 nodes for the relevant scope and subscription type." ; 432 } 433 } 434 description "Type for defining whether on-change or 435 periodic notifications are supported for no, only config=true, 436 only config=false or all data nodes."; 437 } 439 choice update-period { 440 description "Supported update period value or values for 441 periodic subscriptions."; 442 leaf minimum-update-period { 443 type uint32; 444 units "centiseconds"; 445 description "Indicates the minimal update period that is 446 supported for a periodic subscription. 447 A periodic subscription to the selected data nodes must 448 specify a value that is at least as large or greater than 449 this"; 450 reference 451 "The period leaf in RFC 8641 ietf-yang-push YANG module"; 452 } 454 leaf-list supported-update-period { 455 type uint32; 456 units "centiseconds"; 457 description "Supported update period values for a 458 periodic subscription. 459 A periodic subscription to the selected data nodes must 460 specify one of the values in the list; other values 461 are not supported."; 462 reference 463 "The period leaf in RFC 8641 ietf-yang-push YANG module"; 464 } 465 } 467 leaf max-objects-per-update { 468 type uint32 { 469 range "1..max"; 470 } 471 description 472 "Maximum number of objects that can be sent 473 in an update for the selected data nodes."; 474 } 476 leaf minimum-dampening-period { 477 if-feature yp:on-change; 478 type uint32; 479 units "centiseconds"; 480 description 481 "The minimum dampening period supported for on-change 482 subscriptions for the selected data nodes."; 483 } 485 leaf on-change-supported { 486 if-feature yp:on-change; 487 type notification-support; 488 description 489 "Specifies whether the publisher is capable of 490 sending on-change notifications for the selected 491 data store or data nodes and the subtree below them."; 492 } 494 leaf periodic-notifications-supported { 495 type notification-support; 496 description 497 "Specifies whether the publisher is capable of 498 sending periodic notifications for the selected 499 data store or data nodes and the subtree below them."; 500 } 502 leaf-list supported-excluded-change-type { 503 if-feature yp:on-change; 504 type union { 505 type enumeration { 506 enum none { 507 description "None of the change types can be excluded."; 508 } 509 enum all { 510 description 511 "Any combination of change types can be excluded."; 512 } 513 } 514 type yp:change-type; 515 } 516 description "The change types that can be excluded in 517 YANG-Push subscriptions."; 518 } 519 } 520 } 522 container system-capabilities { 523 config false; 524 description "YANG-Push related publisher capabilities. 525 Capability values specified here at the publisher level 526 are valid for all datastores and 527 are used when the capability is not specified on the 528 datastore level or for specific data nodes. "; 530 uses subscription-capabilities { 531 refine subscription-capabilities/supported-excluded-change-type { 532 default none; 533 } 534 } 536 list datastore-capabilities { 537 key datastore; 539 description "Capabilities values per datastore. 540 For non-NMDA servers/publishers the config=false data is 541 considered as if it was part of the running datastore."; 543 leaf datastore { 544 type leafref { 545 path /yanglib:yang-library/yanglib:datastore/yanglib:name; 546 } 547 description "The datastore for which capabilities are defined. 548 Only individual datastores can be specified 549 e.g. ds:conventional is not allowed."; 550 } 552 list per-node-capabilities { 553 key "node-selector"; 554 description 555 "Each list entry specifies notification capabilities 556 for the selected data nodes. The same capabilities apply for 557 the data nodes in the subtree below them unless another list 558 entry with a more specific node selector is present."; 560 leaf node-selector { 561 type nacm:node-instance-identifier; 562 description 563 "Selects the data nodes for which capabilities are 564 specified. The special value '/' denotes all data nodes 565 in the datastore. 566 The system SHOULD order list entries according to 567 the tree structure of the data models to make 568 reading/parsing the data model more simple."; 569 } 571 uses subscription-capabilities; 572 } 573 } 574 } 575 } 576 578 3.3. Other System Capabilities 580 Other YANG modules defined in separate documents MAY augment this 581 module to define other capabilities not related to YANG-Push. Every 582 set of such capabilities SHOULD be wrapped in a container similar to 583 the subscription-capabilities container in this YANG module to 584 cleanly separate different groups of capabilities. The "other- 585 capabilities" container SHOULD be augmented as a sibling to the 586 subscription-capabilities container. 588 4. Security Considerations 590 The YANG module specified in this document defines a schema for data 591 that is designed to be accessed via network management protocols such 592 as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer 593 is the secure transport layer, and the mandatory-to-implement secure 594 transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer 595 is HTTPS, and the mandatory-to-implement secure transport is TLS 596 [RFC8446]. 598 The Network Configuration Access Control Model (NACM) [RFC8341] 599 provides the means to restrict access for particular NETCONF or 600 RESTCONF users to a preconfigured subset of all available NETCONF or 601 RESTCONF protocol operations and content. 603 All protocol-accessible data nodes are read-only and cannot be 604 modified. The data in this module is not security sensitive. Access 605 control may be configured, to avoid exposing the read-only data. 607 When that data is in file format, data should be protected against 608 modification or unauthorized access using normal file handling 609 mechanisms. 611 5. IANA Considerations 613 5.1. The IETF XML Registry 615 This document registers one URI in the IETF XML registry [RFC3688]. 616 Following the format in [RFC3688], the following registrations are 617 requested: 619 URI: urn:ietf:params:xml:ns:yang:ietf-notification-capabilities 620 Registrant Contact: The NETCONF WG of the IETF. 621 XML: N/A, the requested URI is an XML namespace. 623 5.2. The YANG Module Names Registry 625 This document registers one YANG module in the YANG Module Names 626 registry [RFC7950]. Following the format in [RFC7950], the the 627 following registrations are requested: 629 name: ietf-notification-capabilities 630 namespace: urn:ietf:params:xml:ns:yang:ietf-notification-capabilities 631 prefix: inc 632 reference: RFC XXXX 634 6. References 636 6.1. Normative References 638 [I-D.ietf-netmod-yang-instance-file-format] 639 Lengyel, B. and B. Claise, "YANG Instance Data File 640 Format", draft-ietf-netmod-yang-instance-file-format-06 641 (work in progress), December 2019. 643 [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., 644 and A. Bierman, Ed., "Network Configuration Protocol 645 (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, 646 . 648 [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure 649 Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011, 650 . 652 [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", 653 RFC 7950, DOI 10.17487/RFC7950, August 2016, 654 . 656 [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF 657 Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, 658 . 660 [RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., 661 and R. Wilton, "Network Management Datastore Architecture 662 (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018, 663 . 665 [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol 666 Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, 667 . 669 [RFC8639] Voit, E., Clemm, A., Gonzalez Prieto, A., Nilsen-Nygaard, 670 E., and A. Tripathy, "Subscription to YANG Notifications", 671 RFC 8639, DOI 10.17487/RFC8639, September 2019, 672 . 674 [RFC8641] Clemm, A. and E. Voit, "Subscription to YANG Notifications 675 for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641, 676 September 2019, . 678 6.2. Informative References 680 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 681 Requirement Levels", BCP 14, RFC 2119, 682 DOI 10.17487/RFC2119, March 1997, 683 . 685 [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, 686 DOI 10.17487/RFC3688, January 2004, 687 . 689 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 690 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 691 May 2017, . 693 [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", 694 BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, 695 . 697 Appendix A. Instance data examples 699 The following example is instance-data describing the notification 700 capabilities of a hypothetical "acme-switch". The switch implements 701 the running, candidate and operational datastores. Every change can 702 be reported on-change from running, nothing from candidate and all 703 config=false data from operational. Periodic subscriptions are 704 supported for running and operational, but not for candidate. 706 707 709 acme-switch-notification-capabilities 710 1 711 712 ietf-notification-capabilities@2019-12-04 713 714 715 Notification capabilities of acme-switch. 716 Acme-switch implements the running, candidate and operational 717 datastores. Every change can be reported on-change from running, 718 nothing from candidate and all config=false data from operational. 719 Periodic subscriptions are supported for running and 720 operational, but not for candidate. 721 722 723 726 727 500 728 2000 729 100 730 731 notifications-for-all-changes-supported 732 733 734 735 ds:operational 736 737 / 738 739 740 notifications-for-state-changes-supported 741 742 743 744 745 746 ds:candidate 747 748 / 749 750 no-notifications-supported 751 752 753 no-notifications-supported 754 755 756 757 758 759 ds:running 760 761 / 762 763 764 notifications-for-all-changes-supported 766 767 768 769 770 771 772 774 Figure 1: Notification Capabilities with datastore level settings 776 The following is the instance-data describing the notification 777 capabilities of a hypothetical "acme-router". The router implements 778 the running, and operational datastores. Every change can be 779 reported on-change from running, but only config=true nodes and some 780 config=false data from operational. Interface statistics are not 781 reported on-change only 2 important counters. Datastore subscription 782 capabilities are not reported on-change as they never change on the 783 acme-router during run-time. 785 786 788 acme-router-notification-capabilities 789 1 790 791 ietf-notification-capabilities@2019-12-04 792 793 794 Defines the notification capabilities of an acme-router. 795 The router only has running, and operational datastores. 796 Every change can be reported on-change from running, but 797 only config=true nodes and some config=false data from operational. 798 Statistics are not reported on-change only 2 important counters, 799 for these a smaller dampening period is possible. 800 801 802 805 806 500 807 2000 808 100 809 810 notifications-for-all-changes-supported 811 812 813 notifications-for-all-changes-supported 815 816 817 all 818 819 820 821 ds:operational 822 823 824 /if:interfaces/if:interface/if:statistics 825 826 827 no-notifications-supported 828 829 830 831 832 833 /if:interfaces/if:interface/if:statistics/if:in-octets 834 835 836 10 837 838 notifications-for-all-changes-supported 839 840 841 842 843 844 /if:interfaces/if:interface/if:statistics/if:out-octets 845 846 847 10 848 849 notifications-for-all-changes-supported 850 851 852 853 854 855 856 858 Figure 2: Notification Capabilities with data node specific settings 860 Appendix B. Changes between revisions 862 v07 - v08 864 o Prepared the YANG model to include other non-YANG-Push related 865 capabilities. 867 o Renamed the top level container to system-capabilities 869 o Added a container subscription-capabilities to the grouping 870 subscription-capabilities to contain all subscription related 871 capabilities 873 o Updated examples according to draft-ietf-netmod-yang-instance- 874 file-format-06. 876 v06 - v07 878 o Updated examples according to draft-ietf-netmod-yang-instance- 879 file-format-05. 881 v05 - v06 883 o Providing the capability data is only a "SHOULD" recommendation. 884 Some reviewers wanted MUST some wanted much less. 886 o The YANG module import statements now indicate the imported 887 modules that must be implemented not just available as import as 888 requested by the YangDoctors review. 890 v04 - v05 892 o Added new capabilities periodic-notifications-supported and 893 supported-excluded-change-type. 895 o Restructured YANG module to make the node-selector's usage similar 896 to how NACM uses it: "/" means the whole datastore. 898 o Small corrections, spelling, rewording 900 o Replaced the term server with the term publisher except in cases 901 where we speak about datastores and functionality based on get, 902 getconfig operations. In this latter case it is really the server 903 functionality that is discussed 905 v03 - v04 906 o Clarified recommended support for on-change notifications about 907 the datastore-subscription-capabilities. 909 v02 - v03 911 o Allow throughput related capabilities to be defined on top, 912 datastore or data node level. Described that specific capability 913 values always override generic ones. 915 o Indicate that non-NMDA servers can also use this model. 917 o Updated according to draft-ietf-netmod-yang-instance-file- 918 format-04 920 v01 - v02 922 o Added instance data examples 924 o On-change capability can be defined per datastore 926 o Added "if-feature yp:on-change" where relevant 928 o Unified units used 930 v00 - v01 932 o Add more capabilities: minimum period, supported period max-number 933 of objects, min dampening period, dampening supported 935 Authors' Addresses 937 Balazs Lengyel 938 Ericsson 939 Magyar Tudosok korutja 11 940 1117 Budapest 941 Hungary 943 Email: balazs.lengyel@ericsson.com 945 Alexander Clemm 946 Futurewei 947 2330 Central Expressway 948 Santa Clara, CA 95050 949 USA 951 Email: ludwig@clemm.org 952 Benoit Claise 953 Cisco Systems, Inc. 954 De Kleetlaan 6a b1 955 1831 Diegem 956 Belgium 958 Email: bclaise@cisco.com