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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(See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-21) exists of draft-ietf-netmod-yang-instance-file-format-06 Summary: 0 errors (**), 0 flaws (~~), 2 warnings (==), 1 comment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: July 18, 2020 Futurewei 6 B. Claise 7 Cisco Systems, Inc. 8 January 15, 2020 10 Generic YANG-related System Capabilities and YANG-Push Notification 11 Capabilities 12 draft-ietf-netconf-notification-capabilities-10 14 Abstract 16 This document proposes two YANG modules. The module ietf-system- 17 capabilities provides a structure that can be used to specify any 18 YANG related system capability. 20 The module ietf-notification-capabilities allows a publisher to 21 specify capabilities related to "Subscription to YANG Datastores" 22 (YANG-Push). It proposes to use YANG Instance Data to document this 23 information and make it already available at implementation-time, but 24 also allow it to be reported at run-time. 26 Status of This Memo 28 This Internet-Draft is submitted in full conformance with the 29 provisions of BCP 78 and BCP 79. 31 Internet-Drafts are working documents of the Internet Engineering 32 Task Force (IETF). Note that other groups may also distribute 33 working documents as Internet-Drafts. The list of current Internet- 34 Drafts is at https://datatracker.ietf.org/drafts/current/. 36 Internet-Drafts are draft documents valid for a maximum of six months 37 and may be updated, replaced, or obsoleted by other documents at any 38 time. It is inappropriate to use Internet-Drafts as reference 39 material or to cite them other than as "work in progress." 41 This Internet-Draft will expire on July 18, 2020. 43 Copyright Notice 45 Copyright (c) 2020 IETF Trust and the persons identified as the 46 document authors. All rights reserved. 48 This document is subject to BCP 78 and the IETF Trust's Legal 49 Provisions Relating to IETF Documents 50 (https://trustee.ietf.org/license-info) in effect on the date of 51 publication of this document. Please review these documents 52 carefully, as they describe your rights and restrictions with respect 53 to this document. Code Components extracted from this document must 54 include Simplified BSD License text as described in Section 4.e of 55 the Trust Legal Provisions and are provided without warranty as 56 described in the Simplified BSD License. 58 Table of Contents 60 1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 61 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 62 2.1. YANG-Push Notification Capabilities . . . . . . . . . . . 3 63 3. Providing System Capability Information . . . . . . . . . . . 5 64 4. System Capabilities Model . . . . . . . . . . . . . . . . . . 6 65 4.1. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 6 66 4.2. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 7 67 5. Notification Capabilities Model . . . . . . . . . . . . . . . 10 68 5.1. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 10 69 5.2. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 11 70 6. Security Considerations . . . . . . . . . . . . . . . . . . . 15 71 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 72 7.1. The IETF XML Registry . . . . . . . . . . . . . . . . . . 15 73 7.2. The YANG Module Names Registry . . . . . . . . . . . . . 16 74 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 16 75 8.1. Normative References . . . . . . . . . . . . . . . . . . 16 76 8.2. Informative References . . . . . . . . . . . . . . . . . 17 77 Appendix A. Instance data examples . . . . . . . . . . . . . . . 17 78 Appendix B. Changes between revisions . . . . . . . . . . . . . 21 79 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23 81 1. Terminology 83 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 84 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 85 "OPTIONAL" in this document are to be interpreted as described in BCP 86 14 [RFC2119] [RFC8174] when, and only when, they appear in all 87 capitals, as shown here. 89 The terms YANG-Push, On-change subscription and Periodic subscription 90 are used as defined in [RFC8641] 92 The terms Subscriber, Publisher and Receiver are used as defined in 93 [RFC8639] 95 The term Server is used as defined in [RFC8342] 96 On-change Notification Capability: The capability of the publisher to 97 send on-change notifications for a specific datastore or a specific 98 data node. 100 Implementation-time information: Information about the publisher's or 101 server's behavior that is made available during the implementation of 102 the publisher/server, available from a source other then a running 103 server. 105 Run-time information: Information about the publisher's or server's 106 behavior that is available from the running server via management 107 protocols such as NETCONF [RFC6241] or RESTCONF [RFC8040]. 109 2. Introduction 111 Systems implementing a server and/or a publisher often have 112 capabilities that are not defined by the YANG model itself. There is 113 a need to publish this capability information as it part of the 114 contract between the server and client. Examples include: maximum 115 size of data that can be stored or transferred, information about 116 counters (whether a node supports on-change telemetry), etc. Such 117 capabilities are often dependent on a vendor's implementation or the 118 available resources at deployment. Many such capabilities are 119 specific to either the complete system, individual YANG datastores or 120 specific parts of the YANG schema, or even to individual data nodes. 121 It is a goal of this document to provide a common way of representing 122 such capabilities in a format that is: 124 o vendor independent 126 o machine readable 128 o available in identical format both in implementation-time and run- 129 time 131 2.1. YANG-Push Notification Capabilities 133 A specific case where we need to specify capabilities is the YANG- 134 Push functionality. As defined in [RFC8641] a publisher may allow 135 subscribers to subscribe to updates from a datastore and subsequently 136 push such update notifications to the receiver. Notifications may be 137 sent periodically or on-change (more or less immediately after each 138 change). 140 A publisher supporting YANG-Push has a number of capabilities defined 141 in [RFC8641] that are often determined during the implementation of 142 the publisher. These include: 144 o Supported (reporting) periods for periodic subscriptions 146 o Maximum number of objects that can be sent in an update 148 o The set of datastores or data nodes for which periodic 149 notification is supported 151 Additional capabilities if the optional on-change feature is 152 supported include: 154 o Supported dampening periods for on-change subscriptions 156 o The set of datastores or data nodes for which on-change 157 notification is supported 159 Publishers have limitations in how many update notifications and how 160 many datastore node updates they can send out in a certain time- 161 period. 163 Publishers might not support periodic subscriptions to all 164 datastores. 166 In some cases, a publisher supporting on-change notifications will 167 not be able to push updates for some object types on-change. Reasons 168 for this might be that the value of the datastore node changes 169 frequently (e.g., in-octets counter), that small object changes are 170 frequent and irrelevant to the receiver (e.g., a temperature gauge 171 changing 0.1 degrees within a predetermined and acceptable range), or 172 that the implementation is not capable of on-change notification for 173 a particular object. In those cases, it will be important for 174 subscriber applications to have a way to identify which objects on- 175 change notifications are supported and for which ones not. 177 Faced with the reality that support for on-change notification does 178 not mean that such notifications will be sent for any specific data 179 node, subscriber/management applications can not rely on the on- 180 change functionality unless the subscriber has some means to identify 181 which objects on-change notifications are supported. YANG models are 182 meant to be used as an interface contract. Without identification of 183 the data nodes actually supporting on-change, this contract would be 184 incomplete. 186 Clients of a server, subscribers to a publisher need a method to 187 gather capability information. 189 Implementation-time information is needed by Network Management 190 System (NMS) implementers. A NMS implementation that wants to 191 support notifications, needs the information about on-change 192 notification capability. If the information is not documented in a 193 way available to the NMS designer, but only as instance data from the 194 network node once it is deployed, the NMS implementation will be 195 delayed, because it has to wait for the network node to be ready. In 196 addition, the assumption that all NMS implementers will have a 197 correctly configured network node available to retrieve data from is 198 an expensive proposition and may not always hold. (An NMS may need 199 to be able to handle many dozens of network node types.) Often a 200 fully functional NMS is a requirement for introducing a new network 201 node type into a network, so delaying NMS readiness effectively also 202 delays the time at which a new network node type can be introduced 203 into the network. 205 Implementation-time information is needed by system integrators. 206 When introducing a network node type into their network, operators 207 often need to integrate the node type into their own management 208 system. The NMS may have management functions that depend on on- 209 change notifications. The network operator needs to plan his 210 management practices and NMS implementation before he even decides to 211 buy the specific network node type. Moreover the decision to buy the 212 node type sometimes depends on these management possibilities. 214 Run-time information is needed: 216 o for any "purely model driven" application, e.g., a NETCONF- 217 browser. Such applications depend on reading models and 218 capabilities in run-time to support all the publisher's available 219 functionality. 221 o in case the capability might change during run-time e.g., due to 222 licensing, HW constraints etc. 224 o to check that capability information provided early, already in 225 implementation-time is indeed what the publisher implements (is 226 the supplied documentation correct?) 228 3. Providing System Capability Information 230 Capability information is represented by instance-data based on one 231 or more "capability defining YANG modules". This allows a user to 232 discover capabilities both at implementation-time and run-time. 234 o For the implementation-time use-case: Capabilities SHOULD be 235 provided by the implementer as YANG instance data files complying 236 to [I-D.ietf-netmod-yang-instance-file-format]. The file SHALL be 237 available already in implementation-time retrievable in a way that 238 does not depend on a live network node. E.g., download from 239 product website. 241 o For the run-time use-case: Capabilities SHOULD be available via 242 NETCONF [RFC6241] or RESTCONF [RFC8040] from the live server 243 (implementing the publisher) during run-time. Implementations 244 which support changing these capabilities at run-time SHOULD 245 support on-change notifications about the system-capabilities 246 container. 248 The module ietf-system-capabilities is defined to provide a structure 249 that can be used to specify any YANG related system capability. 251 The module ietf-notification-capabilities is defined to allow a 252 publisher to specify capabilities related to "Subscription to YANG 253 Datastores" (YANG-Push) augmenting ietf-system-capabilities. 255 4. System Capabilities Model 257 The module ietf-system-capabilities is defined to provide a structure 258 that can be used to specify any YANG related system capability. 260 Capability values can be specified on system/publisher level, 261 datastore level (by selecting all nodes in the datastore) or for 262 specific data nodes of a specific datastore (and their contained sub- 263 trees). Capability values specified for a specific datastore or 264 node-set override values specified on the system/publisher level. 266 This module itself does not contain any capabilities. It SHOULD be 267 used by other modules to augment-in specific capability information. 268 Every set of such capabilities SHOULD be wrapped in a container under 269 the augment statement to cleanly separate different groups of 270 capabilities. These "wrapper containers" SHALL be augmented in at 271 /sysc:system-capabilities and /sysc:system-capabilities/ 272 sysc:datastore-capabilities/sysc:per-node-capabilities. 274 Note: The solution is usable for both NMDA and non-NMDA systems. For 275 non-NMDA servers/publishers config=false data is considered as if it 276 was part of the running datastore. 278 4.1. Tree Diagram 280 The following tree diagram [RFC8340] provides an overview of the data 281 model. 283 module: ietf-system-capabilities 284 +--ro system-capabilities 285 +--ro datastore-capabilities* [datastore] 286 +--ro datastore -> /yanglib:yang-library/datastore/name 287 +--ro per-node-capabilities* [] 288 +--ro (node-selection)? 289 +--:(node-selector) 290 +--ro node-selector? nacm:node-instance-identifier 292 4.2. YANG Module 294 file "ietf-system-capabilities@2020-01-14.yang" 296 module ietf-system-capabilities { 297 yang-version 1.1; 298 namespace 299 "urn:ietf:params:xml:ns:yang:ietf-system-capabilities"; 300 prefix sysc; 302 import ietf-netconf-acm { prefix nacm; } 304 import ietf-yang-library { 305 prefix yanglib; 306 description "Revision 2019-01-04 or a 307 revision derived from it is REQUIRED."; 308 } 310 organization 311 "IETF NETCONF (Network Configuration) Working Group"; 312 contact 313 "WG Web: 314 WG List: 316 Editor: Balazs Lengyel 317 "; 318 description 319 "This module specifies a module intended to contain system 320 capabilities. System capabilities may include capabilities of a 321 NETCONF or RESTCONF server or a notification publisher. 323 This module does not contain any specific capabilities it only 324 provides a structure where containers containing the actual 325 capabilities should be augmented in. 327 Capability values can be specified on system level, 328 datastore level (by selecting all nodes in the datastore) or 329 for specific data nodes of a specific datastore (and their 330 contained sub-trees). 332 Capability values specified for a specific datastore or 333 node-set override values specified on the system/publisher level. 335 To find a capability value for a specific data node in a 336 specific datastore the user SHALL 337 1) search for a datastore-capabilities list entry for 338 the specific datastore. 339 2) If the datastore entry is found within that entry process all 340 per-node-capabilities entries in the order they appear in the list. 341 The first entry that specifies the specific capability and has a 342 node-selector selecting the specific data node defines the 343 capability value. 344 3) If the capability value is not found above and the specific 345 capability is specified under the system-capabilities container 346 (outside the datastore-capabilities list) this value shall be used. 347 4) If no values are found in the previous steps the 348 system/publisher is not capable of providing a value because 349 it is unknown, the capability is changing for some reason, 350 there is no specified limit etc. In this case the 351 system's behavior is unspecified. 353 The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 354 'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 355 'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this document 356 are to be interpreted as described in BCP 14 (RFC 2119) 357 (RFC 8174) when, and only when, they appear in all 358 capitals, as shown here. 360 Copyright (c) 2020 IETF Trust and the persons identified as 361 authors of the code. All rights reserved. 363 Redistribution and use in source and binary forms, with or 364 without modification, is permitted pursuant to, and subject 365 to the license terms contained in, the Simplified BSD License 366 set forth in Section 4.c of the IETF Trust's Legal Provisions 367 Relating to IETF Documents 368 (http://trustee.ietf.org/license-info). 370 This version of this YANG module is part of RFC XXXX 371 (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself 372 for full legal notices."; 374 revision 2020-01-14 { 375 description 376 "Initial version"; 377 reference 378 "RFC XXX: YANG-Push Notification Capabilities"; 379 } 380 container system-capabilities { 381 config false; 382 description "System capabilities. 383 Capability values specified here at the system level 384 are valid for all datastores and 385 are used when the capability is not specified on the 386 datastore level or for specific data nodes."; 388 // augmentation point for system level capabilities 390 list datastore-capabilities { 391 key datastore; 393 description "Capabilities values per datastore. 394 For non-NMDA servers/publishers config=false data is 395 considered as if it was part of the running datastore."; 397 leaf datastore { 398 type leafref { 399 path /yanglib:yang-library/yanglib:datastore/yanglib:name; 400 } 401 description "The datastore for which capabilities are defined. 402 Only individual datastores can be specified 403 e.g., ds:conventional is not allowed."; 404 } 406 list per-node-capabilities { 407 description 408 "Each list entry specifies capabilities for the selected 409 data nodes. The same capabilities apply for the data nodes 410 in the subtree below the selected nodes. 411 The system SHALL order the entries according to their 412 precedence. The order of the entries MUST NOT change unless 413 the underlying capabilities also change."; 415 choice node-selection { 416 description 417 "A method to select all or some nodes within a datastore."; 419 leaf node-selector { 420 type nacm:node-instance-identifier; 421 description 422 "Selects the data nodes for which capabilities are 423 specified. The special value '/' denotes all data nodes 424 in the datastore."; 425 } 426 } 427 // augmentation point for datastore or data node level 428 // capabilities 429 } 430 } 431 } 432 } 434 436 5. Notification Capabilities Model 438 The YANG module ietf-notification-capabilities is defined to provide 439 YANG-Push related capability information. 441 5.1. Tree Diagram 443 The following tree diagram [RFC8340] provides an overview of the data 444 model. 446 module: ietf-notification-capabilities 447 augment /sysc:system-capabilities: 448 +--ro subscription-capabilities 449 +--ro (update-period)? 450 | +--:(minimum-update-period) 451 | | +--ro minimum-update-period? uint32 452 | +--:(supported-update-period) 453 | +--ro supported-update-period* uint32 454 +--ro max-nodes-per-update? uint32 455 +--ro minimum-dampening-period? uint32 {yp:on-change}? 456 +--ro on-change-supported? notification-support 457 | {yp:on-change}? 458 +--ro periodic-notifications-supported? notification-support 459 +--ro supported-excluded-change-type* union {yp:on-change}? 460 augment /sysc:system-capabilities/sysc:datastore-capabilities/ + 461 | sysc:per-node-capabilities: 462 +--ro subscription-capabilities 463 +--ro (update-period)? 464 | +--:(minimum-update-period) 465 | | +--ro minimum-update-period? uint32 466 | +--:(supported-update-period) 467 | +--ro supported-update-period* uint32 468 +--ro max-nodes-per-update? uint32 469 +--ro minimum-dampening-period? uint32 {yp:on-change}? 470 +--ro on-change-supported? notification-support 471 | {yp:on-change}? 472 +--ro periodic-notifications-supported? notification-support 473 +--ro supported-excluded-change-type* union {yp:on-change}? 475 5.2. YANG Module 477 file "ietf-notification-capabilities@2020-01-14.yang" 479 module ietf-notification-capabilities { 480 yang-version 1.1; 481 namespace 482 "urn:ietf:params:xml:ns:yang:ietf-notification-capabilities"; 483 prefix inc; 485 import ietf-yang-push { prefix yp; } 486 import ietf-system-capabilities { prefix sysc; } 488 organization 489 "IETF NETCONF (Network Configuration) Working Group"; 490 contact 491 "WG Web: 492 WG List: 494 Editor: Balazs Lengyel 495 "; 496 description 497 "This module specifies YANG-Push related publisher capabilities. 499 The module contains 500 - specification of which data nodes support on-change or periodic 501 notifications. 502 - capabilities related to the throughput of notification data the 503 publisher can support. (Note that for a specific subscription 504 the publisher MAY still allow only longer periods or smaller 505 updates depending on e.g., actual load conditions.) 507 Capability values can be specified on system/publisher level, 508 datastore level or for specific data nodes of a specific datastore 509 (and their contained sub-trees), as defined in the 510 ietf-system-capabilities module. 512 If, different data nodes covered by a single subscription 513 have different values for a specific capability, then using values 514 that are only acceptable for some of these data nodes, but not for 515 others, may result in the rejection of the subscription. 517 The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 518 'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 519 'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this document 520 are to be interpreted as described in BCP 14 (RFC 2119) 521 (RFC 8174) when, and only when, they appear in all 522 capitals, as shown here. 524 Copyright (c) 2020 IETF Trust and the persons identified as 525 authors of the code. All rights reserved. 527 Redistribution and use in source and binary forms, with or 528 without modification, is permitted pursuant to, and subject 529 to the license terms contained in, the Simplified BSD License 530 set forth in Section 4.c of the IETF Trust's Legal Provisions 531 Relating to IETF Documents 532 (http://trustee.ietf.org/license-info). 534 This version of this YANG module is part of RFC XXXX 535 (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself 536 for full legal notices."; 538 revision 2020-01-14 { 539 description 540 "Initial version"; 541 reference 542 "RFC XXX: YANG-Push Notification Capabilities"; 543 } 545 grouping subscription-capabilities { 546 description "Capabilities related to YANG-Push subscriptions 547 and notifications"; 549 container subscription-capabilities { 550 description "Capabilities related to YANG-Push subscriptions 551 and notifications"; 553 typedef notification-support { 554 type bits { 555 bit config-changes { 556 description "The publisher is capable of sending 557 notifications for config=true nodes for the relevant 558 scope and subscription type." ; 559 } 560 bit state-changes { 561 description "The publisher is capable of sending 562 notifications for config=false nodes for the relevant 563 scope and subscription type." ; 564 } 565 } 566 description "Type for defining whether on-change or 567 periodic notifications are supported for none, only 568 config=true, only config=false or all data nodes."; 569 } 571 choice update-period { 572 description "Supported update period value or values for 573 periodic subscriptions."; 574 leaf minimum-update-period { 575 type uint32; 576 units "centiseconds"; 577 description "Indicates the minimal update period that is 578 supported for a periodic subscription. 579 A subscription request to the selected data 580 nodes with a smaller period than what this leaf specifies 581 will result in a 'period-unsupported' error."; 582 reference 583 "The period leaf in RFC 8641 ietf-yang-push YANG module"; 584 } 586 leaf-list supported-update-period { 587 type uint32; 588 units "centiseconds"; 589 description "Supported update period values for a 590 periodic subscription. 591 A subscription request to the selected data nodes with a 592 period not included in the leaf-list will result in a 593 'period-unsupported' error."; 594 reference 595 "The period leaf in RFC 8641 ietf-yang-push YANG module"; 596 } 597 } 599 leaf max-nodes-per-update { 600 type uint32 { 601 range "1..max"; 602 } 603 description 604 "Maximum number of data nodes that can be sent 605 in an update. The publisher MAY support more data nodes, 606 but SHOULD support at least this number."; 607 } 609 leaf minimum-dampening-period { 610 if-feature yp:on-change; 611 type uint32; 612 units "centiseconds"; 613 description 614 "The minimum dampening period supported for on-change 615 subscriptions for the selected data nodes."; 616 } 618 leaf on-change-supported { 619 if-feature yp:on-change; 620 type notification-support; 621 description 622 "Specifies whether the publisher is capable of 623 sending on-change notifications for the selected 624 data store or data nodes and the subtree below them."; 625 } 627 leaf periodic-notifications-supported { 628 type notification-support; 629 description 630 "Specifies whether the publisher is capable of 631 sending periodic notifications for the selected 632 data store or data nodes and the subtree below them."; 633 } 635 leaf-list supported-excluded-change-type { 636 if-feature yp:on-change; 637 type union { 638 type enumeration { 639 enum none { 640 value -2 ; 641 description "None of the change types can be excluded."; 642 } 643 enum all { 644 value -1 ; 645 description 646 "Any combination of change types can be excluded."; 647 } 648 } 649 type yp:change-type; 650 } 651 description "The change types that can be excluded in 652 YANG-Push subscriptions."; 653 } 654 } 655 } 657 augment /sysc:system-capabilities { 658 description "Add system level capabilities"; 659 uses subscription-capabilities { 660 refine subscription-capabilities/supported-excluded-change-type { 661 default none; 662 } 663 } 664 } 666 augment "/sysc:system-capabilities/sysc:datastore-capabilities" + 667 "/sysc:per-node-capabilities" { 669 description "Add datastore and node level capabilities"; 670 uses subscription-capabilities { 671 refine subscription-capabilities/supported-excluded-change-type { 672 default none; 673 } 674 } 675 } 676 } 678 680 6. Security Considerations 682 The YANG modules specified in this document define a schema for data 683 that is designed to be accessed via network management protocols such 684 as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer 685 is the secure transport layer, and the mandatory-to-implement secure 686 transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer 687 is HTTPS, and the mandatory-to-implement secure transport is TLS 688 [RFC8446]. 690 The Network Configuration Access Control Model (NACM) [RFC8341] 691 provides the means to restrict access for particular NETCONF or 692 RESTCONF users to a preconfigured subset of all available NETCONF or 693 RESTCONF protocol operations and content. 695 All protocol-accessible data nodes are read-only and cannot be 696 modified. The data in these modules is not security sensitive. 697 Access control may be configured, to avoid exposing the read-only 698 data. 700 When that data is in file format, data should be protected against 701 modification or unauthorized access using normal file handling 702 mechanisms. 704 7. IANA Considerations 706 7.1. The IETF XML Registry 708 This document registers two URIs in the IETF XML registry [RFC3688]. 709 Following the format in [RFC3688], the following registrations are 710 requested: 712 URI: urn:ietf:params:xml:ns:yang:ietf-system-capabilities 713 Registrant Contact: The NETCONF WG of the IETF. 714 XML: N/A, the requested URI is an XML namespace. 716 URI: urn:ietf:params:xml:ns:yang:ietf-notification-capabilities 717 Registrant Contact: The NETCONF WG of the IETF. 718 XML: N/A, the requested URI is an XML namespace. 720 7.2. The YANG Module Names Registry 722 This document registers two YANG modules in the YANG Module Names 723 registry. Following the format in [RFC7950], the the following 724 registrations are requested: 726 name: ietf-system-capabilities 727 namespace: urn:ietf:params:xml:ns:yang:ietf-system-capabilities 728 prefix: sysc 729 reference: RFC XXXX 731 name: ietf-notification-capabilities 732 namespace: urn:ietf:params:xml:ns:yang:ietf-notification-capabilities 733 prefix: inc 734 reference: RFC XXXX 736 8. References 738 8.1. Normative References 740 [I-D.ietf-netmod-yang-instance-file-format] 741 Lengyel, B. and B. Claise, "YANG Instance Data File 742 Format", draft-ietf-netmod-yang-instance-file-format-06 743 (work in progress), December 2019. 745 [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., 746 and A. Bierman, Ed., "Network Configuration Protocol 747 (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, 748 . 750 [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure 751 Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011, 752 . 754 [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", 755 RFC 7950, DOI 10.17487/RFC7950, August 2016, 756 . 758 [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF 759 Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, 760 . 762 [RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., 763 and R. Wilton, "Network Management Datastore Architecture 764 (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018, 765 . 767 [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol 768 Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, 769 . 771 [RFC8639] Voit, E., Clemm, A., Gonzalez Prieto, A., Nilsen-Nygaard, 772 E., and A. Tripathy, "Subscription to YANG Notifications", 773 RFC 8639, DOI 10.17487/RFC8639, September 2019, 774 . 776 [RFC8641] Clemm, A. and E. Voit, "Subscription to YANG Notifications 777 for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641, 778 September 2019, . 780 8.2. Informative References 782 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 783 Requirement Levels", BCP 14, RFC 2119, 784 DOI 10.17487/RFC2119, March 1997, 785 . 787 [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, 788 DOI 10.17487/RFC3688, January 2004, 789 . 791 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 792 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 793 May 2017, . 795 [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", 796 BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, 797 . 799 [RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration 800 Access Control Model", STD 91, RFC 8341, 801 DOI 10.17487/RFC8341, March 2018, 802 . 804 Appendix A. Instance data examples 806 The following example is instance-data describing the notification 807 capabilities of a hypothetical "acme-switch". The switch implements 808 the running, candidate and operational datastores. Every change can 809 be reported on-change from running, nothing from candidate and all 810 config=false data from operational. Periodic subscriptions are 811 supported for running and operational, but not for candidate. 813 814 816 acme-switch-notification-capabilities 817 1 818 819 ietf-system-capabilities@2020-01-14 820 ietf-notification-capabilities@2020-01-14 821 822 823 Notification capabilities of acme-switch. 824 Acme-switch implements the running, candidate and operational 825 datastores. Every change can be reported on-change from running, 826 nothing from candidate and all config=false data from operational. 827 Periodic subscriptions are supported for running and 828 operational, but not for candidate. 829 830 831 836 837 500 838 2000 839 100 840 841 config-changes state-changes 842 843 844 845 ds:operational 846 847 / 848 849 850 state-changes 851 852 853 854 855 856 ds:candidate 857 858 / 859 860 861 862 863 864 865 866 ds:running 867 868 / 869 870 871 config-changes state-changes 872 873 874 875 876 877 878 880 Figure 1: Notification Capabilities with datastore level settings 882 The following is the instance-data describing the notification 883 capabilities of a hypothetical "acme-router". The router implements 884 the running, and operational datastores. Every change can be 885 reported on-change from running, but only config=true nodes and some 886 config=false data from operational. Interface statistics are not 887 reported on-change only 2 important counters. Datastore subscription 888 capabilities are not reported on-change as they never change on the 889 acme-router during run-time. 891 892 894 acme-router-notification-capabilities 895 1 896 897 ietf-system-capabilities@2020-01-14 898 ietf-notification-capabilities@2020-01-14 899 900 901 Defines the notification capabilities of an acme-router. 902 The router only has running, and operational datastores. 903 Every change can be reported on-change from running, but 904 only config=true nodes and some config=false data from operational. 905 Statistics are not reported on-change only 2 important counters, 906 for these a smaller dampening period is possible. 907 908 909 914 915 500 916 2000 917 100 918 919 config-changes state-changes 920 921 922 config-changes state-changes 923 924 925 all 926 927 928 929 ds:operational 930 931 932 /if:interfaces/if:interface/if:statistics/if:in-octets 933 934 935 10 936 937 938 config-changes state-changes 939 940 941 942 943 944 /if:interfaces/if:interface/if:statistics/if:out-octets 945 946 947 10 948 949 950 config-changes state-changes 951 952 953 954 955 956 /if:interfaces/if:interface/if:statistics 957 958 959 960 961 962 963 964 966 Figure 2: Notification Capabilities with data node specific settings 968 Appendix B. Changes between revisions 970 v09 - v10 972 o Removed description text from imports about the need for 973 implementing the imported module. 975 o Changed notification-support to bits with shorter names 977 o Assigned enum values to supported-excluded-change-type 979 o Made node-selector a choice to allow for future alternative 980 selection methods. 982 o Changed precedence of per-node-capabilities entries. Precedence 983 is now according to the position of entries in the list. 985 v08 - v09 987 o Split the YANG module into two: ietf-system-capabilities and ietf- 988 notification-capabilities. Restructured/updated the draft 989 accordingly. 991 v07 - v08 993 o Prepared the YANG model to include other non-YANG-Push related 994 capabilities. 996 o Renamed the top level container to system-capabilities 998 o Added a container subscription-capabilities to the grouping 999 subscription-capabilities to contain all subscription related 1000 capabilities 1002 o Updated examples according to draft-ietf-netmod-yang-instance- 1003 file-format-06. 1005 v06 - v07 1007 o Updated examples according to draft-ietf-netmod-yang-instance- 1008 file-format-05. 1010 v05 - v06 1012 o Providing the capability data is only a "SHOULD" recommendation. 1013 Some reviewers wanted MUST some wanted much less. 1015 o The YANG module import statements now indicate the imported 1016 modules that must be implemented not just available as import as 1017 requested by the YangDoctors review. 1019 v04 - v05 1021 o Added new capabilities periodic-notifications-supported and 1022 supported-excluded-change-type. 1024 o Restructured YANG module to make the node-selector's usage similar 1025 to how NACM uses it: "/" means the whole datastore. 1027 o Small corrections, spelling, rewording 1029 o Replaced the term server with the term publisher except in cases 1030 where we speak about datastores and functionality based on get, 1031 getconfig operations. In this latter case it is really the server 1032 functionality that is discussed 1034 v03 - v04 1036 o Clarified recommended support for on-change notifications about 1037 the datastore-subscription-capabilities. 1039 v02 - v03 1041 o Allow throughput related capabilities to be defined on top, 1042 datastore or data node level. Described that specific capability 1043 values always override generic ones. 1045 o Indicate that non-NMDA servers can also use this model. 1047 o Updated according to draft-ietf-netmod-yang-instance-file- 1048 format-04 1050 v01 - v02 1052 o Added instance data examples 1054 o On-change capability can be defined per datastore 1056 o Added "if-feature yp:on-change" where relevant 1058 o Unified units used 1060 v00 - v01 1062 o Add more capabilities: minimum period, supported period max-number 1063 of objects, min dampening period, dampening supported 1065 Authors' Addresses 1067 Balazs Lengyel 1068 Ericsson 1069 Magyar Tudosok korutja 11 1070 1117 Budapest 1071 Hungary 1073 Email: balazs.lengyel@ericsson.com 1075 Alexander Clemm 1076 Futurewei 1077 2330 Central Expressway 1078 Santa Clara, CA 95050 1079 USA 1081 Email: ludwig@clemm.org 1083 Benoit Claise 1084 Cisco Systems, Inc. 1085 De Kleetlaan 6a b1 1086 1831 Diegem 1087 Belgium 1089 Email: bclaise@cisco.com