idnits 2.17.1 draft-ietf-i2rs-ephemeral-state-12.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 (June 30, 2016) is 2855 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) == Missing Reference: 'I-D.ietf-i2rs-architecture' is mentioned on line 398, but not defined == Missing Reference: 'RFC6241' is mentioned on line 466, but not defined == Missing Reference: 'I-D.ietf-netconf-restconf' is mentioned on line 430, but not defined == Missing Reference: 'I-D.ietf-i2rs-pub-sub-requirements' is mentioned on line 409, but not defined == Missing Reference: 'I-D.ietf-i2rs-protocol-security-requirements' is mentioned on line 404, but not defined == Missing Reference: 'I-D.ietf-i2rs-security-environment-reqs' is mentioned on line 414, but not defined == Missing Reference: 'I-D.ietf-i2rs-traceability' is mentioned on line 419, but not defined == Missing Reference: 'I-D.ietf-netconf-call-home' is mentioned on line 425, but not defined == Missing Reference: 'I-D.ietf-netconf-server-model' is mentioned on line 435, but not defined == Missing Reference: 'I-D.ietf-netconf-yang-library' is mentioned on line 440, but not defined == Missing Reference: 'I-D.ietf-netconf-yang-patch' is mentioned on line 445, but not defined == Missing Reference: 'I-D.ietf-netconf-yang-push' is mentioned on line 450, but not defined == Missing Reference: 'I-D.ietf-netconf-zerotouch' is mentioned on line 456, but not defined == Missing Reference: 'I-D.ietf-netmod-yang-metadata' is mentioned on line 461, but not defined == Unused Reference: 'RFC6536' is defined on line 488, but no explicit reference was found in the text == Outdated reference: A later version (-03) exists of draft-hares-i2rs-protocol-strawman-02 -- Obsolete informational reference (is this intentional?): RFC 6536 (Obsoleted by RFC 8341) Summary: 0 errors (**), 0 flaws (~~), 17 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 I2RS working group J. Haas 3 Internet-Draft Juniper 4 Intended status: Standards Track S. Hares 5 Expires: January 1, 2017 Huawei 6 June 30, 2016 8 I2RS Ephemeral State Requirements 9 draft-ietf-i2rs-ephemeral-state-12 11 Abstract 13 This document covers requests to the NETMOD and NETCONF Working 14 Groups for functionality to support the ephemeral state requirements 15 to implement the I2RS architecture. 17 Status of This Memo 19 This Internet-Draft is submitted in full conformance with the 20 provisions of BCP 78 and BCP 79. 22 Internet-Drafts are working documents of the Internet Engineering 23 Task Force (IETF). Note that other groups may also distribute 24 working documents as Internet-Drafts. The list of current Internet- 25 Drafts is at http://datatracker.ietf.org/drafts/current/. 27 Internet-Drafts are draft documents valid for a maximum of six months 28 and may be updated, replaced, or obsoleted by other documents at any 29 time. It is inappropriate to use Internet-Drafts as reference 30 material or to cite them other than as "work in progress." 32 This Internet-Draft will expire on January 1, 2017. 34 Copyright Notice 36 Copyright (c) 2016 IETF Trust and the persons identified as the 37 document authors. All rights reserved. 39 This document is subject to BCP 78 and the IETF Trust's Legal 40 Provisions Relating to IETF Documents 41 (http://trustee.ietf.org/license-info) in effect on the date of 42 publication of this document. Please review these documents 43 carefully, as they describe your rights and restrictions with respect 44 to this document. Code Components extracted from this document must 45 include Simplified BSD License text as described in Section 4.e of 46 the Trust Legal Provisions and are provided without warranty as 47 described in the Simplified BSD License. 49 Table of Contents 51 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 52 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 53 2. Review of Requirements from I2RS architecture document . . . 3 54 3. Ephemeral State Requirements . . . . . . . . . . . . . . . . 5 55 3.1. Persistence . . . . . . . . . . . . . . . . . . . . . . . 5 56 3.2. Constraints . . . . . . . . . . . . . . . . . . . . . . . 5 57 3.3. Hierarchy . . . . . . . . . . . . . . . . . . . . . . . . 5 58 3.4. Ephemeral Configuration overlapping Local Configuration . 6 59 4. YANG Features for Ephemeral State . . . . . . . . . . . . . . 6 60 5. NETCONF Features for Ephemeral State . . . . . . . . . . . . 6 61 6. RESTCONF Features for Ephemeral State . . . . . . . . . . . . 6 62 7. Requirements regarding Supporting Multi-Head Control via 63 Client Priority . . . . . . . . . . . . . . . . . . . . . . . 6 64 8. Multiple Message Transactions . . . . . . . . . . . . . . . . 7 65 9. Pub/Sub Requirements Expanded for Ephemeral State . . . . . . 7 66 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 67 11. Security Considerations . . . . . . . . . . . . . . . . . . . 8 68 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 69 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 70 13.1. Normative References: . . . . . . . . . . . . . . . . . 9 71 13.2. Informative References . . . . . . . . . . . . . . . . . 11 72 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 74 1. Introduction 76 The Interface to the Routing System (I2RS) Working Group is chartered 77 with providing architecture and mechanisms to inject into and 78 retrieve information from the routing system. The I2RS Architecture 79 document [I-D.ietf-i2rs-architecture] abstractly documents a number 80 of requirements for implementing the I2RS requirements. Section 2 81 reviews 10 key requirements related to ephemeral state. 83 The I2RS Working Group has chosen to use the YANG data modeling 84 language [RFC6020] as the basis to implement its mechanisms. 86 Additionally, the I2RS Working group has chosen to re-use two 87 existing protocols, NETCONF [RFC6241] and its similar but lighter- 88 weight relative RESTCONF [I-D.ietf-netconf-restconf], as the 89 protocols for carrying I2RS. 91 What does re-use of a protocol mean? Re-use means that while YANG, 92 NETCONF and RESTCONF are a good starting basis for the I2RS protocol, 93 the creation of the I2RS protocol implementations requires that the 94 I2RS requirements 95 1. select features from YANG, NETCONF, and RESTCONF per version of 96 the I2RS protocol (See sections 4, 5, and 6) 98 2. propose additions to YANG, NETCONF, and RESTCONF per version of 99 the I2RS protocol for key functions (ephemeral state, protocol 100 security, publication/subscription service, traceability), 102 3. suggest protocol strawman (e.g. 103 [I-D.hares-i2rs-protocol-strawman]) as ideas for the NETCONF, 104 RESTCONF, and YANG changes. 106 The purpose of these requirements and the suggested protocol straw 107 man is to provide a quick turnaround on creating the I2RS protocol. 109 Support for ephemeral state is I2RS protocol requirement that 110 requires datastore changes (see section 3), YANG additions (see 111 section 4), NETCONF additions (see section 5), and RESTCONF additions 112 (see section 6). 114 Sections 7-9 provide details that expand upon the changes in sections 115 3-6 to clarify requirements discussed by the I2RS and NETCONF working 116 groups. Sections 7 provide additional requirements that detail how 117 write-conflicts should be resolved if two I2RS client write the same 118 data. Section 8 provides an additional requirement that details on 119 I2RS support of multiple message transactions. Section 9 highlights 120 two requirements in the I2RS publication/subscription requirements 121 [I-D.ietf-i2rs-pub-sub-requirements] that must be expanded for 122 ephemeral state. 124 1.1. Requirements Language 126 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 127 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 128 document are to be interpreted as described in RFC 2119 [RFC2119]. 130 2. Review of Requirements from I2RS architecture document 132 The I2RS architecture defines important high-level requirements for 133 the I2RS protocol. The following are ten requirements that 134 [I-D.ietf-i2rs-architecture] contains which provide context for the 135 ephemeral data state requirements given in sections 3-8: 137 1. The I2RS protocol SHOULD support highly reliable notifications 138 (but not perfectly reliable notifications) from an I2RS agent to 139 an I2RS client. 141 2. The I2RS protocol SHOULD support a high bandwidth, asynchronous 142 interface, with real-time guarantees on getting data from an 143 I2RS agent by an I2RS client. 145 3. The I2RS protocol will operate on data models which MAY be 146 protocol independent or protocol dependent. 148 4. I2RS Agent MUST record the client identity when a node is 149 created or modified. The I2RS Agent SHOULD to be able to read 150 the client identity of a node and use the client identity's 151 associated priority to resolve conflicts. The secondary 152 identity is useful for traceability and may also be recorded. 154 5. Client identity MUST have only one priority for the client's 155 identifier. A collision on writes is considered an error, but 156 the priority associated with each client identifier is utilized 157 to compare requests from two different clients in order to 158 modify an existing node entry. Only an entry from a client 159 which is higher priority can modify an existing entry (First 160 entry wins). Priority only has meaning at the time of use. 162 6. The Agent identity and the Client identity SHOULD be passed 163 outside of the I2RS protocol in a authentication and 164 authorization protocol (AAA). Client priority may be passed in 165 the AAA protocol. The values of identities are originally set 166 by operators, and not standardized. 168 7. An I2RS Client and I2RS Agent MUST mutually authenticate each 169 other based on pre-established authenticated identities. 171 8. Secondary identity data is read-only meta-data that is recorded 172 by the I2RS agent associated with a data model's node is 173 written, updated or deleted. Just like the primary identity, 174 the secondary identity SHOULD only be recorded when the data 175 node is written or updated or deleted 177 9. I2RS agent MAY have a lower priority I2RS client attempting to 178 modify a higher priority client's entry in a data model. The 179 filtering out of lower priority clients attempting to write or 180 modify a higher priority client's entry in a data model SHOULD 181 be effectively handled and not put an undue strain on the I2RS 182 agent. 184 10. The I2RS protocol MUST support the use of a secure transport. 185 However, certain functions such as notifications MAY use a non- 186 secure transport. Each model or service (notification, logging) 187 must define within the model or service the valid uses of a non- 188 secure transport. 190 3. Ephemeral State Requirements 192 In requirements Ephemeral-REQ-01 to Ephemeral-05, Ephemeral state is 193 defined as potentially including both ephemeral configured state and 194 operational state. 196 3.1. Persistence 198 Ephemeral-REQ-01: I2RS requires ephemeral state; i.e. state that does 199 not persist across reboots. If state must be restored, it should be 200 done solely by replay actions from the I2RS client via the I2RS 201 agent. 203 While at first glance this may seem equivalent to the writable- 204 running data store in NETCONF, running-config can be copied to a 205 persistent data store, like startup config. I2RS ephemeral state 206 MUST NOT be persisted. 208 3.2. Constraints 210 Ephemeral-REQ-02: Non-ephemeral state MUST NOT refer to ephemeral 211 state for constraint purposes; it SHALL be considered a validation 212 error if it does. 214 Ephemeral-REQ-03: Ephemeral state may have constraints that refer to 215 operational state, this includes potentially fast changing or short 216 lived operational state nodes, such as MPLS LSP-ID or a BGP IN-RIB. 218 Ephemeral-REQ-04: Ephemeral state MUST be able to refer to non- 219 ephemeral state as a constraint. 221 Ephemeral-REQ-05: I2RS pub-sub, logging, RPC or other mechanisms may 222 lead to undesirable or unsustainable resource consumption on a system 223 implementing an I2RS Agent. It is RECOMMENDED that mechanisms be 224 made available to permit prioritization of I2RS operations, when 225 appropriate, to permit implementations to shed work load when 226 operating under constrained resources. An example of such a work 227 shedding mechanism is rate-limiting. 229 3.3. Hierarchy 231 Ephemeral-REQ-06: The ability to: 233 1. to define a YANG module or submodule schema that only contains 234 data nodes with the property of being ephemeral, and 236 2. to augment a YANG data model with additional YANG schema nodes 237 that have the property of being ephemeral. 239 3.4. Ephemeral Configuration overlapping Local Configuration 241 Ephemeral-REQ-07: Ephemeral configuration state could override 242 overlapping local configuration state, or vice-versa. 243 Implementations MUST provide a mechanism to choose which takes 244 precedence. This mechanism MUST include local configuration (policy) 245 and MAY be provided via the I2RS protocol mechanisms. 247 4. YANG Features for Ephemeral State 249 Ephemeral-REQ-08: YANG MUST have a way to indicate in a data model 250 that schema nodes have the following properties: ephemeral, writable/ 251 not-writable, and status/configuration. 253 5. NETCONF Features for Ephemeral State 255 Ephemeral-REQ-09: The conceptual changes to NETCONF 257 1. Support for communication mechanisms to enable an I2RS client to 258 determine that an I2RS agent supports the mechanisms needed for 259 I2RS operation. 261 2. The ephemeral state must support notification of write conflicts 262 using the priority requirements defined in section 7 below in 263 requirements Ephemeral-REQ-11 through Ephemeral-REQ-14). 265 6. RESTCONF Features for Ephemeral State 267 Ephemeral-REQ-10: The conceptual changes to RESTCONF are: 269 1. Support for communication mechanisms to enable an I2RS client to 270 determine that an I2RS agent supports the mechanisms needed for 271 I2RS operation. 273 2. The ephemeral state must support notification of write conflicts 274 using the priority requirements defined in section 7 below in 275 requirements Ephemeral-REQ-11 through Ephemeral-REQ-14). 277 7. Requirements regarding Supporting Multi-Head Control via Client 278 Priority 280 To support Multi-Headed Control, I2RS requires that there be a 281 decidable means of arbitrating the correct state of data when 282 multiple clients attempt to manipulate the same piece of data. This 283 is done via a priority mechanism with the highest priority winning. 284 This priority is per-client. 286 Ephemeral-REQ-11: The data nodes MAY store I2RS client identity and 287 not the effective priority at the time the data node is stored. Per 288 SEC-REQ-07 in section 3.1 of 289 [I-D.ietf-i2rs-protocol-security-requirements], an identifier must 290 have just one priority. Therefore, the data nodes MAY store I2RS 291 client identity and not the effective priority of the I2RS client at 292 the time the data node is stored. The priority MAY be dynamically 293 changed by AAA, but the exact actions are part of the protocol 294 definition as long as collisions are handled as described in 295 Ephemeral-REQ-12, Ephemeral-REQ-13, and Ephemeral-REQ-14. 297 Ephemeral-REQ-12: When a collision occurs as two clients are trying 298 to write the same data node, this collision is considered an error 299 and priorities were created to give a deterministic result. When 300 there is a collision, a notification (which includes indicating data 301 node the collision occurred on) MUST BE sent to the original client 302 to give the original client a chance to deal with the issues 303 surrounding the collision. The original client may need to fix their 304 state. 306 Ephemeral-REQ-13: The requirement to support multi-headed control is 307 required for collisions and the priority resolution of collisions. 308 Multi-headed control is not tied to ephemeral state. I2RS is not 309 mandating how AAA supports priority. Mechanisms which prevent 310 collisions of two clients trying to modify the same node of data are 311 the focus. 313 Ephemeral-REQ-14: A deterministic conflict resolution mechanism MUST 314 be provided to handle the error scenario that two clients, with the 315 same priority, update the same configuration data node. The I2RS 316 architecture gives one way that this could be achieved, by specifying 317 that the first update wins. Other solutions, that prevent 318 oscillation of the config data node, are also acceptable. 320 8. Multiple Message Transactions 322 Ephemeral-REQ-15: Section 7.9 of the [I-D.ietf-i2rs-architecture] 323 states the I2RS architecture does not include multi-message atomicity 324 and roll-back mechanisms. I2RS notes multiple operations in one or 325 more messages handling can handle errors within the set of operations 326 in many ways. No multi-message commands SHOULD cause errors to be 327 inserted into the I2RS ephemeral state. 329 9. Pub/Sub Requirements Expanded for Ephemeral State 331 I2RS clients require the ability to monitor changes to ephemeral 332 state. While subscriptions are well defined for receiving 333 notifications, the need to create a notification set for all 334 ephemeral configuration state may be overly burdensome to the user. 336 There is thus a need for a general subscription mechanism that can 337 provide notification of changed state, with sufficient information to 338 permit the client to retrieve the impacted nodes. This should be 339 doable without requiring the notifications to be created as part of 340 every single I2RS module. 342 The publication/subscription requirements for I2RS are in 343 [I-D.ietf-i2rs-pub-sub-requirements], and the following general 344 requirements SHOULD be understood to be expanded to to include 345 ephemeral state: 347 o Pub-Sub-REQ-01: The Subscription Service MUST support 348 subscriptions against ephemeral data in operational data stores, 349 configuration data stores or both. 351 o Pub-Sub-REQ-02: The Subscription Service MUST support filtering so 352 that subscribed updates under a target node might publish only 353 ephemeral data in operational data or configuration data, or 354 publish both ephemeral and operational data. 356 10. IANA Considerations 358 There are no IANA requirements for this document. 360 11. Security Considerations 362 The security requirements for the I2RS protocol are covered in 363 [I-D.ietf-i2rs-protocol-security-requirements] document. The 364 security requirements for the I2RS protocol environment are in 365 [I-D.ietf-i2rs-security-environment-reqs]. 367 12. Acknowledgements 369 This document is an attempt to distill lengthy conversations on the 370 I2RS mailing list for an architecture that was for a long period of 371 time a moving target. Some individuals in particular warrant 372 specific mention for their extensive help in providing the basis for 373 this document: 375 o Alia Atlas 377 o Andy Bierman 379 o Martin Bjorklund 380 o Dean Bogdanavich 382 o Rex Fernando 384 o Joel Halpern 386 o Thomas Nadeau 388 o Juergen Schoenwaelder 390 o Kent Watsen 392 o Robert Wilton 394 13. References 396 13.1. Normative References: 398 [I-D.ietf-i2rs-architecture] 399 Atlas, A., Halpern, J., Hares, S., Ward, D., and T. 400 Nadeau, "An Architecture for the Interface to the Routing 401 System", draft-ietf-i2rs-architecture-15 (work in 402 progress), April 2016. 404 [I-D.ietf-i2rs-protocol-security-requirements] 405 Hares, S., Migault, D., and J. Halpern, "I2RS Security 406 Related Requirements", draft-ietf-i2rs-protocol-security- 407 requirements-06 (work in progress), May 2016. 409 [I-D.ietf-i2rs-pub-sub-requirements] 410 Voit, E., Clemm, A., and A. Prieto, "Requirements for 411 Subscription to YANG Datastores", draft-ietf-i2rs-pub-sub- 412 requirements-09 (work in progress), May 2016. 414 [I-D.ietf-i2rs-security-environment-reqs] 415 Migault, D., Halpern, J., and S. Hares, "I2RS Environment 416 Security Requirements", draft-ietf-i2rs-security- 417 environment-reqs-01 (work in progress), April 2016. 419 [I-D.ietf-i2rs-traceability] 420 Clarke, J., Salgueiro, G., and C. Pignataro, "Interface to 421 the Routing System (I2RS) Traceability: Framework and 422 Information Model", draft-ietf-i2rs-traceability-11 (work 423 in progress), May 2016. 425 [I-D.ietf-netconf-call-home] 426 Watsen, K., "NETCONF Call Home and RESTCONF Call Home", 427 draft-ietf-netconf-call-home-17 (work in progress), 428 December 2015. 430 [I-D.ietf-netconf-restconf] 431 Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF 432 Protocol", draft-ietf-netconf-restconf-14 (work in 433 progress), June 2016. 435 [I-D.ietf-netconf-server-model] 436 Watsen, K. and J. Schoenwaelder, "NETCONF Server and 437 RESTCONF Server Configuration Models", draft-ietf-netconf- 438 server-model-09 (work in progress), March 2016. 440 [I-D.ietf-netconf-yang-library] 441 Bierman, A., Bjorklund, M., and K. Watsen, "YANG Module 442 Library", draft-ietf-netconf-yang-library-06 (work in 443 progress), April 2016. 445 [I-D.ietf-netconf-yang-patch] 446 Bierman, A., Bjorklund, M., and K. Watsen, "YANG Patch 447 Media Type", draft-ietf-netconf-yang-patch-09 (work in 448 progress), June 2016. 450 [I-D.ietf-netconf-yang-push] 451 Clemm, A., Prieto, A., Voit, E., Tripathy, A., and E. 452 Nilsen-Nygaard, "Subscribing to YANG datastore push 453 updates", draft-ietf-netconf-yang-push-03 (work in 454 progress), June 2016. 456 [I-D.ietf-netconf-zerotouch] 457 Watsen, K. and M. Abrahamsson, "Zero Touch Provisioning 458 for NETCONF or RESTCONF based Management", draft-ietf- 459 netconf-zerotouch-08 (work in progress), April 2016. 461 [I-D.ietf-netmod-yang-metadata] 462 Lhotka, L., "Defining and Using Metadata with YANG", 463 draft-ietf-netmod-yang-metadata-07 (work in progress), 464 March 2016. 466 [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., 467 and A. Bierman, Ed., "Network Configuration Protocol 468 (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, 469 . 471 13.2. Informative References 473 [I-D.hares-i2rs-protocol-strawman] 474 Hares, S., Bierman, A., and a. amit.dass@ericsson.com, 475 "I2RS protocol strawman", draft-hares-i2rs-protocol- 476 strawman-02 (work in progress), May 2016. 478 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 479 Requirement Levels", BCP 14, RFC 2119, 480 DOI 10.17487/RFC2119, March 1997, 481 . 483 [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for 484 the Network Configuration Protocol (NETCONF)", RFC 6020, 485 DOI 10.17487/RFC6020, October 2010, 486 . 488 [RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration 489 Protocol (NETCONF) Access Control Model", RFC 6536, 490 DOI 10.17487/RFC6536, March 2012, 491 . 493 Authors' Addresses 495 Jeff Haas 496 Juniper 498 Email: jhaas@juniper.net 500 Susan Hares 501 Huawei 502 Saline 503 US 505 Email: shares@ndzh.com