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2 Interface to the Routing System (i2rs) E. Voit
3 Internet-Draft A. Clemm
4 Intended status: Informational A. Gonzalez Prieto
5 Expires: October 17, 2016 Cisco Systems
6 April 15, 2016
8 Requirements for Subscription to YANG Datastores
9 draft-ietf-i2rs-pub-sub-requirements-06
11 Abstract
13 This document provides requirements for a service that allows client
14 applications to subscribe to updates of a YANG datastore. Based on
15 criteria negotiated as part of a subscription, updates will be pushed
16 to targeted recipients. Such a capability eliminates the need for
17 periodic polling of YANG datastores by applications and fills a
18 functional gap in existing YANG transports (i.e. Netconf and
19 Restconf). Such a service can be summarized as a "pub/sub" service
20 for YANG datastore updates. Beyond a set of basic requirements for
21 the service, various refinements are addressed. These refinements
22 include: periodicity of object updates, filtering out of objects
23 underneath a requested a subtree, and delivery QoS guarantees.
25 Status of This Memo
27 This Internet-Draft is submitted in full conformance with the
28 provisions of BCP 78 and BCP 79.
30 Internet-Drafts are working documents of the Internet Engineering
31 Task Force (IETF). Note that other groups may also distribute
32 working documents as Internet-Drafts. The list of current Internet-
33 Drafts is at http://datatracker.ietf.org/drafts/current/.
35 Internet-Drafts are draft documents valid for a maximum of six months
36 and may be updated, replaced, or obsoleted by other documents at any
37 time. It is inappropriate to use Internet-Drafts as reference
38 material or to cite them other than as "work in progress."
40 This Internet-Draft will expire on October 17, 2016.
42 Copyright Notice
44 Copyright (c) 2016 IETF Trust and the persons identified as the
45 document authors. All rights reserved.
47 This document is subject to BCP 78 and the IETF Trust's Legal
48 Provisions Relating to IETF Documents
49 (http://trustee.ietf.org/license-info) in effect on the date of
50 publication of this document. Please review these documents
51 carefully, as they describe your rights and restrictions with respect
52 to this document. Code Components extracted from this document must
53 include Simplified BSD License text as described in Section 4.e of
54 the Trust Legal Provisions and are provided without warranty as
55 described in the Simplified BSD License.
57 Table of Contents
59 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
60 2. Business Drivers . . . . . . . . . . . . . . . . . . . . . . 3
61 2.1. Pub/Sub in I2RS . . . . . . . . . . . . . . . . . . . . . 3
62 2.2. Pub/Sub variants on Network Elements . . . . . . . . . . 5
63 2.3. Existing Generalized Pub/Sub Implementations . . . . . . 5
64 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
65 4. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 7
66 4.1. Assumptions for Subscriber Behavior . . . . . . . . . . . 7
67 4.2. Subscription Service Requirements . . . . . . . . . . . . 7
68 4.2.1. General . . . . . . . . . . . . . . . . . . . . . . . 7
69 4.2.2. Negotiation . . . . . . . . . . . . . . . . . . . . . 9
70 4.2.3. Update Distribution . . . . . . . . . . . . . . . . . 9
71 4.2.4. Transport . . . . . . . . . . . . . . . . . . . . . . 10
72 4.2.5. Security Requirements . . . . . . . . . . . . . . . . 11
73 4.2.6. Subscription QoS . . . . . . . . . . . . . . . . . . 11
74 4.2.7. Filtering . . . . . . . . . . . . . . . . . . . . . . 13
75 4.2.8. Assurance and Monitoring . . . . . . . . . . . . . . 13
76 5. Security Considerations . . . . . . . . . . . . . . . . . . . 14
77 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
78 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
79 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
80 8.1. Normative References . . . . . . . . . . . . . . . . . . 14
81 8.2. Informative References . . . . . . . . . . . . . . . . . 15
82 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
84 1. Introduction
86 Applications interacting with YANG datastores require capabilities
87 beyond the traditional client-server configuration of network
88 elements. One class of such applications are service-assurance
89 applications which must maintain a continuous view of operational
90 data and state. Another class of applications are security
91 applications which must continuously track changes made upon network
92 elements to ensure compliance to corporate policy.
94 Periodic fetching of data is not an adequate solution for
95 applications requiring frequent or prompt updates of remote object
96 state. Applying polling-based solutions here imposes load on
97 networks, devices, and applications. Additionally, polling solutions
98 are brittle in the face of communication glitches, and have
99 limitations in their ability to synchronize and calibrate retrieval
100 intervals across a network. These limitations can be addressed by
101 including generic object subscription mechanisms within Network
102 Elements, and allowing these mechanisms to be applied in the context
103 of data that is conceptually contained in YANG datastores.
105 This document aggregates requirements for such subscription from a
106 variety of deployment scenarios.
108 2. Business Drivers
110 For decades, information delivery of current network state has been
111 accomplished either by fetching from operations interfaces, or via
112 dedicated, customized networking protocols. With the growth of
113 centralized orchestration infrastructures, imperative policy
114 distribution, and YANG's ascent as the dominant data modeling
115 language for use in programmatic interfaces to network elements, this
116 mixture of fetch plus custom networking protocols is no longer
117 sufficient. What is needed is a push mechanism that is able to
118 deliver object changes as they happen.
120 These push distribution mechanisms will not replace existing
121 networking protocols. Instead they will supplement these protocols,
122 providing different response time, peering, scale, and security
123 characteristics.
125 Push solutions will not displace all existing operations
126 infrastructure needs. And SNMP and MIBs will remain widely deployed
127 and the defacto choice for many monitoring solutions. But some
128 functions could be displaced. Arguably the biggest shortcoming of
129 SNMP for those applications concerns the need to rely on periodic
130 polling, because it introduces additional load on the network and
131 devices, because it is brittle in case polling cycles are missed, and
132 because is hard to synchronize and calibrate across a network. If
133 applications can only use polling type interaction patterns with YANG
134 datastores, similar issues can be expected.
136 2.1. Pub/Sub in I2RS
138 Various I2RS documents highlight the need to provide Pub/Sub
139 capabilities between network elements. From [i2rs-arch], there are
140 references throughout the document beginning in section 6.2. Some
141 specific examples include:
143 o section 7.6 provides high level pub/sub (notification) guidance
144 o section 6.4.2 identifies "subscribing to an information stream of
145 route changes receiving notifications about peers coming up or
146 going down"
148 o section 6.3 notes that when local config preempts I2RS, external
149 notification might be necessary
151 In addition [i2rs-usecase] has relevant requirements. A small subset
152 includes:
154 o L-Data-REQ-12: The I2RS interface should support user
155 subscriptions to data with the following parameters: push of data
156 synchronously or asynchronously via registered subscriptions...
158 o L-DATA-REQ-07: The I2RS interface (protocol and IMs) should allow
159 a subscriber to select portions of the data model.
161 o PI-REQ01: monitor the available routes installed in the RIB of
162 each forwarding device, including near real time notification of
163 route installation and removal.
165 o BGP-REQ10: I2RS client should be able to instruct the I2RS
166 agent(s) to notify the I2RS client when the BGP processes on an
167 associated routing system observe a route change to a specific set
168 of IP Prefixes and associated prefixes....The I2RS agent should be
169 able to notify the client via publish or subscribe mechanism.
171 o IGP-REQ-07: The I2RS interface (protocol and IMs) should support a
172 mechanism where the I2RS Clients can subscribe to the I2RS Agent's
173 notification of critical node IGP events.
175 o MPLS-LDP-REQ-03: The I2RS Agent notifications should allow an I2RS
176 client to subscribe to a stream of state changes regarding the LDP
177 sessions or LDP LSPs from the I2RS Agent.
179 o L-Data-REQ-01: I2rs must be able to collect large data set from
180 the network with high frequency and resolution with minimal impact
181 to the device's CPU and memory.
183 And [i2rs-traceability] has Pub/Sub requirements listed in
184 Section 7.4.3.
186 o I2RS Agents should support publishing I2RS trace log information
187 to that feed as described in [i2rs-arch]. Subscribers would then
188 receive a live stream of I2RS interactions in trace log format and
189 could flexibly choose to do a number of things with the log
190 messages
192 2.2. Pub/Sub variants on Network Elements
194 This document is intended to cover requirements beyond I2RS. Looking
195 at history, there are many examples of switching and routing
196 protocols which have done explicit or implicit pub/sub in the past.
197 In addition, new policy notification mechanisms which operate on
198 Switches and Routers are being specified now. A small subset of
199 current and past subscriptions includes:
201 o Multicast topology establishment is accomplished before any
202 content delivery is made to endpoints (IGMP, PIM, etc.)
204 o Secure Automation and Continuous Monitoring (SACM) allows
205 subscription into devices which then may push spontaneous changes
206 in their configured hardware and software[sacm-requirements]
208 o In MPLS VPNs [RFC6513] a Customer Edge router exchanges PIM
209 control messages before PE Routing Adjacencies are passed.
210 [RFC6513]
212 o After OSPF establishes its adjacencies, Link State Advertisement
213 will then commence [RFC2328]
215 Worthy of note in the examples above is the wide variety of
216 underlying transports. A generalized Pub/Sub mechanism therefore
217 should be structured to support alternative transports. Based on
218 current I2RS requirements, NETCONF should the initially supported
219 transport based on the need for connection-oriented/unicast
220 communication. Eventual support Multicast and Broadcast subscription
221 update distribution will be needed as well.
223 2.3. Existing Generalized Pub/Sub Implementations
225 TIBCO, RSS, CORBA, and other technologies all show precursor Pub/Sub
226 technologies. However there are new needs described in Section 4
227 below which these technologies do not serve. We need a new pub-sub
228 technology.
230 There are at least two widely deployed generalized pub/sub
231 implementations which come close to current needs: XMPP[XEP-0060] and
232 DDS[OMG-DDS]. Both serve as proof-points that a highly scalable
233 distributed datastore implementation connecting millions of edge
234 devices is possible.
236 Because of these proof points, we can be comfortable that the
237 underlying technologies can enable reusable generalized YANG object
238 distribution. Analysis will need to fully dimension the speed and
239 scale of such object distribution for various subtree sizes and
240 transport types.
242 3. Terminology
244 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
245 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
246 document are to be interpreted as described in [RFC2119].
248 A Subscriber makes requests for set(s) of YANG object data.
250 A Publisher is responsible for distributing subscribed YANG object
251 data per the terms of a Subscription. In general, a Publisher is the
252 owner of the YANG datastore that is subjected to the Subscription.
254 A Receiver is the target to which a Publisher pushes updates. In
255 general, the Receiver and Subscriber will be the same entity. A
256 Subscription Service provides Subscriptions to Subscribers of YANG
257 data.
259 A Subscription Service interacts with the Publisher of the YANG data
260 as needed to provide the data per the terms of the Subscription.
262 A Subscription Request for one or more YANG subtrees (including
263 single leafs) is made by the Subscriber of a Publisher and is
264 targeted to a Receiver. A Subscription may include constraints which
265 dictate how often or under what conditions YANG information updates
266 might be sent.
268 A Subscription is a contract between a Subscription Service and a
269 Subscriber that stipulates the data to be pushed and the associated
270 terms.
272 A YANG datastore is a conceptual datastore that contains hierarchical
273 data defined in YANG data models. It is what is referred in existing
274 RFCs as "NETCONF datastore". However, as the same datastore is no
275 longer tied to NETCONF as a specific transport, the term "YANG
276 datastore" is deemed more appropriate.
278 An Update provides object changes which have occurred within
279 subscribed YANG subtree(s). An Update must include the current
280 status of (data) node instances which according to any filtering are
281 reportably different from the previously provided state. An Update
282 may include a bundled set of ordered/sequential changes for a given
283 object which have been made since the last update.
285 A Filter contains evaluation criteria which are evaluated against
286 YANG object(s) within a Subscription. There are two types of
287 Filters: Subtree Filters which identify selected objects/nodes
288 published under a target data node, and object Property Filters where
289 an object should only be published if it has propert(ies) meeting
290 specified Filter criteria. For "on-change" notifications, passing
291 through the Filter requires that a subscribed object is now different
292 that from the previous Push, AND at least one of the YANG objects
293 being evaluated has changed since the last Update.
295 4. Requirements
297 Many of the requirements within this section have been morphed from
298 XMPP[XEP-0060] and DDS[OMG-DDS] requirements specifications.
300 4.1. Assumptions for Subscriber Behavior
302 This document provides requirements for the Subscription Service. It
303 does not define all the requirements for the Subscriber/Receiver.
304 However in order to frame the desired behavior of the Subscription
305 Service, it is important to specify key input constraints.
307 A Subscriber SHOULD avoid attempting to establish multiple
308 Subscriptions pertaining to the same information, i.e. referring to
309 the same datastore YANG subtrees.
311 A Subscriber MAY provide Subscription QoS criteria to the
312 Subscription Service; if the Subscription Service is unable to meet
313 those criteria, the Subscription SHOULD NOT be established.
315 When a Subscriber needs to restart, the Subscriber MAY have to
316 resubscribe. There is no requirement for the life span of the
317 Subscription to extend beyond the life span of the Subscriber.
319 A Subscriber MUST be able to infer when a Subscription Service is no
320 longer active and when no more updates are being sent.
322 A Subscriber MAY check with a Subscription Service to validate the
323 existence and monitored subtrees of a Subscription.
325 A Subscriber MUST be able to periodically lease and extend the lease
326 a Subscription from a Subscription Service.
328 4.2. Subscription Service Requirements
330 4.2.1. General
332 A Subscription Service MUST support the ability to create, renew,
333 timeout, and terminate a Subscription.
335 A Subscription Service MUST be able to support and independently
336 track one or more Subscription Requests by the same Subscriber.
338 A Subscription Service MUST be able to support an add/change/delete
339 of one or more YANG subtrees as part of the same Subscription
340 Request.
342 A Subscription Service MUST support Subscriptions against operational
343 datastores, configuration datastores, or both.
345 A Subscription Service MUST be able support a Subtree Filter so that
346 subscribed updates under a target node might publish only operational
347 data, only configuration data, or both.
349 A Subscription MAY include filters as defined within a Subscription
350 Request, therefore the Subscription Service MUST publish only data
351 nodes that meet the filter criteria within a Subscription.
353 A Subscription Service MUST support the ability to subscribe to
354 periodic updates. The subscription period MUST be configurable as
355 part of the subscription request.
357 A Subscription Service SHOULD support the ability to subscribe to
358 updates "on-change", i.e., whenever values of subscribed data objects
359 change.
361 For "on-change" updates, the Subscription Service MUST support a
362 dampening period that needs to pass before the first or subsequent
363 "on-change" updates are sent. The dampening period SHOULD be
364 configurable as part of the subscription request.
366 A Subscription Service MUST allow Subscriptions to be monitored.
367 Specifically, a Subscription Service MUST at a minimum maintain
368 information about which Subscriptions are being serviced, the terms
369 of those subscriptions (e.g., what data is being subscribed,
370 associated filters, update policy - on change, periodic), and the
371 overall status of the Subscription - e.g., active or suspended.
373 A Subscription Service SHOULD be able to interpret Subscription QoS
374 parameters, and only establish a Subscription if it is possible to
375 meet the QoS needs of the provided QoS parameters.
377 A Subscription Service MUST support terminating of a Subscription
378 when requested by the Subscriber.
380 A Subscription Service SHOULD support the ability to suspend and to
381 resume a Subscription on request of a client.
383 A Subscription Service MAY at its discretion revoke or suspend an
384 existing subscription. Reasons may include transitory resource
385 limitation, credential expiry, failure to reconfirm a subscription,
386 loss of connectivity with the Receiver, operator CLI, and/or others.
387 When this occurs, the Subscription Service MUST notify the Subscriber
388 and update subscription status.
390 A Subscription Service MAY offer the ability to modify a subscription
391 filter. If such an ability is offered, the service MUST provide
392 subscribers with an indication telling at what point the modified
393 subscription goes into effect.
395 4.2.2. Negotiation
397 A Subscription Service MUST be able to negotiate the following terms
398 of a Subscription:
400 o The policy: i.e. whether updates are on-change or periodic
402 o The interval, for periodic publication policy
404 o The dampening period, for on-change update policy (if supported)
406 o Any filters associated with a subtree subscription
408 A Subscription Service SHOULD be able to negotiate QoS criteria for a
409 Subscription. Examples of Subscription QoS criteria may include
410 reliability of the Subscription Service, reaction time between a
411 monitored YANG subtree/object change and a corresponding notification
412 push, and the Subscription Service's ability to support certain
413 levels of object liveliness.
415 In cases where a Subscription Request cannot be fulfilled, the
416 Subscription Service MUST include in its decline a set of criteria
417 that would have been acceptable when the Subscription Request was
418 made. For example, if periodic updates were requested with too short
419 update intervals for the specified data set, an alternative
420 acceptable interval period might be returned from the Publisher. If
421 on-change updates were requested with too-aggressive a dampening
422 period, then an acceptable dampening period may be returned, or
423 alternatively an indication that only periodic updates are supported
424 for the requested object(s).
426 4.2.3. Update Distribution
428 For "on-change" updates, the Subscription Service MUST only send
429 deltas to the object data for which a change occurred. [Otherwise
430 the subscriber might not know what has actually undergone change.]
431 The updates for each object MUST include an indication whether it was
432 removed, added, or changed.
434 When a Subscription Service is not able to send updates per its
435 subscription contract, the Subscription MUST notify subscribers and
436 put the subscription into a state indicating the Subscription was
437 suspended by the service. When able to resume service, subscribers
438 need to be notified as well. If unable to resume service, the
439 Subscription Service MAY terminate the subscription and notify
440 Subscribers accordingly.
442 When a Subscription with "on-change" updates is suspended and then
443 resumed, the first update SHOULD include updates of any changes that
444 occurred while the Subscription was suspended, with the current
445 value. The Subscription Service MUST provide a clear indication when
446 this capability is not supported (because in this case a client
447 application may have to synchronize state separately).
449 Multiple objects being pushed to a Subscriber, perhaps from different
450 Subscriptions, SHOULD be bundled together into a single Update.
452 The sending of an Update MUST NOT be delayed beyond the Push Latency
453 of any enclosed object changes.
455 The sending of an Update MUST NOT be delayed beyond the dampening
456 period of any enclosed object changes.
458 The sending of an Update MUST NOT occur before the dampening period
459 expires for any enclosed object changes.
461 A Subscription Service MAY, as an option, support a persistence/
462 replay capability.
464 4.2.4. Transport
466 A Subscription Service SHOULD support different transports.
468 A Subscription Service SHOULD support different encodings of payload.
470 It MUST be possible for Receivers to associate the update with a
471 specific Subscription.
473 In the case of connection-oriented transport, when a transport
474 connection drops, the associated Subscription SHOULD be terminated.
475 It is up the Subscriber to request a new Subscription.
477 4.2.5. Security Requirements
479 As part of the Subscription establishment, there MUST be mutual
480 authentication between the Subscriber and the Subscription Service.
482 When there are multiple Subscribers, it SHOULD be possible to provide
483 cryptographic authentication in such a way that no Subscriber can
484 pose as the original Subscription Service.
486 Versioning MUST be supported.
488 A Subscription could be used to attempt to retrieve information that
489 a client has not authorized access to. Therefore it is important
490 that data pushed based on Subscriptions is authorized in the same way
491 that regular data retrieval operations are authorized. Data being
492 pushed to a client MUST be filtered accordingly, just like if the
493 data were being retrieved on-demand. For Unicast transports, the
494 NETCONF Authorization Control Model applies.
496 Additions or changes within a subscribed subtree structure MUST be
497 validated against authorization methods before Subscription Updates
498 including new subtree information are pushed.
500 A loss of authenticated access to subtree or node SHOULD be
501 communicated to the Subscriber.
503 Subscription requests, including requests to create, terminate,
504 suspend, and resume Subscriptions MUST be properly authorized.
506 When the Subscriber and Receiver are different, the Receiver MUST be
507 able to terminate any Subscription to it where objects are being
508 delivered over a Unicast transport.
510 A Subscription Service SHOULD decline a Subscription Request if it is
511 likely to deplete its resources. It is preferable to decline a
512 Subscription when originally requested, rather than having to
513 terminate it prematurely later.
515 4.2.6. Subscription QoS
517 A Subscription Service SHOULD be able to negotiate the following
518 Subscription QoS parameters with a Subscriber: Dampening,
519 Reliability, Deadline, and Bundling.
521 4.2.6.1. Liveliness
523 A Subscription Service MUST be able to respond to requests to verify
524 the Liveliness of a subscription.
526 A Subscription Service MUST be able to report the currently monitored
527 Nodes of a Subscription.
529 4.2.6.2. Dampening
531 A Subscription Service MUST be able to negotiate the minimum time
532 separation since the previous update before transmitting a subsequent
533 update for Subscription. (Note: this is intended to confine the
534 visibility of volatility into something digestible by the receiver.)
536 4.2.6.3. Reliability
538 A Subscription Service MAY send Updates over Best Effort and Reliable
539 transports.
541 4.2.6.4. Coherence
543 For a particular Subscription, every update to a subscribed object
544 MUST be sent to the Receiver in sequential order.
546 4.2.6.5. Presentation
548 The Subscription Service MAY have the ability to bundle a set of
549 discrete object notifications into a single publishable update for a
550 Subscription. A bundle MAY include information on different Data
551 Nodes and/or multiple updates about a single Data Node.
553 For any bundled updates, the Subscription Service MUST provide
554 information for a Receiver to reconstruct the order and timing of
555 updates.
557 4.2.6.6. Deadline
559 The Subscription Service MUST be able to push updates at a regular
560 cadence that corresponds with Subscriber specified start and end
561 timestamps. (Note: the regular cadence can drive one, a discrete
562 quantity, or an unbounded set of periodic updates.)
564 4.2.6.7. Push Latency
566 The Subscription Service SHOULD be able to delay Updates on object
567 push for a configurable period per Subscriber.
569 It MUST be possible for an administrative entity to determine the
570 Push latency between object change in a monitored subtree and the
571 Subscription Service Push of the update transmission.
573 4.2.7. Filtering
575 If no filtering criteria are provided, or if filtering criteria are
576 met, updates for a subscribed object MUST be pushed, subject to the
577 QoS limits established for the subscription.
579 It MUST be possible for the Subscription Service to receive Filter(s)
580 from a Subscriber and apply them to corresponding object(s) within a
581 Subscription.
583 It MUST be possible to attach one or more Subtree and/or Property
584 Filters to a subscription. Mandatory Property Filter types include:
586 o For character-based object properties, filter values which are
587 exactly equal to a provided string, not equal to the string, or
588 containing a string.
590 o For numeric based object properties, filter values which are =,
591 !=, <, <=, >, >= a provided number.
593 It SHOULD be possible for Property Filtering criteria to evaluate
594 more than one property of a particular subscribed object as well as
595 apply multiple filters against a single property.
597 It SHOULD be possible to establish query match criteria on additional
598 objects to be used in conjunction with Property Filtering criteria on
599 a subscribed object. (For example: if A has changed AND B=1, then
600 Push A.) Query match capability may be done on objects within the
601 datastore even if those objects are not included within the
602 subscription. This of course assumes the subscriber has read access
603 to those objects.
605 4.2.8. Assurance and Monitoring
607 It MUST be possible to fetch the state of a single subscription from
608 a Subscription Service.
610 It MUST be possible to fetch the state of all subscriptions of a
611 particular Subscriber.
613 It MUST be possible to fetch a list and status of all Subscription
614 Requests over a period of time. If there us a failure, some failure
615 reasons MAY include:
617 o Improper security credentials provided to access the target node;
619 o Target node referenced does not exist;
621 o Subscription type requested is not available upon the target node;
623 o Out of resources, or resources not available;
625 o Incomplete negotiations with the Subscriber.
627 5. Security Considerations
629 There are no additional security considerations beyond the
630 requirements listed in Section 4.2.5.
632 6. IANA Considerations
634 This document has no actions for IANA.
636 7. Acknowledgements
638 We wish to acknowledge the helpful contributions, comments, and
639 suggestions that were received from Ambika Tripathy and Prabhakara
640 Yellai as well as the helpfulness of related end-to-end system
641 context info from Nancy Cam Winget, Ken Beck, and David McGrew.
643 8. References
645 8.1. Normative References
647 [i2rs-arch]
648 Atlas, A., "An Architecture for the Interface to the
649 Routing System", February 2016,
650 .
653 [i2rs-traceability]
654 Clarke, J., Salgueiro, G., and C. Pignataro, "Interface to
655 the Routing System (I2RS) Traceability: Framework and
656 Information Model", February 2016,
657 .
660 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
661 Requirement Levels", BCP 14, RFC 2119,
662 DOI 10.17487/RFC2119, March 1997,
663 .
665 [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328,
666 DOI 10.17487/RFC2328, April 1998,
667 .
669 [RFC6513] Rosen, E., Ed. and R. Aggarwal, Ed., "Multicast in MPLS/
670 BGP IP VPNs", RFC 6513, DOI 10.17487/RFC6513, February
671 2012, .
673 8.2. Informative References
675 [i2rs-usecase]
676 Hares, S. and M. Chen, "Summary of I2RS Use Case
677 Requirements", March 2016,
678 .
681 [OMG-DDS] "Data Distribution Service for Real-time Systems, version
682 1.2", January 2007, .
684 [sacm-requirements]
685 Cam Winget, N., "Secure Automation and Continuous
686 Monitoring (SACM) Requirements", March 2016,
687 .
690 [XEP-0060]
691 Millard, P., "XEP-0060: Publish-Subscribe", July 2010,
692 .
694 Authors' Addresses
696 Eric Voit
697 Cisco Systems
699 Email: evoit@cisco.com
701 Alexander Clemm
702 Cisco Systems
704 Email: alex@cisco.com
706 Alberto Gonzalez Prieto
707 Cisco Systems
709 Email: albertgo@cisco.com