-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathdraft-ietf-netconf-distributed-notif-03.xml
911 lines (735 loc) · 33.1 KB
/
draft-ietf-netconf-distributed-notif-03.xml
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
<?xml version="1.0" encoding="US-ASCII"?>
<!DOCTYPE rfc SYSTEM "rfc2629.dtd">
<?rfc toc="yes"?>
<?rfc tocompact="yes"?>
<?rfc tocdepth="3"?>
<?rfc tocindent="yes"?>
<?rfc symrefs="yes"?>
<?rfc sortrefs="yes"?>
<?rfc comments="yes"?>
<?rfc inline="yes"?>
<?rfc compact="yes"?>
<?rfc subcompact="no"?>
<rfc category="std" docName="draft-ietf-netconf-distributed-notif-03"
ipr="trust200902">
<front>
<title abbrev="Distributed Notifications">Subscription to Distributed
Notifications</title>
<author fullname="Tianran Zhou" initials="T." surname="Zhou">
<organization>Huawei</organization>
<address>
<postal>
<street>156 Beiqing Rd., Haidian District</street>
<city>Beijing</city>
<region/>
<code/>
<country>China</country>
</postal>
<phone/>
<facsimile/>
<email>[email protected]</email>
<uri/>
</address>
</author>
<author fullname="Guangying Zheng" initials="G." surname="Zheng">
<organization>Huawei</organization>
<address>
<postal>
<street>101 Yu-Hua-Tai Software Road</street>
<city>Nanjing</city>
<code/>
<region>Jiangsu</region>
<country>China</country>
</postal>
<phone/>
<facsimile/>
<email>[email protected]</email>
</address>
</author>
<author fullname="Eric Voit" initials="E." surname="Voit">
<organization>Cisco Systems</organization>
<address>
<postal>
<street/>
<city/>
<code/>
<region/>
<country>United States of America</country>
</postal>
<phone/>
<facsimile/>
<email>[email protected]</email>
</address>
</author>
<author fullname="Thomas Graf" initials="T." surname="Graf">
<organization>Swisscom</organization>
<address>
<postal>
<street>Binzring 17</street>
<city>Zuerich 8045</city>
<region/>
<code/>
<country>Switzerland</country>
</postal>
<phone/>
<facsimile/>
<email>[email protected]</email>
<uri/>
</address>
</author>
<author fullname="Pierre Francois" initials="P." surname="Francois">
<organization>INSA-Lyon</organization>
<address>
<postal>
<street/>
<city>Lyon</city>
<region/>
<code/>
<country>France</country>
</postal>
<phone/>
<facsimile/>
<email>[email protected]</email>
<uri/>
</address>
</author>
<date day="11" month="January" year="2022"/>
<workgroup>NETCONF</workgroup>
<abstract>
<t>This document describes extensions to the YANG notifications
subscription to allow metrics being published directly from processors
on line cards to target receivers, while subscription is still
maintained at the route processor in a distributed forwarding
system.</t>
</abstract>
<note title="Requirements Language">
<t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in <xref
target="RFC2119">RFC 2119</xref>.</t>
</note>
</front>
<middle>
<section title="Introduction">
<t>The mechanism to support a subscription of a continuous and
customized stream of updates from a YANG datastore is defined in <xref
target="RFC8639"/> and <xref target="RFC8641"/>. Requirements for
Subscription to YANG Datastores are defined in <xref
target="RFC7923"/></t>
<t>By streaming data from publishers to receivers, much better
performance and fine-grained sampling can be achieved than with polling.
In a distributed forwarding system, the packet forwarding is delegated
to multiple processors on line cards. To not to overwhelm the route
processor resources, it is not uncommon that data records are published
directly from processors on line cards to target Receivers to further
increase efficiency on the routing system.</t>
<t>This documents complement the general subscription requirements
defined in section 4.2.1 of <xref target="RFC7923"/> by the paragraph: A
Subscription Service MAY support the ability to export from multiple
software processes on a single routing system and expose the information
which software process produced which message to maintain data
integrity.</t>
</section>
<section title="Terminologies">
<t>The following terms are defined in <xref target="RFC8639"/> and are
not redefined here:</t>
<t>Subscriber</t>
<t>Publisher</t>
<t>Receiver</t>
<t>Subscription</t>
<t>In addition, this document defines the following terms:</t>
<t>Global Subscription: the Subscription requested by the subscriber. It
may be decomposed into multiple Component Subscriptions.</t>
<t>Component Subscription: is the Subscription that defines a data
source which is managed and controlled by a single Publisher.</t>
<t>Global Capability: is the overall subscription capability that the
group of Publishers can expose to the Subscriber.</t>
<t>Component Capability: is the subscription capability that each
Publisher can expose to the Subscriber.</t>
<t>Master: is the Publisher that interacts with the Subscriber to deal
with the Global Subscription. It decomposes the Global Subscription to
multiple Component Subscriptions and interacts with the Agents.</t>
<t>Agent: is the Publisher that interacts with the Master to deal with
the Component Subscription and pushing the data to the Receiver.</t>
<t>Observation Domain: An Observation Domain is the largest set of
Observation Points for which metrics can be collected by a metering
process. For example, a router line card may be an Observation Domain if
it is composed of several interfaces, each of which is an Observation
Point. In the YANG notification messages it generates, the Observation
Domain includes its Observation Domain ID, which is unique per publisher
process. That way, the collecting process can identify the specific
Observation Domain from the publisher that sends the YANG notification
messages. Every Observation Point is associated with an Observation
Domain.</t>
<t>Observation Domain ID: A 32-bit identifier of the Observation Domain
that is locally unique to the publisher process. The publisher processes
uses the Observation Domain ID to uniquely identify to the collecting
process the Observation Domain that meters the metrics. Receivers SHOULD
use the transport session and the Observation Domain ID field to
separate different publisher streams originating from the same
publisher.</t>
</section>
<section title="Motivation">
<t>Lost and corrupt YANG notification messages need to be recognized at
the receiver to ensure data integrity even when multiple publisher
processes publishing from the same transport session.</t>
<t>To preserve data integrity down to the publisher process, the
Observation Domain ID in the transport message header of the YANG
notification message is introduced. In case of UDP transport, this is
described in Section 3.2 of <xref target="I-D.ietf-netconf-udp-notif">
UDP based transport</xref>.</t>
</section>
<section title="Solution Overview">
<t>Figure 2 below shows the distributed data export framework.</t>
<t>A collector usually includes two components,</t>
<t><list style="symbols">
<t>the Subscriber generates the subscription instructions to express
what and how the Receiver want to receive the data;</t>
<t>the Receiver is the target for the data publication.</t>
</list></t>
<t>For one subscription, there can be one or more Receivers. And the
Subscriber does not necessarily share the same IP address as the
Receivers.</t>
<t>In this framework, the Publisher pushes data to the Receiver
according to the subscription. The Publisher is either in the Master or
Agent role. The Master knows all the capabilities that his Agents are
able to provide and exposes the Global Capability to the collector. The
Subscriber maintains the Global Subscription at the Master and
disassembles the Global Subscription to multiple Component
Subscriptions, depending from which source data is needed. The Component
Subscriptions are then distributed to the corresponding Publisher Agents
on route and processors on line cards.</t>
<t>Publisher Agents collects metrics according to the Component
Subscription, add its metadata, encapsulate and pushes data to the
Receiver where packets are reassembled and decapsulated.</t>
<t><figure title="Fig. 2 The Distributed Data Export Framework">
<artwork align="center"><![CDATA[
+-----------------------------------------+
| Collector |-------------+ |
| +------------+ | |
| +------------+ || Receiver | | |
| | Subscriber | |--------------+ |
| +-----^-+----+ +------------^ |
| | | | |
+-----------------------------------------+
Global | | Global |
Capability| | Subscription |
+-----------------------------------------+
| | | | |
| +--------+-v-------------------+ | |
| | Publisher(Master) | | |
| +--------^-+-------------------+ | |
| | | | |
| | | | |
| Component | | Component Push | |
| Capability| | Subscription | |
| +--------+-v-------------------+ | |
| | Publisher(Agent) +--+ |
| +------------------------------+ |
| |
| Device |
+-----------------------------------------+
]]></artwork>
</figure></t>
<t>Master and Agents interact with each other in several ways: <list
style="symbols">
<t>Agents need to register at the Master at the beginning of their
process life-cycle</t>
<t>Contracts are created between the Master and each Agent on the
Component Capability, and the format for streaming data
structure.</t>
<t>The Master relays the component subscriptions to the Agents.</t>
<t>The Agents announce the status of their Component Subscriptions
to the Master. The status of the overall subscription is maintained
by the Master. The Master is responsible for notifying the
subscriber in case of problems with the Component Subscriptions.</t>
</list>The technical mechanisms or protocols used for the coordination
of operational information between Master and Agent is out-of-scope of
this document.</t>
</section>
<section title="Subscription Decomposition">
<t>The Collector can only subscribe to the Master. This requires the
Master to:</t>
<t><list style="numbers">
<t>expose the Global Capability that can be served by multiple
Publisher Agents;</t>
<t>disassemble the Global Subscription to multiple Component
Subscriptions, and distribute them to the Publisher Agents of the
corresponding metric sources so that they not overlap;</t>
<t>notify on changes when portions of a subscription moving between
different Publisher Agents over time.</t>
</list></t>
<t>And the Agent to:</t>
<t><list style="symbols">
<t>Inherit the Global Subscription properties from Publisher Master
for its Component Subscription;</t>
<t>share the same life-cycle as the Global Subscription;</t>
<t>share the same Subscription ID as the Global Subscription.</t>
</list></t>
</section>
<section title="Publication Composition">
<t>The Publisher Agent collects data and encapsulates the packets per
Component Subscription. The format and structure of the data records are
defined by the YANG schema, so that the decomposition at the Receiver
can benefit from the structured and hierarchical data records.</t>
<t>The Receiver is able to associate the YANG data records with <xref
target="RFC8639">Subscription ID</xref> to the subscribed subscription
and with <xref target="I-D.ietf-netconf-notification-messages">Message
Observation Domain ID</xref> to one of the Publisher Agents software
processes to enable message integrity.</t>
<t>For the dynamic subscription, the output of the
"establish-subscription" RPC defined in <xref target="RFC8639"/> MUST
include a list of Message Observation Domain IDs to indicate how the
Global Subscription is decomposed into several Component
Subscriptions.</t>
<t>The "subscription-started" and "subscription-modified" notification
defined in <xref target="RFC8639"/> MUST also include a list of Message
Observation Domain IDs to notify the current Publishers for the
corresponding Global Subscription.</t>
</section>
<section title="Subscription State Change Notifications">
<t>In addition to sending event records to Receivers, the Master MUST
also send <xref target="RFC8639">subscription state change
notifications</xref> when events related to subscription management have
occurred. All the subscription state change notifications MUST be
delivered by the Master.</t>
<t>When the subscription decomposition result changed, the
"subscription-modified" notification MUST be sent to indicate the new
list of Publishers.</t>
</section>
<section title="Publisher Configurations">
<t>This document assumes that all Publisher Agents are preconfigured to
push data. The actual working Publisher Agents are selected based on the
subscription decomposition result.</t>
<t>All Publisher Agents share the same source IP address for data
export. For connectionless data transport such as <xref
target="I-D.ietf-netconf-udp-notif">UDP based transport</xref> the same
Layer 4 source port for data export can be used. For connection based
data transport such as <xref target="I-D.ietf-netconf-https-notif">
HTTPS based transport</xref>, each Publisher Agent MUST be able to
acknowledge packet retrieval from Receivers, and therefore requires a
dedicated Layer 4 source port per software process.</t>
<t>The specific configuration on transports is described in the
resposible documents.</t>
</section>
<section title="YANG Tree">
<t/>
<t><figure>
<artwork><![CDATA[
module: ietf-distributed-notif
augment /sn:subscriptions/sn:subscription:
+--ro message-observation-domain-id* string
augment /sn:subscription-started:
+--ro message-observation-domain-id* string
augment /sn:subscription-modified:
+--ro message-observation-domain-id* string
augment /sn:establish-subscription/sn:output:
+--ro message-observation-domain-id* string
]]></artwork>
</figure></t>
</section>
<section title="YANG Module">
<t/>
<t><figure>
<artwork><![CDATA[
<CODE BEGINS> file "[email protected]"
module ietf-distributed-notif {
yang-version 1.1;
namespace
"urn:ietf:params:xml:ns:yang:ietf-distributed-notif";
prefix dn;
import ietf-subscribed-notifications {
prefix sn;
}
organization "IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: <http:/tools.ietf.org/wg/netconf/>
WG List: <mailto:[email protected]>
Editor: Tianran Zhou
<mailto:[email protected]>
Editor: Guangying Zheng
<mailto:[email protected]>";
description
"Defines augmentation for ietf-subscribed-notifications to
enable the distributed publication with single subscription.
Copyright (c) 2018 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject to
the license terms contained in, the Simplified BSD License set
forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see the
RFC itself for full legal notices.";
revision 2021-05-07 {
description
"Initial version";
reference
"RFC XXXX: Subscription to Distributed Notifications";
}
grouping message-observation-domain-ids {
description
"Provides a reusable list of message-observation-domain-ids.";
leaf-list message-observation-domain-id {
type string;
config false;
ordered-by user;
description
"Software process which created the message (e.g.,
processor 1 on line card 1). This field is
used to notify the collector the working originator.";
}
}
augment "/sn:subscriptions/sn:subscription" {
description
"This augmentation allows the message
Observation Domain ID to be exposed for a subscription.";
uses message-observation-domain-ids;
}
augment "/sn:subscription-started" {
description
"This augmentation allows MSO specific parameters to be
exposed for a subscription.";
uses message-observation-domain-ids;
}
augment "/sn:subscription-modified" {
description
"This augmentation allows MSO specific parameters to be
exposed for a subscription.";
uses message-observation-domain-ids;
}
augment "/sn:establish-subscription/sn:output" {
description
"This augmentation allows MSO specific parameters to be
exposed for a subscription.";
uses message-observation-domain-ids;
}
}
<CODE ENDS>
]]></artwork>
</figure></t>
</section>
<section anchor="IANA" title="IANA Considerations">
<t>This document registers the following namespace URI in the <xref
target="RFC3688">IETF XML Registry</xref>:</t>
<t><list style="empty">
<t>URI: urn:ietf:params:xml:ns:yang:ietf-distributed-notif</t>
<t>Registrant Contact: The IESG.</t>
<t>XML: N/A; the requested URI is an XML namespace.</t>
</list>This document registers the following YANG module in the <xref
target="RFC3688">YANG Module Names registry</xref>:</t>
<t><list style="empty">
<t>Name: ietf-distributed-notif</t>
<t>Namespace: urn:ietf:params:xml:ns:yang:ietf-distributed-notif</t>
<t>Prefix: dn</t>
<t>Reference: RFC XXXX</t>
</list></t>
</section>
<section anchor="Security" title="Security Considerations">
<t>The YANG module specified in this document defines a schema for data
that is designed to be accessed via network management protocols such as
<xref target="RFC6241">NETCONF</xref> or <xref
target="RFC8040">RESTCONF</xref>. The lowest NETCONF layer is the secure
transport layer, and the mandatory-to-implement secure transport is
<xref target="RFC6242">Secure Shell (SSH)</xref>. The lowest RESTCONF
layer is HTTPS, and the mandatory-to-implement secure transport is <xref
target="RFC5246">TLS</xref>.</t>
<t>The NETCONF <xref target="RFC6536">Access Control Model (NACM)</xref>
provides the means to restrict access for particular NETCONF or RESTCONF
users to a preconfigured subset of all available NETCONF or RESTCONF
protocol operations and content.</t>
<t>The new data nodes introduced in this YANG module may be considered
sensitive or vulnerable in some network environments. It is thus
important to control read access (e.g., via get-config or notification)
to this data nodes. These are the subtrees and data nodes and their
sensitivity/vulnerability:</t>
<t><list style="symbols">
<t>/subscriptions/subscription/message-observation-domain-ids</t>
</list>The entries in the two lists above will show where subscribed
resources might be located on the publishers. Access control MUST be set
so that only someone with proper access permissions has the ability to
access this resource.</t>
<t>Other Security Considerations is the same as those discussed in <xref
target="RFC8639"/>.</t>
</section>
<section title="Contributors">
<figure>
<artwork><![CDATA[ Alexander Clemm
Futurewai
2330 Central Expressway
Santa Clara
California
United States of America
Email: [email protected]]]></artwork>
</figure>
</section>
<section anchor="Acknowledgements" title="Acknowledgements">
<t>We thank Kent Watsen, Mahesh Jethanandani, Martin Bjorklund, Tim
Carey and Qin Wu for their constructive suggestions for improving this
document.</t>
</section>
</middle>
<back>
<references title="Normative References">
<?rfc include="reference.RFC.2119"?>
<?rfc include='reference.RFC.5246'?>
<?rfc include='reference.RFC.3688'?>
<?rfc include='reference.RFC.6241'?>
<?rfc include='reference.RFC.8040'?>
<?rfc include='reference.RFC.8639'?>
<?rfc include='reference.RFC.8641'?>
<?rfc include='reference.RFC.6536'?>
<?rfc include='reference.RFC.6242'?>
<?rfc include='reference.RFC.7923'?>
</references>
<references title="Informative References">
<?rfc include="reference.I-D.ietf-netconf-notification-messages"?>
<reference anchor="I-D.ietf-netconf-udp-notif" target="">
<front>
<title>UDP-based Transport for Configured Subscriptions</title>
<author fullname="Tianran Zhou" initials="T." surname="Zhou">
<organization>Huawei</organization>
</author>
<author fullname="Guangying Zheng" initials="G." surname="Zheng">
<organization>Huawei</organization>
</author>
<author fullname="Paolo Lucente" initials="P." surname="Lucente">
<organization>NTT</organization>
</author>
<author fullname="Thomas Graf" initials="T." surname="Graf">
<organization>Swisscom</organization>
</author>
<author fullname="Pierre Francois" initials="P." surname="Francois">
<organization>INSA-Lyon</organization>
</author>
<date month="July" year="2020"/>
</front>
<seriesInfo name="Internet-Draft"
value="draft-ietf-netconf-udp-notif-01"/>
</reference>
<?rfc include='reference.I-D.ietf-netconf-https-notif'?>
</references>
<section title="Examples">
<t>This appendix is non-normative.</t>
<section title="Dynamic Subscription">
<t>Figure 3 shows a typical dynamic subscription to the device with
distributed data export capability.</t>
<t><figure title="Fig. 3 Call Flow for Dynamic Subscription">
<artwork><![CDATA[
+-------------+ +-------------+ +-------------+
| Subscriber/ | | Publisher | | Publisher |
| Receiver | | (Master) | | (Agent) |
+-------------+ +------+------+ +------+------+
| | |
| establish-subscription | |
+------------------------------>+ component |
| | subscription |
| RPC Reply: OK, id #22 +-------------->+
| Observation Domain ID [#1,#2] | |
+<------------------------------+ |
| | |
| notif-mesg, id #22 | |
| Observation Domain ID #1 | |
+<------------------------------+ |
| | |
| notif-mesg, id#22 | |
| Observation Domain ID #2 | |
+<----------------------------------------------+
| | |
| modify-subscription (id#22) | |
+------------------------------>+ component |
| | subscription |
| RPC Reply: OK, id #22 +-------------->+
+<------------------------------+ |
| | |
| subscription-modified, id#22 | |
| Observation Domain ID [#1] | |
+<------------------------------+ |
| | |
| notif-mesg, id #22 | |
| Observation Domain ID #1 | |
+<------------------------------+ |
| | |
| | |
+ + +
]]></artwork>
</figure></t>
<t>A "establish-subscription" RPC request as per <xref
target="RFC8641"/> is sent to the Master with a successful response.
An example of using NETCONF:</t>
<t><figure title="Fig. 4 "establish-subscription" Request">
<artwork><![CDATA[
<netconf:rpc message-id="101"
xmlns:netconf="urn:ietf:params:xml:ns:netconf:base:1.0">
<establish-subscription
xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications"
xmlns:yp="urn:ietf:params:xml:ns:yang:ietf-yang-push">
<yp:datastore
xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
ds:operational
</yp:datastore>
<yp:datastore-xpath-filter
xmlns:ex="https://example.com/sample-data/1.0">
/ex:foo
</yp:datastore-xpath-filter>
<yp:periodic>
<yp:period>500</yp:period>
</yp:periodic>
</establish-subscription>
</netconf:rpc>]]></artwork>
</figure>As the device is able to fully satisfy the request, the
request is given a subscription ID of 22. The response as in Figure 5
indicates that the subscription is decomposed into two component
subscriptions which will be published by two message Observation
Domain ID: #1 and #2.</t>
<t><figure
title="Fig. 5 "establish-subscription" Positive RPC Response">
<artwork><![CDATA[<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<id
xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications">
22
</id>
<message-observation-domain-id
xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications>
1
</message-observation-domain-id>
<message-observation-domain-id
xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications>
2
</message-observation-domain-id>
</rpc-reply>]]></artwork>
</figure>Then, both Publishers send notifications with the
corresponding piece of data to the Receiver.</t>
<t>The subscriber may invoke the "modify-subscription" RPC for a
subscription it previously established. The RPC has no difference to
the single publisher case as in [RFC8641]. Figure 6 provides an
example where a subscriber attempts to modify the period and datastore
XPath filter of a subscription using NETCONF.</t>
<t><figure title="Fig. 6 "modify-subscription" Request">
<artwork><![CDATA[ <rpc message-id="102"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<modify-subscription
xmlns=
"urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications"
xmlns:yp="urn:ietf:params:xml:ns:yang:ietf-yang-push">
<id>22</id>
<yp:datastore
xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
ds:operational
</yp:datastore>
<yp:datastore-xpath-filter
xmlns:ex="https://example.com/sample-data/1.0">
/ex:bar
</yp:datastore-xpath-filter>
<yp:periodic>
<yp:period>250</yp:period>
</yp:periodic>
</modify-subscription>
</rpc>]]></artwork>
</figure></t>
<t>If the modification is successfully accepted, the
"subscription-modified" subscription state notification is sent to the
subscriber by the Master. The notification, Figure 7 for example,
indicates the modified subscription is decomposed into one component
subscription which will be published by message Observation Domain
#1.</t>
<t><figure
title="Fig. 7 "subscription-modified" Subscription State Notification">
<artwork><![CDATA[<notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
<eventTime>2007-09-01T10:00:00Z</eventTime>
<subscription-modified
xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications"
xmlns:yp="urn:ietf:params:xml:ns:yang:ietf-yang-push">
<id>22</id>
<yp:datastore
xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
ds:operational
</yp:datastore>
<yp:datastore-xpath-filter
xmlns:ex="https://example.com/sample-data/1.0">
/ex:bar
</yp:datastore-xpath-filter>
<yp:periodic>
<yp:period>250</yp:period>
</yp:periodic>
<message-observation-domain-id
xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-notificationss>
1
</message-observation-domain-id>
</subscription-modified>
</notification>]]></artwork>
</figure></t>
<t/>
</section>
<section title="Configured Subscription">
<t>Figure 8 shows a typical configured subscription to the device with
distributed data export capability.</t>
<t/>
<t><figure title="Fig. 8 Call Flow for Configured Subscription">
<artwork><![CDATA[
+-------------+ +-------------+ +-------------+
| Receiver | | Publisher | | Publisher |
| | | (Master) | | (Agent) |
+------+------+ +------+------+ +------+------+
| | |
| subscription-started, id#39 | |
| Observation Domain ID [#1,#2] | |
+<------------------------------+ |
| | |
| notif-mesg, id#39 | |
| Observation Domain ID #1 | |
+<------------------------------+ |
| | |
| notif-mesg, id#39 | |
| Observation Domain ID #2 | |
+<----------------------------------------------+
| | |
| | |
| | |
]]></artwork>
</figure></t>
<t>Before starting to push data, the "subscription-started"
subscription state notification is sent to the Receiver. The following
example assumes the NETCONF transport has already established. The
notification indicates that the configured subscription is decomposed
into two component subscriptions which will be published by two
message Observation Domain: #1 and #2.</t>
<t><figure
title="Fig. 9 "subscription-started" Subscription State Notification">
<artwork><![CDATA[
<notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
<eventTime>2007-09-01T10:00:00Z</eventTime>
<subscription-started
xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications"
xmlns:yp="urn:ietf:params:xml:ns:yang:ietf-yang-push">
<identifier>39</identifier>
<yp:datastore
xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
ds:operational
</yp:datastore>
<yp:datastore-xpath-filter
xmlns:ex="https://example.com/sample-data/1.0">
/ex:foo
</yp:datastore-xpath-filter>
<yp:periodic>
<yp:period>250</yp:period>
</yp:periodic>
<message-observation-domain-id
xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications>
1
</message-observation-domain-id>
<message-observation-domain-id
xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications>
2
</message-observation-domain-id>
</subscription-started>
</notification>]]></artwork>
</figure></t>
<t>Then, both Publishers send notifications with the corresponding
data record to the Receiver.</t>
</section>
</section>
</back>
</rfc>