< draft-ietf-netconf-restconf-notif-13.txt		draft-ietf-netconf-restconf-notif-14.txt >
	NETCONF E. Voit		NETCONF E. Voit
	Internet-Draft R. Rahman		Internet-Draft R. Rahman
	Intended status: Standards Track E. Nilsen-Nygaard		Intended status: Standards Track E. Nilsen-Nygaard
	Expires: August 18, 2019 Cisco Systems		Expires: December 12, 2019 Cisco Systems
	A. Clemm		A. Clemm
	Huawei		Huawei
	A. Bierman		A. Bierman
	YumaWorks		YumaWorks
	February 14, 2019		June 10, 2019
	Dynamic subscription to YANG Events and Datastores over RESTCONF		Dynamic subscription to YANG Events and Datastores over RESTCONF
	draft-ietf-netconf-restconf-notif-13		draft-ietf-netconf-restconf-notif-14
	Abstract		Abstract
	This document provides a RESTCONF binding to the dynamic subscription		This document provides a RESTCONF binding to the dynamic subscription
	capability of both subscribed notifications and YANG-Push.		capability of both subscribed notifications and YANG-Push.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	skipping to change at page 1, line 36 ¶		skipping to change at page 1, line 36 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at https://datatracker.ietf.org/drafts/current/.		Drafts is at https://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on August 18, 2019.		This Internet-Draft will expire on December 12, 2019.
	Copyright Notice		Copyright Notice
	Copyright (c) 2019 IETF Trust and the persons identified as the		Copyright (c) 2019 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 2, line 15 ¶		skipping to change at page 2, line 15 ¶
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3		2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
	3. Dynamic Subscriptions . . . . . . . . . . . . . . . . . . . . 3		3. Dynamic Subscriptions . . . . . . . . . . . . . . . . . . . . 3
	3.1. Transport Connectivity . . . . . . . . . . . . . . . . . 4		3.1. Transport Connectivity . . . . . . . . . . . . . . . . . 4
	3.2. Discovery . . . . . . . . . . . . . . . . . . . . . . . . 4		3.2. Discovery . . . . . . . . . . . . . . . . . . . . . . . . 4
	3.3. RESTCONF RPCs and HTTP Status Codes . . . . . . . . . . . 4		3.3. RESTCONF RPCs and HTTP Status Codes . . . . . . . . . . . 4
	3.4. Call Flow for Server-Sent Events (SSE) . . . . . . . . . 7		3.4. Call Flow for Server-Sent Events . . . . . . . . . . . . 7
	4. QoS Treatment . . . . . . . . . . . . . . . . . . . . . . . . 9		4. QoS Treatment . . . . . . . . . . . . . . . . . . . . . . . . 9
	5. Notification Messages . . . . . . . . . . . . . . . . . . . . 10		5. Notification Messages . . . . . . . . . . . . . . . . . . . . 10
	6. YANG Tree . . . . . . . . . . . . . . . . . . . . . . . . . . 10		6. YANG Tree . . . . . . . . . . . . . . . . . . . . . . . . . . 10
	7. YANG module . . . . . . . . . . . . . . . . . . . . . . . . . 10		7. YANG module . . . . . . . . . . . . . . . . . . . . . . . . . 10
	8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12		8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
	9. Security Considerations . . . . . . . . . . . . . . . . . . . 12		9. Security Considerations . . . . . . . . . . . . . . . . . . . 12
	10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13		10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13
	11. References . . . . . . . . . . . . . . . . . . . . . . . . . 13		11. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
	11.1. Normative References . . . . . . . . . . . . . . . . . . 13		11.1. Normative References . . . . . . . . . . . . . . . . . . 13
	11.2. Informative References . . . . . . . . . . . . . . . . . 15		11.2. Informative References . . . . . . . . . . . . . . . . . 15
	Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 15		Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 16
	A.1. Dynamic Subscriptions . . . . . . . . . . . . . . . . . . 16		A.1. Dynamic Subscriptions . . . . . . . . . . . . . . . . . . 16
	A.1.1. Establishing Dynamic Subscriptions . . . . . . . . . 16		A.1.1. Establishing Dynamic Subscriptions . . . . . . . . . 16
	A.1.2. Modifying Dynamic Subscriptions . . . . . . . . . . . 18		A.1.2. Modifying Dynamic Subscriptions . . . . . . . . . . . 19
	A.1.3. Deleting Dynamic Subscriptions . . . . . . . . . . . 20		A.1.3. Deleting Dynamic Subscriptions . . . . . . . . . . . 21
	A.2. Subscription State Notifications . . . . . . . . . . . . 21		A.2. Subscription State Notifications . . . . . . . . . . . . 21
	A.2.1. subscription-modified . . . . . . . . . . . . . . . . 21		A.2.1. subscription-modified . . . . . . . . . . . . . . . . 22
	A.2.2. subscription-completed, subscription-resumed, and		A.2.2. subscription-completed, subscription-resumed, and
	replay-complete . . . . . . . . . . . . . . . . . . . 22		replay-complete . . . . . . . . . . . . . . . . . . . 22
	A.2.3. subscription-terminated and subscription-suspended . 22		A.2.3. subscription-terminated and subscription-suspended . 22
	A.3. Filter Example . . . . . . . . . . . . . . . . . . . . . 22		A.3. Filter Example . . . . . . . . . . . . . . . . . . . . . 23
	Appendix B. Changes between revisions . . . . . . . . . . . . . 24		Appendix B. Changes between revisions . . . . . . . . . . . . . 24
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27
	1. Introduction		1. Introduction
	Mechanisms to support event subscription and push are defined in		Mechanisms to support event subscription and push are defined in
	[I-D.draft-ietf-netconf-subscribed-notifications]. Enhancements to		[I-D.draft-ietf-netconf-subscribed-notifications]. Enhancements to
	[I-D.draft-ietf-netconf-subscribed-notifications] which enable YANG		[I-D.draft-ietf-netconf-subscribed-notifications] which enable YANG
	datastore subscription and push are defined in		datastore subscription and push are defined in
	[I-D.ietf-netconf-yang-push]. This document provides a transport		[I-D.ietf-netconf-yang-push]. This document provides a transport
	specification for dynamic subscriptions over RESTCONF [RFC8040].		specification for dynamic subscriptions over RESTCONF [RFC8040].
	Driving these requirements is [RFC7923].		Requirements for these mechanisms are captured in [RFC7923].
	The streaming of notifications encapsulating the resulting		The streaming of notifications encapsulating the resulting
	information push is done via the mechanism described in section 6.3		information push is done via the mechanism described in section 6.3
	of [RFC8040].		of [RFC8040].
	2. Terminology		2. Terminology
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
	document are to be interpreted as described in RFC 2119 [RFC2119].		"OPTIONAL" in this document are to be interpreted as described in BCP
			14 [RFC2119] [RFC8174] when, and only when, they appear in all
			capitals, as shown here.
	The following terms use the definitions from		The following terms use the definitions from
	[I-D.draft-ietf-netconf-subscribed-notifications]: dynamic		[I-D.draft-ietf-netconf-subscribed-notifications]: dynamic
	subscription, event stream, notification message, publisher,		subscription, event stream, notification message, publisher,
	receiver, subscriber, and subscription.		receiver, subscriber, and subscription.
	Other terms reused include datastore, which is defined in [RFC8342],		Other terms reused include datastore, which is defined in [RFC8342],
	and HTTP2 stream which maps to the definition of "stream" within		and HTTP2 stream which maps to the definition of "stream" within
	[RFC7540], Section 2.		[RFC7540], Section 2.
	[ note to the RFC Editor - please replace XXXX within this document		[ note to the RFC Editor - please replace XXXX within this document
	with the number of this document ]		with the number of this document ]
	3. Dynamic Subscriptions		3. Dynamic Subscriptions
	This section provides specifics on how to establish and maintain		This section provides specifics on how to establish and maintain
	dynamic subscriptions over RESTCONF [RFC8040]. Subscribing to event		dynamic subscriptions over RESTCONF [RFC8040]. Subscribing to event
	streams is accomplished in this way via RPCs defined within		streams is accomplished in this way via RPCs defined within
	[I-D.draft-ietf-netconf-subscribed-notifications] Section 2.4, the		[I-D.draft-ietf-netconf-subscribed-notifications] Section 2.4. The
	RPCs are done via RESTCONF POSTs. YANG datastore subscription is		RPCs are done via RESTCONF POSTs. YANG datastore subscription is
	accomplished via augmentations to		accomplished via augmentations to
	[I-D.draft-ietf-netconf-subscribed-notifications] as described within		[I-D.draft-ietf-netconf-subscribed-notifications] as described within
	[I-D.ietf-netconf-yang-push] Section 4.4.		[I-D.ietf-netconf-yang-push] Section 4.4.
	As described in [RFC8040] Section 6.3, a GET needs to be made against		As described in [RFC8040] Section 6.3, a GET needs to be made against
	a specific URI on the publisher. Subscribers cannot pre-determine		a specific URI on the publisher. Subscribers cannot pre-determine
	the URI against which a subscription might exist on a publisher, as		the URI against which a subscription might exist on a publisher, as
	the URI will only exist after the "establish-subscription" RPC has		the URI will only exist after the "establish-subscription" RPC has
	been accepted. Therefore, the POST for the "establish-subscription"		been accepted. Therefore, the POST for the "establish-subscription"
	skipping to change at page 4, line 11 ¶		skipping to change at page 4, line 11 ¶
	does not move to the active state as per Section 2.4.1. of		does not move to the active state as per Section 2.4.1. of
	[I-D.draft-ietf-netconf-subscribed-notifications] until the GET is		[I-D.draft-ietf-netconf-subscribed-notifications] until the GET is
	received.		received.
	3.1. Transport Connectivity		3.1. Transport Connectivity
	For a dynamic subscription, where a RESTCONF session doesn't already		For a dynamic subscription, where a RESTCONF session doesn't already
	exist, a new RESTCONF session is initiated from the subscriber.		exist, a new RESTCONF session is initiated from the subscriber.
	As stated in Section 2.1 of [RFC8040], a subscriber MUST establish		As stated in Section 2.1 of [RFC8040], a subscriber MUST establish
	the HTTP session over TLS [RFC5246] in order to secure the content in		the HTTP session over TLS [RFC8446] in order to secure the content in
	transit.		transit.
	Without the involvement of additional protocols, HTTP sessions by		Without the involvement of additional protocols, HTTP sessions by
	themselves do not allow for a quick recognition of when the		themselves do not allow for a quick recognition of when the
	communication path has been lost with the publisher. Where quick		communication path has been lost with the publisher. Where quick
	recognition of the loss of a publisher is required, a subscriber		recognition of the loss of a publisher is required, a subscriber
	SHOULD use a TLS heartbeat [RFC6520], just from receiver to		SHOULD use a TLS heartbeat [RFC6520], just from subscriber to
	publisher, to track HTTP session continuity.		publisher, to track HTTP session continuity.
	Loss of the heartbeat MUST result in any subscription related TCP		Loss of the heartbeat MUST result in any subscription related TCP
	sessions between those endpoints being torn down. A subscriber can		sessions between those endpoints being torn down. A subscriber can
	then attempt to re-establish the dynamic subscription by using the		then attempt to re-establish the dynamic subscription by using the
	procedure described in Section 3.		procedure described in Section 3.4.
	3.2. Discovery		3.2. Discovery
	Subscribers can learn what event streams a RESTCONF server supports		Subscribers can learn what event streams a RESTCONF server supports
	by querying the "streams" container of ietf-subscribed-		by querying the "streams" container of ietf-subscribed-
	notification.yang in		notification.yang in
	[I-D.draft-ietf-netconf-subscribed-notifications]. Support for the		[I-D.draft-ietf-netconf-subscribed-notifications]. Support for the
	"streams" container of ietf-restconf-monitoring.yang in [RFC8040] is		"streams" container of ietf-restconf-monitoring.yang in [RFC8040] is
	not required. If it is supported, the event streams which are in the		not required. In the case when the RESTCONF binding specified by
	"streams" container of ietf-subscribed-notifications.yang SHOULD also		this document is used to convey the "streams" container from ietf-
	be in the "streams" container of ietf-restconf-monitoring.yang.		restconf-monitoring.yang (i.e., that feature is supported), any event
			streams contained therein are also expected to be present in the
			"streams" container of ietf-restconf-monitoring.yang.
	Subscribers can learn what datastores a RESTCONF server supports by		Subscribers can learn what datastores a RESTCONF server supports by
	following Section 2 of [I-D.draft-ietf-netconf-nmda-restconf].		following Section 2 of [I-D.draft-ietf-netconf-nmda-restconf].
	3.3. RESTCONF RPCs and HTTP Status Codes		3.3. RESTCONF RPCs and HTTP Status Codes
	Specific HTTP responses codes as defined in [RFC7231] section 6 will		Specific HTTP responses codes as defined in [RFC7231] section 6 will
	indicate the result of RESTCONF RPC requests with publisher. An HTTP		indicate the result of RESTCONF RPC requests with the publisher. An
	status code of 200 is the proper response to any successful RPC		HTTP status code of 200 is the proper response to any successful RPC
	defined within [I-D.draft-ietf-netconf-subscribed-notifications] or		defined within [I-D.draft-ietf-netconf-subscribed-notifications] or
	[I-D.ietf-netconf-yang-push].		[I-D.ietf-netconf-yang-push].
	If a publisher fails to serve the RPC request for one of the reasons		If a publisher fails to serve the RPC request for one of the reasons
	indicated in [I-D.draft-ietf-netconf-subscribed-notifications]		indicated in [I-D.draft-ietf-netconf-subscribed-notifications]
	Section 2.4.6 or [I-D.ietf-netconf-yang-push] Appendix A, this will		Section 2.4.6 or [I-D.ietf-netconf-yang-push] Appendix A, this will
	be indicated by "406" status code transported in the HTTP response.		be indicated by an appropriate error code, as shown below,
			transported in the HTTP response.
	When a "406" status code is returned, the RPC reply MUST include an		When an HTTP error code is returned, the RPC reply MUST include an
	"rpc-error" element per [RFC8040] Section 7.1 with the following		"rpc-error" element per [RFC8040] Section 7.1 with the following
	parameter values:		parameter values:
	o an "error-type" node of "application".		o an "error-type" node of "application".
	o an "error-tag" node with the value being a string that corresponds		o an "error-tag" node with the value being a string that corresponds
	to an identity associated with the error. This "error-tag" will		to an identity associated with the error. This "error-tag" will
	come from one of two places. Either it will correspond to the		come from one of two places. Either it will correspond to the
	error identities within		error identities within
	[I-D.draft-ietf-netconf-subscribed-notifications] section 2.4.6		[I-D.draft-ietf-netconf-subscribed-notifications] section 2.4.6
	for general subscription errors:		for general subscription errors:
	error identity uses error-tag		error identity uses error-tag HTTP Code
	---------------------- --------------		---------------------- -------------- ---------
	dscp-unavailable invalid-value		dscp-unavailable invalid-value 400
	encoding-unsupported invalid-value		encoding-unsupported invalid-value 400
	filter-unsupported invalid-value		filter-unsupported invalid-value 400
	insufficient-resources resource-denied		insufficient-resources resource-denied 409
	no-such-subscription invalid-value		no-such-subscription invalid-value 404
	replay-unsupported operation-not-supported		replay-unsupported operation-not-supported 501
	Or this "error-tag" will correspond to the error identities within		Or this "error-tag" will correspond to the error identities within
	[I-D.ietf-netconf-yang-push] Appendix A.1 for subscription errors		[I-D.ietf-netconf-yang-push] Appendix A.1 for subscription errors
	specific to YANG datastores:		specific to YANG datastores:
	error identity uses error-tag		error identity uses error-tag HTTP Code
	---------------------- --------------		---------------------- -------------- ---------
	cant-exclude operation-not-supported		cant-exclude operation-not-supported 501
	datastore-not-subscribable invalid-value		datastore-not-subscribable invalid-value 400
	no-such-subscription-resync invalid-value		no-such-subscription-resync invalid-value 404
	on-change-unsupported operation-not-supported		on-change-unsupported operation-not-supported 501
	on-change-sync-unsupported operation-not-supported		on-change-sync-unsupported operation-not-supported 501
	period-unsupported invalid-value		period-unsupported invalid-value 400
	update-too-big too-big		update-too-big too-big 400
	sync-too-big too-big		sync-too-big too-big 400
	unchanging-selection operation-failed		unchanging-selection operation-failed 500
	o an "error-app-tag" node with the value being a string that		o an "error-app-tag" node with the value being a string that
	corresponds to an identity associated with the error, as defined		corresponds to an identity associated with the error, as defined
	in [I-D.draft-ietf-netconf-subscribed-notifications] section 2.4.6		in [I-D.draft-ietf-netconf-subscribed-notifications] section 2.4.6
	for general subscriptions, and [I-D.ietf-netconf-yang-push]		for general subscriptions, and [I-D.ietf-netconf-yang-push]
	Appendix A.1, for datastore subscriptions. The tag to use depends		Appendix A.1, for datastore subscriptions. The tag to use depends
	on the RPC for which the error occurred. Viable errors for		on the RPC for which the error occurred. Viable errors for
	different RPCs are as follows:		different RPCs are as follows:
	RPC select an identity with a base		RPC select an identity with a base
	skipping to change at page 6, line 35 ¶		skipping to change at page 6, line 35 ¶
	---------------------- ------------------------------------		---------------------- ------------------------------------
	target: event stream establish-subscription-stream-error-info		target: event stream establish-subscription-stream-error-info
	target: datastore establish-subscription-datastore-error-info		target: datastore establish-subscription-datastore-error-info
	modify-subscription returns hints in yang-data structure		modify-subscription returns hints in yang-data structure
	---------------------- ------------------------------------		---------------------- ------------------------------------
	target: event stream modify-subscription-stream-error-info		target: event stream modify-subscription-stream-error-info
	target: datastore modify-subscription-datastore-error-info		target: datastore modify-subscription-datastore-error-info
	The yang-data included within "error-info" SHOULD NOT include the		The yang-data included within "error-info" SHOULD NOT include the
	optional leaf "error-reason", as such a leaf would be redundant		optional leaf "reason", as such a leaf would be redundant
	with information that is already placed within the		with information that is already placed within the
	"error-app-tag".		"error-app-tag".
	In case of an rpc error as a result of a "delete-subscription", a		In case of an rpc error as a result of a "delete-subscription", a
	"kill-subscription", or a "resync-subscription" request, no		"kill-subscription", or a "resync-subscription" request, no
	"error-info" needs to be included, as the "subscription-id" is		"error-info" needs to be included, as the "subscription-id" is
	the only RPC input parameter and no hints regarding this RPC input		the only RPC input parameter and no hints regarding this RPC input
	parameters need to be provided.		parameters need to be provided.
	Note that "error-path" [RFC8040] does not need to be included with		Note that "error-path" [RFC8040] does not need to be included with
	the "rpc-error" element, as subscription errors are generally		the "rpc-error" element, as subscription errors are generally
	associated with the choice of RPC input parameters.		associated with the choice of RPC input parameters.
	3.4. Call Flow for Server-Sent Events (SSE)		3.4. Call Flow for Server-Sent Events
	The call flow is defined in Figure 1. The logical connections		The call flow for Server-Sent Events (SSE) is defined in Figure 1.
	denoted by (a) and (b) can be a TCP connection or an HTTP2 stream		The logical connections denoted by (a) and (b) can be a TCP
	(multiple HTTP2 streams can be carried in one TCP connection).		connection or an HTTP2 stream (multiple HTTP2 streams can be carried
	Requests to [I-D.draft-ietf-netconf-subscribed-notifications] or		in one TCP connection). Requests to
			[I-D.draft-ietf-netconf-subscribed-notifications] or
	[I-D.ietf-netconf-yang-push] augmented RPCs are sent on a connection		[I-D.ietf-netconf-yang-push] augmented RPCs are sent on a connection
	indicated by (a). A successful "establish-subscription" will result		indicated by (a). A successful "establish-subscription" will result
	in an RPC response returned with both a subscription identifier which		in an RPC response returned with both a subscription identifier which
	uniquely identifies a subscription, as well as a URI which uniquely		uniquely identifies a subscription, as well as a URI which uniquely
	identifies the location of subscription on the publisher (b). This		identifies the location of subscription on the publisher (b). This
	URI is defined via the "uri" leaf the Data Model in Section 7.		URI is defined via the "uri" leaf the Data Model in Section 7.
	An HTTP GET is then sent on a separate logical connection (b) to the		An HTTP GET is then sent on a separate logical connection (b) to the
	URI on the publisher. This initiates the publisher to initiate the		URI on the publisher. This signals the publisher to initiate the
	flow of notification messages which are sent in SSE [W3C-20150203] as		flow of notification messages which are sent in SSE [W3C-20150203] as
	a response to the GET.		a response to the GET. There can not be 2 or more simultaneous GET
			requests on a subscription URI: any GET request received while there
			is a current GET request on the same URI MUST be rejected with HTTP
			error code 409.
			As described in [RFC8040] Section 6.4, RESTCONF servers SHOULD NOT
			send the "event" or "id" fields in the SSE event notifications.
	+--------------+ +--------------+		+--------------+ +--------------+
	| Subscriber | | Publisher |		| Subscriber | | Publisher |
	| | | |		| | | |
	| Logical | | Logical |		| Logical | | Logical |
	| Connection | | Connection |		| Connection | | Connection |
	| (a) (b) | | (a) (b) |		| (a) (b) | | (a) (b) |
	+--------------+ +--------------+		+--------------+ +--------------+
	| RESTCONF POST (RPC:establish-subscription) |		| RESTCONF POST (RPC:establish-subscription) |
	|--------------------------------------------->|		|--------------------------------------------->|
	skipping to change at page 9, line 4 ¶		skipping to change at page 8, line 52 ¶
	o All subscription state notifications from a publisher MUST be		o All subscription state notifications from a publisher MUST be
	returned in a separate SSE message used by the subscription to		returned in a separate SSE message used by the subscription to
	which the state change refers.		which the state change refers.
	o Subscription RPCs MUST NOT use the connection currently providing		o Subscription RPCs MUST NOT use the connection currently providing
	notification messages for that subscription.		notification messages for that subscription.
	o In addition to an RPC response for a "modify-subscription" RPC		o In addition to an RPC response for a "modify-subscription" RPC
	traveling over (a), a "subscription-modified" state change		traveling over (a), a "subscription-modified" state change
	notification MUST be sent within (b). This allows the receiver to		notification MUST be sent within (b). This allows the receiver to
	know exactly when the new terms of the subscription have been		know exactly when, within the stream of events, the new terms of
	applied to the notification messages. See arrow (c).		the subscription have been applied to the notification messages.
			See arrow (c).
	o In addition to any required access permissions (e.g., NACM), RPCs		o In addition to any required access permissions (e.g., NACM), RPCs
	modify-subscription, resync-subscription and delete-subscription		modify-subscription, resync-subscription and delete-subscription
	SHOULD only be allowed by the same RESTCONF username [RFC8040]		SHOULD only be allowed by the same RESTCONF username [RFC8040]
	which invoked establish-subscription.		which invoked establish-subscription. Such a restriction
			generally serves to preserve users' privacy, but exceptions might
			be made for administrators that may need to modify or delete other
			users' subscriptions.
	o The kill-subscription RPC can be invoked by any RESTCONF username		o The kill-subscription RPC can be invoked by any RESTCONF username
	with the required administrative permissions.		with the required administrative permissions.
	A publisher MUST terminate a subscription in the following cases:		A publisher MUST terminate a subscription in the following cases:
	o Receipt of a "delete-subscription" or a "kill-subscription" RPC		o Receipt of a "delete-subscription" or a "kill-subscription" RPC
	for that subscription.		for that subscription.
	o Loss of TLS heartbeat		o Loss of TLS heartbeat
	A publisher MAY terminate a subscription at any time as stated in		A publisher MAY terminate a subscription at any time as stated in
	[I-D.draft-ietf-netconf-subscribed-notifications] Section 1.3		[I-D.draft-ietf-netconf-subscribed-notifications] Section 1.3
	4. QoS Treatment		4. QoS Treatment
	To meet subscription quality of service promises, the publisher MUST		Qos treatment for event streams is described in
	take any existing subscription "dscp" and apply it to the DSCP		[I-D.draft-ietf-netconf-subscribed-notifications] Section 2.3. In
	marking in the IP header.		addition, where HTTP2 transport is available to a notification
	In addition, where HTTP2 transport is available to a notification
	message queued for transport to a receiver, the publisher MUST:		message queued for transport to a receiver, the publisher MUST:
	o take any existing subscription "priority", as specified by the		o take the "weighting" leaf node in
	"weighting" leaf node in
	[I-D.draft-ietf-netconf-subscribed-notifications], and copy it		[I-D.draft-ietf-netconf-subscribed-notifications], and copy it
	into the HTTP2 stream weight, [RFC7540] section 5.3, and		into the HTTP2 stream weight, [RFC7540] section 5.3, and
	o take any existing subscription "dependency", as specified by the		o take any existing subscription "dependency", as specified by the
	"dependency" leaf node in		"dependency" leaf node in
	[I-D.draft-ietf-netconf-subscribed-notifications], and use the		[I-D.draft-ietf-netconf-subscribed-notifications], and use the
	HTTP2 stream for the parent subscription as the HTTP2 stream		HTTP2 stream for the parent subscription as the HTTP2 stream
	dependency, [RFC7540] section 5.3.1, of the dependent		dependency, [RFC7540] section 5.3.1, of the dependent
	subscription.		subscription.
	o set the exclusive flag, [RFC7540] section 5.3.1, to 0.		o set the exclusive flag, [RFC7540] section 5.3.1, to 0.
			For dynamic subscriptions with the same DSCP value to a specific
			publisher, it is recommended that the subscriber sends all URI GET
			requests on a common HTTP2 session. Conversely, a subscriber can not
			use a common HTTP2 session for subscriptions with different DSCP
			values.
	5. Notification Messages		5. Notification Messages
	Notification messages transported over RESTCONF will be encoded		Notification messages transported over RESTCONF will be encoded
	according to [RFC8040], section 6.4.		according to [RFC8040], section 6.4.
	6. YANG Tree		6. YANG Tree
	The YANG model defined in Section 7 has one leaf augmented into three		The YANG model defined in Section 7 has one leaf augmented into three
	places of [I-D.draft-ietf-netconf-subscribed-notifications].		places of [I-D.draft-ietf-netconf-subscribed-notifications].
	skipping to change at page 12, line 47 ¶		skipping to change at page 12, line 51 ¶
	Reference: RFC XXXX: RESTCONF Transport for Event Notifications		Reference: RFC XXXX: RESTCONF Transport for Event Notifications
	9. Security Considerations		9. Security Considerations
	The YANG module specified in this document defines a schema for data		The YANG module specified in this document defines a schema for data
	that is designed to be accessed via network management transports		that is designed to be accessed via network management transports
	such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF		such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF
	layer is the secure transport layer, and the mandatory-to-implement		layer is the secure transport layer, and the mandatory-to-implement
	secure transport is Secure Shell (SSH) [RFC6242]. The lowest		secure transport is Secure Shell (SSH) [RFC6242]. The lowest
	RESTCONF layer is HTTPS, and the mandatory-to-implement secure		RESTCONF layer is HTTPS, and the mandatory-to-implement secure
	transport is TLS [RFC5246].		transport is TLS [RFC8446].
	The one new data node introduced in this YANG module may be		The one new data node introduced in this YANG module may be
	considered sensitive or vulnerable in some network environments. It		considered sensitive or vulnerable in some network environments. It
	is thus important to control read access (e.g., via get, get-config,		is thus important to control read access (e.g., via get, get-config,
	or notification) to this data nodes. These are the subtrees and data		or notification) to this data nodes. These are the subtrees and data
	nodes and their sensitivity/vulnerability:		nodes and their sensitivity/vulnerability:
	Container: "/subscriptions"		Container: "/subscriptions"
	o "uri": leaf will show where subscribed resources might be located		o "uri": leaf will show where subscribed resources might be located
	on a publisher. Access control must be set so that only someone		on a publisher. Access control must be set so that only someone
	with proper access permissions, and perhaps even HTTP session has		with proper access permissions, i.e., the same RESTCONF [RFC8040]
	the ability to access this resource.		user credentials which invoked the corresponding "establish-
			subscription", has the ability to access this resource.
	The subscription URI is implementation specific and is encrypted via		The subscription URI is implementation specific and is encrypted via
	the use of TLS. Therefore, even if an attacker succeeds in guessing		the use of TLS. Therefore, even if an attacker succeeds in guessing
	the subscription URI, a RESTCONF username [RFC8040] with the required		the subscription URI, a RESTCONF username [RFC8040] with the required
	administrative permissions must be used to be able to access or		administrative permissions must be used to be able to access or
	modify that subscription.		modify that subscription. It is recommended that the subscription
			URI values not be easily predictable.
			The access permission considerations for the RPCs modify-
			subscription, resync-subscription, delete-subscription and kill-
			subscription are described in Section 3.4.
			If a buggy or compromised RESTCONF subscriber sends a number of
			"establish-subscription" requests, then these subscriptions
			accumulate and may use up system resources. In such a situation, the
			publisher MAY also suspend or terminate a subset of the active
			subscriptions from that RESTCONF subscriber in order to reclaim
			resources and preserve normal operation for the other subscriptions.
	10. Acknowledgments		10. Acknowledgments
	We wish to acknowledge the helpful contributions, comments, and		We wish to acknowledge the helpful contributions, comments, and
	suggestions that were received from: Ambika Prasad Tripathy, Alberto		suggestions that were received from: Ambika Prasad Tripathy, Alberto
	Gonzalez Prieto, Susan Hares, Tim Jenkins, Balazs Lengyel, Kent		Gonzalez Prieto, Susan Hares, Tim Jenkins, Balazs Lengyel, Kent
	Watsen, Michael Scharf, Guangying Zheng, Martin Bjorklund, Qin Wu and		Watsen, Michael Scharf, Guangying Zheng, Martin Bjorklund, Qin Wu and
	Robert Wilton.		Robert Wilton.
	11. References		11. References
	skipping to change at page 14, line 9 ¶		skipping to change at page 14, line 28 ¶
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119,		Requirement Levels", BCP 14, RFC 2119,
	DOI 10.17487/RFC2119, March 1997,		DOI 10.17487/RFC2119, March 1997,
	<https://www.rfc-editor.org/info/rfc2119>.		<https://www.rfc-editor.org/info/rfc2119>.
	[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,		[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
	DOI 10.17487/RFC3688, January 2004,		DOI 10.17487/RFC3688, January 2004,
	<https://www.rfc-editor.org/info/rfc3688>.		<https://www.rfc-editor.org/info/rfc3688>.
	[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
	(TLS) Protocol Version 1.2", RFC 5246,
	DOI 10.17487/RFC5246, August 2008,
	<https://www.rfc-editor.org/info/rfc5246>.
	[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for		[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
	the Network Configuration Protocol (NETCONF)", RFC 6020,		the Network Configuration Protocol (NETCONF)", RFC 6020,
	DOI 10.17487/RFC6020, October 2010,		DOI 10.17487/RFC6020, October 2010,
	<https://www.rfc-editor.org/info/rfc6020>.		<https://www.rfc-editor.org/info/rfc6020>.
	[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,		[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
	and A. Bierman, Ed., "Network Configuration Protocol		and A. Bierman, Ed., "Network Configuration Protocol
	(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,		(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
	<https://www.rfc-editor.org/info/rfc6241>.		<https://www.rfc-editor.org/info/rfc6241>.
	skipping to change at page 14, line 43 ¶		skipping to change at page 15, line 9 ¶
	[RFC7540] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext		[RFC7540] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext
	Transfer Protocol Version 2 (HTTP/2)", RFC 7540,		Transfer Protocol Version 2 (HTTP/2)", RFC 7540,
	DOI 10.17487/RFC7540, May 2015,		DOI 10.17487/RFC7540, May 2015,
	<https://www.rfc-editor.org/info/rfc7540>.		<https://www.rfc-editor.org/info/rfc7540>.
	[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF		[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
	Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,		Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
	<https://www.rfc-editor.org/info/rfc8040>.		<https://www.rfc-editor.org/info/rfc8040>.
			[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
			2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
			May 2017, <https://www.rfc-editor.org/info/rfc8174>.
	[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,		[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
	and R. Wilton, "Network Management Datastore Architecture		and R. Wilton, "Network Management Datastore Architecture
	(NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,		(NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
	<https://www.rfc-editor.org/info/rfc8342>.		<https://www.rfc-editor.org/info/rfc8342>.
			[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
			Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
			<https://www.rfc-editor.org/info/rfc8446>.
	[W3C-20150203]		[W3C-20150203]
	"Server-Sent Events, World Wide Web Consortium CR CR-		Hickson, I., "Server-Sent Events, World Wide Web
	eventsource-20121211", February 2015,		Consortium CR CR-eventsource-20121211", February 2015,
	<https://www.w3.org/TR/2015/REC-eventsource-20150203/>.		<https://www.w3.org/TR/2015/REC-eventsource-20150203/>.
	11.2. Informative References		11.2. Informative References
	[I-D.draft-ietf-netconf-netconf-event-notifications]		[I-D.draft-ietf-netconf-netconf-event-notifications]
	Clemm, Alexander., Voit, Eric., Gonzalez Prieto, Alberto.,		Clemm, Alexander., Voit, Eric., Gonzalez Prieto, Alberto.,
	Nilsen-Nygaard, E., and A. Tripathy, "NETCONF support for		Nilsen-Nygaard, E., and A. Tripathy, "NETCONF support for
	event notifications", May 2018,		event notifications", May 2018,
	<https://datatracker.ietf.org/doc/		<https://datatracker.ietf.org/doc/
	draft-ietf-netconf-netconf-event-notifications/>.		draft-ietf-netconf-netconf-event-notifications/>.
	skipping to change at page 15, line 31 ¶		skipping to change at page 16, line 5 ¶
	[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer		[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
	Protocol (HTTP/1.1): Semantics and Content", RFC 7231,		Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
	DOI 10.17487/RFC7231, June 2014,		DOI 10.17487/RFC7231, June 2014,
	<https://www.rfc-editor.org/info/rfc7231>.		<https://www.rfc-editor.org/info/rfc7231>.
	[RFC7923] Voit, E., Clemm, A., and A. Gonzalez Prieto, "Requirements		[RFC7923] Voit, E., Clemm, A., and A. Gonzalez Prieto, "Requirements
	for Subscription to YANG Datastores", RFC 7923,		for Subscription to YANG Datastores", RFC 7923,
	DOI 10.17487/RFC7923, June 2016,		DOI 10.17487/RFC7923, June 2016,
	<https://www.rfc-editor.org/info/rfc7923>.		<https://www.rfc-editor.org/info/rfc7923>.
			[RFC7951] Lhotka, L., "JSON Encoding of Data Modeled with YANG",
			RFC 7951, DOI 10.17487/RFC7951, August 2016,
			<https://www.rfc-editor.org/info/rfc7951>.
	[RFC8347] Liu, X., Ed., Kyparlis, A., Parikh, R., Lindem, A., and M.		[RFC8347] Liu, X., Ed., Kyparlis, A., Parikh, R., Lindem, A., and M.
	Zhang, "A YANG Data Model for the Virtual Router		Zhang, "A YANG Data Model for the Virtual Router
	Redundancy Protocol (VRRP)", RFC 8347,		Redundancy Protocol (VRRP)", RFC 8347,
	DOI 10.17487/RFC8347, March 2018,		DOI 10.17487/RFC8347, March 2018,
	<https://www.rfc-editor.org/info/rfc8347>.		<https://www.rfc-editor.org/info/rfc8347>.
	[XPATH] Clark, J. and S. DeRose, "XML Path Language (XPath)		[XPATH] Clark, J. and S. DeRose, "XML Path Language (XPath)
	Version 1.0", November 1999,		Version 1.0", November 1999,
	<http://www.w3.org/TR/1999/REC-xpath-19991116>.		<http://www.w3.org/TR/1999/REC-xpath-19991116>.
	Appendix A. Examples		Appendix A. Examples
	This section is non-normative. To allow easy comparison, this		This section is non-normative. To allow easy comparison, this
	section mirrors the functional examples shown with NETCONF over XML		section mirrors the functional examples shown with NETCONF over XML
	within [I-D.draft-ietf-netconf-netconf-event-notifications]. In		within [I-D.draft-ietf-netconf-netconf-event-notifications]. In
	addition, HTTP2 vs HTTP1.1 headers are not shown as the contents of		addition, HTTP2 vs HTTP1.1 headers are not shown as the contents of
	the JSON encoded objects are identical within.		the JSON encoded objects are identical within.
			The subscription URI values used in the examples in this section are
			purely illustrative, and are not indicative of the expected usage
			which is described in Section 9.
			The DSCP values are only for example purposes and are all indicated
			in decimal since the encoding is JSON [RFC7951].
	A.1. Dynamic Subscriptions		A.1. Dynamic Subscriptions
	A.1.1. Establishing Dynamic Subscriptions		A.1.1. Establishing Dynamic Subscriptions
	The following figure shows two successful "establish-subscription"		The following figure shows two successful "establish-subscription"
	RPC requests as per		RPC requests as per
	[I-D.draft-ietf-netconf-subscribed-notifications]. The first request		[I-D.draft-ietf-netconf-subscribed-notifications]. The first request
	is given a subscription identifier of 22, the second, an identifier		is given a subscription identifier of 22, the second, an identifier
	of 23.		of 23.
	skipping to change at page 17, line 12 ¶		skipping to change at page 17, line 45 ¶
	To provide examples of the information being transported, example		To provide examples of the information being transported, example
	messages for interactions in Figure 2 are detailed below:		messages for interactions in Figure 2 are detailed below:
	POST /restconf/operations		POST /restconf/operations
	/ietf-subscribed-notifications:establish-subscription		/ietf-subscribed-notifications:establish-subscription
	{		{
	"ietf-subscribed-notifications:input": {		"ietf-subscribed-notifications:input": {
	"stream-xpath-filter": "/example-module:foo/",		"stream-xpath-filter": "/example-module:foo/",
	"stream": "NETCONF",		"stream": "NETCONF",
	"dscp": "10"		"dscp": 10
	}		}
	}		}
	Figure 3: establish-subscription request (a)		Figure 3: establish-subscription request (a)
	As publisher was able to fully satisfy the request, the publisher		As publisher was able to fully satisfy the request, the publisher
	sends the subscription identifier of the accepted subscription, and		sends the subscription identifier of the accepted subscription, and
	the URI:		the URI:
	HTTP status code - 200		HTTP status code - 200
	{		{
	"id": "22",		"id": 22,
	"uri": "https://example.com/restconf/subscriptions/22"		"uri": "https://example.com/restconf/subscriptions/22"
	}		}
	Figure 4: establish-subscription success (b)		Figure 4: establish-subscription success (b)
	Upon receipt of the successful response, the subscriber does a GET		Upon receipt of the successful response, the subscriber does a GET
	the provided URI to start the flow of notification messages. When		the provided URI to start the flow of notification messages. When
	the publisher receives this, the subscription is moved to the active		the publisher receives this, the subscription is moved to the active
	state (c).		state (c).
	skipping to change at page 18, line 5 ¶		skipping to change at page 18, line 34 ¶
	Figure 5: establish-subscription subsequent POST		Figure 5: establish-subscription subsequent POST
	While not shown in Figure 2, if the publisher had not been able to		While not shown in Figure 2, if the publisher had not been able to
	fully satisfy the request, or subscriber has no authorization to		fully satisfy the request, or subscriber has no authorization to
	establish the subscription, the publisher would have sent an RPC		establish the subscription, the publisher would have sent an RPC
	error response. For instance, if the "dscp" value of 10 asserted by		error response. For instance, if the "dscp" value of 10 asserted by
	the subscriber in Figure 3 proved unacceptable, the publisher may		the subscriber in Figure 3 proved unacceptable, the publisher may
	have returned:		have returned:
	HTTP status code - 406		HTTP status code - 400
	{ "ietf-restconf:errors" : {		{ "ietf-restconf:errors" : {
	"error" : [		"error" : [
	{		{
	"error-type": "application",		"error-type": "application",
	"error-tag": "invalid-value",		"error-tag": "invalid-value",
	"error-severity": "error",		"error-severity": "error",
	"error-app-tag":		"error-app-tag":
	"ietf-subscribed-notifications:dscp-unavailable"		"ietf-subscribed-notifications:dscp-unavailable"
	}		}
	skipping to change at page 19, line 14 ¶		skipping to change at page 19, line 25 ¶
	+------------+ +-----------+		+------------+ +-----------+
	| Subscriber | | Publisher |		| Subscriber | | Publisher |
	+------------+ +-----------+		+------------+ +-----------+
	| |		| |
	| notification message (id#23)|		| notification message (id#23)|
	|<-----------------------------|		|<-----------------------------|
	| |		| |
	|modify-subscription (id#23) |		|modify-subscription (id#23) |
	|----------------------------->| (d)		|----------------------------->| (d)
	| HTTP 406 error (with hint)|		| HTTP 400 error (with hint)|
	|<-----------------------------| (e)		|<-----------------------------| (e)
	| |		| |
	|modify-subscription (id#23) |		|modify-subscription (id#23) |
	|----------------------------->|		|----------------------------->|
	| HTTP 200 OK |		| HTTP 200 OK |
	|<-----------------------------|		|<-----------------------------|
	| |		| |
	| notif-mesg (id#23)|		| notif-mesg (id#23)|
	|<-----------------------------|		|<-----------------------------|
	| |		| |
	skipping to change at page 19, line 39 ¶		skipping to change at page 20, line 10 ¶
	subscription as per [I-D.ietf-netconf-yang-push], the modification		subscription as per [I-D.ietf-netconf-yang-push], the modification
	request made in (d) may look like that shown in Figure 8. As can be		request made in (d) may look like that shown in Figure 8. As can be
	seen, the modifications being attempted are the application of a new		seen, the modifications being attempted are the application of a new
	xpath filter as well as the setting of a new periodic time interval.		xpath filter as well as the setting of a new periodic time interval.
	POST /restconf/operations		POST /restconf/operations
	/ietf-subscribed-notifications:modify-subscription		/ietf-subscribed-notifications:modify-subscription
	{		{
	"ietf-subscribed-notifications:input": {		"ietf-subscribed-notifications:input": {
	"id": "23",		"id": 23,
	"ietf-yang-push:datastore-xpath-filter":		"ietf-yang-push:datastore-xpath-filter":
	"/example-module:foo/example-module:bar",		"/example-module:foo/example-module:bar",
	"ietf-yang-push:periodic": {		"ietf-yang-push:periodic": {
	"ietf-yang-push:period": "500"		"ietf-yang-push:period": 500
	}		}
	}		}
	}		}
	Figure 8: Subscription modification request (c)		Figure 8: Subscription modification request (c)
	If the publisher can satisfy both changes, the publisher sends a		If the publisher can satisfy both changes, the publisher sends a
	positive result for the RPC. If the publisher cannot satisfy either		positive result for the RPC. If the publisher cannot satisfy either
	of the proposed changes, the publisher sends an RPC error response		of the proposed changes, the publisher sends an RPC error response
	(e). The following is an example RPC error response for (e) which		(e). The following is an example RPC error response for (e) which
	includes a hint. This hint is an alternative time period value which		includes a hint. This hint is an alternative time period value which
	might have resulted in a successful modification:		might have resulted in a successful modification:
	HTTP status code - 406		HTTP status code - 400
	{ "ietf-restconf:errors" : {		{ "ietf-restconf:errors" : {
	"error" : [		"error" : [
	"error-type": "application",		"error-type": "application",
	"error-tag": "invalid-value",		"error-tag": "invalid-value",
	"error-severity": "error",		"error-severity": "error",
	"error-app-tag": "ietf-yang-push:period-unsupported",		"error-app-tag": "ietf-yang-push:period-unsupported",
	"error-info": {		"error-info": {
	"ietf-yang-push":		"ietf-yang-push":
	"modify-subscription-datastore-error-info": {		"modify-subscription-datastore-error-info": {
	"period-hint": "3000"		"period-hint": 3000
	}		}
	}		}
	]		]
	}		}
	}		}
	Figure 9: Modify subscription failure with Hint (e)		Figure 9: Modify subscription failure with Hint (e)
	A.1.3. Deleting Dynamic Subscriptions		A.1.3. Deleting Dynamic Subscriptions
	skipping to change at page 21, line 7 ¶		skipping to change at page 21, line 30 ¶
	If the publisher can satisfy the request, the publisher replies with		If the publisher can satisfy the request, the publisher replies with
	success to the RPC request.		success to the RPC request.
	If the publisher cannot satisfy the request, the publisher sends an		If the publisher cannot satisfy the request, the publisher sends an
	error-rpc element indicating the modification didn't work. Figure 11		error-rpc element indicating the modification didn't work. Figure 11
	shows a valid response for existing valid subscription identifier,		shows a valid response for existing valid subscription identifier,
	but that subscription identifier was created on a different transport		but that subscription identifier was created on a different transport
	session:		session:
	HTTP status code - 406		HTTP status code - 404
	{		{
	"ietf-restconf:errors" : {		"ietf-restconf:errors" : {
	"error" : [		"error" : [
	"error-type": "application",		"error-type": "application",
	"error-tag": "invalid-value",		"error-tag": "invalid-value",
	"error-severity": "error",		"error-severity": "error",
	"error-app-tag":		"error-app-tag":
	"ietf-subscribed-notifications:no-such-subscription"		"ietf-subscribed-notifications:no-such-subscription"
	]		]
	skipping to change at page 21, line 37 ¶		skipping to change at page 22, line 13 ¶
	[I-D.draft-ietf-netconf-subscribed-notifications]).		[I-D.draft-ietf-netconf-subscribed-notifications]).
	A.2.1. subscription-modified		A.2.1. subscription-modified
	A "subscription-modified" encoded in JSON would look like:		A "subscription-modified" encoded in JSON would look like:
	{		{
	"ietf-restconf:notification" : {		"ietf-restconf:notification" : {
	"eventTime": "2007-09-01T10:00:00Z",		"eventTime": "2007-09-01T10:00:00Z",
	"ietf-subscribed-notifications:subscription-modified": {		"ietf-subscribed-notifications:subscription-modified": {
	"id": "39",		"id": 39,
	"uri": "https://example.com/restconf/subscriptions/22"		"uri": "https://example.com/restconf/subscriptions/22"
	"stream-xpath-filter": "/example-module:foo",		"stream-xpath-filter": "/example-module:foo",
	"stream": {		"stream": {
	"ietf-netconf-subscribed-notifications" : "NETCONF"		"ietf-netconf-subscribed-notifications" : "NETCONF"
	}		}
	}		}
	}		}
	}		}
	Figure 12: subscription-modified subscription state notification		Figure 12: subscription-modified subscription state notification
	A.2.2. subscription-completed, subscription-resumed, and replay-		A.2.2. subscription-completed, subscription-resumed, and replay-
	complete		complete
	A "subscription-completed" would look like:		A "subscription-completed" would look like:
	{		{
	"ietf-restconf:notification" : {		"ietf-restconf:notification" : {
	"eventTime": "2007-09-01T10:00:00Z",		"eventTime": "2007-09-01T10:00:00Z",
	"ietf-subscribed-notifications:subscription-completed": {		"ietf-subscribed-notifications:subscription-completed": {
	"id": "39",		"id": 39,
	}		}
	}		}
	}		}
	Figure 13: subscription-completed notification in JSON		Figure 13: subscription-completed notification in JSON
	The "subscription-resumed" and "replay-complete" are virtually		The "subscription-resumed" and "replay-complete" are virtually
	identical, with "subscription-completed" simply being replaced by		identical, with "subscription-completed" simply being replaced by
	"subscription-resumed" and "replay-complete".		"subscription-resumed" and "replay-complete".
	A.2.3. subscription-terminated and subscription-suspended		A.2.3. subscription-terminated and subscription-suspended
	A "subscription-terminated" would look like:		A "subscription-terminated" would look like:
	{		{
	"ietf-restconf:notification" : {		"ietf-restconf:notification" : {
	"eventTime": "2007-09-01T10:00:00Z",		"eventTime": "2007-09-01T10:00:00Z",
	"ietf-subscribed-notifications:subscription-terminated": {		"ietf-subscribed-notifications:subscription-terminated": {
	"id": "39",		"id": 39,
	"error-id": "suspension-timeout"		"error-id": "suspension-timeout"
	}		}
	}		}
	}		}
	Figure 14: subscription-terminated subscription state notification		Figure 14: subscription-terminated subscription state notification
	The "subscription-suspended" is virtually identical, with		The "subscription-suspended" is virtually identical, with
	"subscription-terminated" simply being replaced by "subscription-		"subscription-terminated" simply being replaced by "subscription-
	suspended".		suspended".
	skipping to change at page 24, line 24 ¶		skipping to change at page 24, line 47 ¶
	}		}
	Figure 17		Figure 17
	For more examples of subtree filters, see [RFC6241], section 6.4.		For more examples of subtree filters, see [RFC6241], section 6.4.
	Appendix B. Changes between revisions		Appendix B. Changes between revisions
	(To be removed by RFC editor prior to publication)		(To be removed by RFC editor prior to publication)
	v12 - v13		v13 - v14
			o Addressed review comments from IESG.
			v12 - v13
	o Enhanced "error-tag" values based on SN review.		o Enhanced "error-tag" values based on SN review.
	v11 - v12		v11 - v12
	o Added text in 3.2 for expected behavior when ietf-restconf-		o Added text in 3.2 for expected behavior when ietf-restconf-
	monitoring.yang is also supported.		monitoring.yang is also supported.
	o Added section 2 to the reference to draft-ietf-netconf-nmda-		o Added section 2 to the reference to draft-ietf-netconf-nmda-
	restconf.		restconf.
End of changes. 54 change blocks.
	85 lines changed or deleted		134 lines changed or added
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