One document matched: draft-ietf-netconf-rfc5277bis-01.xml
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<?rfc tocdepth="2"?>
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<rfc category="std" docName="draft-ietf-netconf-rfc5277bis-01" ipr="trust200902">
<front>
<title abbrev="Event Notifications">Subscribing to Event Notifications</title>
<author fullname="Alexander Clemm" initials="A" surname="Clemm">
<organization>Sympotech</organization>
<address>
<email>alex@sympotech.com</email>
</address>
</author>
<author fullname="Alberto Gonzalez Prieto" initials="A"
surname="Gonzalez Prieto">
<organization>Cisco Systems</organization>
<address>
<email>albertgo@cisco.com</email>
</address>
</author>
<author fullname="Eric Voit" initials="E." surname="Voit">
<organization>Cisco Systems</organization>
<address>
<email>evoit@cisco.com</email>
</address>
</author>
<author fullname="Einar Nilsen-Nygaard" initials="E"
surname="Nilsen-Nygaard">
<organization>Cisco Systems</organization>
<address>
<email>einarnn@cisco.com</email>
</address>
</author>
<author fullname="Ambika Prasad Tripathy" initials="A" surname="Tripathy">
<organization>Cisco Systems</organization>
<address>
<email>ambtripa@cisco.com</email>
</address>
</author>
<author fullname="Sharon Chisholm" initials="S" surname="Chisholm">
<organization>Ciena</organization>
<address>
<email>schishol@ciena.com</email>
</address>
</author>
<author fullname="Hector Trevino" initials="H" surname="Trevino">
<organization>Cisco Systems</organization>
<address>
<email>htrevino@cisco.com</email>
</address>
</author>
<date day="27" month="October" year="2016"/>
<area>Operations & Management</area>
<workgroup>NETCONF</workgroup>
<keyword>Draft</keyword>
<abstract>
<t>This document defines capabilities and operations for subscribing to content and providing asynchronous notification message delivery on that content. Notification delivery can occur over a variety of protocols used commonly in conjunction with YANG, such as NETCONF and RESTCONF. The capabilities and operations defined in this document when using in conjunction with draft-ietf-netconf-netconf-event-notifications are intended to replace RFC 5277.</t>
</abstract>
</front>
<middle>
<section title="Introduction">
<t>This document defines mechanisms that provide an asynchronous message notification delivery service in a protocol-agnostic manner.
This document defines capabilities and operations for providing asynchronous message notification delivery
for notifications including those necessary to establish, monitor,
and support subscriptions to notification delivery.
</t>
<t>Notification delivery can occur over a variety of protocols used
commonly in conjunction with YANG, such as NETCONF <xref target="RFC6241"/>
(defined in <xref target="I-D.ietf-netconf-netconf-event-notif"/>)
and Restconf <xref target="I-D.ietf-netconf-restconf"/>
(defined in <xref target="I-D.ietf-netconf-restconf-notif"/>).
The capabilities
and operations defined in this document are intended to replace RFC 5277,
along with their mapping onto NETCONF transport.
</t>
<section title="Motivation">
<t> The motivation for this work is to enable the sending of transport agnostic asynchronous notification messages driven by a YANG Subscription that are consistent with the data model (content) and security model. Predating this work was used within a NETCONF implementation. [RFC5277] which defined a limited defines a notification mechanism for for NETCONF. However, there are various [RFC5277] has limitations:, many of which have been exposed in [RFC7923].</t>
<t>The scope of the work aims at meeting the operational needs of network subscriptions:</t>
<t><list style="symbols">
<t>Ability to dynamically or statically subscribe to event notifications available on a publisher.</t>
<t>Ability to negotiate acceptable dynamic subscription parameters.</t>
<t>Ability to filter the subset of notifications to be pushed with stream-specific semantics. </t>
<t>Ability for the notification payload to be interpreted independently of the transport protocol. (In other words, the encoded notification fully describes itself.) </t>
<t>Mechanism to communicate the notifications.</t>
<t>Ability to replay locally logged notifications.</t>
</list></t>
</section>
<section title="Terminology">
<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>
<t>Configured subscription: A subscription installed via a configuration interface which persists across reboots.</t>
<t>Dynamic subscription: A subscription agreed between subscriber and publisher via create, establish, modify, and delete RPC control plane signaling messages.</t>
<t>Event: An occurrence of something that may be of interest. (e.g., a configuration change, a fault, a change in status, crossing a threshold, or an external input to the system.)</t>
<t>Event notification: A set of information intended for a Receiver indicating that one or more Event(s) have occurred. Details of the Event(s) may be included within the Notification.</t>
<t>Filter: Evaluation criteria, which may be applied against a targeted set of objects/events in a subscription. Information traverses the filter only if specified filter criteria are met.</t>
<t>NACM: NETCONF Access Control Model.</t>
<t>OAM: Operations, Administration, Maintenance.</t>
<t>Publisher: An entity responsible for streaming Event Notifications per the terms of a Subscriptions</t>
<t>Receiver: A target to which a publisher pushes event notifications. For dynamic subscriptions, the receiver and subscriber will often be the same entity.</t>
<t>RPC: Remote Procedure Call.</t>
<t>Stream (also referred to as "event stream"): A continuous ordered set of events grouped under an explicit criteria.</t>
<t>Subscriber: An entity able to request and negotiate a contract for the receipt of event notifications from a publisher.</t>
<t>Subscription: A contract with a publisher, stipulating which information receiver(s) wishes to have pushed from the publisher without the need for further solicitation.</t>
</section>
<section title="Solution Overview">
<t>This document describes mechanisms for subscribing and receiving event notifications from an event server publisher. This document builds on top of the capabilities defined in <xref target="RFC5277"/>, extending them, and generalizing them to be protocol-agnostic.</t>
<t>Some enhancements over RFC 5277 include the ability to have multiple subscriptions on a single transport session, to terminate a single subscriptions without terminating the transport session, and to modify existing subscriptions. </t>
<t>These enhancements do not affect existing RFC 5277 subscribers that do not support these particular subscription requirements.</t>
<t>The solution supports subscribing to event notifications using two mechanisms:</t>
<t><list style="numbers">
<t>Dynamic subscriptions, where a subscriber initiates a subscription negotiation with a publisher via RPC.
A subscriber initiates a negotiation by issuing a subscription request. If the publisher wants to serve this request, it will accept it, and then start pushing event notifications as negotiated.
If the publisher does not wish to serve it as requested, it may respond with subscription parameters which it would have accepted.</t>
<t>Configured subscriptions, which is an optional mechanism that enables managing subscriptions via a configuration interface so that a publisher can send event notifications to configured receiver(s).</t>
</list></t>
<t>Some key characteristics of configured and dynamic subscriptions include:</t>
<t><list style="symbols">
<t>The lifetime of a dynamic subscription is limited by the lifetime of the subscriber session used to establish it. Typically loss of the transport session tears down any dependent dynamic subscriptions.</t>
<t>The lifetime of a configured subscription is driven by configuration being present on the running configuration.
This implies configured subscriptions persist across reboots, and persists even when transport is unavailable.
This also means configured subscriptions do not support negotiation.</t>
<t>Subscriptions can be modified or terminated at any point of their lifetime. configured subscriptions can be modified by any configuration client with write rights on the configuration of the subscription.</t>
</list></t>
<t>Note that there is no mixing-and-matching of dynamic and configured subscriptions. Specifically, a configured subscription cannot be modified or deleted using RPC. Similarly, a subscription created via RPC cannot be modified through configuration operations.</t>
<t>The publisher may decide to terminate a dynamic subscription at any time. Similarly, it may decide to temporarily suspend the sending of event notifications for either configured or dynamic subscriptions. Such termination or suspension may be driven by the publisher running out of resources to serve the subscription, or by internal errors on the publisher. </t>
</section>
</section>
<section title="Solution">
<section title="Event Streams">
<t>An event stream is a set of events available for subscription from a publisher. It is out of the scope of this document to identify a) how streams are defined, b) how events are defined/generated, and c) how events are assigned to streams. </t>
<t>That said, some event streams will be standardized whereas others may be vendor specific. One standardized event stream is the "NETCONF" notification event stream. The NETCONF event stream contains all NETCONF XML event notifications supported by the publisher, except for those belonging only to streams that
explicitly indicate that they must be excluded from the NETCONF stream, such as notifications that serve OAM and signaling purposes.</t>
<t>The following is a high-level description of the flow of a notification. Note that it does not mandate and/or preclude an implementation. As events are raised, they are assigned to streams. An event may be assigned to multiple streams. The event is distributed to subscribers and receivers based on the current subscriptions and access control. Access control is needed because if any receiver of that subscription does not have permission to receive an event, then it never makes it into a notification, and processing of the event is completed for that subscription.</t>
</section>
<section title="Event Stream Discovery">
<t>A publisher maintains a list of available event streams as operational data. This list contains both standardized and vendor-specific event streams. A client can retrieve this list like any other YANG-defined data, for example using the <get> operation when using NETCONF. </t>
</section>
<section title="Filters">
<t>a publisher implementation SHOULD support the ability to perform filtering of notification records per RFC 5277. (TODO: since 5277 is to be obsoleted, we should describe the filter here.)</t>
</section>
<section title="Subscription State Model at the Publisher">
<t>Below is the state machine of a subscription for the publisher.
It is important to
note that a subscription doesn't exist at the publisher until it is
accepted and made active. The mere request by a subscriber to
establish a subscription is insufficient for that asserted
subscription to be externally visible via this state machine.</t>
<figure align="center" anchor="publisher-states"
title="Subscription states at publisher">
<artwork align="left"><![CDATA[
.-------.
| start |
'-------'
|
establish
|
| .----------modify--------------.
v v '
.-----------. .-----------.
.--------. | |------>suspend------->| |
modify '| active | | suspended |
'--------->| |<----resume----<------| |
'-----------' '-----------'
| |
delete delete
| |
v |
.-------. |
| end |<-----------------------------'
'-------'
]]></artwork>
</figure>
<t>Of interest in this state machine are the following: <list
style="symbols">
<t>Successful <establish-subscription> or
<modify-subscription> requests put the subscription into an
active state.</t>
<t>Failed <modify-subscription> requests will leave the
subscription in its previous state, with no visible change to any
streaming updates.</t>
<t>A <delete-subscription> request will delete the entire
subscription.</t>
</list></t>
</section>
</section>
<section title="Data Model Trees for Event Notifications">
<t>The YANG data model for event notifications is depicted in this section. </t>
<figure align="left">
<artwork align="left" xml:space="preserve"><![CDATA[
module: ietf-event-notifications
+--ro streams
| +--ro stream* stream
+--rw filters
| +--rw filter* [filter-id]
| +--rw filter-id filter-id
| +--rw (filter-type)?
| +--:(rfc5277)
| +--rw filter?
+--rw subscription-config {configured-subscriptions}?
| +--rw subscription* [subscription-id]
| +--rw subscription-id subscription-id
| +--rw stream? stream
| +--rw encoding? encoding
| +--rw (filter-type)?
| | +--:(rfc5277)
| | | +--rw filter?
| | +--:(by-reference)
| | +--rw filter-ref? filter-ref
| +--rw startTime? yang:date-and-time
| +--rw stopTime? yang:date-and-time
| +--rw receivers
| | +--rw receiver* [address]
| | +--rw address inet:host
| | +--rw port inet:port-number
| | +--rw protocol? transport-protocol
| +--rw (push-source)?
| +--:(interface-originated)
| | +--rw source-interface? if:interface-ref
| +--:(address-originated)
| +--rw source-vrf? uint32
| +--rw source-address inet:ip-address-no-zone
+--ro subscriptions
+--ro subscription* [subscription-id]
+--ro subscription-id subscription-id
+--ro configured-subscription?
| empty {configured-subscriptions}?
+--ro subscription-status? subscription-status
+--ro stream? stream
+--ro encoding? encoding
+--ro (filter-type)?
| +--:(rfc5277)
| | +--ro filter?
| +--:(by-reference)
| +--ro filter-ref? filter-ref
+--ro startTime? yang:date-and-time
+--ro stopTime? yang:date-and-time
+--ro receivers
| +--ro receiver* [address]
| +--ro address inet:host
| +--ro port inet:port-number
| +--ro protocol? transport-protocol
+--ro (push-source)?
+--:(interface-originated)
| +--ro source-interface? if:interface-ref
+--:(address-originated)
+--ro source-vrf? uint32
+--ro source-address inet:ip-address-no-zone
rpcs:
+---x establish-subscription
| +---w input
| | +---w stream? stream
| | +---w encoding? encoding
| | +---w (filter-type)?
| | | +--:(rfc5277)
| | | | +---w filter?
| | | +--:(by-reference)
| | | +---w filter-ref? filter-ref
| | +---w startTime? yang:date-and-time
| | +---w stopTime? yang:date-and-time
| +--ro output
| +--ro subscription-result subscription-result
| +--ro (result)?
| +--:(success)
| | +--ro subscription-id subscription-id
| +--:(no-success)
| +--ro stream? stream
| +--ro encoding? encoding
| +--ro (filter-type)?
| | +--:(rfc5277)
| | | +--ro filter?
| | +--:(by-reference)
| | +--ro filter-ref? filter-ref
| +--ro startTime? yang:date-and-time
| +--ro stopTime? yang:date-and-time
+---x create-subscription
| +---w input
| +---w stream? stream
| +---w encoding? encoding
| +---w (filter-type)?
| | +--:(rfc5277)
| | +---w filter?
| +---w startTime? yang:date-and-time
| +---w stopTime? yang:date-and-time
+---x modify-subscription
| +---w input
| | +---w subscription-id? subscription-id
| | +---w (filter-type)?
| | | +--:(rfc5277)
| | | | +---w filter?
| | | +--:(by-reference)
| | | +---w filter-ref? filter-ref
| | +---w startTime? yang:date-and-time
| | +---w stopTime? yang:date-and-time
| +--ro output
| +--ro subscription-result subscription-result
| +--ro (result)?
| +--:(success)
| | +--ro subscription-id subscription-id
| +--:(no-success)
| +--ro stream? stream
| +--ro encoding? encoding
| +--ro (filter-type)?
| | +--:(rfc5277)
| | | +--ro filter?
| | +--:(by-reference)
| | +--ro filter-ref? filter-ref
| +--ro startTime? yang:date-and-time
| +--ro stopTime? yang:date-and-time
+---x delete-subscription
+---w input
| +---w subscription-id subscription-id
+--ro output
+--ro subscription-result subscription-result
notifications:
+---n replay-complete
| +--ro subscription-id subscription-id
+---n notification-complete
| +--ro subscription-id subscription-id
+---n subscription-started
| +--ro subscription-id subscription-id
| +--ro stream? stream
| +--ro encoding? encoding
| +--ro (filter-type)?
| | +--:(rfc5277)
| | | +--ro filter?
| | +--:(by-reference)
| | +--ro filter-ref? filter-ref
| +--ro startTime? yang:date-and-time
| +--ro stopTime? yang:date-and-time
+---n subscription-suspended
| +--ro subscription-id subscription-id
| +--ro reason? subscription-susp-reason
+---n subscription-resumed
| +--ro subscription-id subscription-id
+---n subscription-modified
| +--ro subscription-id subscription-id
| +--ro stream? stream
| +--ro encoding? encoding
| +--ro (filter-type)?
| | +--:(rfc5277)
| | | +--ro filter?
| | +--:(by-reference)
| | +--ro filter-ref? filter-ref
| +--ro startTime? yang:date-and-time
| +--ro stopTime? yang:date-and-time
+---n subscription-terminated
+--ro subscription-id subscription-id
+--ro reason? subscription-term-reason
]]></artwork>
</figure>
<t>The data model is structured as follows:
<list style="symbols">
<t>"Streams" contains a list of event streams that are supported by the publisher and that can be subscribed to.</t>
<t>"Filters" contains a configurable list of filters that can be applied
to a subscription. This allows users to reference an
existing filter definition as an alternative to defining a filter inline
for each subscription. </t>
<t>"Subscription-config" contains the configuration of configured subscriptions. The parameters of each configured subscription are a superset of the parameters of a dynamic subscription and use the same groupings. In addition, the configured subscriptions must also specify intended receivers and may specify the push source from which to send the stream of notification messages.</t>
<t>"Subscriptions" contains a list of all subscriptions on a publisher, both
configured and dynamic. It can be used to retrieve information about the
subscriptions which an
publisher is serving. </t>
</list>
The data model also contains a number of notifications that allow a publisher to signal information about a subscription. Finally, the data model contains
a number of RPC definitions that are used to manage dynamic subscriptions.
</t>
</section>
<section title="Dynamic Subscriptions">
<t>Dynamic subscriptions are managed via RPC.</t>
<section title="Establishing a Subscription" anchor="sec_establish_subs">
<t>This operation includes and extends the "create-subscription" operation defined in RFC 5277.
It allows a subscriber to request the creation of a subscription both via RPC
and configuration operations.
When invoking the RPC, establish-subscription permits negotiating the subscription terms,
changing them dynamically.</t>
<t>The input parameters of the operation are those of create subscription plus:
<list style="symbols">
<t>filter-ref: filters that have been previously (and separately) configured can be referenced by a subscription.
This mechanism enables the reuse of filters.</t>
<t>encoding: by default, updates are encoded using XML. Other encodings may be supported, such as JSON. </t>
</list>
</t>
<t>If the publisher cannot satisfy the request, it sends a negative <subscription-result> element.</t>
<t>If the subscriber has no authorization to establish the subscription,
the <subscription-result> indicates an authorization error.
If the request is rejected because the publisher is not able to serve it,
the publisher SHOULD include in the returned error what subscription parameters would have been accepted
for the request when it was processed.
However, they is no guarantee that subsequent requests with those parameters for this subscriber or others will be accepted.
For instance, consider a subscription from <xref target="I-D.ietf-netconf-yang-push"/>,
which augments the establish-subscription with some additional parameters, including "period". </t>
<t>Subscription requests will fail if a filter with invalid syntax is provided or if the name of a non-existent stream is provided. </t>
</section>
<section title="Modifying a Subscription">
<t>This operation permits modifying the terms of a dynamic subscription previously established. Subscriptions created
by configuration cannot be modified. Dynamic subscriptions can be modified one or multiple times. If the publisher accepts the request, it immediately starts sending events based on the new terms, completely ignoring the previous ones. If the publisher rejects the request, the subscription remains as prior to the request. That is, the request has no impact whatsoever. The contents of negative responses to modify-subscription requests are the subset of the establish subscription request parameters which are allowed to be dynamically modified.</t>
<t>Dynamic subscriptions established via RPC can only be modified (or deleted) via RPC using the same transport session used to establish that subscription.</t>
<t>Configured subscriptions cannot be modified (or deleted) using RPCs. Instead, configured subscriptions are modified (or deleted) as part of regular configuration operations. Publishers MUST reject any attempts to modify (or delete) configured subscriptions via RPC.</t>
</section>
<section title="Deleting a Subscription">
<t>This operation permits canceling a subscription previously established. If the publisher accepts the request, it immediately stops sending events for the subscription. If the publisher rejects the request, all subscriptions remain as prior to the request. That is, the request has no impact whatsoever.</t>
<t>Subscriptions created via RPC can only be deleted via RPC using the same transport session used for subscription establishment. Configured subscriptions cannot be deleted using RPCs. Instead, configured subscriptions are deleted as part of regular configuration operations. Publishers MUST reject any RPC attempt to delete configured subscriptions.</t>
<t>The only parameter to delete-subscription is the identifier of the subscription to delete.</t>
<t>If the publisher can satisfy the request, it sends an OK element. </t>
<t>If the publisher cannot satisfy the request, it sends an error-rpc element.</t>
</section>
</section>
<section title="Configured Subscriptions">
<t>A configured subscription is a subscription installed via a configuration interface.</t>
<t>Configured subscriptions persist across reboots, and persist even when transport is unavailable. This also means configured subscriptions do not support negotiation.</t>
<t>Configured subscriptions can be modified by any configuration client with write permissions for the configuration of the subscription. Subscriptions can be modified or terminated at any point of their lifetime.</t>
<t>Supporting configured subscriptions is optional and advertised using the "configured-subscriptions" feature.</t>
<t>In addition to subscription parameters that apply to dynamic
subscriptions, the
following additional parameters apply to configured subscriptions:
<list style="symbols">
<t>One or more receiver IP addresses (and corresponding ports)
intended as the destination for push updates for each
subscription. In addition, the transport protocol for each
destination may be defined.</t>
<t>Optional parameters to identify an egress interface or IP
address / VRF where a subscription updates should be pushed from
the publisher.</t>
</list></t>
<section title="Establishing a Configured Subscription" anchor="sec_establish_static_subs">
<t>Configured subscriptions are established using configuration operations against the top-level subtree subscription-config. There are two key differences between RPC and configuration operations for subscription establishment. Firstly, configuration operations do not support negotiation while RPCs do. Secondly, while RPCs mandate that the subscriber establishing the subscription is the only receiver of the notifications, configuration operations permit specifying receivers independent of any tracked subscriber.
Immediately after a subscription is successfully established, the publisher sends to its receivers a control-plane notification stating the subscription has been established (subscription-started).</t>
<t>Because there is no explicit association with an existing transport session, configured configuration operations require additional parameters to indicate the receivers of the notifications and possibly the source of the notifications such as a specific egress interface.</t>
<t>For example at subscription establishment, a client may send:</t>
<figure align="center" anchor="establish-static-subs" title="Establish configured subscription">
<artwork align="left">
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"
xmlns:nc="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<running/>
</target>
<subscription-config
xmlns="urn:ietf:params:xml:ns:netconf:notification:1.1">
<subscription>
<subscription-id>
1922
</subscription-id>
<stream>
foo
</stream>
<receiver>
<address>
1.2.3.4
</address>
<port>
1234
</port>
</receiver>
</subscription>
</subscription-config>
</edit-config>
</rpc>
</artwork>
</figure>
<t>if the request is accepted, the publisher would reply:</t>
<figure align="center" anchor="success-establish-static-subs" title="Response to a successful configured subscription establishment">
<artwork align="left">
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
</artwork>
</figure>
<t>if the request is not accepted because the publisher cannot serve it, the publisher may reply:</t>
<figure align="center" anchor="failed-establish-static-subs" title="Response to a failed configured subscription establishment">
<artwork align="left">
<rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<rpc-error>
<error-type>application</error-type>
<error-tag>resource-denied</error-tag>
<error-severity>error</error-severity>
<error-message xml:lang="en">
Temporarily the publisher cannot serve this
subscription due to the current workload.
</error-message>
</rpc-error>
</rpc-reply>
</artwork>
</figure>
</section>
<section title="Modifying a Configured Subscription">
<t>Configured subscriptions can be modified using configuration operations against the top-level subtree subscription-config.</t>
<t>Immediately after a subscription is successfully modified, the publisher sends to the existing receivers a control-plane notification stating the subscription has been modified (i.e., subscription-modified).</t>
<t>If the modification involved adding and/or removing receivers, those modified receivers are sent control-plane notifications, indicating they have been added (i.e, subscription-started to a specific receiver) or removed (i.e., subscription-terminated to a specific receiver.)</t>
</section>
<section title="Deleting a Configured Subscription">
<t>Subscriptions can be deleted using configuration operations against the top-level subtree subscription-config. For example, in RESTCONF:</t>
<figure align="center" anchor="delete-static-subs" title="Deleting a configured subscription">
<artwork align="left">
DELETE /subscription-config/subscription=1922 HTTP/1.1
Host: example.com
HTTP/1.1 204 No Content
Date: Sun, 24 Jul 2016 11:23:40 GMT
Server: example-server
</artwork>
</figure>
<t>Immediately after a subscription is successfully deleted, the publisher sends to all receivers a control-plane notification stating the subscription has been terminated (subscription-terminated).</t>
</section>
</section>
<section title="Event (Data Plane) Notifications">
<t>Once a subscription has been set up, the publisher streams (asynchronously) the event notifications per the terms of the subscription. We refer to these as data plane notifications. For dynamic subscriptions set up via RPC operations, event notifications are sent over the session used to create or establish the subscription. For configured subscriptions, event notifications are sent over the specified connections.</t>
<t>An event notification is sent to the receiver(s) when an event of interest (i.e., meeting the specified filtering criteria) has occurred. An event notification is a complete and well-formed XML document. Note that <notification> is not a Remote Procedure Call (RPC) method but rather the top-level element identifying the one-way message as a notification. Note that event notifications never trigger responses.</t>
<t>The event notification always includes an <eventTime> element. It is the time the event was generated by the event source. This parameter is of type dateTime and compliant to <xref target="RFC3339"/>. Implementations must support time zones.</t>
<t>The event notifications must also include the subscription-id if the establish-subscription was used in its establishment, or if it was configured via an operational interface. </t>
<t>The event notification also contains notification-specific tagged content, if any.</t>
<t>The following is an example of an event notification from <xref target="RFC7950"/>:</t>
<figure align="center" anchor="link-failure-notif" title="Definition of a data plane notification">
<artwork align="left">
notification link-failure {
description "A link failure has been detected";
leaf if-name {
type leafref {
path "/interface/name";
}
}
leaf if-admin-status {
type admin-status;
}
leaf if-oper-status {
type oper-status;
}
}
</artwork>
</figure>
<figure align="center" anchor="simple-data-plane-notif" title="Data plane notification">
<artwork align="left">
<notification
xmlns=" urn:ietf:params:xml:ns:netconf:notification:1.0">
<eventTime>2007-09-01T10:00:00Z</eventTime>
<link-failure xmlns="http://acme.example.com/system">
<if-name>so-1/2/3.0</if-name>
<if-admin-status>up</if-admin-status>
<if-oper-status>down</if-oper-status>
</link-failure>
</notification>
</artwork>
</figure>
<t>The equivalent using json encoding would be</t>
<figure align="center" anchor="simple-data-plane-notif-json" title="Data plane notification using JSON encoding">
<artwork align="left">
<notification
xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
<eventTime>2007-09-01T10:00:00Z</eventTime>
<notification-contents-json>
{
"acme-system:link-failure": {
"if-name": "so-1/2/3.0",
"if-admin-status": "up",
"if-oper-status": "down "
}
}
</notification-contents-json>
</notification>
</artwork>
</figure>
</section>
<section title="Control Plane Notifications">
<t>In addition to data plane notifications, a publisher may send control plane notifications to indicate to receivers that an event related to the subscription management has occurred.
</t>
<t>Control plane notifications are unlike other notifications in that they are not general-purpose
notifications. They cannot be filtered out,
and they are delivered only to the receiver of a subscription. The definition of control plane notifications is distinct from other notifications
by making use of a YANG extension tagging them as control plane notification.
</t>
<t>Control plane notifications include indications that a replay of notifications has been
completed, that a subscription is done sending notifications because an end time has been reached,
and that a subscription has started, been modified, been terminated, or been suspended.
They are described in the following subsections.
</t>
<section title="replayComplete">
<t>This notification is originally defined in <xref target="RFC5277"/>. It is sent to indicate that all of the replay notifications have been sent. This notification must not be sent for any other reason. </t>
<t>In the case of a subscription without a stop time or a stop time which has not been reached, after the <replayComplete> notification has been sent, it can be expected that any notifications generated since the start of the subscription creation will be sent, followed by notifications in sequence as they arise naturally within the system.</t>
</section>
<section title="notificationComplete">
<t>This notification is originally defined in <xref target="RFC5277"/>. It is sent to indicate that a subscription, which includes a stop time, has finished passing events.</t>
</section>
<section title="subscription-started">
<t>This notification indicates that a configured subscription has started and data updates are beginning to be sent. This notification includes the parameters of the subscription, except for the receiver(s) addressing information and push-source information. Note that for RPC-based subscriptions, no such notifications are sent.</t>
</section>
<section title="subscription-modified">
<t>This notification indicates that a configured subscription has been modified successfully. This notification includes the parameters of the subscription, except for the receiver(s) addressing information and push-source information. Note that for RPC-based subscriptions, no such notifications are sent.</t>
</section>
<section title="subscription-terminated">
<t>This notification indicates that a subscription has been terminated by the publisher. The notification includes the reason for the termination. The publisher may decide to terminate a subscription when it is running out of resources for serving it, an internal error occurs, etc. Publisher-driven terminations are notified to all receivers. The management plane can also terminate configured subscriptions using configuration operations.</t>
<t>Subscribers can terminate via RPC subscriptions established via RPC. In such cases, no subscription-terminated notifications are sent. </t>
</section>
<section title="subscription-suspended">
<t>This notification indicates that a publisher has suspended a subscription. The notification includes the reason for the suspension. A possible reason is the lack of resources to serve it. No further data plane notifications will be sent until the subscription resumes. Suspensions are notified to the subscriber (in the case of dynamic subscriptions) and all receivers (in the case of configured subscriptions). </t>
</section>
<section title="subscription-resumed">
<t>This notification indicates that a previously suspended dubscription has been resumed. Data plane notifications generated in the future will be sent after the subscription terms. Resumptions are notified to the subscriber (in the case of dynamic subscriptions) and all receivers (in the case of configured subscriptions).</t>
</section>
</section>
<section title="Data Model for Event Notifications">
<figure>
<artwork xml:space="preserve"><![CDATA[
<CODE BEGINS> file "ietf-event-notifications@2016-10-27.yang"
module ietf-event-notifications {
namespace
"urn:ietf:params:xml:ns:yang:ietf-event-notifications";
prefix notif-bis;
import ietf-yang-types {
prefix yang;
}
import ietf-inet-types {
prefix inet;
}
import ietf-interfaces {
prefix if;
}
organization "IETF";
contact
"WG Web: <http://tools.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org>
WG Chair: Mahesh Jethanandani
<mailto:mjethanandani@gmail.com>
WG Chair: Mehmet Ersue
<mailto:mehmet.ersue@nokia.com>
Editor: Alexander Clemm
<mailto:alex@sympotech.com>
Editor: Alberto Gonzalez Prieto
<mailto:albertgo@cisco.com>
Editor: Eric Voit
<mailto:evoit@cisco.com>
Editor: Einar Nilsen-Nygaard
<mailto:einarnn@cisco.com>
Editor: Ambika Prasad Tripathy
<mailto:ambtripa@cisco.com>
Editor: Sharon Chisholm
<mailto:schishol@ciena.com>
Editor: Hector Trevino
<mailto:htrevino@cisco.com";
description
"This module contains conceptual YANG specifications
for NETCONF Event Notifications.";
revision 2016-10-27 {
description
"Tweaks to remove two notifications,
RPC for create subscription refined with stream default,
new grouping to eliminate some dymanically modifiable
parameters in modifiy subscription RPC";
reference
"draft-ietf-netconf-rfc5277bis-01";
}
/*
* FEATURES
*/
feature json {
description
"This feature indicates that JSON encoding of notifications
is supported.";
}
feature configured-subscriptions {
description
"This feature indicates that management plane configuration
of subscription is supported.";
}
/*
* EXTENSIONS
*/
extension control-plane-notif {
description
"This statement applies only to notifications.
It indicates that the notification is a control-plane
notification (aka OAM notification). Therefore it does
not participate in a regular event stream and does not
need to be specifically subscribed to.";
}
/*
* IDENTITIES
*/
/* Identities for streams */
identity stream {
description
"Base identity to represent a generic stream of event
notifications.";
}
identity NETCONF {
base stream;
description
"Default NETCONF event stream, containing events based on
notifications defined as YANG modules that are supported
by the system.";
}
/* Identities for subscription results */
identity subscription-result {
description
"Base identity for RPC responses to requests surrounding
management (e.g. creation, modification, deletion) of
subscriptions.";
}
identity ok {
base subscription-result;
description
"OK - RPC was successful and was performed as requested.";
}
identity error {
base subscription-result;
description
"RPC was not successful.
Base identity for error return codes.";
}
identity error-no-such-subscription {
base error;
description
"A subscription with the requested subscription ID
does not exist.";
}
identity error-no-such-option {
base error;
description
"A requested parameter setting is not supported.";
}
identity error-insufficient-resources {
base error;
description
"The publisher has insufficient resources to support the
subscription as requested.";
}
identity error-configured-subscription {
base error;
description
"Cannot apply RPC to a configured subscription, i.e.
to a subscription that was not established via RPC.";
}
identity error-other {
base error;
description
"An unspecified error has occurred (catch all).";
}
/* Identities for subscription stream status */
identity subscription-stream-status {
description
"Base identity for the status of subscriptions and
datastreams.";
}
identity active {
base subscription-stream-status;
description
"Status is active and healthy.";
}
identity inactive {
base subscription-stream-status;
description
"Status is inactive, for example outside the
interval between start time and stop time.";
}
identity suspended {
base subscription-stream-status;
description
"The status is suspended, meaning that the publisher
is currently unable to provide the negotiated updates
for the subscription.";
}
identity in-error {
base subscription-stream-status;
description
"The status is in error or degraded, meaning that
stream and/or subscription is currently unable to provide
the negotiated notifications.";
}
/* Identities for subscription errors */
identity subscription-errors {
description
"Base identity for subscription error status.
This identity is not to be confused with error return
codes for RPCs";
}
identity internal-error {
base subscription-errors;
description
"Subscription failures caused by server internal error.";
}
identity no-resources {
base subscription-errors;
description
"Lack of resources, e.g. CPU, memory, bandwidth";
}
identity subscription-deleted {
base subscription-errors;
description
"The subscription was terminated because the subscription
was deleted.";
}
identity other {
base subscription-errors;
description
"Fallback reason - any other reason";
}
/* Identities for encodings */
identity encodings {
description
"Base identity to represent data encodings";
}
identity encode-xml {
base encodings;
description
"Encode data using XML";
}
identity encode-json {
base encodings;
description
"Encode data using JSON";
}
/* Identities for transports */
identity transport {
description
"An identity that represents a transport protocol for
event notifications";
}
identity netconf {
base transport;
description
"Netconf notifications as a transport.";
}
/*
* TYPEDEFs
*/
typedef subscription-id {
type uint32;
description
"A type for subscription identifiers.";
}
typedef filter-id {
type uint32;
description
"A type to identify filters which can be associated with a
subscription.";
}
typedef subscription-result {
type identityref {
base subscription-result;
}
description
"The result of a subscription operation";
}
typedef subscription-term-reason {
type identityref {
base subscription-errors;
}
description
"Reason for a publisher to terminate a subscription.";
}
typedef subscription-susp-reason {
type identityref {
base subscription-errors;
}
description
"Reason for a publisher to suspend a subscription.";
}
typedef encoding {
type identityref {
base encodings;
}
description
"Specifies a data encoding, e.g. for a data subscription.";
}
typedef subscription-status {
type identityref {
base subscription-stream-status;
}
description
"Specifies the status of a subscription or datastream.";
}
typedef transport-protocol {
type identityref {
base transport;
}
description
"Specifies transport protocol used to send notifications to a
receiver.";
}
typedef push-source {
type enumeration {
enum "interface-originated" {
description
"Notifications will be sent from a specific interface on
a publisher";
}
enum "address-originated" {
description
"Notifications will be sent from a specific address on a
publisher";
}
}
description
"Specifies from where notifications will be sourced when
being sent by the publisher.";
}
typedef stream {
type identityref {
base stream;
}
description
"Specifies a system-provided datastream.";
}
typedef filter-ref {
type leafref {
path "/notif-bis:filters/notif-bis:filter/notif-bis:filter-id";
}
description
"This type is used to reference a filter.";
}
/*
* GROUPINGS
*/
grouping base-filter {
description
"This grouping defines the base for filters for
notification events.
It includes the filter defined in 5277 and
it enables extending filtering to other
types of filters";
choice filter-type {
description
"A filter needs to be a single filter of a given type.
Mixing and matching of multiple filters does not occur
at the level of this grouping.";
case rfc5277 {
anyxml filter {
description
"Filter per RFC 5277. Notification filter.
If a filter element is specified to look for data of a
particular value, and the data item is not present
within a particular event notification for its value to
be checked against, the notification will be filtered
out. For example, if one were to check for
'severity=critical' in a configuration event
notification where this field was not supported, then
the notification would be filtered out. For subtree
filtering, a non-empty node set means that the filter
matches. For XPath filtering, the mechanisms defined
in [XPATH] should be used to convert the returned
value to boolean.";
}
}
}
}
grouping subscription-info-basic-non-modifiable {
description
"This grouping describes the information in a basic
subscription request.";
leaf stream {
type stream;
description
"Indicates which stream of events is of interest.
If not present, events in the default NETCONF stream
will be sent.";
}
leaf encoding {
type encoding;
default "encode-xml";
description
"The type of encoding for the subscribed data.
Default is XML";
}
}
grouping subscription-info-basic-modifiable {
description
"This grouping describes some objects which may be changed
in a subscription via an RPC.";
uses base-filter;
leaf startTime {
type yang:date-and-time;
description
"Used to trigger the replay feature
and indicate that the replay should start at the time
specified. If <startTime> is not present, this is not a
replay subscription. It is not valid to specify start
times that are later than the current time. If the
<startTime> specified is earlier than the log can support,
the replay will begin with the earliest available
notification. This parameter is of type dateTime and
compliant to [RFC3339]. Implementations must
support time zones.";
}
leaf stopTime {
type yang:date-and-time;
must "current() > ../startTime" {
description
"stopTime must be used with and be later than <startTime>";
}
description
"Used with the optional replay feature to indicate the
newest notifications of interest. If <stopTime> is
not present, the notifications will continue until the
subscription is terminated. Must be used with and be
later than <startTime>. Values of <stopTime> in the
future are valid. This parameter is of type dateTime and
compliant to [RFC3339]. Implementations must support time
zones.";
}
}
grouping subscription-info-all-modifiable {
description
"This grouping describes all rpc modifiable objects in a
subscription.";
uses subscription-info-basic-modifiable {
augment "filter-type" {
description
"Post-5277 subscriptions allow references to existing
filters";
case by-reference {
description
"Incorporate a filter that has been configured
separately.";
leaf filter-ref {
type filter-ref;
description
"References filter which is associated with the
subscription.";
}
}
}
}
}
grouping subscription-info {
description
"This grouping describes information concerning a
subscription.";
uses subscription-info-basic-non-modifiable;
uses subscription-info-all-modifiable;
}
grouping push-source-info {
description
"Defines the sender source from which notifications
for a configured subscription are sent.";
choice push-source {
description
"Identifies the egress interface on the Publisher from
which notifications will or are being sent.";
case interface-originated {
description
"When the push source is out of an interface on the
Publisher established via static configuration.";
leaf source-interface {
type if:interface-ref;
description
"References the interface for notifications.";
}
}
case address-originated {
description
"When the push source is out of an IP address on the
Publisher established via static configuration.";
leaf source-vrf {
type uint32 {
range "16..1048574";
}
description
"Label of the vrf.";
}
leaf source-address {
type inet:ip-address-no-zone;
mandatory true;
description
"The source address for the notifications.";
}
}
}
}
grouping receiver-info {
description
"Defines where and how to deliver notifications for a
configured subscription. This includes
specifying the receiver, as well as defining
any network and transport aspects when sending of
notifications occurs outside of Netconf.";
container receivers {
description
"Set of receivers in a subscription.";
list receiver {
key "address";
min-elements 1;
description
"A single host or multipoint address intended as a target
for the notifications for a subscription.";
leaf address {
type inet:host;
mandatory true;
description
"Specifies the address for the traffic to reach a
remote host. One of the following must be
specified: an ipv4 address, an ipv6 address,
or a host name.";
}
leaf port {
type inet:port-number;
mandatory true;
description
"This leaf specifies the port number to use for
messages destined for a receiver.";
}
leaf protocol {
type transport-protocol;
default "netconf";
description
"This leaf specifies the transport protocol used
to deliver messages destined for the receiver.";
}
}
}
}
grouping subscription-response {
description
"Defines the output to the rpc's establish-subscription
and modify-subscription.";
leaf subscription-result {
type subscription-result;
mandatory true;
description
"Indicates whether subscription is operational,
or if a problem was encountered.";
}
choice result {
description
"Depending on the subscription result, different
data is returned.";
case success {
description
"This case is used when the subscription request
was successful and a subscription was created/modified
as a result";
leaf subscription-id {
type subscription-id;
mandatory true;
description
"Identifier used for this subscription.";
}
}
case no-success {
description
"This case applies when a subscription request
was not successful and no subscription was
created (or modified) as a result. In this case,
information MAY be returned that indicates
suggested parameter settings that would have a
high likelihood of succeeding in a subsequent
establish-subscription or modify-subscription
request.";
uses subscription-info;
}
}
}
/*
* RPCs
*/
rpc establish-subscription {
description
"This RPC allows a subscriber to create
(and possibly negotiate) a subscription on its own behalf.
If successful, the subscription
remains in effect for the duration of the subscriber's
association with the publisher, or until the subscription
is terminated by virtue of a delete-subscription request.
In case an error (as indicated by subscription-result)
is returned, the subscription is
not created. In that case, the RPC output
MAY include suggested parameter settings
that would have a high likelihood of succeeding in a
subsequent establish-subscription request.";
input {
uses subscription-info;
}
output {
uses subscription-response;
}
}
rpc create-subscription {
description
"This operation initiates an event notification subscription
that will send asynchronous event notifications to the
initiator of the command until the association terminates.
It is not possible to modify or delete a subscription
that was created using this operation. It is included for
reasons of backward compatibility with RFC 5277
implementations.";
input {
uses subscription-info-basic-non-modifiable{
refine "stream" {
default "NETCONF";
}
}
uses subscription-info-basic-modifiable;
}
}
rpc modify-subscription {
description
"This RPC allows a subscriber to modify a subscription
that was previously created using establish-subscription.
If successful, the subscription
remains in effect for the duration of the subscriber's
association with the publisher, or until the subscription
is terminated by virtue of a delete-subscription request.
In case an error is returned (as indicated by
subscription-result), the subscription is
not modified and the original subscription parameters
remain in effect. In that case, the rpc error response
MAY include suggested parameter settings
that would have a high likelihood of succeeding in a
subsequent modify-subscription request.";
input {
leaf subscription-id {
type subscription-id;
description
"Identifier to use for this subscription.";
}
uses subscription-info-all-modifiable;
}
output {
uses subscription-response;
}
}
rpc delete-subscription {
description
"This RPC allows a subscriber to delete a subscription that
was previously created using establish-subscription.";
input {
leaf subscription-id {
type subscription-id;
mandatory true;
description
"Identifier of the subscription that is to be deleted.
Only subscriptions that were created using
establish-subscription can be deleted via this RPC.";
}
}
output {
leaf subscription-result {
type subscription-result;
mandatory true;
description
"Indicates whether subscription is operational,
or if a problem was encountered.";
}
}
}
/*
* NOTIFICATIONS
*/
notification replay-complete {
notif-bis:control-plane-notif;
description
"This notification is sent to indicate that all of the
replay notifications have been sent. It must not be
sent for any other reason.";
leaf subscription-id {
type subscription-id;
mandatory true;
description
"This references the affected subscription.";
}
}
notification notification-complete {
notif-bis:control-plane-notif;
description
"This notification is sent to indicate that a
subscription, which includes a stop time, has
finished passing events.";
leaf subscription-id {
type subscription-id;
mandatory true;
description
"This references the affected subscription.";
}
}
notification subscription-started {
notif-bis:control-plane-notif;
description
"This notification indicates that a subscription has
started and notifications are beginning to be sent.
This notification shall only be sent to receivers
of a subscription; it does not constitute a general-purpose
notification.";
leaf subscription-id {
type subscription-id;
mandatory true;
description
"This references the affected subscription.";
}
uses subscription-info;
}
notification subscription-suspended {
notif-bis:control-plane-notif;
description
"This notification indicates that a suspension of the
subscription by the publisher has occurred. No further
notifications will be sent until subscription
resumes.
This notification shall only be sent to receivers
of a subscription; it does not constitute a general-purpose
notification.";
leaf subscription-id {
type subscription-id;
mandatory true;
description
"This references the affected subscription.";
}
leaf reason {
type subscription-susp-reason;
description
"Provides a reason for why the subscription was
suspended.";
}
}
notification subscription-resumed {
notif-bis:control-plane-notif;
description
"This notification indicates that a subscription that had
previously been suspended has resumed. Notifications
will once again be sent.";
leaf subscription-id {
type subscription-id;
mandatory true;
description
"This references the affected subscription.";
}
}
notification subscription-modified {
notif-bis:control-plane-notif;
description
"This notification indicates that a subscription has
been modified. Notifications sent from this point
on will conform to the modified terms of the
subscription.";
leaf subscription-id {
type subscription-id;
mandatory true;
description
"This references the affected subscription.";
}
uses subscription-info;
}
notification subscription-terminated {
notif-bis:control-plane-notif;
description
"This notification indicates that a subscription has been
terminated.";
leaf subscription-id {
type subscription-id;
mandatory true;
description
"This references the affected subscription.";
}
leaf reason {
type subscription-term-reason;
description
"Provides a reason for why the subscription was
terminated.";
}
}
/*
* DATA NODES
*/
container streams {
config false;
description
"This container contains a leaf list of built-in
streams that are provided by the system.";
leaf-list stream {
type stream;
description
"Identifies the built-in streams that are supported by the
system. Built-in streams are associated with their own
identities, each of which carries a special semantics.
In case configurable custom streams are supported,
as indicated by the custom-stream identity, the
configuration of those custom streams is provided
separately.";
}
}
container filters {
description
"This container contains a list of configurable filters
that can be applied to subscriptions. This facilitates
the reuse of complex filters once defined.";
list filter {
key "filter-id";
description
"A list of configurable filters that can be applied to
subscriptions.";
leaf filter-id {
type filter-id;
description
"An identifier to differentiate between filters.";
}
uses base-filter;
}
}
container subscription-config {
if-feature "configured-subscriptions";
description
"Contains the list of subscriptions that are configured,
as opposed to established via RPC or other means.";
list subscription {
key "subscription-id";
description
"Content of a subscription.";
leaf subscription-id {
type subscription-id;
description
"Identifier to use for this subscription.";
}
uses subscription-info;
uses receiver-info {
if-feature "configured-subscriptions";
}
uses push-source-info {
if-feature "configured-subscriptions";
}
}
}
container subscriptions {
config false;
description
"Contains the list of currently active subscriptions,
i.e. subscriptions that are currently in effect,
used for subscription management and monitoring purposes.
This includes subscriptions that have been setup via RPC
primitives, e.g. create-subscription, establish-
subscription, and modify-subscription, as well as
subscriptions that have been established via
configuration.";
list subscription {
key "subscription-id";
config false;
description
"Content of a subscription.
Subscriptions can be created using a control channel
or RPC, or be established through configuration.";
leaf subscription-id {
type subscription-id;
description
"Identifier of this subscription.";
}
leaf configured-subscription {
if-feature "configured-subscriptions";
type empty;
description
"The presence of this leaf indicates that the
subscription originated from configuration, not
through a control channel or RPC.";
}
leaf subscription-status {
type subscription-status;
description
"The status of the subscription.";
}
uses subscription-info;
uses receiver-info {
if-feature "configured-subscriptions";
}
uses push-source-info {
if-feature "configured-subscriptions";
}
}
}
}
<CODE ENDS>
]]></artwork>
</figure>
</section>
<section title="Backwards Compatibility">
<t>Capabilities are advertised in messages sent by each peer during session establishment <xref target="RFC6241"/>. Publishers supporting the features in this document must advertise both capabilities "urn:ietf:params:netconf:capability:notification:1.0" and "urn:ietf:params:netconf:capability:notification:1.1".</t>
<t>An example of a hello message by a publisher during session establishment would be:</t>
<figure align="center" anchor="simple-hello" title="Hello message">
<artwork align="left">
<hello xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<capabilities>
<capability>
urn:ietf:params:xml:ns:netconf:base:1.0
</capability>
<capability>
urn:ietf:params:netconf:capability:startup:1.0
</capability>
<capability>
urn:ietf:params:netconf:capability:notification:1.0
</capability>
<capability>
urn:ietf:params:netconf:capability:notification:1.1
</capability>
</capabilities>
<session-id>4</session-id>
</hello>
</artwork>
</figure>
<t>Subscribers that only support <xref target="RFC5277"/> recognize capability "urn:ietf:params:netconf:capability:notification:1.0" and ignore capability "urn:ietf:params:netconf:capability:notification:1.1". This allows them interacting with the publisher as per [RFC5277]. Subscribers that support the features in this document recognize both capabilities. This allows them interacting with the publisher as per this document.</t>
<t>Note that to support backwards compatibility, the yang models in this document include two types of naming conventions. That used in <xref target="RFC5277"/>, e.g., replayComplete; and that commonly used in yang models, e.g., subscription-started.</t>
</section>
<section title="Security Considerations">
<t>The <notification> elements are never sent before the transport layer, including capabilities exchange, has been established and the manager has been securely established.</t>
<t>A secure transport is highly recommended and the publisher must ensure that the user has sufficient authorization to perform the function they are requesting against the specific subset of content involved. When a <get> is received that refers to the content defined in this memo, clients should only be able to view the content for which they have sufficient privileges. <create-subscription> and <establish-subscription> operations can be considered like deferred <get>, and the content that different users can access may vary. This different access is reflected in the <notificationt> to which different users are able to subscribe. </t>
<t>The contents of notifications, as well as the names of event streams, may contain sensitive information and care should be taken to ensure that they are viewed only by authorized users. The publisher MUST NOT include any content in a notification that the user is not authorized to view.</t>
<t>If a malicious or buggy subscriber sends a number of <create-subscription> requests, then these subscriptions accumulate and may use up system resources. In such a situation, subscriptions can be terminated by terminating the suspect underlying NETCONF sessions using the <kill-session> operation. If the subscriber uses <establish-subscription>, the publisher can also suspend or terminate subscriptions with per-subscription granularity.</t>
<t>A subscription could be configured on another receiver's behalf, with the goal of flooding that receiver with updates. One or more publishers could be used to overwhelm a receiver, which doesn't even support subscriptions. Subscribers that do not want pushed data need only terminate or refuse any transport sessions from the publisher. In addition, the NETCONF Authorization Control Model <xref target="RFC6536"/> SHOULD be used to control and restrict authorization of subscription configuration. This control models permits specifying per-user permissions to receive specific event notification types. The permissions are specified as a set of access control rules.</t>
<t>Note that streams can define additional authorization requirements. For instance, in <xref target="I-D.ietf-netconf-yang-push"/>, each of the elements in its data plane notifications must also go through access control.</t>
</section>
<section title="Acknowledgments">
<t>For their valuable comments, discussions, and feedback, we wish to acknowledge Andy Bierman, Yang Geng, Peipei Guo, Susan Hares, Tim Jenkins, Balazs Lengyel, Kent Watsen, Michael Scharf, and Guangying Zheng.
</t>
</section>
</middle>
<back>
<references title="Normative References">
<?rfc include="reference.RFC.2119"?>
<?rfc include="reference.RFC.3339"?>
<?rfc include="reference.RFC.5277"?>
<?rfc include="reference.RFC.6241"?>
<?rfc include="reference.RFC.6536"?>
<reference anchor="RFC7950">
<front>
<title>The YANG 1.1 Data Modeling Language</title>
<author fullname="Martin Bjorklund" initials="M" surname="Bjorklund">
<organization/>
</author>
<date month="August" year="2016"/>
</front>
<seriesInfo name="RFC" value="7950"/>
</reference>
</references>
<references title="Informative References">
<reference anchor="I-D.ietf-netconf-restconf">
<front>
<title>RESTCONF Protocol</title>
<author fullname="A. Bierman" initials="A." surname="Bierman">
<organization/>
</author>
<author fullname="M. Bjorklund" initials="M." surname="Bjorklund">
<organization/>
</author>
<author fullname="K. Watsen" initials="K." surname="Watsen">
<organization/>
</author>
<date day="28" month="September" year="2016"/>
</front>
<seriesInfo name="I-D" value="draft-ietf-netconf-restconf-17"/>
</reference>
<reference anchor="I-D.ietf-netconf-yang-push"
target="https://datatracker.ietf.org/doc/draft-ietf-netconf-yang-push/">
<front>
<title>Subscribing to YANG datastore push updates</title>
<author fullname="A Clemm" initials="Alexander" surname="Clemm">
</author>
<author fullname="A Gonzalez Prieto" initials="Alberto"
surname="Gonzalez Prieto">
</author>
<author fullname="E Voit" initials="Eric" surname="Voit">
</author>
<author fullname="Ambika Prasad Tripathy" initials="A" surname="Tripathy">
</author>
<author fullname="Einar Nilsen-Nygaard" initials="E"
surname="Nilsen-Nygaard">
</author>
<date day="15" month="June" year="2016"/>
</front>
</reference>
<reference anchor="I-D.ietf-netconf-netconf-event-notif"
target="https://datatracker.ietf.org/doc/draft-ietf-netconf-netconf-event-notifications/">
<front>
<title>NETCONF support for event notifications</title>
<author fullname="A Gonzalez Prieto" initials="Alberto"
surname="Gonzalez Prieto">
</author>
<author fullname="A Clemm" initials="Alexander" surname="Clemm">
</author>
<author fullname="E Voit" initials="Eric" surname="Voit">
</author>
<author fullname="Einar Nilsen-Nygaard" initials="E"
surname="Nilsen-Nygaard">
</author>
<author fullname="Ambika Prasad Tripathy" initials="A" surname="Tripathy">
</author>
<author fullname="Sharon Chisholm" initials="S"
surname="Chisholm">
</author>
<author fullname="Hector Trevino" initials="H" surname="Trevino">
</author>
<date day="31" month="August" year="2016"/>
</front>
</reference>
<reference anchor="I-D.ietf-netconf-restconf-notif"
target="https://datatracker.ietf.org/doc/draft-ietf-netconf-restconf-notif/">
<front>
<title>Restconf and HTTP transport for event notifications</title>
<author fullname="E Voit" initials="Eric" surname="Voit">
</author>
<author fullname="A Clemm" initials="Alexander" surname="Clemm">
</author>
<author fullname="Ambika Prasad Tripathy" initials="A" surname="Tripathy">
</author>
<author fullname="Einar Nilsen-Nygaard" initials="E"
surname="Nilsen-Nygaard">
</author>
<author fullname="A Gonzalez Prieto" initials="Alberto"
surname="Gonzalez Prieto">
</author>
<date day="26" month="August" year="2016"/>
</front>
</reference>
</references>
<section title="Issues that are currently being worked and resolved">
<t>(To be removed by RFC editor prior to publication)</t>
<section title="Unresolved and yet-to-be addressed issues">
<t>EN1 - Definition of basic set of Stream types. What streams are provided and what do they contain (includes default 5277 stream).</t>
<t>EN2 - Clarify interplay between filter definitions and different streams.
Includes information in subtrees of event payloads.</t>
<t>EN3 - Mechanisms for diagnostics, e.g. deal with dropped updates, monitoring when they occur, etc</t>
</section>
<section title="Agreement in principal">
<t>EN4 - How to allow for seamless integration with non-standard encodings and transports (like GPB/GRPC). Specify requirements encoding and transport must meet, provide examples. </t>
<t>EN7 - Detecting loss of a sequential update notification, and mechanisms to resend. Implications to transports must be thought through.</t>
<t>EN6 - Stream discovery. Allow to discover additional stream properties. </t>
<t>EN12 - Test-only option for a subscription is desired. But it still needs to be defined.</t>
<t>EN14 - Ensure that Configured Subscriptions are fully defined in YANG model.</t>
</section>
<section title="Resolved Issues">
<t>EN5 - This draft obsoletes 5277, as opposed to being in parallel with it </t>
<t>EN8 - No mandatory transport</t>
<t>EN15 - Term for Dynamic and Static Subscriptions (move to "Configured")</t>
<t>EN9 - Multiple receivers per Configured Subscription is ok.</t>
<t>EN13 - RFC6241 Subtree-filter definition in 5277bis cannot apply to elements of an event. Must explicitly define how 6241 doesn't apply filtering within a 5277bis event.</t>
<t>EN10 - Replay support will be provided for selected stream types (modify vs. delete)</t>
<t>EN11 - Required layering security requirements/considerations will be added into the YANG model for Configured Subscriptions. It will be up to the transport to meet these requirements.</t>
</section>
</section>
<section title="Changes between revisions">
<t>(To be removed by RFC editor prior to publication)</t>
<t>v00 - v01</t>
<t><list style="symbols">
<t>YANG Model changes. New groupings for subscription info to allow restriction of what is changable via RPC. Removed notifications for adding and removing receivers of configured subscriptions.</t>
<t>Expanded/renamed defintions from event server to publisher, and client to subscriber as applicable. Updated the definitions to include and expand on RFC 5277.</t>
<t>Removal of redundant with other drafts</t>
<t>Many other clean-ups of wording and terminology</t>
</list>
</t>
</section>
</back>
</rfc>| PAFTECH AB 2003-2026 | 2026-04-24 07:45:52 |