NETCONF Support for Event Notifications
draft-ietf-netconf-netconf-event-notifications-03
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 8640.
|
|
|---|---|---|---|
| Authors | Alberto Gonzalez Prieto , Alexander Clemm , Eric Voit , Einar Nilsen-Nygaard , Ambika Tripathy | ||
| Last updated | 2017-06-07 | ||
| Replaces | draft-gonzalez-netconf-event-notifications | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Formats | |||
| Reviews |
TSVART Last Call review
(of
-17)
by Wesley Eddy
Ready w/issues
YANGDOCTORS Last Call review
(of
-16)
by Reshad Rahman
Ready w/issues
|
||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | WG Document | |
| Document shepherd | (None) | ||
| IESG | IESG state | Became RFC 8640 (Proposed Standard) | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ietf-netconf-netconf-event-notifications-03
NETCONF A. Gonzalez Prieto
Internet-Draft VMWare
Intended status: Standards Track A. Clemm
Expires: December 9, 2017 Huawei
E. Voit
E. Nilsen-Nygaard
A. Tripathy
Cisco Systems
June 7, 2017
NETCONF Support for Event Notifications
draft-ietf-netconf-netconf-event-notifications-03
Abstract
This document defines how to transport network subscriptions and
event messages on top of the Network Configuration protocol
(NETCONF). This includes the full set of RPCs, subscription state
changes, and message payloads needing asynchronous delivery. The
capabilities and operations defined in this document used in
conjunction with [subscribe] are intended to obsolete [RFC5277]. In
addition, the capabilities within those two documents along with
[yang-push] are intended to enable an extract of a YANG datastore on
a remote device.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 9, 2017.
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 1]
Internet-Draft NETCONF-notifications June 2017
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Solution . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Event Stream Discovery . . . . . . . . . . . . . . . . . 3
3.2. Mandatory NETCONF support for Streams and Datastores . . 4
3.3. Dynamic Subscriptions . . . . . . . . . . . . . . . . . . 4
3.4. Configured Subscriptions . . . . . . . . . . . . . . . . 11
4. Security Considerations . . . . . . . . . . . . . . . . . . . 24
5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 25
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 25
6.1. Normative References . . . . . . . . . . . . . . . . . . 25
6.2. Informative References . . . . . . . . . . . . . . . . . 26
Appendix A. Changes between revisions . . . . . . . . . . . . . 26
A.1. v01 to v03 . . . . . . . . . . . . . . . . . . . . . . . 26
A.2. v00 to v01 . . . . . . . . . . . . . . . . . . . . . . . 26
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27
1. Introduction
This document defines mechanisms that provide an asynchronous message
notification delivery service for the NETCONF protocol [RFC6241]
based on [subscribe]. This is an optional capability built on top of
the base NETCONF definition.
[subscribe] plus this transport specification document provides a
superset of the capabilities previously defined in [RFC5277]. Newly
introduced capabilities include the ability to have multiple
subscriptions on a single NETCONF session, the ability to terminate
subscriptions without terminating the client session, and the ability
to modify existing subscriptions.
In addition, [yang-push] plus the capabilities of this document
provide a mechanism for a NETCONF client to maintain a subset/extract
of an actively changing YANG datastore.
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 2]
Internet-Draft NETCONF-notifications June 2017
2. Terminology
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 RFC 2119 [RFC2119].
The following terms are defined in [RFC6241]: client, server,
operation, RPC.
The following terms are defined in [subscribe]: event, event
notification, stream, publisher, receiver, subscriber, subscription,
configured subscription.
Note that a publisher in [subscribe] corresponds to a server in
[RFC6241]. Similarly, a subscriber corresponds to a client. A
receiver is also a client. In the remainder of this document, we
will use the terminology in [RFC6241] to simplify [subscribe]'s
mental mappings to embedded NETCONF terminology.
3. Solution
In this section, we describe and exemplify how [subscribe] is to be
supported over NETCONF.
3.1. Event Stream Discovery
In the context of [subscribe] an event stream exposes a continuous
set of events available for subscription. A NETCONF client can
retrieve the list of available event streams from a NETCONF server
using the "get" operation. The reply contains the elements defined
in the YANG model under the container "/streams", which includes the
stream identities supported on the NETCONF server.
The following example illustrates the retrieval of the list of
available event streams using the <get> operation.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get>
<filter type="subtree">
<streams
xmlns="urn:ietf:params:xml:ns:yang:ietf-event-notifications"/>
</filter>
</get>
</rpc>
Figure 1: Get streams
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 3]
Internet-Draft NETCONF-notifications June 2017
The NETCONF server returns a list of event streams available. In
this example, the list contains the NETCONF, SNMP, and SYSLOG
streams.
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<data>
<streams
xmlns="urn:ietf:params:xml:ns:yang:ietf-event-notifications">
<stream>NETCONF</stream>
<stream>SNMP</stream>
<stream>SYSLOG</stream>
</streams>
</data>
</rpc-reply>
Figure 2: Get streams response
For [yang-push], a similar get is needed to retrieve available
datastore names.
3.2. Mandatory NETCONF support for Streams and Datastores
A NETCONF server implementation supporting [subscribe] must support
the "NETCONF" notification event stream.
A NETCONF server implementation supporting [yang-push] must support
the "running" datastore.
3.3. Dynamic Subscriptions
3.3.1. Establishing Dynamic Subscriptions
The dynamic subscription RFC and interactions operation is defined in
[subscribe].
3.3.1.1. Usage Example
An example of interactions over NETCONF transport for one sample
subscription is below:
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 4]
Internet-Draft NETCONF-notifications June 2017
<netconf:rpc netconf:message-id="102"
xmlns:netconf="urn:ietf:params:xml:ns:netconf:base:1.0">
<establish-subscription
xmlns="urn:ietf:params:xml:ns:netconf:notification:2.0">
<stream>NETCONF</stream>
<filter-type>xpath</filter-type>
<filter> xmlns:ex="http://example.com/event/1.0"
select="/ex:event[ex:eventClass='fault' and
(ex:severity='minor' or ex:severity='major'
or ex:severity='critical')]"
</filter>
</establish-subscription>
</netconf:rpc>
Figure 3: establish-subscription over NETCONF
3.3.1.2. Positive Response
If the NETCONF server can satisfy the request, the server sends a
positive <subscription-result> element, and the subscription-id of
the accepted subscription.
<rpc-reply message-id="102"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<subscription-result
xmlns="urn:ietf:params:xml:ns:netconf:notification:2.0">
ok
</subscription-result>
<identifier
xmlns="urn:ietf:params:xml:ns:netconf:notification:2.0">
52
</identifier>
</rpc-reply>
Figure 4: Successful establish-subscription
3.3.1.3. Negative Response
If the NETCONF server cannot satisfy the request, or client has no
authorization to establish the subscription, the server will send a
negative <subscription-result> element. For instance:
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 5]
Internet-Draft NETCONF-notifications June 2017
<rpc-reply message-id="103"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<subscription-result
xmlns="urn:ietf:params:xml:ns:netconf:notification:2.0">
stream-unavailable
</subscription-result>
</rpc-reply>
Figure 5: Unsuccessful establish subscription
If the client requests parameters the NETCONF server cannot serve,
the negative <subscription-result> may include additional
information. For instance, consider the following subscription from
[yang-push], which augments the establish-subscription with some
additional parameters, including "period". If the client requests a
which period the NETCONF server cannot serve, the back-and-forth
exchange may be:
<netconf:rpc message-id="101"
xmlns:netconf="urn:ietf:params:xml:ns:netconf:base:1.0">
<establish-subscription
xmlns="urn:ietf:params:xml:ns:netconf:notification:2.0">
<stream>push-update</stream>
<filter-type>subtree</filter-type>
<filter>xmlns:ex="http://example.com/sample-data/1.0"
select="/ex:foo"</filter>
<period xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-push:1.0">
500
</period>
<encoding>encode-xml</encoding>
</establish-subscription>
</netconf:rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<subscription-result
xmlns="urn:ietf:params:xml:ns:netconf:notification:2.0">
error-insufficient-resources
</subscription-result>
<period
xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-push:1.0">
2000
</period>
</rpc-reply>
Figure 6: Subscription establishment negotiation
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 6]
Internet-Draft NETCONF-notifications June 2017
3.3.1.4. Message Flow Examples
+------------+ +-----------+
| Client | | Server |
+------------+ +-----------+
| |
| Capability Exchange |
|<---------------------------->|
| |
| |
| Establish Subscription |
|----------------------------->|
| RPC Reply: OK, id = 22 |
|<-----------------------------|
| |
| Notification (id 22) |
|<-----------------------------|
| |
| |
| Establish Subscription |
|----------------------------->|
| RPC Reply: OK, id = 23 |
|<-----------------------------|
| |
| |
| Notification (id 22) |
|<-----------------------------|
| Notification (id 23) |
|<-----------------------------|
| |
| |
Figure 7: Multiple subscription establishments over a NETCONF session
3.3.2. Modifying a Subscription
This operation is defined in [subscribe] and enhanced in [yang-push].
3.3.2.1. Usage Example
The following demonstrates modifying a subscription. Consider a
subscription from [yang-push], which augments the establish-
subscription with some additional parameters, including "period". A
subscription may be established as follows.
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 7]
Internet-Draft NETCONF-notifications June 2017
<netconf:rpc message-id="101"
xmlns:netconf="urn:ietf:params:xml:ns:netconf:base:1.0">
<establish-subscription
xmlns="urn:ietf:params:xml:ns:netconf:notification:2.0">
/* Question, shouldn't this be yang-push 1.0 as that
is where the referenced augmentations are? */
<datastore>running</datastore>
<filter-type>subtree</filter-type>
<filter>xmlns:ex="http://example.com/sample-data/1.0"
select="/ex:foo"</filter>
<period xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-push:1.0">
1000
</period>
</establish-subscription>
</netconf:rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<subscription-result
xmlns="urn:ietf:params:xml:ns:netconf:notification:2.0">
ok
</subscription-result>
<identifier
xmlns="urn:ietf:params:xml:ns:netconf:notification:2.0">
1922
</identifier>
</rpc-reply>
Figure 8: Establish subscription to be modified
The subscription may be modified with and RPC request such as:
<netconf:rpc message-id="102"
xmlns:netconf="urn:ietf:params:xml:ns:netconf:base:1.0">
<modify-subscription
xmlns="urn:ietf:params:xml:ns:netconf:notification:2.0">
<identifier>1922</identifier>
<period>100</period>
</modify-subscription>
</netconf:rpc>
Figure 9: Modify subscription
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 8]
Internet-Draft NETCONF-notifications June 2017
3.3.2.2. Positive Response
If the NETCONF server can satisfy the request, the server sends a
positive <subscription-result> element. This response is like that
to an establish-subscription request, but without the subscription
identifier.
<rpc-reply message-id="102"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<subscription-result
xmlns="urn:ietf:params:xml:ns:netconf:notification:2.0">
ok
</subscription-result>
</rpc-reply>
Figure 10: Successful modify subscription
3.3.2.3. Negative Response
If the NETCONF server cannot satisfy the request, the server sends a
negative <subscription-result> element. Its contents and semantics
are identical to those in an establish-subscription request. For
instance:
<rpc-reply message-id="102"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<subscription-result
xmlns="urn:ietf:params:xml:ns:netconf:notification:2.0">
*** why is the namespace not yang-push?
period-unsupported
</subscription-result>
<period-hint>500</period-hint>
</rpc-reply>
Figure 11: Unsuccessful modify subscription
3.3.2.4. Message Flow Example
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 9]
Internet-Draft NETCONF-notifications June 2017
+------------+ +-----------+
| Client | | Server |
+------------+ +-----------+
| |
| Capability Exchange |
|<---------------------------->|
| |
| Establish Subscription |
|<---------------------------->|
| |
| Notification (id 22) |
|<-----------------------------|
| |
| Modify Subscription |
|----------------------------->|
| RPC Reply: OK |
|<-----------------------------|
| |
| Notification (id 22) |
|<-----------------------------|
| |
Figure 12: Message flow for successful subscription modification
3.3.3. Deleting a Subscription
This operation is defined in [subscribe] for events, and enhanced in
[yang-push] for datastores.
3.3.3.1. Usage Example
The following demonstrates deleting a subscription.
<netconf:rpc message-id="101"
xmlns:netconf="urn:ietf:params:xml:ns:netconf:base:1.0">
<delete-subscription
xmlns="urn:ietf:params:xml:ns:netconf:notification:2.0">
<identifier>1922</identifier>
</delete-subscription>
</netconf:rpc>
Figure 13: Delete subscription
3.3.3.2. Positive Response
If the NETCONF server can satisfy the request, the server sends an OK
element. For example:
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 10]
Internet-Draft NETCONF-notifications June 2017
<rpc-reply message-id="103"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
Figure 14: Successful delete subscription
3.3.3.3. Negative Response
If the NETCONF server cannot satisfy the request, the server sends an
error-rpc element indicating the modification didn't work. For
example:
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<rpc-error>
<error-type>application</error-type>
<error-tag>invalid-value</error-tag>
<error-severity>error</error-severity>
<error-path
xmlns:t="urn:ietf:params:xml:ns:netconf:notification:2.0">
/t:identifier
</error-path>
<error-message xml:lang="en">
no-such-subscription
</error-message>
</rpc-error>
</rpc-reply>
Figure 15: Unsuccessful delete subscription
3.4. Configured Subscriptions
Configured subscriptions are established, modified, and deleted using
configuration operations against the top-level subtree of [subscribe]
or [yang-push] via normal NETCONF operations. In this section, we
present examples of how to manage the configuration subscriptions
using a NETCONF client. Key differences from dunamic subscriptions
over NETCONF is that subscription lifetimes are decoupled from
NETCONF sessions.
3.4.1. Establishing a Configured Subscription
For subscription establishment, a NETCONF client may send:
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 11]
Internet-Draft NETCONF-notifications June 2017
<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:2.0">
<subscription>
<identifier>
1922
</identifier>
<stream>
foo
</stream>
<receiver>
<address>
1.2.3.4
</address>
<port>
1234
</port>
</receiver>
</subscription>
</subscription-config>
</edit-config>
</rpc>
Figure 16: Establish static subscription
if the request is accepted, the server would reply:
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
Figure 17: Response to a successful static subscription establishment
if the request is not accepted because the server cannot serve it, no
configuration is changed. Int this case the server may reply:
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 12]
Internet-Draft NETCONF-notifications June 2017
<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 server cannot serve this
subscription due to the current workload.
</error-message>
</rpc-error>
</rpc-reply>
Figure 18: Response to a failed static subscription establishment
For every configured receiver, once NETCONF transport session between
the server and the receiver is recognized as active, the server will
issue a "subscription-started" notification. After that, the server
will send notifications to the receiver as per the subscription
notification.
Note that the server assumes that the receiver is ready to accept
notifications on the NETCONF session. This may require coordination
between the client that configures the subscription and the clients
for which the notifications are intended. This coordination is out
of the scope of this document.
3.4.2. Call Home for Configured Subscriptions
Once this configuration is active, if NETCONF transport is needed but
does not exist to one or more target IP address plus port, the server
initiates a transport session via [RFC8071] to those receiver(s) in
the subscription using the address and port specified.
3.4.3. Full Establish Message Flow
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 13]
Internet-Draft NETCONF-notifications June 2017
+----------+ +-----------+ +---------+ +---------+
| Client | | Server | | Rcver A | | Rcver B |
+----------+ +-----------+ +---------+ +---------+
| | | |
| Capability Exchange | | |
|<-------------------------->| | |
| | | |
| | | |
| Edit-config | | |
|--------------------------->| | |
| RPC Reply: OK | | |
|<---------------------------| | |
| | Call Home | |
| |<-------------->| |
| |<--------------------------->|
| | | |
| | Subscription | |
| | Started | |
| | (id 22) | |
| |--------------->| |
| |---------------------------->|
| | | |
| | Notification | |
| | (id 22) | |
| |--------------->| |
| |---------------------------->|
| | | |
Figure 19: Message flow for configured subscription establishment
3.4.4. Modifying a Configured Subscription
Configured subscriptions can be modified using configuration
operations against the top-level subtree subscription-config.
For example, the subscription established in the previous section
could be modified as follows, choosing a different receiver:
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 14]
Internet-Draft NETCONF-notifications June 2017
<rpc message-id="102"
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:2.0">
<subscription>
<identifier>
1922
</identifier>
<stream>
foo
</stream>
<receiver>
<address>
1.2.3.5
</address>
<port>
1234
</port>
</receiver>
</subscription>
</subscription-config>
</edit-config>
</rpc>
Figure 20: Modify configured subscription
if the request is accepted, the server would reply:
<rpc-reply message-id="102"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
Figure 21: A successful configured subscription modification
3.4.4.1. Message Flow Example
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 15]
Internet-Draft NETCONF-notifications June 2017
+----------+ +-----------+ +---------+ +---------+
| Client | | Server | | Rcver A | | Rcver B |
+----------+ +-----------+ +---------+ +---------+
| | | |
| Capability Exchange | | |
|<-------------------------->| | |
| | | |
| | | |
| Edit-config | | |
|--------------------------->| | |
| RPC Reply: OK | | |
|<---------------------------| | |
| | Call Home | |
| |<-------------->| |
| |<--------------------------->|
| | | |
| | Subscription | |
| | Started | |
| | (id 22) | |
| |--------------->| |
| |---------------------------->|
| | | |
| | Notification | |
| | (id 22) | |
| |--------------->| |
| |---------------------------->|
| | | |
| Edit-config | | |
|--------------------------->| | |
| RPC Reply: OK | | |
|<---------------------------| | |
| | Subscription | |
| | Modified | |
| | (id 22) | |
| |--------------->| |
| |---------------------------->|
| | | |
| | Notification | |
| | (id 22) | |
| |--------------->| |
| |---------------------------->|
| | | |
Figure 22: Message flow for subscription modification (configured
subscription)
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 16]
Internet-Draft NETCONF-notifications June 2017
3.4.5. Deleting a Configured Subscription
Subscriptions can be deleted using configuration operations against
the top-level subtree subscription-config. For example:
<rpc message-id="103"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<running/>
</target>
<subscription-config
xmlns:xc="urn:ietf:params:xml:ns:netconf:notification:2.0">
<subscription xc:operation="delete">
<identifier>
1922
</identifier>
</subscription>
</subscription-config>
</edit-config>
</rpc>
<rpc-reply message-id="103"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
Figure 23: Deleting a configured subscription
3.4.5.1. Message Flow Example
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 17]
Internet-Draft NETCONF-notifications June 2017
+----------+ +-----------+ +---------+ +---------+
| Client | | Server | | Rcver A | | Rcver B |
+----------+ +-----------+ +---------+ +---------+
| | | |
| Capability Exchange | | |
|<-------------------------->| | |
| | | |
| | | |
| Edit-config | | |
|--------------------------->| | |
| RPC Reply: OK | | |
|<---------------------------| | |
| | Call Home | |
| |<-------------->| |
| |<--------------------------->|
| | | |
| | Subscription | |
| | Started | |
| | (id 22) | |
| |--------------->| |
| |---------------------------->|
| | | |
| | | |
| | Notification | |
| | (id 22) | |
| |--------------->| |
| |---------------------------->|
| | | |
| Edit-config | | |
|--------------------------->| | |
| RPC Reply: OK | | |
|<---------------------------| | |
| | Subscription | |
| | Terminated | |
| | (id 22) | |
| |--------------->| |
| |---------------------------->|
| | | |
Figure 24: Message flow for subscription deletion (configured
subscription)
3.4.6. Event (Data Plane) Notifications
Once a dynamic or configured subscription has been created, the
NETCONF server sends (asynchronously) event notifications from the
subscribed stream to receiver(s) over NETCONF. We refer to these as
data plane notifications.
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 18]
Internet-Draft NETCONF-notifications June 2017
The following is an example of an event notification from [RFC6020]:
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;
}
}
Figure 25: Definition of a data plane notification
This notification might result in the following, prior to it being
placed into NETCONF. Note that the mandatory eventTime and
Subscription id have been added.
<notification
xmlns=" urn:ietf:params:xml:ns:netconf:notification:2.0">
<eventTime>2007-09-01T10:00:00Z</eventTime>
<subscription-id>39</subscription-id>
<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>
Figure 26: Data plane notification
The equivalent using JSON encoding would be
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 19]
Internet-Draft NETCONF-notifications June 2017
<notification
xmlns="urn:ietf:params:xml:ns:netconf:notification:2.0">
<eventTime>2007-09-01T10:00:00Z</eventTime>
<subscription-id>39</subscription-id>
<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>
Figure 27: Data plane notification using JSON encoding
3.4.7. Control Plane Notifications
In addition to data plane notifications, a server may send control
plane notifications (defined in [subscribe]) to indicate to receivers
that an event related to the subscription management has occurred.
Control plane notifications cannot be filtered out. Next we
exemplify them using both XML, and JSON encodings for the
notification-specific content:
3.4.7.1. subscription-started and subscription-modified
A subscription-started would look like:
<notification
xmlns=" urn:ietf:params:xml:ns:netconf:notification:2.0">
<eventTime>2007-09-01T10:00:00Z</eventTime>
<subscription-started
xmlns="urn:ietf:params:xml:ns:yang:ietf-event-notifications"/>
<identifier>39</identifier>
<filter-type>xpath</filter-type>
<filter xmlns:ex="http://example.com/event/1.0"
select="/ex:event[ex:eventClass='fault' and
(ex:severity='minor' or ex:severity='major'
or ex:severity='critical')]"/>
</subscription-started/>
</notification>
Figure 28: subscription-started control plane notification
The equivalent using JSON encoding would be:
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 20]
Internet-Draft NETCONF-notifications June 2017
<notification
xmlns=" urn:ietf:params:xml:ns:netconf:notification:2.0">
<eventTime>2007-09-01T10:00:00Z</eventTime>
<notification-contents-json>
{
"notif-bis:subscription-started": {
"identifier" : 39
((Open Item: express everything including the filter in json))
}
}
</notification-contents-json>
</notification>
Figure 29: subscription-started control plane notification (JSON)
The subscription-modified is identical, with just the word "started"
being replaced by "modified".
3.4.7.2. notification-complete, subscription-resumed, and replay-
complete
A notification-complete would look like:
<notification
xmlns=" urn:ietf:params:xml:ns:netconf:notification:2.0">
<eventTime>2007-09-01T10:00:00Z</eventTime>
<notification-complete
xmlns="urn:ietf:params:xml:ns:yang:ietf-event-notifications">
<identifier>39</identifier>
</notification-complete>
</notification>
Figure 30: notification control plane notification XML
The equivalent using JSON encoding would be:
<notification
xmlns=" urn:ietf:params:xml:ns:netconf:notification:2.0">
<eventTime>2007-09-01T10:00:00Z</eventTime>
<notification-contents-json>
{
"netmod-notif:notification-complete": {
"identifier" : 39
}
</notification-contents-json>
</notification>
Figure 31: notification control plane notification JSON
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 21]
Internet-Draft NETCONF-notifications June 2017
The subscription-resumed and replay-complete are virutally identical,
with "notification-complete" simply being replaced by "subscription-
resumed" and "replay-complete" in both encodings.
3.4.7.3. subscription-terminated and subscription-suspended
A subscription-terminated would look like:
<notification
xmlns=" urn:ietf:params:xml:ns:netconf:notification:2.0">
<eventTime>2007-09-01T10:00:00Z</eventTime>
<subscription-terminated
xmlns="urn:ietf:params:xml:ns:yang:ietf-event-notifications">
<identifier>39</identifier>
<error-id>no-such-subscription</error-id>
</subscription-terminated>
</notification>
Figure 32: subscription-modified control plane notification
The above, and the subscription-suspended are virutally identical,
with "subscription-terminated" simply being replaced by
"subscription-suspended".
3.4.7.4. Notification Message Flow Examples
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 22]
Internet-Draft NETCONF-notifications June 2017
+------------+ +-----------+
| Client | | Server |
+------------+ +-----------+
| |
| Capability Exchange |
|<---------------------------->|
| |
| Establish Subscription |
|<---------------------------->|
| |
| Notification |
|<-----------------------------|
| |
| |
| Subscription Suspended |
|<-----------------------------|
| |
| |
| |
| Subscription Resumed |
|<-----------------------------|
| |
| Notification |
|<-----------------------------|
| |
Figure 33: subscription-suspended and Resumed Notifications
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 23]
Internet-Draft NETCONF-notifications June 2017
+----------+ +-----------+ +---------+ +---------+
| Client | | Server | | Rcver A | | Rcver B |
+----------+ +-----------+ +---------+ +---------+
| | | |
| Capability Exchange | | |
|<-------------------------->| | |
| | | |
| Edit-config | | |
|--------------------------->| | |
| RPC Reply: OK | | |
|<---------------------------| | |
| | Subscription | |
| | Started | |
| |--------------->| |
| |---------------------------->|
| | | |
| | Notification | |
| |--------------->| |
| |---------------------------->|
| | | |
| | Subscription | |
| | Suspended | |
| |--------------->| |
| | | |
| | Notification | |
| |---------------------------->|
| | | |
| | Subscription | |
| | Resumed | |
| |--------------->| |
| | | |
| | Notification | |
| |--------------->| |
| |---------------------------->|
| | | |
Figure 34: Suspended and resumed for a single configured receiver
4. Security Considerations
The <notification> elements are never sent before the transport layer
and the NETCONF layer, including capabilities exchange, have been
established and the manager has been identified and authenticated.
A secure transport must be used and the server must ensure that the
user has sufficient authorization to perform the function they are
requesting against the specific subset of content involved.
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 24]
Internet-Draft NETCONF-notifications June 2017
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 NETCONF server
MUST NOT include any content in a notification that the user is not
authorized to view.
If a malicious or buggy NETCONF client sends a number of <establish-
subscription>requests, then these subscriptions accumulate and may
use up system resources. In such a situation, subscriptions MAY be
terminated by terminating the suspect underlying NETCONF sessions.
The server MAY also suspend or terminate a subset of the active
subscriptions on the NETCONF session .
Configured subscriptions from one or more publishers could be used to
overwhelm a receiver, which perhaps doesn't even support
subscriptions. Clients that do not want pushed data need only
terminate or refuse any transport sessions from the publisher.
The NETCONF Authorization Control Model [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.
5. Acknowledgments
We wish to acknowledge the helpful contributions, comments, and
suggestions that were received from: Andy Bierman, Yan Gang, Sharon
Chisholm, Hector Trevino, Peipei Guo, Susan Hares, Tim Jenkins,
Balazs Lengyel, Kent Watsen, and Guangying Zheng.
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC5277] Chisholm, S. and H. Trevino, "NETCONF Event
Notifications", RFC 5277, DOI 10.17487/RFC5277, July 2008,
<http://www.rfc-editor.org/info/rfc5277>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<http://www.rfc-editor.org/info/rfc6020>.
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 25]
Internet-Draft NETCONF-notifications June 2017
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<http://www.rfc-editor.org/info/rfc6241>.
[RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration
Protocol (NETCONF) Access Control Model", RFC 6536,
DOI 10.17487/RFC6536, March 2012,
<http://www.rfc-editor.org/info/rfc6536>.
[RFC8071] Watsen, K., "NETCONF Call Home and RESTCONF Call Home",
RFC 8071, DOI 10.17487/RFC8071, February 2017,
<http://www.rfc-editor.org/info/rfc8071>.
6.2. Informative References
[subscribe]
Voit, Eric., Clemm, A., Gonzalez Prieto, A., Nilsen-
Nygaard, E., and A. Tripathy, "Subscribing to Event
Notifications", April 2016,
<https://datatracker.ietf.org/doc/draft-ietf-netconf-
subscribed-notifications/>.
[yang-push]
Clemm, A., Gonzalez Prieto, A., Voit, Eric., Tripathy, A.,
and E. Nilsen-Nygaard, "Subscribing to YANG datastore push
updates", April 2017, <https://datatracker.ietf.org/doc/
draft-ietf-netconf-yang-push/>.
Appendix A. Changes between revisions
(To be removed by RFC editor prior to publication)
A.1. v01 to v03
o Text simplifications throughout
o v02 had no meaningful changes
A.2. v00 to v01
o Added Call Home in solution for configured subscriptions.
o Clarified support for multiple subscription on a single session.
No need to support multiple create-subscription.
o Added mapping between terminology in [yang-push] and [RFC6241]
(the one followed in this document).
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 26]
Internet-Draft NETCONF-notifications June 2017
o Editorial improvements.
Authors' Addresses
Alberto Gonzalez Prieto
VMWare
Email: alberto.gonzalezprieto@yahoo.com
Alexander Clemm
Huawei
Email: ludwig@clemm.org
Eric Voit
Cisco Systems
Email: evoit@cisco.com
Einar Nilsen-Nygaard
Cisco Systems
Email: einarnn@cisco.com
Ambika Prasad Tripathy
Cisco Systems
Email: ambtripa@cisco.com
Gonzalez Prieto, et al. Expires December 9, 2017 [Page 27]