draft-ietf-netconf-restconf-notif-08.txt   draft-ietf-netconf-restconf-notif-09.txt 
NETCONF E. Voit NETCONF E. Voit
Internet-Draft R. Rahman Internet-Draft R. Rahman
Intended status: Standards Track E. Nilsen-Nygaard Intended status: Standards Track E. Nilsen-Nygaard
Expires: April 7, 2019 Cisco Systems Expires: April 22, 2019 Cisco Systems
A. Clemm A. Clemm
Huawei Huawei
A. Bierman A. Bierman
YumaWorks YumaWorks
October 4, 2018 October 19, 2018
RESTCONF Transport for Event Notifications Dynamic subscription to YANG Events and Datastores over RESTCONF
draft-ietf-netconf-restconf-notif-08 draft-ietf-netconf-restconf-notif-09
Abstract Abstract
This document defines a RESTCONF binding to the dynamic subscription This document provides a RESTCONF binding to the dynamic subscription
capability of both subscribed notifications and YANG-Push. capability of both subscribed notifications and YANG-Push.
Subscriptions to publisher defined event streams or nodes/subtrees of
YANG Datastores is supported.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 7, 2019. This Internet-Draft will expire on April 22, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Dynamic Subscriptions . . . . . . . . . . . . . . . . . . . . 3 3. Dynamic Subscriptions . . . . . . . . . . . . . . . . . . . . 3
3.1. Transport Connectivity . . . . . . . . . . . . . . . . . 4 3.1. Transport Connectivity . . . . . . . . . . . . . . . . . 4
3.2. Discovery . . . . . . . . . . . . . . . . . . . . . . . . 4 3.2. Discovery . . . . . . . . . . . . . . . . . . . . . . . . 4
3.3. RESTCONF RPCs and HTTP Status Codes . . . . . . . . . . . 4 3.3. RESTCONF RPCs and HTTP Status Codes . . . . . . . . . . . 4
3.4. Call Flow for Server-Sent Events (SSE) . . . . . . . . . 6 3.4. Call Flow for Server-Sent Events (SSE) . . . . . . . . . 6
4. QoS Treatment . . . . . . . . . . . . . . . . . . . . . . . . 8 4. QoS Treatment . . . . . . . . . . . . . . . . . . . . . . . . 8
5. Mandatory JSON and datastore support . . . . . . . . . . . . 8 5. Notification Messages . . . . . . . . . . . . . . . . . . . . 8
6. Notification Messages . . . . . . . . . . . . . . . . . . . . 8 6. YANG Tree . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7. YANG Tree . . . . . . . . . . . . . . . . . . . . . . . . . . 8 7. YANG module . . . . . . . . . . . . . . . . . . . . . . . . . 8
8. YANG module . . . . . . . . . . . . . . . . . . . . . . . . . 9 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 9. Security Considerations . . . . . . . . . . . . . . . . . . . 11
10. Security Considerations . . . . . . . . . . . . . . . . . . . 11 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 11.1. Normative References . . . . . . . . . . . . . . . . . . 11
12.1. Normative References . . . . . . . . . . . . . . . . . . 12 11.2. Informative References . . . . . . . . . . . . . . . . . 13
12.2. Informative References . . . . . . . . . . . . . . . . . 13
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 14 Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 14
A.1. Dynamic Subscriptions . . . . . . . . . . . . . . . . . . 14 A.1. Dynamic Subscriptions . . . . . . . . . . . . . . . . . . 14
A.1.1. Establishing Dynamic Subscriptions . . . . . . . . . 14 A.1.1. Establishing Dynamic Subscriptions . . . . . . . . . 14
A.1.2. Modifying Dynamic Subscriptions . . . . . . . . . . . 17 A.1.2. Modifying Dynamic Subscriptions . . . . . . . . . . . 17
A.1.3. Deleting Dynamic Subscriptions . . . . . . . . . . . 18 A.1.3. Deleting Dynamic Subscriptions . . . . . . . . . . . 18
A.2. Subscription State Notifications . . . . . . . . . . . . 19 A.2. Subscription State Notifications . . . . . . . . . . . . 19
A.2.1. subscription-modified . . . . . . . . . . . . . . . . 19 A.2.1. subscription-modified . . . . . . . . . . . . . . . . 19
A.2.2. subscription-completed, subscription-resumed, and A.2.2. subscription-completed, subscription-resumed, and
replay-complete . . . . . . . . . . . . . . . . . . . 20 replay-complete . . . . . . . . . . . . . . . . . . . 20
A.2.3. subscription-terminated and subscription-suspended . 20 A.2.3. subscription-terminated and subscription-suspended . 20
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and HTTP2 stream which maps to the definition of "stream" within and HTTP2 stream which maps to the definition of "stream" within
[RFC7540], Section 2. [RFC7540], Section 2.
[ note to the RFC Editor - please replace XXXX within this document [ note to the RFC Editor - please replace XXXX within this document
with the number of this document ] with the number of this document ]
3. Dynamic Subscriptions 3. Dynamic Subscriptions
This section provides specifics on how to establish and maintain This section provides specifics on how to establish and maintain
dynamic subscriptions over RESTCONF [RFC8040]. Subscribing to event dynamic subscriptions over RESTCONF [RFC8040]. Subscribing to event
streams is accomplished in this way via a RESTCONF POST into RPCs streams is accomplished in this way via RPCs defined within
defined within [I-D.draft-ietf-netconf-subscribed-notifications] [I-D.draft-ietf-netconf-subscribed-notifications] Section 2.4, the
Section 2.4. YANG datastore subscription is accomplished via RPCs are done via RESTCONF POSTs. YANG datastore subscription is
augmentations to [I-D.draft-ietf-netconf-subscribed-notifications] as accomplished via augmentations to
described within [I-D.ietf-netconf-yang-push] Section 4.4. [I-D.draft-ietf-netconf-subscribed-notifications] as described within
[I-D.ietf-netconf-yang-push] Section 4.4.
As described in [RFC8040] Section 6.3, a GET needs to be made against As described in [RFC8040] Section 6.3, a GET needs to be made against
a specific URI on the publisher. Subscribers cannot pre-determine a specific URI on the publisher. Subscribers cannot pre-determine
the URI against which a subscription might exist on a publisher, as the URI against which a subscription might exist on a publisher, as
the URI will only exist after the "establish-subscription" RPC has the URI will only exist after the "establish-subscription" RPC has
been accepted. The subscription URI will be determined and sent as been accepted. Therefore, the POST for the "establish-subscription"
part of the response to the "establish-subscription" RPC, and a RPC replaces the GET request for the "location" leaf which is used in
subsequent GET to this URI will be done in order to start the flow of [RFC8040] to obtain the URI. The subscription URI will be determined
notification messages back to the subscriber. A subscription does and sent as part of the response to the "establish-subscription" RPC,
not move to the active state as per Section 2.4.1. of and a subsequent GET to this URI will be done in order to start the
flow of notification messages back to the subscriber. A subscription
does not move to the active state as per Section 2.4.1. of
[I-D.draft-ietf-netconf-subscribed-notifications] until the GET is [I-D.draft-ietf-netconf-subscribed-notifications] until the GET is
received. The POST for the "establish-subscription" RPC replaces the received.
GET request for the "location" leaf which is used in [RFC8040] to
obtain the URI.
3.1. Transport Connectivity 3.1. Transport Connectivity
For a dynamic subscription, where an HTTP client session doesn't For a dynamic subscription, where a RESTCONF session doesn't already
already exist, a new client session is initiated from the subscriber. exist, a new RESTCONF session is initiated from the subscriber.
As stated in Section 2.1 of [RFC8040], a subscriber MUST establish As stated in Section 2.1 of [RFC8040], a subscriber MUST establish
the HTTP session over TLS [RFC5246] in order to secure the content in the HTTP session over TLS [RFC5246] in order to secure the content in
transit. transit.
Without the involvement of additional protocols, HTTP sessions by Without the involvement of additional protocols, HTTP sessions by
themselves do not allow for a quick recognition of when the themselves do not allow for a quick recognition of when the
communication path has been lost with the publisher. Where quick communication path has been lost with the publisher. Where quick
recognition of the loss of a publisher is required, a subscriber recognition of the loss of a publisher is required, a subscriber
SHOULD use a TLS heartbeat [RFC6520], just from receiver to SHOULD use a TLS heartbeat [RFC6520], just from receiver to
publisher, to track HTTP session continuity. Loss of the heartbeat publisher, to track HTTP session continuity.
MUST result in any subscription related TCP sessions between those
endpoints being torn down. A subscriber can then attempt to re- Loss of the heartbeat MUST result in any subscription related TCP
establish. sessions between those endpoints being torn down. A subscriber can
then attempt to re-establish the dynamic subscription by using the
procedure described in Section 3.
3.2. Discovery 3.2. Discovery
Subscribers can learn what event streams a RESTCONF server supports Subscribers can learn what event streams a RESTCONF server supports
by querying the "streams" container of ietf-subscribed- by querying the "streams" container of ietf-subscribed-
notification.yang in notification.yang in
[I-D.draft-ietf-netconf-subscribed-notifications]. Support for the [I-D.draft-ietf-netconf-subscribed-notifications]. Support for the
"streams" container of ietf-restconf-monitoring.yang in [RFC6520] is "streams" container of ietf-restconf-monitoring.yang in [RFC8040] is
not required. not required.
Subscribers can learn what datastores a RESTCONF server supports by Subscribers can learn what datastores a RESTCONF server supports by
following [I-D.draft-ietf-netconf-nmda-restconf]. following [I-D.draft-ietf-netconf-nmda-restconf].
3.3. RESTCONF RPCs and HTTP Status Codes 3.3. RESTCONF RPCs and HTTP Status Codes
Specific HTTP responses codes as defined in [RFC7231] section 6 will Specific HTTP responses codes as defined in [RFC7231] section 6 will
indicate the result of RESTCONF RPC requests with publisher. An HTTP indicate the result of RESTCONF RPC requests with publisher. An HTTP
status code of 200 is the proper response to any successful RPC status code of 200 is the proper response to any successful RPC
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modify-subscription modify-subscription-error modify-subscription modify-subscription-error
delete-subscription delete-subscription-error delete-subscription delete-subscription-error
kill-subscription kill-subscription-error kill-subscription kill-subscription-error
resynch-subscription resynch-subscription-error resynch-subscription resynch-subscription-error
Each error identity will be inserted as the "error-app-tag" using Each error identity will be inserted as the "error-app-tag" using
JSON encoding following the form <modulename>:<identityname>. An JSON encoding following the form <modulename>:<identityname>. An
example of such as valid encoding would be "ietf-subscribed- example of such as valid encoding would be "ietf-subscribed-
notifications:no-such-subscription". notifications:no-such-subscription".
o In case of error responses to an "establish-subscription" or In case of error responses to an "establish-subscription" or "modify-
"modify-subscription" request there is the option of including an subscription" request there is the option of including an "error-
"error-info" node. This node may contain hints for parameter info" node. This node may contain hints for parameter settings that
settings that might lead to successful RPC requests in the future. might lead to successful RPC requests in the future. Following are
Following are the yang-data structures which may be returned: the yang-data structures which may be returned:
establish-subscription returns hints in yang-data structure establish-subscription returns hints in yang-data structure
---------------------- ------------------------------------ ---------------------- ------------------------------------
target: event stream establish-subscription-stream-error-info target: event stream establish-subscription-stream-error-info
target: datastore establish-subscription-datastore-error-info target: datastore establish-subscription-datastore-error-info
modify-subscription returns hints in yang-data structure modify-subscription returns hints in yang-data structure
---------------------- ------------------------------------ ---------------------- ------------------------------------
target: event stream modify-subscription-stream-error-info target: event stream modify-subscription-stream-error-info
target: datastore modify-subscription-datastore-error-info target: datastore modify-subscription-datastore-error-info
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optional leaf "error-reason", as such a leaf would be redundant optional leaf "error-reason", as such a leaf would be redundant
with information that is already placed within the with information that is already placed within the
"error-app-tag". "error-app-tag".
In case of an rpc error as a result of a "delete-subscription", a In case of an rpc error as a result of a "delete-subscription", a
"kill-subscription", or a "resynch-subscription" request, no "kill-subscription", or a "resynch-subscription" request, no
"error-info" needs to be included, as the "subscription-id" is "error-info" needs to be included, as the "subscription-id" is
the only RPC input parameter and no hints regarding this RPC input the only RPC input parameter and no hints regarding this RPC input
parameters need to be provided. parameters need to be provided.
Note that "error-path" does not need to be included with the "rpc- Note that "error-path" [RFC8040] does not need to be included with
error" element, as subscription errors are generally not associated the "rpc-error" element, as subscription errors are generally
with nodes in the datastore but with the choice of RPC input associated with the choice of RPC input parameters.
parameters.
3.4. Call Flow for Server-Sent Events (SSE) 3.4. Call Flow for Server-Sent Events (SSE)
The call flow is defined in Figure 1. The logical connections The call flow is defined in Figure 1. The logical connections
denoted by (a) and (b) can be a TCP connection or an HTTP2 stream. denoted by (a) and (b) can be a TCP connection or an HTTP2 stream
(multiple HTTP2 streams can be carried in one TCP connection).
Requests to [I-D.draft-ietf-netconf-subscribed-notifications] or Requests to [I-D.draft-ietf-netconf-subscribed-notifications] or
[I-D.ietf-netconf-yang-push] augmented RPCs are sent on a connection [I-D.ietf-netconf-yang-push] augmented RPCs are sent on a connection
indicated by (a). A successful "establish-subscription" will result indicated by (a). A successful "establish-subscription" will result
in an RPC response returned with both a subscription identifier which in an RPC response returned with both a subscription identifier which
uniquely identifies a subscription, as well as a URI which uniquely uniquely identifies a subscription, as well as a URI which uniquely
identifies the location of subscription on the publisher (b). This identifies the location of subscription on the publisher (b). This
URI is defined via the "uri" leaf the Data Model in Section 8. URI is defined via the "uri" leaf the Data Model in Section 7.
An HTTP GET is then sent on a separate logical connection (b) to the An HTTP GET is then sent on a separate logical connection (b) to the
URI on the publisher. This initiates the publisher to initiate the URI on the publisher. This initiates the publisher to initiate the
flow of notification messages which are sent in SSE [W3C-20150203] as flow of notification messages which are sent in SSE [W3C-20150203] as
a response to the GET. a response to the GET.
+--------------+ +--------------+ +--------------+ +--------------+
| Subscriber | | Publisher | | Subscriber | | Publisher |
| | | | | | | |
| Logical | | Logical | | Logical | | Logical |
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4. QoS Treatment 4. QoS Treatment
To meet subscription quality of service promises, the publisher MUST To meet subscription quality of service promises, the publisher MUST
take any existing subscription "dscp" and apply it to the DSCP take any existing subscription "dscp" and apply it to the DSCP
marking in the IP header. marking in the IP header.
In addition, where HTTP2 transport is available to a notification In addition, where HTTP2 transport is available to a notification
message queued for transport to a receiver, the publisher MUST: message queued for transport to a receiver, the publisher MUST:
o take any existing subscription "priority" and copy it into the o take any existing subscription "priority", as specified by the
HTTP2 stream priority, and "dscp" leaf node in
[I-D.draft-ietf-netconf-subscribed-notifications], and copy it
o take any existing subscription "dependency" and map the HTTP2 into the HTTP2 stream priority, [RFC7540] section 5.3, and
stream for the parent subscription into the HTTP2 stream
dependency.
5. Mandatory JSON and datastore support
A publisher supporting [I-D.ietf-netconf-yang-push] MUST support the
"operational" datastore as defined by [RFC8342].
The "encode-json" feature of o take any existing subscription "dependency", as specified by the
[I-D.draft-ietf-netconf-subscribed-notifications] is mandatory to "dependency" leaf node in
support. This indicates that JSON is a valid encoding for RPCs, [I-D.draft-ietf-netconf-subscribed-notifications], and use the
state change notifications, and subscribed content. HTTP2 stream for the parent subscription as the HTTP2 stream
dependency, [RFC7540] section 5.3.1, of the dependent
subscription.
6. Notification Messages 5. Notification Messages
Notification messages transported over HTTP will be encoded using Notification messages transported over RESTCONF will be encoded
one-way operation schema defined within [RFC5277], section 4. according to [RFC8040], section 6.4.
7. YANG Tree 6. YANG Tree
The YANG model defined in Section 8 has one leaf augmented into four The YANG model defined in Section 7 has one leaf augmented into four
places of [I-D.draft-ietf-netconf-subscribed-notifications], plus two places of [I-D.draft-ietf-netconf-subscribed-notifications], plus two
identities. As the resulting full tree is large, it will only be identities. As the resulting full tree is large, it will only be
inserted at later stages of this document. inserted at later stages of this document.
8. YANG module 7. YANG module
This module references This module references
[I-D.draft-ietf-netconf-subscribed-notifications]. [I-D.draft-ietf-netconf-subscribed-notifications].
<CODE BEGINS> file "ietf-restconf-subscribed-notifications@2018-10-03.yang" <CODE BEGINS> file "ietf-restconf-subscribed-notifications@2018-10-19.yang"
module ietf-restconf-subscribed-notifications { module ietf-restconf-subscribed-notifications {
yang-version 1.1; yang-version 1.1;
namespace namespace
"urn:ietf:params:xml:ns:yang:ietf-restconf-subscribed-notifications"; "urn:ietf:params:xml:ns:yang:ietf-restconf-subscribed-notifications";
prefix rsn; prefix rsn;
import ietf-subscribed-notifications { import ietf-subscribed-notifications {
prefix sn; prefix sn;
} }
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Redistribution and use in source and binary forms, with or without Redistribution and use in source and binary forms, with or without
modification, is permitted pursuant to, and subject to the license modification, is permitted pursuant to, and subject to the license
terms contained in, the Simplified BSD License set forth in Section terms contained in, the Simplified BSD License set forth in Section
4.c of the IETF Trust's Legal Provisions Relating to IETF Documents 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info). (https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see the RFC This version of this YANG module is part of RFC XXXX; see the RFC
itself for full legal notices."; itself for full legal notices.";
revision 2018-10-03 { revision 2018-10-19 {
description description
"Initial version"; "Initial version";
reference reference
"RFC XXXX: RESTCONF Transport for Event Notifications"; "RFC XXXX: RESTCONF Transport for Event Notifications";
} }
identity restconf {
base sn:transport;
description
"RESTCONF is used as transport for notification messages and state
change notifications.";
}
grouping uri { grouping uri {
description description
"Provides a reusable description of a URI."; "Provides a reusable description of a URI.";
leaf uri { leaf uri {
type inet:uri; type inet:uri;
config false; config false;
description description
"Location of a subscription specific URI on the publisher."; "Location of a subscription specific URI on the publisher.";
} }
} }
augment "/sn:establish-subscription/sn:output" { augment "/sn:establish-subscription/sn:output" {
description description
"This augmentation allows RESTCONF specific parameters for a "This augmentation allows RESTCONF specific parameters for a
response to a publisher's subscription request."; response to a publisher's subscription request.";
uses uri; uses uri;
} }
augment "/sn:subscriptions/sn:subscription" { augment "/sn:subscriptions/sn:subscription" {
description description
"This augmentation allows RESTCONF specific parameters to be "This augmentation allows RESTCONF specific parameters to be
exposed for a subscription."; exposed for a subscription.";
uses uri; uses uri;
} }
augment "/sn:subscription-modified" { augment "/sn:subscription-modified" {
description description
"This augmentation allows RESTCONF specific parameters to be included "This augmentation allows RESTCONF specific parameters to be included
part of the notification that a subscription has been modified."; part of the notification that a subscription has been modified.";
uses uri; uses uri;
} }
} }
<CODE ENDS> <CODE ENDS>
9. IANA Considerations 8. IANA Considerations
This document registers the following namespace URI in the "IETF XML This document registers the following namespace URI in the "IETF XML
Registry" [RFC3688]: Registry" [RFC3688]:
URI: urn:ietf:params:xml:ns:yang:ietf-restconf-subscribed- URI: urn:ietf:params:xml:ns:yang:ietf-restconf-subscribed-
notifications notifications
Registrant Contact: The IESG. Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace. XML: N/A; the requested URI is an XML namespace.
This document registers the following YANG module in the "YANG Module This document registers the following YANG module in the "YANG Module
Names" registry [RFC6020]: Names" registry [RFC6020]:
Name: ietf-restconf-subscribed-notifications Name: ietf-restconf-subscribed-notifications
Namespace: urn:ietf:params:xml:ns:yang:ietf-restconf-subscribed- Namespace: urn:ietf:params:xml:ns:yang:ietf-restconf-subscribed-
notifications notifications
Prefix: rsn Prefix: rsn
Reference: RFC XXXX: RESTCONF Transport for Event Notifications Reference: RFC XXXX: RESTCONF Transport for Event Notifications
10. Security Considerations 9. Security Considerations
The YANG module specified in this document defines a schema for data The YANG module specified in this document defines a schema for data
that is designed to be accessed via network management transports that is designed to be accessed via network management transports
such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF
layer is the secure transport layer, and the mandatory-to-implement layer is the secure transport layer, and the mandatory-to-implement
secure transport is Secure Shell (SSH) [RFC6242]. The lowest secure transport is Secure Shell (SSH) [RFC6242]. The lowest
RESTCONF layer is HTTPS, and the mandatory-to-implement secure RESTCONF layer is HTTPS, and the mandatory-to-implement secure
transport is TLS [RFC5246]. transport is TLS [RFC5246].
The one new data node introduced in this YANG module may be The one new data node introduced in this YANG module may be
skipping to change at page 12, line 5 skipping to change at page 11, line 37
or notification) to this data nodes. These are the subtrees and data or notification) to this data nodes. These are the subtrees and data
nodes and their sensitivity/vulnerability: nodes and their sensitivity/vulnerability:
Container: "/subscriptions" Container: "/subscriptions"
o "uri": leaf will show where subscribed resources might be located o "uri": leaf will show where subscribed resources might be located
on a publisher. Access control must be set so that only someone on a publisher. Access control must be set so that only someone
with proper access permissions, and perhaps even HTTP session has with proper access permissions, and perhaps even HTTP session has
the ability to access this resource. the ability to access this resource.
11. Acknowledgments 10. Acknowledgments
We wish to acknowledge the helpful contributions, comments, and We wish to acknowledge the helpful contributions, comments, and
suggestions that were received from: Ambika Prasad Tripathy, Alberto suggestions that were received from: Ambika Prasad Tripathy, Alberto
Gonzalez Prieto, Susan Hares, Tim Jenkins, Balazs Lengyel, Kent Gonzalez Prieto, Susan Hares, Tim Jenkins, Balazs Lengyel, Kent
Watsen, Michael Scharf, Guangying Zheng and Martin Bjorklund. Watsen, Michael Scharf, Guangying Zheng, Martin Bjorklund and Qin Wu.
12. References 11. References
12.1. Normative References 11.1. Normative References
[I-D.draft-ietf-netconf-subscribed-notifications] [I-D.draft-ietf-netconf-subscribed-notifications]
Voit, E., Clemm, A., Gonzalez Prieto, A., Tripathy, A., Voit, E., Clemm, A., Gonzalez Prieto, A., Tripathy, A.,
and E. Nilsen-Nygaard, "Custom Subscription to Event and E. Nilsen-Nygaard, "Custom Subscription to Event
Streams", draft-ietf-netconf-subscribed-notifications-13 Streams", draft-ietf-netconf-subscribed-notifications-13
(work in progress), April 2018. (work in progress), April 2018.
[I-D.ietf-netconf-yang-push] [I-D.ietf-netconf-yang-push]
Clemm, A., Voit, E., Gonzalez Prieto, A., Prasad Tripathy, Clemm, A., Voit, E., Gonzalez Prieto, A., Prasad Tripathy,
A., Nilsen-Nygaard, E., Bierman, A., and B. Lengyel, A., Nilsen-Nygaard, E., Bierman, A., and B. Lengyel,
skipping to change at page 13, line 44 skipping to change at page 13, line 29
[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., [RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
and R. Wilton, "Network Management Datastore Architecture and R. Wilton, "Network Management Datastore Architecture
(NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018, (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
<https://www.rfc-editor.org/info/rfc8342>. <https://www.rfc-editor.org/info/rfc8342>.
[W3C-20150203] [W3C-20150203]
"Server-Sent Events, World Wide Web Consortium CR CR- "Server-Sent Events, World Wide Web Consortium CR CR-
eventsource-20121211", February 2015, eventsource-20121211", February 2015,
<https://www.w3.org/TR/2015/REC-eventsource-20150203/>. <https://www.w3.org/TR/2015/REC-eventsource-20150203/>.
12.2. Informative References 11.2. Informative References
[I-D.draft-ietf-netconf-netconf-event-notifications] [I-D.draft-ietf-netconf-netconf-event-notifications]
Clemm, Alexander., Voit, Eric., Gonzalez Prieto, Alberto., Clemm, Alexander., Voit, Eric., Gonzalez Prieto, Alberto.,
Nilsen-Nygaard, E., and A. Tripathy, "NETCONF support for Nilsen-Nygaard, E., and A. Tripathy, "NETCONF support for
event notifications", May 2018, event notifications", May 2018,
<https://datatracker.ietf.org/doc/ <https://datatracker.ietf.org/doc/
draft-ietf-netconf-netconf-event-notifications/>. draft-ietf-netconf-netconf-event-notifications/>.
[I-D.draft-ietf-netconf-nmda-restconf] [I-D.draft-ietf-netconf-nmda-restconf]
Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
skipping to change at page 15, line 38 skipping to change at page 15, line 38
|<------------------------------| |<------------------------------|
| HTTP 200 OK,notif-mesg (id#23)| | HTTP 200 OK,notif-mesg (id#23)|
|<------------------------------| |<------------------------------|
| | | |
Figure 2: Multiple subscriptions over RESTCONF/HTTP Figure 2: Multiple subscriptions over RESTCONF/HTTP
To provide examples of the information being transported, example To provide examples of the information being transported, example
messages for interactions in Figure 2 are detailed below: messages for interactions in Figure 2 are detailed below:
POST /restconf/operations/subscriptions:establish-subscription POST /restconf/operations/ietf-subscribed-notifications:establish-subscription
{ {
"ietf-subscribed-notifications:input": { "ietf-subscribed-notifications:input": {
"stream": "NETCONF", "stream": "NETCONF",
"stream-xpath-filter": "/ds:foo/", "stream-xpath-filter": "/example-module:foo/",
"dscp": "10" "dscp": "10"
}
} }
}
Figure 3: establish-subscription request (a) Figure 3: establish-subscription request (a)
As publisher was able to fully satisfy the request, the publisher As publisher was able to fully satisfy the request, the publisher
sends the subscription identifier of the accepted subscription, and sends the subscription identifier of the accepted subscription, and
the URI: the URI:
HTTP status code - 200 HTTP status code - 200
{ {
"id": "22", "id": "22",
"uri": "/subscriptions/22" "uri": "https://example.com/restconf/subscriptions/22"
} }
Figure 4: establish-subscription success (b) Figure 4: establish-subscription success (b)
Upon receipt of the successful response, the subscriber does a GET Upon receipt of the successful response, the subscriber does a GET
the provided URI to start the flow of notification messages. When the provided URI to start the flow of notification messages. When
the publisher receives this, the subscription is moved to the active the publisher receives this, the subscription is moved to the active
state (c). state (c).
GET /restconf/operations/subscriptions/22 GET /restconf/subscriptions/22
Figure 5: establish-subscription subsequent POST Figure 5: establish-subscription subsequent POST
While not shown in Figure 2, if the publisher had not been able to While not shown in Figure 2, if the publisher had not been able to
fully satisfy the request, or subscriber has no authorization to fully satisfy the request, or subscriber has no authorization to
establish the subscription, the publisher would have sent an RPC establish the subscription, the publisher would have sent an RPC
error response. For instance, if the "dscp" value of 10 asserted by error response. For instance, if the "dscp" value of 10 asserted by
the subscriber in Figure 3 proved unacceptable, the publisher may the subscriber in Figure 3 proved unacceptable, the publisher may
have returned: have returned:
skipping to change at page 18, line 5 skipping to change at page 18, line 5
| | | |
Figure 7: Interaction model for successful subscription modification Figure 7: Interaction model for successful subscription modification
If the subscription being modified in Figure 7 is a datastore If the subscription being modified in Figure 7 is a datastore
subscription as per [I-D.ietf-netconf-yang-push], the modification subscription as per [I-D.ietf-netconf-yang-push], the modification
request made in (d) may look like that shown in Figure 8. As can be request made in (d) may look like that shown in Figure 8. As can be
seen, the modifications being attempted are the application of a new seen, the modifications being attempted are the application of a new
xpath filter as well as the setting of a new periodic time interval. xpath filter as well as the setting of a new periodic time interval.
POST /restconf/operations/subscriptions:modify-subscription POST /restconf/operations/ietf-subscribed-notifications:modify-subscription
{ {
"ietf-subscribed-notifications:input": { "ietf-subscribed-notifications:input": {
"id": "23", "id": "23",
"ietf-yang-push:datastore-xpath-filter": "/ds:foo/ds:bar", "ietf-yang-push:datastore-xpath-filter": "/example-module:foo/example-module:bar",
"ietf-yang-push:periodic": { "ietf-yang-push:periodic": {
"ietf-yang-push:period": "500" "ietf-yang-push:period": "500"
} }
} }
} }
Figure 8: Subscription modification request (c) Figure 8: Subscription modification request (c)
If the publisher can satisfy both changes, the publisher sends a If the publisher can satisfy both changes, the publisher sends a
positive result for the RPC. If the publisher cannot satisfy either positive result for the RPC. If the publisher cannot satisfy either
of the proposed changes, the publisher sends an RPC error response of the proposed changes, the publisher sends an RPC error response
(e). The following is an example RPC error response for (e) which (e). The following is an example RPC error response for (e) which
includes a hint. This hint is an alternative time period value which includes a hint. This hint is an alternative time period value which
might have resulted in a successful modification: might have resulted in a successful modification:
skipping to change at page 19, line 5 skipping to change at page 19, line 5
} }
} }
Figure 9: Modify subscription failure with Hint (e) Figure 9: Modify subscription failure with Hint (e)
A.1.3. Deleting Dynamic Subscriptions A.1.3. Deleting Dynamic Subscriptions
The following demonstrates deleting a subscription. This The following demonstrates deleting a subscription. This
subscription may have been to either a stream or a datastore. subscription may have been to either a stream or a datastore.
POST /restconf/operations/subscriptions:delete-subscription POST /restconf/operations/ietf-subscribed-notifications:delete-subscription
{ {
"delete-subscription": { "delete-subscription": {
"id": "22" "id": "22"
} }
} }
Figure 10: Delete subscription Figure 10: Delete subscription
If the publisher can satisfy the request, the publisher replies with If the publisher can satisfy the request, the publisher replies with
success to the RPC request. success to the RPC request.
If the publisher cannot satisfy the request, the publisher sends an If the publisher cannot satisfy the request, the publisher sends an
error-rpc element indicating the modification didn't work. Figure 11 error-rpc element indicating the modification didn't work. Figure 11
shows a valid response for existing valid subscription identifier, shows a valid response for existing valid subscription identifier,
but that subscription identifier was created on a different transport but that subscription identifier was created on a different transport
skipping to change at page 20, line 10 skipping to change at page 20, line 10
A.2.1. subscription-modified A.2.1. subscription-modified
A "subscription-modified" encoded in JSON would look like: A "subscription-modified" encoded in JSON would look like:
{ {
"ietf-restconf:notification" : { "ietf-restconf:notification" : {
"eventTime": "2007-09-01T10:00:00Z", "eventTime": "2007-09-01T10:00:00Z",
"ietf-subscribed-notifications:subscription-modified": { "ietf-subscribed-notifications:subscription-modified": {
"id": "39", "id": "39",
"transport": "RESTCONF", "uri": "https://example.com/restconf/subscriptions/22"
"stream-xpath-filter": "/ex:foo", "stream-xpath-filter": "/example-module:foo",
"stream": { "stream": {
"ietf-netconf-subscribed-notifications" : "NETCONF" "ietf-netconf-subscribed-notifications" : "NETCONF"
} }
} }
} }
} }
Figure 12: subscription-modified subscription state notification Figure 12: subscription-modified subscription state notification
A.2.2. subscription-completed, subscription-resumed, and replay- A.2.2. subscription-completed, subscription-resumed, and replay-
skipping to change at page 22, line 5 skipping to change at page 22, line 5
Figure 15: RFC 8347 (VRRP) - Example Notification Figure 15: RFC 8347 (VRRP) - Example Notification
Suppose a subscriber wanted to establish a subscription which only Suppose a subscriber wanted to establish a subscription which only
passes instances of event records where there is a "checksum-error" passes instances of event records where there is a "checksum-error"
as part of a VRRP protocol event. Also assume the publisher places as part of a VRRP protocol event. Also assume the publisher places
such event records into the NETCONF stream. To get a continuous such event records into the NETCONF stream. To get a continuous
series of matching event records, the subscriber might request the series of matching event records, the subscriber might request the
application of an XPath filter against the NETCONF stream. An application of an XPath filter against the NETCONF stream. An
"establish-subscription" RPC to meet this objective might be: "establish-subscription" RPC to meet this objective might be:
POST /restconf/operations/subscriptions:establish-subscription POST /restconf/operations/ietf-subscribed-notifications:establish-subscription
{ {
"ietf-subscribed-notifications:input": { "ietf-subscribed-notifications:input": {
"stream": "NETCONF", "stream": "NETCONF",
"stream-xpath-filter": "/ietf-vrrp:vrrp-protocol-error-event[protocol-error-reason='checksum-error']/", "stream-xpath-filter": "/ietf-vrrp:vrrp-protocol-error-event[protocol-error-reason='checksum-error']/",
} }
} }
Figure 16: Establishing a subscription error reason via XPATH Figure 16: Establishing a subscription error reason via XPath
For more examples of xpath filters, see [XPATH]. For more examples of XPath filters, see [XPATH].
Suppose the "establish-subscription" in Figure 16 was accepted. And Suppose the "establish-subscription" in Figure 16 was accepted. And
suppose later a subscriber decided they wanted to broaden this suppose later a subscriber decided they wanted to broaden this
subscription cover to all VRRP protocol events (i.e., not just those subscription cover to all VRRP protocol events (i.e., not just those
with a "checksum error"). The subscriber might attempt to modify the with a "checksum error"). The subscriber might attempt to modify the
subscription in a way which replaces the XPath filter with a subtree subscription in a way which replaces the XPath filter with a subtree
filter which sends all VRRP protocol events to a subscriber. Such a filter which sends all VRRP protocol events to a subscriber. Such a
"modify-subscription" RPC might look like: "modify-subscription" RPC might look like:
POST /restconf/operations/subscriptions:modify-subscription POST /restconf/operations/ietf-subscribed-notifications:modify-subscription
{ {
"ietf-subscribed-notifications:input": { "ietf-subscribed-notifications:input": {
"stream": "NETCONF", "stream": "NETCONF",
"stream-subtree-filter": "/ietf-vrrp:vrrp-protocol-error-event/", "stream-subtree-filter": {
} "/ietf-vrrp:vrrp-protocol-error-event" : {}
} }
}
}
Figure 17 Figure 17
For more examples of subtree filters, see [RFC6241], section 6.4. For more examples of subtree filters, see [RFC6241], section 6.4.
Appendix B. Changes between revisions Appendix B. Changes between revisions
(To be removed by RFC editor prior to publication) (To be removed by RFC editor prior to publication)
v08 - v09
o Addressed comments received during WGLC.
v07 - v08 v07 - v08
o Aligned with RESTCONF mechanism. o Aligned with RESTCONF mechanism.
o YANG model: removed augment of subscription-started, added o YANG model: removed augment of subscription-started, added
restconf transport. restconf transport.
o Tweaked Appendix A.1 to match draft-ietf-netconf-netconf-event- o Tweaked Appendix A.1 to match draft-ietf-netconf-netconf-event-
notifications-13. notifications-13.
 End of changes. 53 change blocks. 
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