Internet DRAFT - draft-voit-netconf-subscription-and-notif-overview
draft-voit-netconf-subscription-and-notif-overview
NETCONF E. Voit
Internet-Draft Cisco Systems
Intended status: Informational A. Clemm
Expires: March 23, 2018 Huawei
September 19, 2017
Subscription and Notifications Overview
draft-voit-netconf-subscription-and-notif-overview-00
Abstract
Provides an introductory context for NETCONF WG drafts on
subscriptions and notifications. Through this document, a reader can
understand the scope of each draft, as well as the relationships
between each draft.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on March 23, 2018.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Phasing of drafts . . . . . . . . . . . . . . . . . . . . 2
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Scope of Drafts . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. draft-ietf-netconf-subscribed-notifications . . . . . . . 3
2.2. draft-ietf-netconf-yang-push . . . . . . . . . . . . . . 4
2.3. draft-ietf-netconf-netconf-event-notifications . . . . . 4
2.4. draft-ietf-netconf-restconf-notif . . . . . . . . . . . . 4
2.5. draft-ietf-netconf-notification-messages . . . . . . . . 4
3. Relationships between Drafts . . . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . 6
5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6
6. Informative References . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
This document provides an overview of a set of documents that define
mechanisms that allow client applications to subscribe to and receive
notifications and datastore updates. Specifically, this includes the
following documents:
o draft-ietf-netconf-subscribed-notifications
o draft-ietf-netconf-yang-push
o draft-ietf-netconf-netconf-event-notifications
o draft-ietf-netconf-restconf-notif
o draft-ietf-netconf-notification-messages
1.1. Phasing of drafts
This set of drivers has two themes:
1. an evolved subscription configuration data model and state
transition messages, which, when paired with the existing
[RFC5277] encoded one-way operation, provides a solution for yang
push.
2. a new one-way notification operation that can provide robustness,
flexibility, and extensibility.
For theme 1, drafts [subscribed-notifications], [yang-push],
[netconf-event-notifications], and [restconf-notif] provide solutions
for an evolved subscription data model, pushing of YANG datastore
changes as they happen, and periodic reporting of YANG datastore
state. Also enabled is the use of the evolved subscription model and
subscription state transition messages on publisher based event
streams.
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For theme 2, solutions are in the early stages for:
o automatic determination of which common headers to use, and
selection of if/what transport bundling to use without requiring
any change to YANG's 'notification' statement
o continuing, transparent support for RFC5277-encoded notifications
from legacy clients
o general strategy to introduce new behavior where a server
advertises support for new headers and encodings, and client
selects them when available
These items are listed so they are explicitly shown not be covered by
Theme 1.
1.2. Terminology
The terms publisher, receiver, and subscriber are defined in
[subscribed-notifications].
2. Scope of Drafts
This section describes the intent and contents of each draft.
2.1. draft-ietf-netconf-subscribed-notifications
This document defines the YANG module, RPCs, and Notifications for
the customized establishment of subscriptions upon a publisher's
event streams. Also defined are delivery mechanisms for instances of
the resulting events. Effectively this allows a subscriber to
request and receive a continuous, custom influx of publisher-
generated information. Included are:
o Dynamic and configured subscriptions
o Multiple subscriptions / transport
o Multiple configured receivers
o Establish, modify, delete, kill RPC
o State change notifications
o Suspend/resume
o Filtering full notifications
o Stream discovery
o Replay (and start time negotiation)
o Prioritization
o Monitoring / reporting
o QoS
o Error responses
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2.2. draft-ietf-netconf-yang-push
This document extends the YANG module, RPCs, and Notifications from
[subscribed-notifications] to enable the customized establishment of
subscriptions to updates from YANG datastores. Using the definitions
of this document, a subscriber application may request a continuous,
customized stream of updates from a YANG datastore. Included are:
o Datastore on-change and periodic triggers
o Selecting objects within a datastore to subscribe to
o Authorization model per object
o RPC for datastore resynchronization
o Sending of full YANG trees or yang-patch
o Tagging of partial updates
o Tagging of on-change object support
o Negotiation of filters and period lengths
o Datastore-specific error responses and datastore-subscription
specific monitoring
2.3. draft-ietf-netconf-netconf-event-notifications
This document provides a NETCONF binding for
[subscribed-notifications]. Included are:
o Transport mappings for subscription RPCs and state change
notifications
o Transport mapping for RFC-5277 event transport
2.4. draft-ietf-netconf-restconf-notif
This document provides RESTCONF, HTTP2, and HTTP1.1 bindings for the
subscribed-notifications. Included are:
o Transport mapping for subscription protocol messages
o Transport mappings for RFC-5277 one-way operation
o Heartbeats and clean-up
2.5. draft-ietf-netconf-notification-messages
This document defines a new notification message format, using yang-
data. Included are:
o a new notification mechanism to replace the one way operation of
RFC-5277
o a set of common, transport agnostic message header objects to
support functionality such as event severity, message signing,
message loss discovery, message de-duplication, originating
process identification.
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o how to bundle multiple event records into a single notification
message.
o how to ensure these new capabilities are only used with capable
receivers.
This mechanism could have future applicability for updates to
[RFC7950] and [RFC8040].
3. Relationships between Drafts
This section describes the relationships between subscription drafts.
RFC-5277 yang-push
| |
(1)| |(2)
v v
subscribed-notifications
^ ^
(3)| |(4)
| |
restconf-notif netconf-event-notifications
| |
(5)| |(6)
v v
notification-messages
Figure 1: Relationships between drafts
A few notes on the figure above. The initial of text leading text of
each name has been removed to make the figure more readable.
Numbered arrows indicate a relationship of one draft with another.
The nature of each arrow is described below.
Relationship (1) Until [notification-messages] becomes available,
draft [subscribed-notifications] needs RFC-5277's
mechanism for encoding one way notifications.
Relationship (2) The draft [subscribed-notifications] provides the
technical foundation upon which YANG datastore
specific push mechanisms are layered as specified
in [yang-push]. Key here are:
* replacement of event streams with on-change or
periodic triggers upon a YANG Datastore.
* replacement of event filters with datastore
selectors
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Relationship (3) The [restconf-notif] draft supports
[subscribed-notifications] by defining transport
specific guidance where some form of HTTP is used
underneath. Key here are:
* bindings for RPC communications over RESTCONF
* bindings for one-way notifications transported
over HTTP2 and HTTP1.1
* end-to-end deployment guidance for Call Home and
TLS Heartbeat
Relationship (4) The [netconf-event-notifications] draft supports
[subscribed-notifications] by defining NETCONF
transport specifics. Key are:
* bindings for RPC communications over NETCONF
* bindings for one-way notifications transported
over NETCONF
Relationship (5) The [netconf-event-notifications] draft will not
initially have available to it the replacement of
RFC-5277 one way operation. When
[notification-messages] becomes available, it will
be possible to replace the RFC-5277 one-way
operation with a solution which includes common
headers and the ability to bundle many
notifications into a single transportable message.
Relationship (6) The [restconf-notif] draft will not initially have
available to it the replacement of RFC-5277 one way
operation. When [notification-messages] becomes
available, it will be possible to replace the
RFC-5277 one-way operation with a solution which
includes common headers and the ability to bundle
many notifications into a single transportable
message.
4. Security Considerations
Not applicable.
5. Acknowledgments
For his valuable comments framing the value and purposed of this
document: Kent Watsen.
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6. Informative References
[netconf-event-notifications]
Gonzalez Prieto, A., Clemm, A., Voit, E., Nilsen-Nygaard,
E., and A. Tripathy, "NETCONF Support for Event
Notifications", July 2017.
[notification-messages]
Voit, E., Bierman, A., Clemm, A., and T. Jenkins, "YANG
Notification Headers and Bundles", July 2017.
[restconf-notif]
Voit, E., Gonzalez Prieto, A., Tripathy, A., Nilsen-
Nygaard, E., Clemm, A., and A. Bierman, "RESTCONF and HTTP
Transport for Event Notifications", August 2017.
[RFC5277] Chisholm, S. and H. Trevino, "NETCONF Event
Notifications", RFC 5277, DOI 10.17487/RFC5277, July 2008,
<https://www.rfc-editor.org/info/rfc5277>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[subscribed-notifications]
Voit, E., Clemm, A., Gonzalez Prieto, A., Prasad Tripathy,
A., and E. Nilsen-Nygaard, "Custom Subscription to Event
Notifications", September 2017,
<https://datatracker.ietf.org/doc/
draft-ietf-netconf-subscribed-notifications/>.
[yang-push]
Clemm, A., Voit, E., Gonzalez Prieto, A., Prasad Tripathy,
A., Nilsen-Nygaard, E., Bierman, A., and B. Lengyel,
"Subscribing to YANG datastore push updates", September
2017, <https://datatracker.ietf.org/doc/
draft-ietf-netconf-yang-push/>.
Authors' Addresses
Eric Voit
Cisco Systems
Email: evoit@cisco.com
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Alexander Clemm
Huawei
Email: ludwig@clemm.org
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