Adaptive Subscription to YANG Notification
draft-wang-netconf-adaptive-subscription-00
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| Authors | Zitao Wang , Qin Wu , Wei Song , Liang Geng , Peng Liu | ||
| Last updated | 2020-03-03 | ||
| Replaced by | draft-ietf-netconf-adaptive-subscription | ||
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draft-wang-netconf-adaptive-subscription-00
NETCONF Working Group Z. Wang
Internet-Draft Q. Wu
Intended status: Standards Track W. Song
Expires: September 4, 2020 Huawei
L. Geng
P. Liu
China Mobile
March 3, 2020
Adaptive Subscription to YANG Notification
draft-wang-netconf-adaptive-subscription-00
Abstract
This document defines a YANG data model and associated mechanism
enabling subscriber's adaptive subscriptions to a publisher's event
streams. Applying these elements allows a subscriber to
automatically adjust the volume of telemetry traffic sent from
publisher to the receivers.
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 https://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 September 4, 2020.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://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
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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
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Model Overview . . . . . . . . . . . . . . . . . . . . . . . 4
3. Bulk Subscription YANG Module . . . . . . . . . . . . . . . . 4
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
4.1. Updates to the IETF XML Registry . . . . . . . . . . . . 7
4.2. Updates to the YANG Module Names Registry . . . . . . . . 8
5. Security Considerations . . . . . . . . . . . . . . . . . . . 8
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
6.1. Normative References . . . . . . . . . . . . . . . . . . 9
6.2. Informative References . . . . . . . . . . . . . . . . . 10
Appendix A. Adaptive Subscription Example . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction
YANG-Push subscriptions [RFC8641] allow client applications to
subscribe to continuous datastore updates without needing to poll.
It defines a mechanism (i.e.,update trigger) to determine when an
update record needs to be generated. Two type of subscriptions are
introduced in [RFC8641], distinguished by how updates are triggered:
periodic and on-change.
o Periodic subscription allows subscribed data to be streamed to the
destination at a configured fixed periodic interval
o On-change subscription allows update to be triggered when whenever
a change in the subscribed information is detected. The periodic
interval is set to zero value in the on-change subscription case.
However in some cases (e.g., wireless channel contention and
interference causes the WLAN throughput and per-packet delays to vary
over time), both collectors and publishers are configured with
multiple periodic intervals and the subscribed data set can be
streamed out to the destination at adaptive sampling or export rate,
e.g., when wireless signal strength drops below a certain threshold,
more data should be collected at high frequency.
This document defines a YANG data model and associated mechanism
enabling subscriber's adaptive subscriptions to a publisher's event
streams. Applying these elements allows a subscriber to
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automatically adjust the volume of telemetry traffic sent from
publisher to the receivers.
1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
This document uses the following terms:
Event: Something that happens which may be of interest or trigger
the invocation of the rule. A fault, an alarm, a change in
network state, network security threat, hardware malfunction,
buffer untilization crossing a threshold, network connection
setup, an external input to the system, for example [RFC3877].
Client: Defined in [RFC8342].
Configuration: Defined in [RFC8342].
Configured subscription: Defined in [RFC8639]
Configuration datastore: Defined in [RFC8342].
Notification message: Information intended for a receiver
indicating that one or more events have occurred [RFC8639].
Publisher: An entity responsible for streaming notification messages
per the terms of a subscription [RFC8639].
Receiver: A target to which a publisher pushes subscribed event
records. For dynamic subscriptions, the receiver and subscriber
are the same entity [RFC8639].
Subscriber: A client able to request and negotiate a contract for
the generation and push of event records from a publisher. For
dynamic subscriptions, the receiver and subscriber are the same
entity [RFC8639].
Subscription: A contract with a publisher, stipulating the
information that one or more receivers wish to have pushed from
the publisher without the need for further solicitation [RFC8639].
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On-change subscription: A datastore subscription with updates that
are triggered when changes in subscribed datastore nodes are
detected.
Periodic subscription: A datastore subscription with updates that
are triggered periodically according to some time interval.
2. Model Overview
The YANG data model for the "Adaptive Subscription to YANG
Notification" augments the "update-trigger" in the YANG Push model to
add a "adaptive-period" case. Under the "adaptive-period" case, a
"adaptive-period" list is defined. The "adaptive-period" list uses
the key "id" for indexing. Within the "adaptive-period" list, an
"interval" leaf and the corresponding trigger conditions are defined.
When the trigger condition is satisfied, e.g., "op-field" exceeds the
"op-value" and the change of "op-field" is monotonically increasing,
the update interval will be changed into the value of "interval" leaf
and the objects being filtered will be exported every interval
specified by the value of "interval" leaf. The "anchor-time" is used
to indciate at which points in time periodic updates need to be
assembled and sent.
The following tree diagrams [RFC8340] provide an overview of the data
model for "ietf-adaptive-subscription.yang" module.
module: ietf-adaptive-subscription
augment /sn:subscriptions/sn:subscription/yp:update-trigger:
+--:(adaptive-subscription)
+--rw adaptive-subsciptions
+--rw adaptive-period* [id]
| +--rw id string
| +--rw op-field? yang:xpath1.0
| +--rw op-value? string
| +--rw operator? operator
| +--rw interval centiseconds
| +--rw anchor-time yang:date-time
3. Bulk Subscription YANG Module
<CODE BEGINS> file "ietf-adaptive-subscription@2020-02-14.yang"
module ietf-adaptive-subscription {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-adaptive-subscription";
prefix as;
import ietf-subscribed-notifications {
prefix sn;
}
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import ietf-yang-push {
prefix yp;
}
import ietf-yang-types {
prefix yang;
}
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"";
description
"NETCONF Protocol Data Types and Protocol Operations.
Copyright (c) 2020 IETF Trust and the persons identified as
the document authors. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC xxxx; see
the RFC itself for full legal notices.";
revision 2019-12-15 {
description
"Initial revision";
reference
"RFCxxx Adaptive subscription to YANG notification.";
}
typedef centiseconds {
type uint32;
description
"A period of time, measured in units of 0.01 seconds.";
}
typedef operator {
type enumeration {
enum unequal {
description
"Indicates that the comparision type is unequal to.";
}
enum equal {
description
"Indicates that the comparision type is equal to.";
}
enum less {
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description
"Indicates that the comparision type is less than.";
}
enum less-or-equal {
description
"Indicates that the comparision type is less than
or equal to.";
}
enum greater {
description
"Indicates that the comparision type is greater than.";
}
enum greater-or-equal {
description
"Indicates that the comparision type is greater than
or equal to.";
}
}
description
"definition of the operator";
}
augment "/sn:subscriptions/sn:subscription/yp:update-trigger" {
description
"This augmentation adds additional subscription parameters
that apply specifically to adaptive subscription.";
case adaptive-period {
container adaptive-periods {
list adaptive-period {
key "id";
leaf id {
type string;
description
"identifier";
}
leaf op-field {
type yang:xpath1.0;
description
"targeted objects";
}
leaf op-value {
type string;
description
"Compartion value which is static threshold value.";
}
leaf operator {
type operator;
description
"Comparison type.";
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}
leaf interval {
type centiseconds;
mandatory true;
description
"Duration of time that should occur between periodic
push updates, in units of 0.01 seconds.";
}
leaf anchor-time {
type yang:date-and-time;
description
"Designates a timestamp before or after which a series
of periodic push updates are determined. The next
update will take place at a point in time that is a
multiple of a period from the 'anchor-time'.
If an anchor-time is not provided, then the anchor-time
MUST be set with the creation time of the initial
update record. ";
}
description
"List for adaptive periods";
}
description
"Container for adaptive periods.";
}
}
}
}
<CODE ENDS>
4. IANA Considerations
4.1. Updates to the IETF XML Registry
This document registers two URIs in the IETF XML registry [RFC3688].
Following the format in [RFC3688], the following registrations are
requested to be made:
---------------------------------------------------------------------
URI: urn:ietf:params:xml:ns:yang:ietf-adaptive-subscription
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
---------------------------------------------------------------------
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4.2. Updates to the YANG Module Names Registry
This document registers two YANG modules in the YANG Module Names
registry [RFC7950]. . Following the format in [RFC6020], the
following registration has been made:
---------------------------------------------------------------------
Name: ietf-adaptive-subscription
Namespace: urn:ietf:params:xml:ns:yang:ietf-adaptive-subscription
Prefix: as
Reference: RFC xxxx
---------------------------------------------------------------------
5. Security Considerations
The YANG module specified in this document defines a schema for data
that is designed to be accessed via network management protocols such
as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer
is the secure transport layer, and the mandatory-to-implement secure
transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer
is HTTPS, and the mandatory-to-implement secure transport is TLS
[RFC8446].
The NETCONF Configuration Access Control Model (NACM) [RFC8341]
provides the means to restrict access for particular NETCONF or
RESTCONF users to a preconfigured subset of all available NETCONF or
RESTCONF protocol operations and content.
There are a number of data nodes defined in this YANG module that are
writable/creatable/deletable (i.e., config true, which is the
default). These data nodes may be considered sensitive in some
network environments. Write operations (e.g., edit-config) to these
data nodes without proper protection can have a negative effect on
network operations. These are the subtrees and data nodes and their
sensitivity/vulnerability:
o /sn:subscriptions/sn:subscription/yp:update-trigger/adaptive-
periods/adaptive-period/id
o /sn:subscriptions/sn:subscription/yp:update-trigger/adaptive-
periods/adaptive-period/interval
6. References
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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,
<https://www.rfc-editor.org/info/rfc2119>.
[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,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
<https://www.rfc-editor.org/info/rfc6242>.
[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>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/info/rfc8341>.
[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
and R. Wilton, "Network Management Datastore Architecture
(NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
<https://www.rfc-editor.org/info/rfc8342>.
[RFC8407] Bierman, A., "Guidelines for Authors and Reviewers of
Documents Containing YANG Data Models", BCP 216, RFC 8407,
DOI 10.17487/RFC8407, October 2018,
<https://www.rfc-editor.org/info/rfc8407>.
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[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
[RFC8641] Clemm, A. and E. Voit, "Subscription to YANG Notifications
for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641,
September 2019, <https://www.rfc-editor.org/info/rfc8641>.
6.2. Informative References
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/info/rfc6020>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>.
Appendix A. Adaptive Subscription Example
The example YANG module used in this document represents performance
data telemetry on a simple optical device. The collector can control
the rate of telemtry data to be streamed to the destination by
switching to different time interval for the update to be sent.
YANG tree diagram for the "example-opticalbox-telemetry" module:
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module example-opticalbox-telemetry {
namespace "tag:ietf:example:opticalbox";
prefix "optibox";
container opticalstat {
leaf transmit-power {
description "Transmit optical power reading";
type int;
config false;
}
leaf receiving-power {
description " Receiving optical power reading";
type int;
config false;
}
leaf power-threhold {
description "Optical Power Threshold";
type int;
}
leaf high-voltage {
description "High voltage threshold";
type int;
}
leaf low-voltage {
description "Low voltage threshold";
type int;
}
leaf voltage {
description "current voltage reading";
type int;
config false;
}
leaf current-temperature {
description "Current temperature reading";
type int;
config false;
}
leaf cup-usage {
type uint32;
config false;
}
}
}
The adaptive subscription model can be used to keep track of
performance data change such as temperature, voltage, power,cup
usage. In addition, it can adjust update period based on performance
data change, e.g., when the current receiving power is higher than
the pre-configured threshold, the notification for the optical
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performance data from publisher can be sent at a low frequency. When
the current receiving power is lower than the pre-configured
threshold, the notification for the optical performance data can be
sent at a high frequency.
<netconf:rpc message-id="101"
xmlns:netconf="urn:ietf:params:xml:ns:netconf:base:1.0">
<establish-subscription
xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications"
xmlns:yp="urn:ietf:params:xml:ns:yang:ietf-yang-push">
<yp:datastore
xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
ds:operational
</yp:datastore>
<yp:datastore-xpath-filter
xmlns:ex="https://example.com/sample-data/1.0">
/ex:foo
</yp:datastore-xpath-filter>
<as:adaptive-periods>
<as:adaptive-period>
<as:id>01</as:id>
<as:op-field>/opticalstat/current-voltage</as:op-field>
<as:op-value>60</as:op-value>
<as:operator>greater</as:operator>
<as:period>500</as:period>
</as:adaptive-period>
<as:adaptive-period>
<as:id>02</as:id>
<as:op-field>/opticalstat/current-voltage</as:op-field>
<as:op-value>60</as:op-value>
<as:operator>less-or-equal</as:operator>
<as:period>100</as:period>
</as:adaptive-period>
</yp:adaptive-periods>
</establish-subscription>
</netconf:rpc>
In another example, when the time interval for update to be sent is
set to 5 seconds and specific performance data,e.g., 5 receiving
power values
(0.48dB、0.57dB、0.61dB、0.69dB、0.70dB) can
be sampled per second and collected during this time interval
changes. When power changes exceed the preconfigured threhold
(e.g.,0.20dB), all these 5 receiving power values falling within
detection time window or update time interval should be published to
the destinations for data analysis.
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Authors' Addresses
Michael Wang
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: wangzitao@huawei.com
Qin Wu
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: bill.wu@huawei.com
Wei Song
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: songwei80@huawei.com
Liang Geng
China Mobile
32 Xuanwumen West St, Xicheng District
Beijing 10053
Email: gengliang@chinamobile.com
Peng Liu
China Mobile
32 Xuanwumen West St, Xicheng District
Beijing 10053
Email: liupengyjy@chinamobile.com
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