NETCONF Working Group Q. Wu
Internet-Draft W. Song
Intended status: Standards Track Huawei
Expires: April 17, 2021 L. Geng
P. Liu
China Mobile
Q. Ma
Huawei
October 14, 2020
Adaptive Subscription to YANG Notification
draft-wang-netconf-adaptive-subscription-02
Abstract
This document defines a YANG data model and associated mechanism
enabling subscriber's adaptive subscriptions to a publisher's event
streams with various different period intervals to report updates.
Applying these elements allows both subscriber and publisher 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 April 17, 2021.
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
Wu, et al. Expires April 17, 2021 [Page 1]
Internet-Draft Adaptive Subscription October 2020
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
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Model Overview . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Subscription Configuration . . . . . . . . . . . . . . . 5
2.2. YANG RPC . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.1. "establish-subscription" RPC . . . . . . . . . . . . 6
2.2.2. "modify-subscription" RPC . . . . . . . . . . . . . . 6
2.3. Notifications for Adaptive Subscribed Content . . . . . . 6
3. Adaptive Subscription YANG Module . . . . . . . . . . . . . . 7
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
4.1. Updates to the IETF XML Registry . . . . . . . . . . . . 12
4.2. Updates to the YANG Module Names Registry . . . . . . . . 12
5. Security Considerations . . . . . . . . . . . . . . . . . . . 12
6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 13
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
7.1. Normative References . . . . . . . . . . . . . . . . . . 13
7.2. Informative References . . . . . . . . . . . . . . . . . 14
Appendix A. Example YANG Module . . . . . . . . . . . . . . . . 14
A.1. "example-wifi-mac" YANG Module . . . . . . . . . . . . . 15
Appendix B. Adaptive Subscription and Notification Example . . . 18
B.1. "edit-config" Example . . . . . . . . . . . . . . . . . . 18
B.2. Create Adaptive Subscription Example . . . . . . . . . . 19
B.3. "adaptive-update" notification example . . . . . . . . . 21
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22
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
Wu, et al. Expires April 17, 2021 [Page 2]
Internet-Draft Adaptive Subscription October 2020
o On-change subscription allows update to be triggered 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 large scale deployments (e.g., wireless network
performance monitoring) where an increased data collection rate is
being used, it becomes more likely that a burst of streamed data may
temporarily overwhelm a receiver and consume expensive network
resource (e.g., air interface resource). If the rate at which we can
collect a stream of data is set too low, these telemetry data are not
sufficient to detect and diagnose problems and verify correct network
behavior. There is a need for a service to configure both collectors
and publishers with multiple different period intervals and
automatically switch to different period intervals according to
resource usage change, e.g., when the wireless signal strength falls
below a configured low watermark, the subscribed data can be streamed
at a higher rate while when the wireless signal strength crosses a
configured high watermark, the subscribed data can be streamed at
lower rate.
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 both subscriber and
publisher to 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: An event is something that happens that may be of interest -
a configuration change, a fault, a change in status, crossing a
threshold, or an external input to the system, for example.
Often, this results in an asynchronous message, sometimes referred
to as a notification or event notification, being sent to
interested parties to notify them that this event has occurred
[RFC5277].
Client: Defined in [RFC8342].
Configuration: Defined in [RFC8342].
Wu, et al. Expires April 17, 2021 [Page 3]
Internet-Draft Adaptive Subscription October 2020
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].
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
This document defines a YANG module "ietf-adaptive-subscription",
which augments the "update-trigger" choice defined in the "ietf-yang-
push" module [RFC8641] with subscription configuration parameters
that are specific to adaptive subscription.
In addition to Subscription state notifications defined in [RFC8639]
and Notifications for Subscribed Content defined in [RFC8641], "ietf-
adaptive-subscription" YANG module also defines "adaptive-update"
notification to report update interval change.
The following tree diagrams [RFC8340] provide an overview of the data
model for "ietf-adaptive-subscription.yang" module.
Wu, et al. Expires April 17, 2021 [Page 4]
Internet-Draft Adaptive Subscription October 2020
module: ietf-adaptive-subscription
augment /sn:subscriptions/sn:subscription/yp:update-trigger:
+--rw (adaptive-subscription)?
+--:(adaptive-subscriptions)
+--rw adaptive-subscriptions
+--rw adaptive-period* [name]
+--rw name string
+--rw xpath-external-eval string
+--rw watermark? uint32
+--rw period centiseconds
+--rw anchor-time? yang:date-and-time
augment /sn:establish-subscription/sn:input/yp:update-trigger:
+-- (adaptive-subscription)?
+--:(adaptive-subscriptions)
+--rw adaptive-subscriptions
+--rw adaptive-period* [name]
+--rw name string
+--rw xpath-external-eval string
+--rw watermark? uint32
+--rw period centiseconds
+--rw anchor-time? yang:date-and-time
notifications:
+---n adaptive-period-update
+--ro id? sn:subscription-id
+--ro period centiseconds
+--ro anchor-time? yang:date-and-time
+--ro (selection-filter)?
+--:(by-reference)
| +--ro selection-filter-ref selection-filter-ref
+--:(within-subscription)
+--ro (filter-spec)?
+--:(datastore-subtree-filter)
| +--ro datastore-subtree-filter? <anydata> {sn:subtree}?
+--:(datastore-xpath-filter)
+--ro datastore-xpath-filter? yang:xpath1.0 {sn:xpath}?
2.1. Subscription Configuration
For adaptive subscriptions, triggered updates will occur at the
boundaries of specified time intervals when a trigger condition is
satisfied. These boundaries can be calculated from the adaptive
periodic parameters:
o a "period" that defines the new duration between push updates, the
period can be changed based on trigger condition.
o an "anchor-time" update intervals fall on the points in time that
are a multiple of a "period" from an "anchor-time". If an
Wu, et al. Expires April 17, 2021 [Page 5]
Internet-Draft Adaptive Subscription October 2020
"anchor-time" is not provided, then the "anchor-time" MUST be set
with the creation time of the initial update record.
o a "watermark" that defines the threshold value of the targeted
data object, e.g., it can be lower boundary or upper boundary of
targeted data object.
o a "xpath-external-eval" represents an Evaluation criteria that may
be applied against event records in an event stream, which is used
to trigger update interval switch. It contains comparisons of
datastore node with specific threshold (i.e., watermark) and
associated logical operations in the XPath format. Different from
stream-xpath-filter defined in [RFC8639], it doesn't influence the
event records output generation from a publisher.
2.2. YANG RPC
2.2.1. "establish-subscription" RPC
The augmentation of YANG module ietf-yang-push made to RPCs specified
in YANG module ietf-subscribed-notifications [RFC8639] is introduced.
This augmentation concerns the "establish- subscription" RPC, which
is augmented with parameters that are needed to specify adaptive
subscriptions. These parameters are same as one defined in
Section 2.1.
2.2.2. "modify-subscription" RPC
The subscriber MAY invoke the "modify-subscription" RPC for a
subscription it previously established. The subscriber will include
newly desired values in the "modify-subscription" RPC. Parameters
not included MUST remain unmodified. Section 4.4.2 of [RFC8641]
provides an example where a subscriber attempts to modify the period
and datastore XPath filter of a subscription using NETCONF. The
period can be the 'period' parameter defined by ietf-adaptive-
subscription.
2.3. Notifications for Adaptive Subscribed Content
The adaptive update notification is similar to Subscription state
change notifications defined in [RFC8639]. It is inserted into the
sequence of notification messages sent to a particular receiver. The
adaptive update notification cannot be dropped or filtered out, it
cannot be stored in replay buffers, and it is delivered only to
impacted receivers of a subscription. The identification of adaptive
update notification is easy to separate from other notification
messages through the use of the YANG extension "subscription-state-
Wu, et al. Expires April 17, 2021 [Page 6]
Internet-Draft Adaptive Subscription October 2020
notif". This extension tags a notification as a subscription state
change notification.
The objects in the 'adpative-update' notification include:
o a "period" that defines the duration between push updates, the
period can be changed based on trigger condition.
o an "anchor-time"; update intervals fall on the points in time that
are a multiple of a "period" from an "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.
o A selection filter identifying YANG nodes of interest in a
datastore. Filter contents are specified via a reference to an
existing filter or via an in-line definition for only that
subscription. Referenced filters allow an implementation to avoid
evaluating filter acceptability during a dynamic subscription
request. The "case" statement differentiates the options. Note
that filter contents are not affected by "xpath-external-eval"
parameter and "watermark" parameter defined by update trigger.
3. Adaptive 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;
}
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.
Wu, et al. Expires April 17, 2021 [Page 7]
Internet-Draft Adaptive Subscription October 2020
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 seconds {
type uint32;
description
"A period of time, measured in units of 1 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 {
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.";
}
Wu, et al. Expires April 17, 2021 [Page 8]
Internet-Draft Adaptive Subscription October 2020
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";
}
grouping adaptive-subscription-modifiable {
description
"This grouping describes the datastore-specific adaptive subscription
conditions that can be changed during the lifetime of the
subscription.";
choice adaptive-subscription {
description
"Defines necessary conditions for sending an event record to
the subscriber.";
container adaptive-subscriptions {
list adaptive-period {
description
"Defines necessary conditions to switch update interval for
sending an event record to the subscriber. The event record output
generation will not be influeced these conditions.";
key "name";
leaf name {
type string {
length "1..64";
}
description
"The name of the condition to be matched. A device MAY further
restrict the length of this name; space and special
characters are not allowed.";
}
leaf xpath-external-eval {
type string;
description
"A XPath string, representing a logical expression,
which can contain comparisons of datastore values
and logical operations in the XPath format.";
}
leaf watermark {
type uint32;
Wu, et al. Expires April 17, 2021 [Page 9]
Internet-Draft Adaptive Subscription October 2020
description
"The watermark for targeted data object. The high
watermark, lowe watermark can be specified for the
targeted data object.";
}
leaf period {
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'.
For example, for an 'anchor-time' that is set for the
top of a particular minute and a period interval of a
minute, updates will be sent at the top of every
minute that this subscription is active.";
}
}
description
"Container for adaptive subscription.";
}
}
}
augment "/sn:subscriptions/sn:subscription/yp:update-trigger" {
description
"This augmentation adds additional subscription parameters
that apply specifically to adaptive subscription.";
uses adaptive-subscription-modifiable;
}
augment "/sn:establish-subscription/sn:input/yp:update-trigger" {
description
"This augmentation adds additional subscription parameters
that apply specifically to datastore updates to RPC input.";
uses adaptive-subscription-modifiable;
}
notification adaptive-period-update {
sn:subscription-state-notification;
description
"This notification contains a push update that in turn contains
Wu, et al. Expires April 17, 2021 [Page 10]
Internet-Draft Adaptive Subscription October 2020
data subscribed to via a subscription. In the case of a
periodic subscription, this notification is sent for periodic
updates. It can also be used for synchronization updates of
an on-change subscription. This notification shall only be
sent to receivers of a subscription. It does not constitute
a general-purpose notification that would be subscribable as
part of the NETCONF event stream by any receiver.";
leaf id {
type sn:subscription-id;
description
"This references the subscription that drove the
notification to be sent.";
}
leaf period {
type centiseconds;
mandatory true;
description
"New 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'.
For example, for an 'anchor-time' that is set for the
top of a particular minute and a period interval of a
minute, updates will be sent at the top of every
minute that this subscription is active.";
}
uses yp:datastore-criteria {
refine "selection-filter/within-subscription" {
description
"Specifies the selection filter and where it originated
from. If the 'selection-filter-ref' is populated, the
filter in the subscription came from the 'filters'
container. Otherwise, it is populated in-line as part
of the subscription itself.";
}
}
}
}
<CODE ENDS>
Wu, et al. Expires April 17, 2021 [Page 11]
Internet-Draft Adaptive Subscription October 2020
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.
---------------------------------------------------------------------
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
Wu, et al. Expires April 17, 2021 [Page 12]
Internet-Draft Adaptive Subscription October 2020
network operations. These are the subtrees and data nodes and their
sensitivity/vulnerability:
o /sn:subscriptions/sn:subscription/yp:update-trigger/as:adaptive-
subscriptions/as:adaptive-period/as:watermark
o /sn:subscriptions/sn:subscription/yp:update-trigger/as:adaptive-
subscriptions/as:adaptive-period/as:period
o /sn:subscriptions/sn:subscription/yp:update-trigger/as:adaptive-
subscriptions/as:adaptive-period/as:anchor-time
6. Contributors
The authors would like to thank Michale Wang for his major
contributions to the initial modeling and use cases.
7. References
7.1. 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>.
Wu, et al. Expires April 17, 2021 [Page 13]
Internet-Draft Adaptive Subscription October 2020
[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>.
[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>.
7.2. 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. Example YANG Module
The example YANG module used in this document represents a simple
wifi mac interface.
YANG tree diagram for the "example-wifi-mac" module:
Wu, et al. Expires April 17, 2021 [Page 14]
Internet-Draft Adaptive Subscription October 2020
module: example-wifi-mac
+--rw clients
+--ro client* [mac]
+--ro mac yang:mac-address
+--ro rssi? int8
+--ro snr? uint8
+--ro ss? uint8
+--ro phy-rate? uint16
+--ro channel-support* uint8
+--ro neighbors
| +--ro neighbor-bssid? yang:mac-address
| +--ro neighbor-channel? uint8
| +--ro neighbor-rssi? int8
| +--ro neighbor-antenna? uint8
| +--ro channel-load-report? uint8
+--ro ssid
+--ro name? string
+--ro enabled? boolean
+--ro broadcast-filter? boolean
+--ro multicast-filter? boolean
+--ro ipv6-ndp-filter? boolean
+--ro ipv6-ndp-filter-timer? uint16
+--ro station-isolation? boolean
A.1. "example-wifi-mac" YANG Module
module example-wifi-mac {
yang-version 1;
namespace "http://example.com/yang/wifi-mac";
prefix wifi;
import ietf-yang-types {
prefix yang;
}
container clients {
description
"Top-level container for clients operational state data.";
list client {
key "mac";
config false;
description
"List of clients per BSS.";
leaf mac {
type yang:mac-address;
description
"MAC address of the client.";
}
Wu, et al. Expires April 17, 2021 [Page 15]
Internet-Draft Adaptive Subscription October 2020
leaf rssi {
type int8;
description
"The RSSI of this client in dBm. Expressed as negative
number";
}
leaf snr {
type uint8;
description
"The SNR of AP to Client, in dB.";
}
leaf ss {
type uint8;
description
"Number of Spatial Streams supported by the client.";
}
leaf phy-rate {
type uint16;
description
"Last used PHY rate of connected client.";
}
leaf-list channel-support {
type uint8;
description
"List of supported channels.";
}
container neighbors {
description
"Container for Client beacon reports. Requires 802.11k
enabled. See Sec. 5.2.7.1 of 802.11k-2008 Standard.";
leaf neighbor-bssid {
type yang:mac-address;
description
"The BSSID of this neighbor.";
}
leaf neighbor-channel {
type uint8;
description
"The channel of this neighbor.";
}
leaf neighbor-rssi {
type int8;
description
"The RSSI of this neighbor in dBm, expressed as a negative
number.";
}
leaf neighbor-antenna {
type uint8;
Wu, et al. Expires April 17, 2021 [Page 16]
Internet-Draft Adaptive Subscription October 2020
description
"Antenna details for this neighbor.";
}
leaf channel-load-report {
type uint8;
description
"Channel load, as reported by Client to AP
normalized to 255. See Sec. 10.11.9.3 of 802.11ac-2013
Spec.";
}
}
container ssid {
description
"Top level container for ssids, including configuration
and state data.";
leaf name {
type string;
description
"The name of the SSID.";
}
leaf enabled {
type boolean;
default "true";
description
"The desired operational state (up/down) of this SSID.";
}
leaf broadcast-filter {
type boolean;
description
"Convert all downstream broadcast ARP to unicast
only if Station is associated to the AP. Drop packet
if Station is not associated to the AP. All other
broadcast, except DHCP, is dropped by the AP.
DHCP Offers/ACKs are converted to Unicast, over-the-air.";
}
leaf multicast-filter {
type boolean;
description
"Drop all downstream Multicast packets.";
}
leaf ipv6-ndp-filter {
type boolean;
description
"Neighbor Advertisements will be cached at the AP (or WLC)
and unicast in response to Neighbor Solicitations.
Router Advertisements, in response to a Router Solicitation
Wu, et al. Expires April 17, 2021 [Page 17]
Internet-Draft Adaptive Subscription October 2020
are converted to Unicast for over-the-air transmission.";
}
leaf ipv6-ndp-filter-timer {
type uint16;
units "seconds";
description
"Time, in seconds, the ndp-filter will cache
Neighbor Advertisements (NA).";
}
leaf station-isolation {
type boolean;
description
"Block Station peer to peer communication.";
}
}
}
}
}
Appendix B. Adaptive Subscription and Notification Example
The examples within this document use the normative YANG module
"ietf-adaptive-subscription" as defined in Section 3 and the non-
normative example YANG module "example-wifi-mac" as defined in
Appendix A.1.
This section shows some typical adaptive subscription and
notification message exchanges.
B.1. "edit-config" Example
The client configure adaptive subscription parameters on the server.
The adaptive subscription configuration parameters require the server
to scan all clients every 5 seconds if the ssid value of client is
greater than -65dB; If the ssid value of client is less than -65dB,
switch to 60 seconds period value, and then scan all clients every 60
seconds.
Wu, et al. Expires April 17, 2021 [Page 18]
Internet-Draft Adaptive Subscription October 2020
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<running/>
</target>
<config xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
<top xmlns="http://example.com/schema/1.2/config">
<yp:datastore
xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
ds:running
</yp:datastore>
<yp:datastore-xpath-filter
xmlns:ex="https://example.com/sample-data/1.0">
/ex:example-wifi-mac
</yp:datastore-xpath-filter>
<as:adaptive-subscriptions
xmlns:as="urn:ietf:params:xml:ns:yang:ietf-adaptive-subscription">
<as:adaptive-period>
<as:condition-expression>as:clients/as:client[ssid > -65]</as:
condition-expression>
<as:watermark>-65</as:watermark>
<as:period>5</as:period>
</as:adaptive-period>
<as:adaptive-period>
<as:condition-expression>as:clients/as:client[ssid < -65]</as:
condition-expressioni>
<as:watermark>-65</as:watermark>
<as:period>60</as:period>
</as:adaptive-period>
</as:adaptive-subscriptions>
</top>
</config>
</edit-config>
</rpc>
B.2. Create Adaptive Subscription Example
The subscriber sends an "establish-subscription" RPC with the
parameters listed in to request the creation of a adaptive
subscription. The adaptive subscription configuration parameters
require the server to scan all clients every 5 seconds if the ssid
value of client is greater than -65dB; If the ssid value of client is
less than -65dB, switch to 60 seconds period value, and then scan all
clients every 60 seconds. (Section 2)
Wu, et al. Expires April 17, 2021 [Page 19]
Internet-Draft Adaptive Subscription October 2020
<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:running
</yp:datastore>
<yp:datastore-xpath-filter
xmlns:ex="https://example.com/sample-data/1.0">
/ex:example-wifi-mac
</yp:datastore-xpath-filter>
<as:adaptive-subscriptions
xmlns="urn:ietf:params:xml:ns:yang:ietf-adaptive-subscription">
<as:adaptive-period>
<as:condition-expression>as:clients/as:client[ssid > -65]
</as:condition-expressioni>
<as:watermark>-65</as:watermark>
<as:period>5</as:period>
</as:adaptive-period>
<as:adaptive-period>
<as:condition-expression>as:clients/as:client[ssid < -65]
</as:condition-expressioni>
<as:watermark>-65</as:watermark>
<as:period>60</as:period>
</as:adaptive-period>
</as:adaptive-subscriptions>
</establish-subscription>
</netconf:rpc>
In another example, the adaptive subscription configuration
parameters could also require the server to scan all clients every 5
seconds if the difference between maximum value of client ssid and
minimum value of client ssid is greater than 0.20dB; If the
difference between maximum value of client ssid and minimum value of
client ssid is less than 20dB, switch to 60 seconds period value and
then scan all clients every 60 seconds.
Wu, et al. Expires April 17, 2021 [Page 20]
Internet-Draft Adaptive Subscription October 2020
<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:running
</yp:datastore>
<yp:datastore-xpath-filter
xmlns:ex="https://example.com/sample-data/1.0">
/ex:example-wifi-mac
</yp:datastore-xpath-filter>
<as:adaptive-subscriptions>
<as:data-path>as:clients/as:client</as:data-path>
<as:target>ssid</as:target>
<as:adaptive-period>
<as:condition-expression>as:clients/as:client[max(ssid)-min(ssid) >20]
</as:condition-expressioni>
<as:watermark>20</as:watermark>
<as:period>5</as:period>
</as:adaptive-period>
<as:adaptive-period>
<as:condition-expression>as:clients/as:client[max(ssid)-min(ssid) < 20]
</as:condition-expressioni>
<as:watermark>20</as:watermark>
<as:period>60</as:period>
</as:adaptive-period>
</as:adaptive-subscriptions>
</establish-subscription>
</netconf:rpc>
B.3. "adaptive-update" notification example
Upon the server switches to from the update interval 5 seconds to the
new update interval 60 seconds, Before sending event records to
receivers, the "adaptive-update" notification should be generated and
sent to the receivers to inform the receivers that the update
interval value is switched to the new value.
Wu, et al. Expires April 17, 2021 [Page 21]
Internet-Draft Adaptive Subscription October 2020
<notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
<eventTime>2016-11-21T13:51:00Z</eventTime>
<adaptive-update xmlns="http://example.com/ietf-adaptive-subscription">
<id>0</id>
<period>60</period>
<yp:datastore
xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
ds:running
</yp:datastore>
<yp:datastore-xpath-filter
xmlns:ex="https://example.com/sample-data/1.0">
/ex:example-wifi-mac
</yp:datastore-xpath-filter>
</adaptive-update>
</notification>
Authors' Addresses
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
Wu, et al. Expires April 17, 2021 [Page 22]
Internet-Draft Adaptive Subscription October 2020
Peng Liu
China Mobile
32 Xuanwumen West St, Xicheng District
Beijing 10053
Email: liupengyjy@chinamobile.com
Qiufang Ma
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: maqiufang1@huawei.com
Wu, et al. Expires April 17, 2021 [Page 23]