NETCONF G. Zheng
Internet-Draft T. Zhou
Intended status: Standards Track Huawei
Expires: 4 September 2025 T. Graf
Swisscom
P. Francois
A. Huang Feng
INSA-Lyon
P. Lucente
NTT
3 March 2025
UDP-based Transport for Configured Subscriptions
draft-ietf-netconf-udp-notif-20
Abstract
This document describes a UDP-based transport for YANG notifications
to collect data from network nodes. A shim header is defined to
facilitate the data streaming directly from a publishing process on a
network device to telemetry receivers. Such a design enable higher
frequency updates and less performance overhead on publisher and
receiver processes compared to already established notification
mechanisms. A YANG data model is also defined for management of the
described UDP-based transport.
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 4 September 2025.
Copyright Notice
Copyright (c) 2025 IETF Trust and the persons identified as the
document authors. All rights reserved.
Zheng, et al. Expires 4 September 2025 [Page 1]
Internet-Draft UDP-Notif March 2025
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 to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. UDP-Based Transport . . . . . . . . . . . . . . . . . . . . . 5
3.1. Design Overview . . . . . . . . . . . . . . . . . . . . . 5
3.2. Format of the UDP-Notif Message Header . . . . . . . . . 6
3.3. Data Encoding . . . . . . . . . . . . . . . . . . . . . . 8
4. Options . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.1. Segmentation Option . . . . . . . . . . . . . . . . . . . 9
5. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 11
5.1. Congestion Control . . . . . . . . . . . . . . . . . . . 11
5.2. Message Size . . . . . . . . . . . . . . . . . . . . . . 12
5.3. Reliability . . . . . . . . . . . . . . . . . . . . . . . 12
6. Secured layer for UDP-Notif . . . . . . . . . . . . . . . . . 13
6.1. Session Lifecycle . . . . . . . . . . . . . . . . . . . . 13
6.1.1. DTLS Session Initiation . . . . . . . . . . . . . . . 13
6.1.2. Publish Data . . . . . . . . . . . . . . . . . . . . 14
6.1.3. Session Termination . . . . . . . . . . . . . . . . . 14
6.1.4. DTLS Fragmentation . . . . . . . . . . . . . . . . . 15
7. A YANG Data Model for Management of UDP-Notif . . . . . . . . 15
7.1. YANG Module for configuring UDP-Notif . . . . . . . . . . 15
7.2. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 17
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
8.1. IANA Registries . . . . . . . . . . . . . . . . . . . . . 21
8.2. URI . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
8.3. YANG Module Name . . . . . . . . . . . . . . . . . . . . 23
9. Implementation Status . . . . . . . . . . . . . . . . . . . . 23
9.1. Open Source Publisher . . . . . . . . . . . . . . . . . . 23
9.2. Open Source Receiver Library . . . . . . . . . . . . . . 23
9.3. Pmacct Data Collection . . . . . . . . . . . . . . . . . 23
9.4. Huawei VRP . . . . . . . . . . . . . . . . . . . . . . . 23
9.5. 6WIND VSR . . . . . . . . . . . . . . . . . . . . . . . . 23
9.6. Cisco IOS XR . . . . . . . . . . . . . . . . . . . . . . 24
10. Security Considerations . . . . . . . . . . . . . . . . . . . 24
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 25
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 25
12.1. Normative References . . . . . . . . . . . . . . . . . . 25
12.2. Informative References . . . . . . . . . . . . . . . . . 28
Zheng, et al. Expires 4 September 2025 [Page 2]
Internet-Draft UDP-Notif March 2025
Appendix A. UDP-Notif Examples . . . . . . . . . . . . . . . . . 29
A.1. Configuration for UDP-Notif transport with DTLS
disabled . . . . . . . . . . . . . . . . . . . . . . . . 29
A.2. Configuration for UDP-Notif transport with DTLS
enabled . . . . . . . . . . . . . . . . . . . . . . . . . 30
A.3. YANG Push message with UDP-Notif transport protocol . . . 33
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 34
1. Introduction
The mechanism to support a subscription of a continuous and
customized stream of updates from a YANG datastore [RFC8342] is
defined in Subscribed Notifications [RFC8639] and YANG-Push
[RFC8641].
Subscribed Notifications [RFC8639] separate the management and
control of subscriptions from the transport used to deliver the data.
Three transport mechanisms, namely NETCONF transport [RFC8640],
RESTCONF transport [RFC8650], and HTTPS transport
[I-D.ietf-netconf-https-notif] were defined for such notification
messages.
While powerful in their features, and general in their architecture,
the currently available transport mechanisms need to be complemented
to support data publications at high frequency with low overhead.
This is important for network nodes that feature a distributed
architecture with sparse resources on components specialized for
packet forwarding. The currently available transports are TCP-based
requiring the maintenance of connections, states and retransmissions,
which is not necessary for high-frequency continuous notification
content, typically published directly from network processors on line
cards.
This document specifies a transport option for Configured
Subscriptions as defined in Section 2.5 of [RFC8639] that leverages
UDP. Specifically, it facilitates the distributed data collection
mechanism described in [I-D.ietf-netconf-distributed-notif]. In the
case of publishing from multiple network processors on multiple line
cards, centralized designs require data to be internally forwarded
from those network processors to the push server, presumably on a
route processor, which then combines the individual data items into a
single consolidated stream. The centralized data collection
mechanism can result in a performance bottleneck, especially when
large amounts of data are involved.
Zheng, et al. Expires 4 September 2025 [Page 3]
Internet-Draft UDP-Notif March 2025
What is needed is a mechanism that allows for directly publishing
from multiple network processors on line cards, without passing them
through an additional processing stage for internal consolidation.
The UDP-based transport allows for such a distributed data publishing
approach:
* Firstly, a UDP approach reduces the burden of maintaining a large
pool of active TCP connections at the receiver, notably in cases
where it collects data from network processors on line cards from
a large number of network nodes.
* Secondly, as no connection state needs to be maintained, UDP
encapsulation could be implemented by the hardware of the
publisher, which further improves performance.
* Ultimately, such advantages allow for a larger data analysis
feature set, as more voluminous, finer grained data sets can be
streamed to the receiver.
The transport described in this document can be used for transmitting
notification messages over both IPv4 and IPv6. It is designed to be
used in cases where packet loss is not a concern, such as the
collection of statistical metrics that are exported periodically.
This transport can be configured via NETCONF [RFC6241] or RESTCONF
[RFC8040].
This document describes the notification mechanism. It is intended
to be used in conjunction with [RFC8639], extended by
[I-D.ietf-netconf-distributed-notif]. Additionally, this document
defines a YANG data model for management of the UDP-based transport.
The YANG module specified in this document is compliant with Network
Management Datastore Architecture (NMDA) [RFC8639].
Section 3 details the notification mechanism and message format.
Section 4 describes the use of options in the notification message
header. Section 5 covers the applicability of the mechanism.
Section 6 describes a mechanism to secure the protocol in open
networks. Finally, Section 7 defines a YANG data model for
management of the mechanism described in this document.
2. 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.
Zheng, et al. Expires 4 September 2025 [Page 4]
Internet-Draft UDP-Notif March 2025
The following terms are used as defined in Subscribed Notifications
[RFC8639]:
* Notification message
* Subscription
* Configured Subscription
* Subscriber
* Publisher
* Receiver
The following term is used as defined in
[I-D.ietf-netconf-distributed-notif]:
* Message Publisher ID
This document defines the following term:
* Message ID: identifier of a message transported by the UDP-Notif
protocol. More details are presented in Section 3.2.
3. UDP-Based Transport
This section specifies the UDP-Notif transport behavior. Section 3.1
describes the general design of the solution. Section 3.2 specifies
the UDP-Notif message format and Section 3.3 describes the encoding
of the message payload.
3.1. Design Overview
As specified in Section 2.6 of Subscribed Notifications [RFC8639],
the content of a YANG notification is encapsulated in a notification
message, which is then encapsulated and carried using a transport
protocol. Figure 1 illustrates the structure of a UDP-Notif message:
* The Message Header contains information that facilitates the
message transmission before deserializing the notification
message.
* The Notification Message is the encoded content that is
transported by the publication stream. The common encoding
methods are listed in Section 3.2. The structure of the
notification message is defined in Section 2.6 of Subscribed
Notifications [RFC8639].
Zheng, et al. Expires 4 September 2025 [Page 5]
Internet-Draft UDP-Notif March 2025
+-------+ +--------------+ +--------------+
| UDP | | Message | | Notification |
| | | Header | | Message |
+-------+ +--------------+ +--------------+
Figure 1: UDP-Notif Message Overview
When a publisher starts streaming UDP-Notif messages, the first
message generated by the publisher MUST be a separate "subscription-
started" notification to indicate to the receiver that the stream has
started flowing. Then, the notifications can be sent immediately
without delay. Subscription state notifications, defined in
Section 2.7 of [RFC8639], MUST be encapsulated in separate
notification messages.
Note that receivers collecting UDP-Notif messages may not be already
up and running when the configuration of the subscription takes
effect on a monitored network node.
3.2. Format of the UDP-Notif Message Header
The UDP-Notif message header contains information that facilitates
the message transmission between the publisher and the receiver
before deserializing the notification message. The data format is
shown in Figure 2.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-----+-+-------+---------------+-------------------------------+
| Ver |S| MT | Header Len | Message Length |
+-----+-+-------+---------------+-------------------------------+
| Message Publisher ID |
+---------------------------------------------------------------+
| Message ID |
+---------------------------------------------------------------+
~ Options ~
+---------------------------------------------------------------+
Figure 2: UDP-Notif Message Header Format
The Message Header contains the following field:
* Ver indicates the UDP-Notif protocol header version. The values
are allocated by the IANA registry "UDP-Notif header version"
(Section 8.1). The current header version number is 1.
Zheng, et al. Expires 4 September 2025 [Page 6]
Internet-Draft UDP-Notif March 2025
* S-flag represents the space of media type specified in the MT
field. When S-flag is not set, MT represents the standard media
types as defined in the IANA registry "UDP-Notif media types"
(Section 8.1). When S-flag is set, MT represents a private space
to be freely used for non-standard encodings.
* MT is a 4-bit identifier that indicates the media type used for
the notification message. When the S bit is not set, the
following values apply:
- 0: Reserved, MUST NOT be used.
- 1: application/yang-data+json [RFC8040]
- 2: application/yang-data+xml [RFC8040]
- 3: application/yang-data+cbor [RFC9254]
* Header Len (8-bit) records the length of the message header in
octets, including both the fixed header and the options.
* Message Length (16-bit) records the total length of the UDP-Notif
message within one UDP datagram, measured in octets, including the
message header. When the notification message is segmented using
the Segmentation Options defined in Section 4.1, the Message
Length is the total length of the current UDP-Notif segment, not
the length of the entire notification message.
* Message Publisher ID is a 32-bit identifier defined in
[I-D.ietf-netconf-distributed-notif]. This identifier is locally
unique to the publisher node. It identifies the software process
generating the stream of UDP-Notif messages and allow the
disambiguation of an information source. Message unicity is
obtained from the conjunction of the Message Publisher ID and the
Message ID field. If Message Publisher ID unicity is not
preserved through the collection domain, the source IP address of
the UDP datagram MUST be used in addition to the Message Publisher
ID to identify the information source. If a transport layer relay
is used, Message Publisher ID unicity must be preserved through
the collection domain.
* The Message ID is increased monotonically by the publisher of UDP-
Notif messages and MUST start at 1 with the first message. A
publisher MUST use different Message IDs for different messages
generated with the same Message Publisher ID. Note that the main
purpose of the Message ID is to reconstruct messages which are
segmented using the segmentation option described in Section 4.1.
The Message ID values SHOULD be incremented by one for successive
Zheng, et al. Expires 4 September 2025 [Page 7]
Internet-Draft UDP-Notif March 2025
messages originated with the same Message Publisher ID, so that
message loss can be detected at data collection. When the last
value (2^32-1) of Message ID has been reached, the Message ID
wraps around and restarts at 0.
* Options are a variable-length field in the TLV format. When the
Header Length is larger than 12 octets, which is the length of the
fixed header, Options TLVs follow directly after the fixed message
header. Options are described in Section 4.
All the binary fields MUST be encoded in network byte order (big
endian).
3.3. Data Encoding
UDP-Notif message data can be encoded in XML, JSON or CBOR format.
Additional encodings may be supported in the future. This can be
accomplished by augmenting the subscription data model with
additional identity statements used to refer to requested encodings.
The new encoding can be registered in the IANA registry "UDP-Notif
media types" following the procedure defined in Section 8.1.
Subscribed Notifications [RFC8639] states that a transport MUST
identify a default encoding. However, as per [Errata-6211],
Subscribed Notifications does not require to define a default
encoding.
Private encodings can be used by enabling the S-flag of the header.
When the S-flag is set, the value of the MT field is left to be
defined and agreed upon by the users of the private encoding. The MT
field allows for 16 private encodings when S-flag is set.
The encoding of a message data is configured on a subscription basis
and each subscription reference a receiver instance. Publishers MUST
NOT be configured to send notification messages with more than one
encoding to the same receivers.
4. Options
All the options are defined with the format shown in Figure 3.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+--------------------------------
| Type | Length | Variable-length data
+---------------+---------------+--------------------------------
Zheng, et al. Expires 4 September 2025 [Page 8]
Internet-Draft UDP-Notif March 2025
Figure 3: Generic Option Format
* Type: 1-octet describing the option type. The values of the Type
field are allocated by the IANA regsitry "UDP-Notif options types"
(Section 8.1).
* Length: 1-octet representing the total number of octets in the
TLV, including the Type and Length fields.
* Variable-length data: 0 or more octets of data.
When more than one option are used in a UDP-Notif header, the
segmentation option defined in Section 4.1 MUST be placed first, if
present. Placing the segmentation option first can simplify some
implementations for both the publisher and the receiver, notably
those assuming a fixed location for the segmentation option.
Segmented messages where the segmentation option is not the first
option MAY be discarded by the receiver.
4.1. Segmentation Option
The UDP payload length is limited to 65527 bytes (65535 - 8 bytes).
Application-level headers will make the actual payload shorter. Even
though binary encodings such as CBOR may not require more space than
what is left, more voluminous encodings such as JSON and XML may
suffer from this size limitation. Although IPv4 and IPv6 publishers
can fragment outgoing packets exceeding their Maximum Transmission
Unit (MTU), fragmented IP packets may not be desired for operational
and performance reasons [BCP230].
Implementations MUST provide a configurable parameter to control the
maximum size of a UDP-Notif segment. This parameter is defined as
"max-segment-size" in the YANG module specified in Section 7.1.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+-----------------------------+-+
| Type | Length | Segment Number |L|
+---------------+---------------+-----------------------------+-+
Figure 4: Segmentation Option Format
The Segmentation Option (Figure 4) is included when the message
content is segmented into multiple segments. Different segments of
one message share the same Message ID. The fields of this option are
as follows:
* Type: indicates a Segmentation Option. The value is TBD1.
Zheng, et al. Expires 4 September 2025 [Page 9]
Internet-Draft UDP-Notif March 2025
* Length: indicates the length of this option, in octets. It MUST
be set to 4 octets.
* Segment Number: 15-bit value indicating the sequence number of the
current segment. The first segment of a segmented message has a
segment number value of 0. The segment number cannot wrap around.
* L: indicates whether the current segment is the last one of the
message. When 0 is set, the current segment is not the last one.
When 1 is set, the current segment is the last one, meaning that
the total number of segments used to transport this message is the
value of the current Segment Number + 1.
Implementations MUST NOT rely on IP fragmentation to carry large
messages. Implementations MUST either restrict the size of
individual messages to a value that will not lead to IP fragmentation
as per Section 5.2, or support the segmentation option. In the
latter case, the parameter "max-segment-size" MUST be set so that the
size of a UDP-Notif segment and the size of the IP layer together do
not exceed the MTU of the egress interface.
When a message has multiple options and is segmented, all the options
MUST be present on the first segment. The rest of segmented messages
MAY include all the options. The segmentation option MUST be placed
first in all segments.
The receiver SHOULD support the reception of unordered segments. The
implementation of the receiver SHOULD provide an option to discard
the received segments if, after some time, one of the segments is
still missing and the reassembly of the message is not possible. No
retransmission of lost segments are expected from the publisher. If
the receiver collects a segment more than once, the implementation
SHOULD drop the duplicate segment.
Zheng, et al. Expires 4 September 2025 [Page 10]
Internet-Draft UDP-Notif March 2025
To reassemble segmented UDP-Notif messages, the receiver should first
identify UDP-Notif segments belonging to the same message by using
the combination of the Message Publisher ID and Message ID. The
receiver SHOULD wait for all the segments before starting the
reassembly process. Once all the segments are collected, the
receiver should create a new UDP-Notif header with the same Ver,
S-flag, MT, Message Publisher ID and Message ID values. When UDP-
Notif options other than the segmentation option are present in the
first segment, these options need to be appended to the newly created
UDP-Notif header. To reconstruct the original notification message,
the receiver must concatenate the notification message of each UDP-
Notif segments in an ascending order based on the Segment Number.
The new concatenated notification message becomes the notification
message of the newly created UDP-Notif message. The Header Length
and Message Length are then updated accordingly.
5. Applicability
This section provides an applicability for the UDP-Notif mechanism,
following the recommendations of [RFC8085].
The mechanism falls in the category of UDP applications "designed for
use within the network of a single network operator or on networks of
an adjacent set of cooperating network operators, to be deployed in
controlled environments", as defined in [RFC8085]. Implementations
SHOULD thus follow the recommendations in place for such specific
applications. We discuss recommendations on congestion control in
Section 5.1, message size guidelines in Section 5.2 and reliability
considerations in Section 5.3.
The main use case of the UDP-Notif mechanism is the collection of
statistical metrics for accounting purposes, where potential loss is
not a concern, but should however be reported (such as IPFIX Flow
Records exported with UDP [RFC7011]). Such metrics are typically
exported in a periodical subscription as described in Section 3.1 of
[RFC8641].
5.1. Congestion Control
The above application falls into the category of applications
performing transfer of large amounts of data. It is expected that
the operator using the solution configures dedicated class of
services on its related flows. As per [RFC8085], such applications
may choose not to implement any form of congestion control, but
follow the following principles.
Zheng, et al. Expires 4 September 2025 [Page 11]
Internet-Draft UDP-Notif March 2025
It is NOT RECOMMENDED to use the UDP-Notif mechanism over congestion-
sensitive network paths. The only environments where UDP-Notif is
expected to be used are managed networks. The deployments require
that the network path has been explicitly provisioned to handle the
traffic through traffic engineering mechanisms, such as rate limiting
or capacity reservations.
Implementation SHOULD NOT push unbounded volumes of traffic by
default, and SHOULD require the users to explicitly configure such a
mode of operation.
Burst mitigation through packet pacing is RECOMMENDED. Disabling
burst mitigation SHOULD require the users to explicitly configure
such a mode of operation.
Applications SHOULD monitor packet losses and provide means to the
user for retrieving information on such losses. The UDP-Notif
Message ID can be used to deduce congestion based on packet loss
detection. Hence the receiver can notify the publisher to use a
lower streaming rate. The interaction to control the streaming rate
on the publisher is out of the scope of this document.
5.2. Message Size
[RFC8085] recommends not to rely on IP fragmentation for messages
whose size result in IP packets exceeding the MTU along the path.
The segmentation option of the current specification permits
segmentation of the UDP-Notif message content without relying on IP
fragmentation.
It is RECOMMENDED that the size of a Notification Message is small
and segmentation does not result in segmenting the message into too
many segments to avoid dropping the entire message when there is a
lost segment.
A receiver collecting segmented UDP-Notif messages SHOULD have a
configurable parameter to discard segments when they exceed a certain
amount of segments. The generation of too many segments by a
publisher can be used as an abuse to require computation resources
for reassembling large messages at the receiver.
5.3. Reliability
A receiver implementation SHOULD discard packets that were received
but cannot be re-assembled as a complete message within a given
amount of time. This time SHOULD be configurable.
Zheng, et al. Expires 4 September 2025 [Page 12]
Internet-Draft UDP-Notif March 2025
6. Secured layer for UDP-Notif
In unsecured networks, which are not authenticated and encrypted on
layers below transport, UDP-Notif messages MUST be encrypted. In
this section, a mechanism using DTLS [RFC6347][RFC9147] to secure
UDP-Notif protocol is presented.
Implementations using DTLS to secure UDP-Notif messages MUST support
DTLS 1.2 [RFC6347] or later, and SHOULD support DTLS 1.3 [RFC9147].
No DTLS extensions are defined in this document.
When this security layer is used, the publisher MUST always be a DTLS
client, and the Receiver MUST always be a DTLS server. The Receivers
MUST support accepting UDP-Notif Messages on the configured UDP port,
but MAY be configurable to listen on a different port. The publisher
MUST support sending UDP-Notif messages to the specified UDP port
number, but MAY be configurable to send messages to a different port.
The publisher MAY use any source UDP port for transmitting messages.
6.1. Session Lifecycle
This section describes the lifecycle of UDP-Notif messages when they
are encrypted using DTLS.
6.1.1. DTLS Session Initiation
The publisher initiates a DTLS connection by sending a DTLS
ClientHello to the Receiver. Implementations MAY disable the denial
of service countermeasures defined by DTLS 1.2 and DTLS 1.3 if a
given deployment can ensure that DoS attacks are not a concern.
In DTLS 1.3 when the denial of service countermeasures are
implemented, the Receiver responds with a DTLS HelloRetryRequest
containing a stateless cookie. The publisher sends then a second
DTLS ClientHello message containing the received cookie. Details can
be found in Section 5.1 of [RFC9147].
When DTLS is implemented, the publisher MUST NOT send any UDP-Notif
messages before the DTLS handshake has successfully completed.
Implementations MUST NOT use the early data mechanism (also known as
0-RTT data) defined in DTLS 1.3 [RFC9147].
Implementations MUST follow recommendations defined by [BCP195]. If
other cipher suites than the ones recommended by [BCP195] are used,
then implementations MUST NOT negotiate a cipher suite that employs
NULL integrity or authentication algorithms.
Zheng, et al. Expires 4 September 2025 [Page 13]
Internet-Draft UDP-Notif March 2025
Where confidentiality protection with DTLS is required,
implementations must negotiate a cipher suite that employs a non-NULL
encryption algorithm.
6.1.2. Publish Data
When DTLS is used, all UDP-Notif messages MUST be published as DTLS
"application_data". It is possible that multiple UDP-Notif messages
are contained in one DTLS record, or that a publication message is
transferred in multiple DTLS records. The application data is
defined with the following ABNF [RFC5234] expression:
APPLICATION-DATA = 1*UDP-NOTIF-FRAME
UDP-NOTIF-FRAME = MSG-LEN SP UDP-NOTIF-MSG
MSG-LEN = NONZERO-DIGIT *DIGIT
SP = %d32
NONZERO-DIGIT = %d49-57
DIGIT = %d48 / NONZERO-DIGIT
UDP-NOTIF-MSG is defined in Section 3.
The publisher SHOULD attempt to avoid IP fragmentation by using the
Segmentation Option in the UDP-Notif message.
6.1.3. Session Termination
A publisher MUST close the associated DTLS connection if the
connection is not expected to deliver any UDP-Notif Messages later.
It MUST send a DTLS close_notify alert before closing the connection.
A publisher (DTLS client) MAY choose to not wait for the Receiver's
close_notify alert and simply close the DTLS connection. Once the
Receiver gets a close_notify from the publisher, it MUST reply with a
close_notify.
When no data is received from a DTLS connection for a long time, the
Receiver MAY close the connection. Implementations SHOULD set the
timeout value to 10 minutes but application specific profiles MAY
recommend shorter or longer values. The Receiver (DTLS server) MUST
attempt to initiate an exchange of close_notify alerts with the
publisher before closing the connection. Receivers that are
unprepared to receive any more data MAY close the connection after
sending the close_notify alert.
Zheng, et al. Expires 4 September 2025 [Page 14]
Internet-Draft UDP-Notif March 2025
Although closure alerts are a component of TLS and so of DTLS, they,
like all alerts, are not retransmitted by DTLS and so may be lost
over an unreliable network.
6.1.4. DTLS Fragmentation
DTLS 1.2 [RFC6347] and DTLS 1.3 [RFC9147] states that DTLS message
may be fragmented into multiple DTLS records. A DTLS message
carrying a UDP-Notif message SHOULD fit within a single datagram to
avoid DTLS fragmentation. Implementations SHOULD account for DTLS
overhead when determining the maximum UDP-Notif notification message
size.
7. A YANG Data Model for Management of UDP-Notif
7.1. YANG Module for configuring UDP-Notif
The YANG model described in Section 7.2 defines a new receiver
instance for UDP-Notif transport. When this transport is used, four
new leaves and a dtls container allow configuring UDP-Notif receiver
parameters.
The source address of the UDP-Notif message can be configured using
the "source-address" leaf at the subscription level as defined in
Section 2.5 of [RFC8639] or by setting the leaf "local-address" using
the "ietf-udp-notif-transport" YANG module. When both are
configured, the UDP-Notif message MUST use the address configured in
the "local-address" leaf defined in the "ietf-udp-notif-transport"
YANG module.
Zheng, et al. Expires 4 September 2025 [Page 15]
Internet-Draft UDP-Notif March 2025
module: ietf-udp-notif-transport
augment /sn:subscriptions/snr:receiver-instances
/snr:receiver-instance/snr:transport-type:
+--:(udp-notif)
+--rw udp-notif-receiver
+--rw remote-address inet:host
+--rw remote-port inet:port-number
+--rw local-address? inet:ip-address
| {local-binding}?
+--rw local-port? inet:port-number
| {local-binding}?
+--rw dtls! {dtls}?
| +--rw client-identity!
| | +--rw (auth-type)
| | +--:(certificate) {client-ident-x509-cert}?
| | | ...
| | +--:(raw-public-key)
| | | {client-ident-raw-public-key}?
| | | ...
| | +--:(tls12-psk) {client-ident-tls12-psk}?
| | | ...
| | +--:(tls13-epsk) {client-ident-tls13-epsk}?
| | ...
| +--rw server-authentication
| | +--rw ca-certs! {server-auth-x509-cert}?
| | | +--rw (inline-or-truststore)
| | | ...
| | +--rw ee-certs! {server-auth-x509-cert}?
| | | +--rw (inline-or-truststore)
| | | ...
| | +--rw raw-public-keys! {server-auth-raw-public-key}?
| | | +--rw (inline-or-truststore)
| | | ...
| | +--rw tls12-psks? empty
| | | {server-auth-tls12-psk}?
| | +--rw tls13-epsks? empty
| | {server-auth-tls13-epsk}?
| +--rw hello-params {tlscmn:hello-params}?
| +--rw tls-versions
| | +--rw min? identityref
| | +--rw max? identityref
| +--rw cipher-suites
| +--rw cipher-suite*
| tlscsa:tls-cipher-suite-algorithm
+--rw enable-segmentation? boolean
+--rw max-segment-size? uint16
Zheng, et al. Expires 4 September 2025 [Page 16]
Internet-Draft UDP-Notif March 2025
7.2. YANG Module
This YANG module is used to configure, on a publisher, a receiver
willing to consume notification messages. This module augments the
"ietf-subscribed-notif-receivers" module to define a UDP-Notif
transport receiver. The grouping "udp-notif-receiver" defines the
necessary parameters to configure the transport defined in this
document using the generic "udp-client" grouping from the "ietf-udp-
client" module [I-D.ietf-netconf-udp-client-server] and the "tls-
client-grouping" defined in the "ietf-tls-client" module [RFC9645].
<CODE BEGINS> file "ietf-udp-notif-transport@2025-02-14.yang"
module ietf-udp-notif-transport {
yang-version 1.1;
namespace
"urn:ietf:params:xml:ns:yang:ietf-udp-notif-transport";
prefix unt;
import ietf-subscribed-notifications {
prefix sn;
reference
"RFC 8639: Subscription to YANG Notifications";
}
import ietf-subscribed-notif-receivers {
prefix snr;
reference
"RFC YYYY: An HTTPS-based Transport for
Configured Subscriptions";
}
import ietf-udp-client {
prefix udpc;
reference
"RFC ZZZZ: YANG Grouping for UDP Clients and UDP Servers";
}
import ietf-tls-client {
prefix tlsc;
reference
"RFC 9645: YANG Groupings for TLS Clients and TLS Servers";
}
organization "IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: <http:/tools.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org>
Authors: Guangying Zheng
<mailto:zhengguangying@huawei.com>
Tianran Zhou
<mailto:zhoutianran@huawei.com>
Zheng, et al. Expires 4 September 2025 [Page 17]
Internet-Draft UDP-Notif March 2025
Thomas Graf
<mailto:thomas.graf@swisscom.com>
Pierre Francois
<mailto:pierre.francois@insa-lyon.fr>
Alex Huang Feng
<mailto:alex.huang-feng@insa-lyon.fr>
Paolo Lucente
<mailto:paolo@ntt.net>";
description
"Defines a model for configuring UDP-Notif as a transport
for configured subscriptions [RFC8639].
Copyright (c) 2025 IETF Trust and the persons identified as
authors of the code. 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 Revised BSD License set forth in Section
4.c of the IETF Trust's Legal Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX
(https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
for full legal notices.
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 (RFC 2119) (RFC 8174) when, and only when,
they appear in all capitals, as shown here.";
revision 2025-02-14 {
description
"Initial revision";
reference
"RFC XXXX: UDP-based Transport for Configured Subscriptions";
}
/*
* FEATURES
*/
feature encode-cbor {
description
"Indicates that CBOR encoding of notification
messages is supported.";
reference
"RFC 9254: CBOR Encoding of Data Modeled with YANG";
Zheng, et al. Expires 4 September 2025 [Page 18]
Internet-Draft UDP-Notif March 2025
}
feature dtls {
description
"Indicates that DTLS encryption of UDP
packets is supported. UDP-Notif mandates that, in
unsecured networks, DTLS 1.2 or later MUST be supported,
and DTLS 1.3 SHOULD be supported.";
reference
"RFC6347: Datagram Transport Layer Security Version 1.2,
RFC 9147: The Datagram Transport Layer Security (DTLS)
Protocol Version 1.3";
}
/*
* IDENTITIES
*/
identity udp-notif {
base sn:transport;
base sn:configurable-encoding;
description
"UDP-Notif is used as transport for notification messages
and state change notifications.";
}
identity encode-cbor {
base sn:encoding;
description
"Encode data using CBOR.";
reference
"RFC 9254: CBOR Encoding of Data Modeled with YANG";
}
identity unsupported-max-segment-size {
base sn:establish-subscription-error;
base sn:modify-subscription-error;
description
"Error triggered when the specified value 'max-segment-size'
is not supported by the publisher. An implementation may
only support a subset of the uint16.";
reference
"RFC XXXX: UDP-based Transport for Configured Subscriptions";
}
grouping udp-notif-receiver {
description
"Provides a reusable identification of a UDP-Notif target
receiver.";
Zheng, et al. Expires 4 September 2025 [Page 19]
Internet-Draft UDP-Notif March 2025
uses udpc:udp-client {
refine remote-port {
mandatory true;
}
}
container dtls {
if-feature dtls;
presence dtls;
uses tlsc:tls-client-grouping {
// Remove keep-alives for DTLS
refine "keepalives" {
if-feature "not tlsc:tls-client-keepalives";
}
}
description
"Container for configuring DTLS parameters.";
}
leaf enable-segmentation {
type boolean;
default true;
description
"When disabled, the publisher will not segment UDP-Notif
messages and large messages may be fragmented at the IP
layer.";
}
leaf max-segment-size {
type uint16;
description
"UDP-Notif provides a configurable max-segment-size to
control the size of each segment (UDP-Notif header, with
options, included).
The publisher may trigger an 'unsupported-max-segment-size'
error if the publisher does not support the configured
value.";
}
}
augment "/sn:subscriptions/snr:receiver-instances/" +
"snr:receiver-instance/snr:transport-type" {
case udp-notif {
container udp-notif-receiver {
description
"The UDP-notif receiver to send notifications to.";
uses udp-notif-receiver;
}
Zheng, et al. Expires 4 September 2025 [Page 20]
Internet-Draft UDP-Notif March 2025
}
description
"Augments the transport-type choice to include the 'udp-notif'
transport.";
}
}
<CODE ENDS>
8. IANA Considerations
This document describes several new registries, the URIs from IETF
XML Registry and the registration of a new YANG module name.
8.1. IANA Registries
This document requests IANA to create a new registry group called
"UDP-Notif protocol".
Also, this document requests IANA to create the following three
registries called "UDP-Notif media types", "UDP-Notif option types",
and "UDP-Notif header version", under the "UDP-Notif protocol"
registry group.
The registration procedure for all these registries follows the
"Standards Action" policy (Section 4.9 of [RFC8126]).
The first requested registry is the following:
Registry Name: UDP-Notif media types
Maximum value: 15
These are the initial registrations for "UDP-Notif media types":
Value: 0
Description: Reserved
Reference: RFC-to-be
Value: 1
Description: media type application/yang-data+json
Reference: RFC 8040
Value: 2
Description: media type application/yang-data+xml
Reference: RFC 8040
Value: 3
Description: media type application/yang-data+cbor
Reference: RFC 9254
Zheng, et al. Expires 4 September 2025 [Page 21]
Internet-Draft UDP-Notif March 2025
The second requested registry is the following:
Registry Name: UDP-Notif option types
Maximum value: 255
These are the initial registrations for "UDP-Notif options types":
Value: 0
Description: Reserved
Reference: RFC-to-be
Value: TBD1 (suggested value: 1)
Description: Segmentation Option
Reference: RFC-to-be
Note to the RFC-Editor:
* Please replace TBD1 with the values allocated by IANA. There are
multiple instances in the document.
The third requested registry is the following:
Registry Name: UDP-Notif header version
Maximum value: 7
There is an older specification of this transport protocol defined in
[I-D.ietf-netconf-udp-pub-channel] that was deployed in some
networks. To enable differentiating both protocols, different
version numbers are used. The current specification replaces
[I-D.ietf-netconf-udp-pub-channel] and uses 1 as its version while
the header defined in [I-D.ietf-netconf-udp-pub-channel] uses 0.
These are the initial registrations for "UDP-Notif header version"
registry:
Value: 0
Description: UDP based Publication Channel for Streaming Telemetry
Reference: draft-ietf-netconf-udp-pub-channel-05
Value: 1
Description: UDP-based Transport for Configured Subscriptions.
Reference: RFC-to-be
8.2. URI
IANA is also requested to assign a new URI from the IETF XML Registry
[RFC3688]. The following URI is suggested:
Zheng, et al. Expires 4 September 2025 [Page 22]
Internet-Draft UDP-Notif March 2025
URI: urn:ietf:params:xml:ns:yang:ietf-udp-notif-transport
Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace.
8.3. YANG Module Name
This document also requests a new YANG module name in the YANG Module
Names registry [RFC8342] with the following suggestions:
name: ietf-udp-notif-transport
namespace: urn:ietf:params:xml:ns:yang:ietf-udp-notif-transport
maintained by IANA: N
prefix: unt
reference: RFC-to-be
9. Implementation Status
Note to the RFC-Editor: Please remove this section before publishing.
9.1. Open Source Publisher
INSA Lyon implemented this document for a YANG Push publisher in an
example implementation.
The open source code can be obtained here: [INSA-Lyon-Publisher].
9.2. Open Source Receiver Library
INSA Lyon implemented this document for a YANG Push receiver as a
library.
The open source code can be obtained here: [INSA-Lyon-Receiver].
9.3. Pmacct Data Collection
The open source YANG push receiver library has been integrated into
the Pmacct open source Network Telemetry data collection.
9.4. Huawei VRP
Huawei implemented this document for a YANG Push publisher in their
VRP platform.
9.5. 6WIND VSR
6WIND implemented this document for a YANG Push publisher in their
VSR platform.
Zheng, et al. Expires 4 September 2025 [Page 23]
Internet-Draft UDP-Notif March 2025
9.6. Cisco IOS XR
Cisco implemented this document for a YANG Push publisher in their
IOS XR platform.
10. Security Considerations
[RFC8085] states that "UDP applications that need to protect their
communications against eavesdropping, tampering, or message forgery
SHOULD employ end-to-end security services provided by other IETF
protocols". As mentioned above, the proposed mechanism is designed
to be used in controlled environments, as defined in [RFC8085] also
known as "limited domains", as defined in [RFC8799]. Thus, a
security layer is not necessary required. Nevertheless, an
encryption layer MUST be implemented for non secured networks. A
specification of UDP-notif using DTLS 1.3 as its encryption layer is
presented in Section 6.
The following text uses the template described in Section 3.7 of
[I-D.ietf-netmod-rfc8407bis].
The "ietf-udp-notif-transport" YANG module defines a data model that
is designed to be accessed via YANG-based management protocols, such
as NETCONF [RFC6241] and RESTCONF [RFC8040]. These protocols have to
use a secure transport layer (e.g., SSH [RFC6242], TLS [RFC8446], and
QUIC [RFC9000]) and have to use mutual authentication.
The Network 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 or vulnerable
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:
* The data nodes "remote-address", "remote-port", "local-address",
and "local-port" in the "ietf-udp-notif-transport" module specify
transport parameters for the recipient of UDP-Notif messages.
Unauthorized modification of these transport parameters could
redirect notifications to unintended recipients.
Zheng, et al. Expires 4 September 2025 [Page 24]
Internet-Draft UDP-Notif March 2025
This YANG module uses groupings from other YANG modules that define
nodes that may be considered sensitive or vulnerable in network
environments. Refer to the Security Considerations of
[I-D.ietf-netconf-udp-client-server] and [RFC9645] for information as
to which nodes may be considered sensitive or vulnerable in network
environments.
11. Acknowledgements
The authors of this documents would like to thank Lucas Aubard,
Alexander Clemm, Benoit Claise, Ebben Aries, Eric Voit, Huiyang Yang,
Kent Watsen, Mahesh Jethanandani, Marco Tollini, Hannes Tschofenig,
Michael Tuxen, Rob Wilton, Sean Turner, Stephane Frenot, Timothy
Carey, Tim Jenkins, Tom Petch, Yunan Gu, Joseph Touch, Andy Bierman,
Carsten Bormann, Mohamed Boucadair, Weiqiang Cheng, Giuseppe
Fioccola, Camilo Cardona, Qiufang Ma and James Cumming for their
constructive suggestions for improving this document.
12. References
12.1. Normative References
[BCP195] Best Current Practice 195,
<https://www.rfc-editor.org/info/bcp195>.
At the time of writing, this BCP comprises the following:
Moriarty, K. and S. Farrell, "Deprecating TLS 1.0 and TLS
1.1", BCP 195, RFC 8996, DOI 10.17487/RFC8996, March 2021,
<https://www.rfc-editor.org/info/rfc8996>.
Sheffer, Y., Saint-Andre, P., and T. Fossati,
"Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 9325, DOI 10.17487/RFC9325, November
2022, <https://www.rfc-editor.org/info/rfc9325>.
[BCP230] Best Current Practice 230,
<https://www.rfc-editor.org/info/bcp230>.
At the time of writing, this BCP comprises the following:
Bonica, R., Baker, F., Huston, G., Hinden, R., Troan, O.,
and F. Gont, "IP Fragmentation Considered Fragile",
BCP 230, RFC 8900, DOI 10.17487/RFC8900, September 2020,
<https://www.rfc-editor.org/info/rfc8900>.
[I-D.ietf-netconf-distributed-notif]
Zhou, T., Zheng, G., Voit, E., Graf, T., and P. Francois,
"Subscription to Distributed Notifications", Work in
Zheng, et al. Expires 4 September 2025 [Page 25]
Internet-Draft UDP-Notif March 2025
Progress, Internet-Draft, draft-ietf-netconf-distributed-
notif-13, 1 March 2025,
<https://datatracker.ietf.org/api/v1/doc/document/draft-
ietf-netconf-distributed-notif/>.
[I-D.ietf-netconf-https-notif]
Jethanandani, M. and K. Watsen, "An HTTPS-based Transport
for YANG Notifications", Work in Progress, Internet-Draft,
draft-ietf-netconf-https-notif-15, 1 February 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
https-notif-15>.
[I-D.ietf-netconf-udp-client-server]
Feng, A. H., Francois, P., and K. Watsen, "YANG Groupings
for UDP Clients and UDP Servers", Work in Progress,
Internet-Draft, draft-ietf-netconf-udp-client-server-06,
26 February 2025, <https://datatracker.ietf.org/doc/html/
draft-ietf-netconf-udp-client-server-06>.
[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>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<https://www.rfc-editor.org/info/rfc5234>.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
January 2012, <https://www.rfc-editor.org/info/rfc6347>.
[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/info/rfc6991>.
[RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage
Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085,
March 2017, <https://www.rfc-editor.org/info/rfc8085>.
Zheng, et al. Expires 4 September 2025 [Page 26]
Internet-Draft UDP-Notif March 2025
[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>.
[RFC8639] Voit, E., Clemm, A., Gonzalez Prieto, A., Nilsen-Nygaard,
E., and A. Tripathy, "Subscription to YANG Notifications",
RFC 8639, DOI 10.17487/RFC8639, September 2019,
<https://www.rfc-editor.org/info/rfc8639>.
[RFC8640] Voit, E., Clemm, A., Gonzalez Prieto, A., Nilsen-Nygaard,
E., and A. Tripathy, "Dynamic Subscription to YANG Events
and Datastores over NETCONF", RFC 8640,
DOI 10.17487/RFC8640, September 2019,
<https://www.rfc-editor.org/info/rfc8640>.
[RFC8650] Voit, E., Rahman, R., Nilsen-Nygaard, E., Clemm, A., and
A. Bierman, "Dynamic Subscription to YANG Events and
Datastores over RESTCONF", RFC 8650, DOI 10.17487/RFC8650,
November 2019, <https://www.rfc-editor.org/info/rfc8650>.
[RFC9147] Rescorla, E., Tschofenig, H., and N. Modadugu, "The
Datagram Transport Layer Security (DTLS) Protocol Version
1.3", RFC 9147, DOI 10.17487/RFC9147, April 2022,
<https://www.rfc-editor.org/info/rfc9147>.
[RFC9254] Veillette, M., Ed., Petrov, I., Ed., Pelov, A., Bormann,
C., and M. Richardson, "Encoding of Data Modeled with YANG
in the Concise Binary Object Representation (CBOR)",
RFC 9254, DOI 10.17487/RFC9254, July 2022,
<https://www.rfc-editor.org/info/rfc9254>.
Zheng, et al. Expires 4 September 2025 [Page 27]
Internet-Draft UDP-Notif March 2025
[RFC9645] Watsen, K., "YANG Groupings for TLS Clients and TLS
Servers", RFC 9645, DOI 10.17487/RFC9645, October 2024,
<https://www.rfc-editor.org/info/rfc9645>.
12.2. Informative References
[Errata-6211]
Watsen, Kent., "Errata 6211", 2024,
<https://www.rfc-editor.org/errata/eid6211>.
[I-D.ietf-netconf-udp-pub-channel]
Zheng, G., Zhou, T., and A. Clemm, "UDP based Publication
Channel for Streaming Telemetry", Work in Progress,
Internet-Draft, draft-ietf-netconf-udp-pub-channel-05, 11
March 2019, <https://datatracker.ietf.org/doc/html/draft-
ietf-netconf-udp-pub-channel-05>.
[I-D.ietf-netmod-rfc8407bis]
Bierman, A., Boucadair, M., and Q. Wu, "Guidelines for
Authors and Reviewers of Documents Containing YANG Data
Models", Work in Progress, Internet-Draft, draft-ietf-
netmod-rfc8407bis-22, 14 January 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
rfc8407bis-22>.
[INSA-Lyon-Publisher]
"INSA Lyon, YANG Push publisher example implementation",
<https://github.com/network-analytics/udp-notif-scapy>.
[INSA-Lyon-Receiver]
"INSA Lyon, YANG Push receiver library implementation",
<https://github.com/network-analytics/udp-notif-
c-collector>.
[Paolo-Lucente-Pmacct]
"Paolo Lucente, Pmacct open source Network Telemetry Data
Collection", <https://github.com/pmacct/pmacct>.
[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>.
Zheng, et al. Expires 4 September 2025 [Page 28]
Internet-Draft UDP-Notif March 2025
[RFC7011] Claise, B., Ed., Trammell, B., Ed., and P. Aitken,
"Specification of the IP Flow Information Export (IPFIX)
Protocol for the Exchange of Flow Information", STD 77,
RFC 7011, DOI 10.17487/RFC7011, September 2013,
<https://www.rfc-editor.org/info/rfc7011>.
[RFC7951] Lhotka, L., "JSON Encoding of Data Modeled with YANG",
RFC 7951, DOI 10.17487/RFC7951, August 2016,
<https://www.rfc-editor.org/info/rfc7951>.
[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>.
[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>.
[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>.
[RFC8799] Carpenter, B. and B. Liu, "Limited Domains and Internet
Protocols", RFC 8799, DOI 10.17487/RFC8799, July 2020,
<https://www.rfc-editor.org/info/rfc8799>.
[RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", RFC 9000,
DOI 10.17487/RFC9000, May 2021,
<https://www.rfc-editor.org/info/rfc9000>.
Appendix A. UDP-Notif Examples
This non-normative section shows two examples of how the the "ietf-
udp-notif-transport" YANG module can be used to configure a [RFC8639]
based publisher to send notifications to a receiver and an example of
a YANG Push notification message using UDP-Notif transport protocol.
A.1. Configuration for UDP-Notif transport with DTLS disabled
This example shows how UDP-Notif can be configured without DTLS
encryption.
Zheng, et al. Expires 4 September 2025 [Page 29]
Internet-Draft UDP-Notif March 2025
=============== NOTE: '\' line wrapping per RFC 8792 ================
<?xml version='1.0' encoding='UTF-8'?>
<config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<subscriptions xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-\
notifications">
<subscription>
<id>6666</id>
<stream-subtree-filter>some-subtree-filter</stream-subtree-fil\
ter>
<stream>some-stream</stream>
<transport xmlns:unt="urn:ietf:params:xml:ns:yang:ietf-udp-not\
if-transport">unt:udp-notif</transport>
<encoding>encode-json</encoding>
<receivers>
<receiver>
<name>subscription-specific-receiver-def</name>
<receiver-instance-ref xmlns="urn:ietf:params:xml:ns:yang:\
ietf-subscribed-notif-receivers">global-udp-notif-receiver-def</rece\
iver-instance-ref>
</receiver>
</receivers>
<periodic xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-push">
<period>6000</period>
</periodic>
</subscription>
<receiver-instances xmlns="urn:ietf:params:xml:ns:yang:ietf-subs\
cribed-notif-receivers">
<receiver-instance>
<name>global-udp-notif-receiver-def</name>
<udp-notif-receiver xmlns="urn:ietf:params:xml:ns:yang:ietf-\
udp-notif-transport">
<remote-address>192.0.5.1</remote-address>
<remote-port>12345</remote-port>
<enable-segmentation>false</enable-segmentation>
<max-segment-size/>
</udp-notif-receiver>
</receiver-instance>
</receiver-instances>
</subscriptions>
</config>
A.2. Configuration for UDP-Notif transport with DTLS enabled
This example shows how UDP-Notif can be configured with DTLS
encryption.
Zheng, et al. Expires 4 September 2025 [Page 30]
Internet-Draft UDP-Notif March 2025
=============== NOTE: '\' line wrapping per RFC 8792 ================
<?xml version='1.0' encoding='UTF-8'?>
<config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<subscriptions xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-\
notifications">
<subscription>
<id>6666</id>
<stream-subtree-filter>some-subtree-filter</stream-subtree-fil\
ter>
<stream>some-stream</stream>
<transport xmlns:unt="urn:ietf:params:xml:ns:yang:ietf-udp-not\
if-transport">unt:udp-notif</transport>
<encoding>encode-json</encoding>
<receivers>
<receiver>
<name>subscription-specific-receiver-def</name>
<receiver-instance-ref xmlns="urn:ietf:params:xml:ns:yang:\
ietf-subscribed-notif-receivers">global-udp-notif-receiver-dtls-def<\
/receiver-instance-ref>
</receiver>
</receivers>
<periodic xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-push">
<period>6000</period>
</periodic>
</subscription>
<receiver-instances xmlns="urn:ietf:params:xml:ns:yang:ietf-subs\
cribed-notif-receivers">
<receiver-instance>
<name>global-udp-notif-receiver-dtls-def</name>
<udp-notif-receiver xmlns="urn:ietf:params:xml:ns:yang:ietf-\
udp-notif-transport">
<remote-address>192.0.5.1</remote-address>
<remote-port>12345</remote-port>
<enable-segmentation>false</enable-segmentation>
<max-segment-size/>
<dtls>
<client-identity>
<tls13-epsk>
<local-definition>
<key-format>ct:octet-string-key-format</key-format>
<cleartext-key>BASE64VALUE=</cleartext-key>
</local-definition>
<external-identity>example_external_id</external-ide\
ntity>
<hash>sha-256</hash>
<context>example_context_string</context>
<target-protocol>8443</target-protocol>
Zheng, et al. Expires 4 September 2025 [Page 31]
Internet-Draft UDP-Notif March 2025
<target-kdf>12345</target-kdf>
</tls13-epsk>
</client-identity>
<server-authentication>
<ca-certs>
<local-definition>
<certificate>
<name>Server Cert Issuer #1</name>
<cert-data>BASE64VALUE=</cert-data>
</certificate>
<certificate>
<name>Server Cert Issuer #2</name>
<cert-data>BASE64VALUE=</cert-data>
</certificate>
</local-definition>
</ca-certs>
<ee-certs>
<local-definition>
<certificate>
<name>My Application #1</name>
<cert-data>BASE64VALUE=</cert-data>
</certificate>
<certificate>
<name>My Application #2</name>
<cert-data>BASE64VALUE=</cert-data>
</certificate>
</local-definition>
</ee-certs>
<raw-public-keys>
<local-definition>
<public-key>
<name>corp-fw1</name>
<public-key-format>ct:subject-public-key-info-fo\
rmat</public-key-format>
<public-key>BASE64VALUE=</public-key>
</public-key>
<public-key>
<name>corp-fw2</name>
<public-key-format>ct:subject-public-key-info-fo\
rmat</public-key-format>
<public-key>BASE64VALUE=</public-key>
</public-key>
</local-definition>
</raw-public-keys>
<tls13-epsks/>
</server-authentication>
<keepalives>
<test-peer-aliveness>
Zheng, et al. Expires 4 September 2025 [Page 32]
Internet-Draft UDP-Notif March 2025
<max-wait>30</max-wait>
<max-attempts>3</max-attempts>
</test-peer-aliveness>
</keepalives>
</dtls>
</udp-notif-receiver>
</receiver-instance>
</receiver-instances>
</subscriptions>
</config>
A.3. YANG Push message with UDP-Notif transport protocol
This example shows how UDP-Notif is used as a transport protocol to
send a "push-update" notification [RFC8641] encoded in JSON
[RFC7951].
Assuming the publisher needs to send the JSON payload showed in
Figure 5, the UDP-Notif transport is encoded following the Figure 6.
The UDP-Notif message is then encapsulated in a UDP datagram.
{
"ietf-notification:notification": {
"eventTime": "2024-02-10T08:00:11.22Z",
"ietf-yang-push:push-update": {
"id": 1011,
"datastore-contents": {
"ietf-interfaces:interfaces": [
{
"interface": {
"name": "eth0",
"oper-status": "up"
}
}
]
}
}
}
}
Figure 5: JSON Payload to be sent
Zheng, et al. Expires 4 September 2025 [Page 33]
Internet-Draft UDP-Notif March 2025
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-----+-+-------+---------------+-------------------------------+
|Ver=1|0| MT=1 | Header_Len=12 | Message_Length=230 |
+-----+-+-------+---------------+-------------------------------+
| Message Publisher ID=2 |
+---------------------------------------------------------------+
| Message ID=1563 |
+---------------------------------------------------------------+
| YANG Push JSON payload (Len=218 octets) |
|{"ietf-notification:notification":{"eventTime":"2024-02-10T08:0|
|0:11.22Z","ietf-yang-push:push-update":{"id":1011,"datastore-co|
|ntents":{"ietf-interfaces:interfaces":[{"interface":{"name":"et|
|h0","oper-status":"up"}}]}}}} |
+---------------------------------------------------------------+
Figure 6: UDP-Notif transport message
Authors' Addresses
Guangying Zheng
Huawei
101 Yu-Hua-Tai Software Road
Nanjing
Jiangsu,
China
Email: zhengguangying@huawei.com
Tianran Zhou
Huawei
156 Beiqing Rd., Haidian District
Beijing
China
Email: zhoutianran@huawei.com
Thomas Graf
Swisscom
Binzring 17
CH- Zuerich 8045
Switzerland
Email: thomas.graf@swisscom.com
Zheng, et al. Expires 4 September 2025 [Page 34]
Internet-Draft UDP-Notif March 2025
Pierre Francois
INSA-Lyon
Lyon
France
Email: pierre.francois@insa-lyon.fr
Alex Huang Feng
INSA-Lyon
Lyon
France
Email: alex.huang-feng@insa-lyon.fr
Paolo Lucente
NTT
Siriusdreef 70-72
Hoofddorp, WT 2132
Netherlands
Email: paolo@ntt.net
Zheng, et al. Expires 4 September 2025 [Page 35]