| Internet-Draft | UDP-Notif | October 2024 |
| Zheng, et al. | Expires 20 April 2025 | [Page] |
This document describes a UDP-based protocol for YANG notifications to collect data from network nodes. A shim header is proposed to facilitate the data streaming directly from the publishing process on network processor of line cards to receivers. The objective is to provide a lightweight approach to enable higher frequency and less performance impact on publisher and receiver processes compared to already established notification mechanisms.¶
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 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 20 April 2025.¶
Copyright (c) 2024 IETF Trust and the persons identified as the document authors. All rights reserved.¶
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect 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.¶
The mechanism to support a subscription of a continuous and customized stream of updates from a YANG datastore [RFC8342] is defined in [RFC8639] and [RFC8641] and is abbreviated as Sub-Notif. Requirements for Subscription to YANG Datastores are defined in [RFC7923].¶
The mechanism separates 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] have been defined so far 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 velocity from network nodes that feature a distributed architecture. The currently available transports are based on TCP and lack the efficiency needed to continuously send notifications at high velocity.¶
This document specifies a transport option for Sub-Notif 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.¶
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 proposed UDP-based transport allows for such a distributed data publishing approach.¶
Firstly, a UDP approach reduces the burden of maintaining a large amount of active TCP connections at the receiver, notably in cases where it collects data from network processors on line cards from a large amount of network nodes.¶
Secondly, as no connection state needs to be maintained, UDP encapsulation can be easily implemented by the hardware of the publication streamer, 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.¶
This document describes the notification mechanism. It is intended to be used in conjunction with [RFC8639], extended by [I-D.ietf-netconf-distributed-notif].¶
Section 2 describes the control of the proposed transport mechanism. 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 proposed mechanism. Section 6 describes a mechanism to secure the protocol in open networks.¶
This section describes how the proposed mechanism can be controlled using subscription channels based on NETCONF or RESTCONF.¶
As specified in Sub-Notif, configured subscriptions contain the location information of all the receivers, including the IP address and the port number, so that the publisher can actively send UDP-Notif messages to the corresponding receivers.¶
Note that receivers MAY NOT be already up and running when the configuration of the subscription takes effect on the monitored network node. The first message MUST be a separate subscription-started notification to indicate the Receiver that the stream has started flowing. Then, the notifications can be sent immediately without delay. All the subscription state notifications, as defined in Section 2.7 of [RFC8639], MUST be encapsulated in separate notification messages.¶
Note also that the receiver nodes can be different from the nodes managing the subscription. Therefore, publishers MAY NOT be aware of the capabilities supported by the receivers.¶
In this section, we specify 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.¶
As specified in Sub-Notif, the YANG data is encapsulated in a NETCONF/RESTCONF notification message, which is then encapsulated and carried using a transport protocols such as TLS or HTTP2. This document defines a UDP based transport. Figure 1 illustrates the structure of an UDP-Notif message.¶
The Message Header contains information that facilitate the message transmission before deserializing the notification message.¶
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 [RFC8639] and a YANG model has been proposed in [I-D.ahuang-netconf-notif-yang]. [I-D.ietf-netconf-notification-messages] proposes a structure to send bundled notifications in a single message.¶
+-------+ +--------------+ +--------------+ | UDP | | Message | | Notification | | | | Header | | Message | +-------+ +--------------+ +--------------+
The UDP-Notif Message Header contains information that facilitate the message transmission 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 ~ +---------------------------------------------------------------+
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". The current header version number is 1.¶
S represents the space of media type specified in the MT field. When S is unset, MT represents the standard media types as defined in this document. When S is set, MT represents a private space to be freely used for non standard encodings. When S is set, the Private Encoding Option defined in Section 4.2 SHOULD be present in the UDP-Notif message header.¶
MT is a 4 bit identifier to indicate the media type used for the Notification Message. 16 types of encoding can be expressed. When the S bit is unset, the following values apply:¶
Header Len is the length of the message header in octets, including both the fixed header and the options.¶
Message Length is 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, segmented UDP-Notif message, 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 unique to the publisher node and identifies the publishing process of the node to allow the disambiguation of an information source. Message unicity is obtained from the conjunction of the Message Publisher ID and the Message ID field described below. If Message Publisher ID unicity is not preserved through the collection domain, the source IP address of the UDP datagram SHOULD 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 generated continuously by the publisher of UDP-Notif messages. A publisher MUST use different Message ID values 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 Section 4.1. The Message ID values SHOULD be incremented by one for each successive message originated with the same Message Publisher ID, so that message loss can be detected. When the last value (2^32-1) of Message ID has been generated, the Message ID wraps around and restarts at 0. Different subscribers MAY share the same Message ID sequence.¶
Options is 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 (i.e., Message ID). The details of the options are described in Section 4.¶
All the binary fields MUST be encoded in network byte order (big endian).¶
UDP-Notif message data can be encoded in CBOR, XML or JSON format. It is conceivable that 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.¶
Private encodings can be using the S bit of the header. When the S bit is set, the value of the MT field is left to be defined and agreed upon by the users of the private encoding. An option is defined in Section 4.2 for more verbose encoding descriptions than what can be described with the MT field.¶
Implementation MAY support multiple encoding methods per subscription. When bundled notifications are supported between the publisher and the receiver, only subscribed notifications with the same encoding can be bundled in a given message.¶
All the options are defined with the following format, illustrated 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 +---------------+---------------+--------------------------------
Type: 1 octet describing the option type;¶
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 TLV Value.¶
When more than one option is used in the UDP-Notif header, options MUST be ordered by the Type value. Messages with unordered options MAY be dropped by the Receiver.¶
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.¶
Consequently, implementations of the mechanism SHOULD provide a configurable max-segment-size option to control the maximum size of a UDP-Notif segment.¶
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| +---------------+---------------+-----------------------------+-+
The Segmentation Option is to be included when the message content is segmented into multiple segments. Different segments of one message share the same Message ID. An illustration is provided in Figure 4. The fields of this TLV are:¶
Type: Generic option field which indicates a Segmentation Option. The Type value is to be assigned TBD1.¶
Length: Generic option field which indicates the length of this option in octets. It is a fixed value of 4 octets for the Segmentation Option.¶
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: is a flag to indicate 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.¶
An implementation of this specification SHOULD NOT rely on IP fragmentation by default to carry large messages. An implementation of this specification SHOULD either restrict the size of individual messages carried over this protocol, or support the segmentation option. The implementor or user SHOULD configure the max-segment-size so that the size of a UDP-Notif segment and the size of the IP layer together does not exceed the MTU of the egress interface.¶
When a message has multiple options and is segmented using the described mechanism, all the options MUST be present on the first segment ordered by the options Type. The rest of segmented messages MAY include all the options ordered by options type.¶
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. If the receiver collects a segment more than once, the implementation SHOULD drop the duplicate segment.¶
The space to describe private encodings in the MT field of the UDP-Notif header being limited, an option is provided to describe custom encodings. The fields of this option are as follows.¶
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 enc. descr. +---------------+---------------+--------------------------------
Type: Generic option field which indicates a Private Encoding Option. The Type value is to be assigned TBD2.¶
Length: Generic option field which indicates the length of this option in octets. It is a variable value.¶
Enc. Descr: The description of the private encoding used for this message. The values to be used for such private encodings is left to be defined by the users of private encodings.¶
This option SHOULD only be used when the S bit of the header is set, as providing a private encoding description for standard encodings is meaningless.¶
In this section, we provide an applicability statement for the proposed mechanism, following the recommendations of [RFC8085].¶
The proposed 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 of the proposed mechanism SHOULD thus follow the recommendations in place for such specific applications. In the following, we discuss recommendations on congestion control, message size guidelines, reliability considerations and security considerations.¶
The main use case of the proposed 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].¶
The proposed application falls into the category of applications performing transfer of large amounts of data. It is expected that the operator using the solution configures QoS on its related flows. As per [RFC8085], such applications MAY choose not to implement any form of congestion control, but follow the following principles.¶
It is NOT RECOMMENDED to use the proposed 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 of the proposal SHOULD NOT push unlimited amounts 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.¶
[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. Implementation of the current specification SHOULD allow for the configuration of the MTU.¶
It is RECOMMENDED that the size of a Notification Message is small and segmentation does not result in segmenting the message into too much segments to avoid dropping the entire message when there is a lost segment. When a Notification Message is large, it is RECOMMENDED to use a reliable transport such as HTTPS-notif [I-D.ietf-netconf-https-notif].¶
A receiver implementation for this protocol SHOULD deal with potential loss of packets carrying a part of segmented payload, by discarding packets that were received, but cannot be re-assembled as a complete message within a given amount of time. This time SHOULD be configurable.¶
In unsecured networks, UDP-Notif messages MUST be secured or encrypted. In this section, a mechanism using DTLS 1.3 to secure UDP-Notif protocol is presented. The following sections defines the requirements for the implementation of the secured layer of DTLS for UDP-Notif. No DTLS 1.3 extensions are defined in this document.¶
The DTLS 1.3 protocol [RFC9147] is designed to meet the requirements of applications that need to secure datagram transport. Implementations using DTLS to secure UDP-Notif messages MUST use DTLS 1.3 protocol as defined in [RFC9147].¶
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 specified 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, but MAY be configurable to send messages to a different port. The Publisher MAY use any source UDP port for transmitting messages.¶
This section describes the lifecycle of UDP-Notif messages when they are excrypted using DTLS.¶
The Publisher initiates a DTLS connection by sending a DTLS ClientHello to the Receiver. Implementations MAY support the denial of service countermeasures defined by DTLS 1.3 if a given deployment can ensure that DoS attacks are not a concern. When these countermeasures are used, the Receiver responds with a DTLS HelloRetryRequest containing a stateless cookie. The Publisher sends 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. Early data mechanism (also known as 0-RTT data) as defined in [RFC9147] MUST NOT be used.¶
Implementations of this security layer MUST support DTLS 1.3 [RFC9147] and MUST support the mandatory to implement cipher suite TLS_AES_128_GCM_SHA256 and SHOULD implement TLS_AES_256_GCM_SHA384 and TLS_CHACHA20_POLY1305_SHA256 cipher suites, as specified in TLS 1.3 [RFC8446]. If additional cipher suites are supported, then implementations MUST NOT negotiate a cipher suite that employs NULL integrity or authentication algorithms.¶
Where confidentiality protection with DTLS is required, implementations must negotiate a cipher suite that employs a non-NULL encryption algorithm.¶
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.¶
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.¶
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.¶
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 YANG model proposed in this document. When both are configured, the UDP-Notif message MUST use the address configured in the "local-address" leaf defined in the YANG proposed in this document.¶
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-supported}?
+--rw local-port? inet:port-number
| {local-binding-supported}?
+--rw dtls! {dtls13}?
| +--rw client-identity!
| | +--rw (auth-type)
| | +--:(certificate) {client-ident-x509-cert}?
| | | ...
| | +--:(raw-public-key)
| | | {client-ident-raw-public-key}?
| | | ...
| | +--:(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 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 keepalives {tls-client-keepalives}?
| +--rw peer-allowed-to-send? empty
| +--rw test-peer-aliveness!
| +--rw max-wait? uint16
| +--rw max-attempts? uint8
+--rw enable-segmentation? boolean {segmentation}?
+--rw max-segment-size? uint32 {segmentation}?
¶
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-grouping" defines the necessary parameters to configure the transport defined in this document using the generic "udp-client-grouping" grouping from the "ietf-udp-client" module [I-D.ahuang-netconf-udp-client-server] and the "tls-client-grouping" defined in the "ietf-tls-client" module [I-D.ietf-netconf-tls-client-server].¶
<CODE BEGINS> file "ietf-udp-notif-transport@2024-10-17.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 TTTT: YANG Groupings for TLS Clients and TLS Servers";
}
import ietf-tls-common {
prefix tlscmn;
reference
"RFC TTTT: 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>
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.
Copyright (c) 2024 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; see the RFC
itself for full legal notices.";
revision 2024-10-17 {
description
"Initial revision";
reference
"RFC XXXX: UDP-based Transport for Configured Subscriptions";
}
/*
* FEATURES
*/
feature encode-cbor {
description
"This feature indicates that CBOR encoding of notification
messages is supported.";
}
feature dtls13 {
description
"This feature indicates that DTLS 1.3 encryption of UDP
packets is supported.";
}
feature segmentation {
description
"This feature indicates segmentation of notification messages
is supported.";
}
/*
* 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 as described in RFC 9254.";
reference
"RFC 9254: CBOR Encoding of Data Modeled with YANG";
}
grouping udp-notif-receiver-grouping {
description
"Provides a reusable description of a UDP-Notif target
receiver.";
uses udpc:udp-client-grouping {
refine remote-port {
mandatory true;
}
}
container dtls {
if-feature dtls13;
presence dtls;
uses tlsc:tls-client-grouping {
// Using tls-client-grouping without TLS1.2 parameters
// allowing only DTLS 1.3
refine "client-identity/auth-type/tls12-psk" {
// create the logical impossibility of enabling TLS1.2
if-feature "not tlsc:client-ident-tls12-psk";
}
refine "server-authentication/tls12-psks" {
// create the logical impossibility of enabling TLS1.2
if-feature "not tlsc:server-auth-tls12-psk";
}
refine "hello-params/tls-versions/min" {
must "not(derived-from-or-self(current(), "
+ "'tlscmn:tls12'))" {
error-message
"TLS 1.2 is not supported as min TLS version";
}
}
refine "hello-params/tls-versions/max" {
must "not(derived-from-or-self(current(), "
+ "'tlscmn:tls12'))" {
error-message
"TLS 1.2 is not supported as max TLS version";
}
}
}
description
"Container for configuring DTLS 1.3 parameters.";
}
leaf enable-segmentation {
if-feature segmentation;
type boolean;
default true;
description
"The switch for the segmentation feature. When disabled, the
publisher will not allow fragment for a very large data";
}
leaf max-segment-size {
when "../enable-segmentation = 'true'";
if-feature segmentation;
type uint32;
description
"UDP-Notif provides a configurable max-segment-size to
control the size of each segment (UDP-Notif header, with
options, included).";
}
}
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-grouping;
}
}
description
"Augment the transport-type choice to include the 'udp-notif'
transport.";
}
}
<CODE ENDS>¶
This document describes several new registries, the URIs from IETF XML Registry and the registration of a new YANG module name.¶
This document is creating 3 registries called "UDP-Notif media types", "UDP-Notif option types", and "UDP-Notif header version" under the new group "UDP-Notif protocol". The registration procedure is made using the Standards Action process defined in [RFC8126].¶
The first requested registry is the following:¶
Registry Name: UDP-Notif media types Registry Category: UDP-Notif protocol. Registration Procedure: Standard Action as defined in RFC8126 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: <xref target="RFC8040"/>¶
Value: 2 Description: media type application/yang-data+xml Reference: <xref target="RFC8040"/>¶
Value: 3 Description: media type application/yang-data+cbor Reference: <xref target="RFC9254"/>¶
The second requested registry is the following:¶
Registry Name: UDP-Notif option types Registry Category: UDP-Notif protocol. Registration Procedure: Standard Action as defined in RFC8126 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¶
Value: TBD2 (suggested value: 2) Description: Private Encoding Option Reference: RFC-to-be¶
The third requested registry is the following:¶
Registry Name: UDP-Notif header version Registry Category: UDP-Notif protocol. Registration Procedure: Standard Action as defined in RFC8126 Maximum value: 7¶
These are the initial registrations for "UDP-Notif header version":¶
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¶
IANA is also requested to assign a two new URI from the IETF XML Registry [RFC3688]. The following URI is suggested:¶
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.¶
This document also requests a new YANG module names 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 prefix: unt reference: RFC-to-be¶
Note to the RFC-Editor: Please remove this section before publishing.¶
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].¶
INSA Lyon implemented this document for a YANG Push receiver as a library.¶
The open source code can be obtained here: [INSA-Lyon-Receiver].¶
The open source YANG push receiver library has been integrated into the Pmacct open source Network Telemetry data collection.¶
Huawei implemented this document for a YANG Push publisher in their VRP platform.¶
[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, a DTLS layer MUST be implemented in unsecured networks. A specification of udp-notif using DTLS is presented in Section 6.¶
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 and Yunan Gu for their constructive suggestions for improving this document.¶
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.¶
This example shows how UDP-Notif can be configured without DTLS encryption.¶
=============== 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>
¶
This example shows how UDP-Notif can be configured with DTLS encryption.¶
=============== 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>
<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>
<max-wait>30</max-wait>
<max-attempts>3</max-attempts>
</test-peer-aliveness>
</keepalives>
</dtls>
</udp-notif-receiver>
</receiver-instance>
</receiver-instances>
</subscriptions>
</config>
¶
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 6, the UDP-Notif transport is encoded following the Figure 7. The UDP-Notif message is then encapsulated in a UDP frame.¶
{
"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"
}
}
]
}
}
}
}
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"}}]}}}} |
+---------------------------------------------------------------+