Internet-Draft YANG Notifications Sequencing March 2023
Graf, et al. Expires 6 September 2023 [Page]
Network Working Group
Intended Status:
Standards Track
T. Graf
J. Quilbeuf
A. Huang Feng

Support of Hostname and Sequencing in YANG Notifications


This document specifies a new YANG module that augment the NETCONF Event Notification header to support hostname and sequence numbers to identify from which network node and at which time the message was published. This allows to recognize loss, delay and reordering between the publisher and the downstream system storing the message.

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

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 6 September 2023.

1. Introduction

[RFC5277] describes the NETCONF event notification header using a XML Schema. In the metadata of the event notification header, only the eventTime is present indicating at which time the notification message was published. For other encodings, the same schema is implemented using a YANG module in [I-D.ahuang-netconf-notif-yang]. Furthermore, in Section 3.7 of [RFC8641], the subscription ID is added to the "push-update" and "push-change-update" notification messages allowing to recognize to which xpath or sub-tree the node was subscribed to.

When the NETCONF event notification message is forwarded from the receiver to another system, such as a messaging system or a time series database where the message is stored, the transport context is lost since it is not part of the NETCONF event notification message metadata. Therefore, the downstream system is unable to associate the message to the publishing process (the exporting router), nor able to detect message loss or reordering.

Today, network operators workaround this impediment by preserving the transport source IP address and sequence numbers of the publishing process. However, this implies that this information needs to be encoded in the NETCONF event notification message which impacts the semantic readability of the message in the downstream system.

On top of that, the transport source IP address might not represent the management IP address by which the YANG push server should be known. In other terms, the source-host [RFC6470], which is the "Address of the remote host for the session" might not be the management IP address.

By extending the NETCONF Event Notification header with sysName, which could be an IP address or a DNS domain name, and a sequence number as described in [RFC9187], the downstream system is not only able to identify from which network node, subscription, and time the message was published but also, the order of the published messages.

To correlate network data among different Network Telemetry planes as described in Section 3.1 of [RFC9232] or among different YANG push subscription types defined in Section 3.1 of [RFC8641], sysName describes from which network node the state change was observed or from when to when the data was accounted. This is essential for understanding the timely relationship among these different planes and YANG push subscription types.

2. Extend the NETCONF Event Notification Header

Besides the eventTime described in Section 2.2.1 of [RFC5277] the following metadata objects are part of a "push-update" and "push-change-update" notification message.

Describes the hostname as specified in [RFC1213] from where the message was published from.
Generates a unique sequence number as described in [RFC9187] for each published message.

Figure 1 provides an example of a "push-change-update" message with the sysName and sequenceNumber. This "push-change-update" message is encoded XML [W3C.REC-xml-20081126] over the Network Configuration Protocol (NETCONF) as per [RFC8640].

<notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
 <sysName xmlns="urn:ietf:params:xml:ns:yang:ietf-notification-sequencing">
 <sequenceNumber xmlns="urn:ietf:params:xml:ns:yang:ietf-notification-sequencing">
 <push-update xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-push">
      <interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces">
Figure 1: XML Push Example for a subscription-modified notification message

3. YANG Module for Event Notifications

3.1. YANG Tree Diagram

This ietf-notification-sequencing YANG module augments the ietf-notification YANG module specified in [I-D.ahuang-netconf-notif-yang] adding the sysName and the sequenceNumber leaves as described in Section 2 of this document.

module: ietf-notification-sequencing

  augment-structure /inotif:notification:
    +-- sysName           inet:host
    +-- sequenceNumber    yang:counter32

3.2. Full Tree View

The following is the YANG tree diagram [RFC8340] for the ietf-notification-sequencing augmentation within the ietf-notification.

module: ietf-notification

  structure notification:
    +-- eventTime                   yang:date-and-time
    +-- inotifseq:sysName           inet:host
    +-- inotifseq:sequenceNumber    yang:counter32

3.3. YANG Module

<CODE BEGINS> file "ietf-notification-sequencing@2023-03-01.yang"

module ietf-notification-sequencing {
  yang-version 1.1;
  prefix inotifseq;
  import ietf-inet-types {
    prefix inet;
      "RFC 6991: Common YANG Data Types";
  import ietf-yang-types {
    prefix yang;
      "RFC 6991: Common YANG Data Types";
  import ietf-notification {
    prefix inotif;
      "draft-ahuang-netconf-notif-yang: NETCONF Event Notification YANG";
  import ietf-yang-structure-ext {
    prefix sx;
      "RFC 8791: YANG Data Structure Extensions";

  organization "IETF NETCONF (Network Configuration) Working Group";
    "WG Web:   <http:/>
     WG List:  <>

     Authors:  Thomas Graf
               Jean Quilbeuf
               Alex Huang Feng

    "Defines NETCONF Event Notification structure with the sysName and
    the sequenceNumber.

    Copyright (c) 2023 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

    This version of this YANG module is part of RFC XXXX; see the RFC
    itself for full legal notices.";

  revision 2023-03-01 {
      "First revision";
      "RFC XXXX: YANG Notifications Sequencing";

  sx:augment-structure "/inotif:notification" {
    leaf sysName {
      type inet:host;
      mandatory true;
        "IP address or a DNS domain name from the server from which
        the message was published.";
    leaf sequenceNumber {
      type yang:counter32;
      mandatory true;
        "Unique sequence number as described in [RFC3339] for each
        published message.";


4. Security Considerations

The security considerations for the NETCONF Event notifications are described in [RFC5277]. This documents adds no additional security considerations.

5. IANA Considerations

5.1. IETF XML Registry

This document registers the following URIs in the "IETF XML Registry" [RFC3688]:

  URI: urn:ietf:params:xml:ns:yang:ietf-notification-sequencing
  Registrant Contact: The IESG.
  XML: N/A; the requested URI is an XML namespace.

5.2. YANG Module Name

This document registers the following YANG modules in the "YANG Module Names" registry [RFC6020]:

  name: ietf-notification-sequencing
  namespace: urn:ietf:params:xml:ns:yang:ietf-notification-sequencing
  prefix: inotifseq
  reference: RFC XXXX

6. Operational Considerations

6.1. SysName Correlation

In order to allow data corelationamong BGP Monitoring Protocol (BMP) [RFC7854] and YANG push, the same hostname value should be used as described in section 4.4 of [RFC7854] for the information TLV in the init BMP message type.

7. Acknowledgements

The authors would like to thank Rob Wilton, Nick Corran, Pierre Francois, Benoit Claise, Ahmed Elhassany and Ignacio Dominguez Martinez-Casanueva for their review and valuable comments.

8. References

8.1. Normative References

Feng, A. H., Francois, P., Graf, T., and B. Claise, "YANG model for NETCONF Event Notifications", Work in Progress, Internet-Draft, draft-ahuang-netconf-notif-yang-01, , <>.
McCloghrie, K. and M. Rose, "Management Information Base for Network Management of TCP/IP-based internets: MIB-II", STD 17, RFC 1213, DOI 10.17487/RFC1213, , <>.
Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, , <>.
Chisholm, S. and H. Trevino, "NETCONF Event Notifications", RFC 5277, DOI 10.17487/RFC5277, , <>.
Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, , <>.
Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, , <>.
Touch, J., "Sequence Number Extension for Windowed Protocols", RFC 9187, DOI 10.17487/RFC9187, , <>.
Bray, T., Paoli, J., Sperberg-McQueen, M., Maler, E., and F. Yergeau, "Extensible Markup Language (XML) 1.0 (Fifth Edition)", World Wide Web Consortium Recommendation REC-xml-20081126, , <>.

8.2. Informative References

Bierman, A., "Network Configuration Protocol (NETCONF) Base Notifications", RFC 6470, DOI 10.17487/RFC6470, , <>.
Scudder, J., Ed., Fernando, R., and S. Stuart, "BGP Monitoring Protocol (BMP)", RFC 7854, DOI 10.17487/RFC7854, , <>.
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, , <>.
Clemm, A. and E. Voit, "Subscription to YANG Notifications for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641, , <>.
Song, H., Qin, F., Martinez-Julia, P., Ciavaglia, L., and A. Wang, "Network Telemetry Framework", RFC 9232, DOI 10.17487/RFC9232, , <>.

Authors' Addresses

Thomas Graf
Binzring 17
CH-8045 Zurich
Jean Quilbeuf
Alex Huang Feng