Internet-Draft Interface Reference Topology YANG Model October 2023
Ahlberg, et al. Expires 20 April 2024 [Page]
CCAMP Working Group
Intended Status:
Standards Track
J. Ahlberg
Ericsson AB
S. Mansfield
Ericsson Inc
M. Ye
Huawei Technologies
I. Busi
Huawei Technologies
X. Li
NEC Laboratories Europe
D. Spreafico
Nokia - IT

A YANG Data Model for Interface Reference Topology


This document defines a YANG data model to provide a reference from a termination point in a topology model to interface management information.

About This Document

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1. Introduction

This document defines a YANG data model to provide a reference from a termination point in a topology model to interface management information. It introduces a way to reference the information in a YANG data model for interface management [RFC8343] that could be useful for all types of termination points. The model augments "YANG Data Model for Traffic Engineering (TE) Topologies" defined in [RFC8795], which is based on "A YANG Data Model for Network Topologies" defined in [RFC8345].

The interface reference model is expected to be used between a Provisioning Network Controller (PNC) and a Multi Domain Service Coordinator(MDSC) [RFC8453]. Different use cases require access to different attributes and in order not to restrict what use cases can be supported, all attributes supported by the interface management model is with this model made accessible from the topology model.

1.1. Terminology and Definitions

The following acronyms are used in this document:

PNC Provisioning Network Controller

MDSC Multi Domain Service Coordinator

1.2. Tree Structure

A simplified graphical representation of the data model is used in chapter 3.1 of this document. The meaning of the symbols in these diagrams is defined in [RFC8340].

2. Requirements Language

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.

3. Termination Point to Interface Reference YANG Data Model

3.1. YANG Tree

module: ietf-tp-interface-reference-topology

augment /nw:networks/nw:network/nw:node/nt:termination-point/tet:te:
  +--rw tp-to-interface-path?   -> /if:interfaces/interface/name

3.2. Termination Point to Interface Reference YANG Data Module

<CODE BEGINS> file "ietf-tp-interface-reference-topology.yang"

module ietf-tp-interface-reference-topology {
  yang-version "1.1";

   prefix "ifref";

   import ietf-network {
     prefix "nw";
     reference "RFC 8345: A YANG Data Model for Network Topologies";

   import ietf-network-topology {
     prefix "nt";
     reference "RFC 8345: A YANG Data Model for Network Topologies";

   import ietf-te-topology {
     prefix "tet";
     reference "RFC 8795: YANG Data Model for Traffic Engineering
                (TE) Topologies";

   import ietf-interfaces {
     prefix if;
       "RFC 8343";

     "Internet Engineering Task Force (IETF) CCAMP WG";
     "WG List: <>

      Editor: Jonas Ahlberg
      Editor: Scott Mansfield
      Editor: Min Ye
      Editor: Italo Busi
      Editor: Xi Li
      Editor: Daniela Spreafico


     "This is a module for defining a reference from a termination
      point in a te topology to a list element in interfaces
      as defined in RFC 8343.

     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 2023-02-15 {
     "First rough draft.";
     reference "";

    * Groupings
   grouping tp-to-interface-ref {

       "Grouping used for reference between a termination point and
        an interface.";
     leaf tp-to-interface-path {
       type leafref {
         path '/if:interfaces/if:interface/if:name';
         "Leafref expression referencing a list element, identified
          by its name, in interfaces as defined in RFC 8343.";

    * Data nodes


   augment "/nw:networks/nw:network/nw:node/nt:termination-point/"
           + "tet:te" {
       "Augmentation to add possibility to reference an element
        in the list of interfaces as defined by RFC 8343.";
     uses tp-to-interface-ref;


4. Security Considerations

The YANG modules specified in this document define schemas for data that is designed to be accessed via network management protocols such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS [RFC8446].

The NETCONF access control model [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.

The YANG module specified in this document imports and augments the ietf-network and ietf-network-topology models defined in [RFC8345]. The security considerations from [RFC8345] are applicable to the module in this document.

There is a data node defined in this YANG module that is writable/creatable/deletable (i.e., config true, which is the default). This data node may be considered sensitive or vulnerable in some network environments. Write operations (e.g., edit-config) to this data node without proper protection can have a negative effect on network operations. This is the subtrees and data node and its sensitivity/vulnerability:

  • tp-to-interface-path: A malicious client could set an arbitrary path that could allow a client to retrieve incorrect information. Troubleshooting would be difficult because the bad path would not be detectable until the client tries to use the leaf to identify to radio link terminal.

5. IANA Considerations

IANA is asked to assign a new URI from the "IETF XML Registry" [RFC3688] as follows:

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

It is proposed that IANA should record YANG module names in the "YANG Module Names" registry [RFC6020] as follows:

    Name: ietf-tp-interface-reference-topology
    Maintained by IANA?: N
    Prefix: ifref
    Reference: RFC XXXX

6. References

6.1. Normative References

Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <>.
Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, , <>.
Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, , <>.
Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, , <>.
Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, , <>.
Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, , <>.
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <>.
Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, , <>.
Bjorklund, M., "A YANG Data Model for Interface Management", RFC 8343, DOI 10.17487/RFC8343, , <>.
Clemm, A., Medved, J., Varga, R., Bahadur, N., Ananthakrishnan, H., and X. Liu, "A YANG Data Model for Network Topologies", RFC 8345, DOI 10.17487/RFC8345, , <>.
Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, , <>.
Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and O. Gonzalez de Dios, "YANG Data Model for Traffic Engineering (TE) Topologies", RFC 8795, DOI 10.17487/RFC8795, , <>.

6.2. Informative References

Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, , <>.
Ceccarelli, D., Ed. and Y. Lee, Ed., "Framework for Abstraction and Control of TE Networks (ACTN)", RFC 8453, DOI 10.17487/RFC8453, , <>.

Appendix A. Examples of the Interface Reference Topology Model

This appendix provides some examples and illustrations of how the Interface Reference Topology Model can be used. There is one extended tree to illustrate the Model and a JSON based instantiation of the Interface Reference Model for a small network example.

A.1. A tree for a complete Interface Reference Topology Model

The tree below shows the leafs for extending a Network Topology Model defined in [RFC8345], Traffic Engineering (TE) Topologies model defined in [RFC8795] with a possibility to reference interface management information.

module: ietf-network
  +--rw networks
     +--rw network* [network-id]
        +--rw network-id                network-id
        +--rw node* [node-id]
           +--rw node-id               node-id
           +--rw nt:termination-point* [tp-id]
              +--rw nt:tp-id           tp-id
              +--rw tet:te!
                 +--rw ifref:tp-to-interface-path?
                   -> /if:interfaces/interface/name

A.2. A JSON example

  "ietf-interfaces:interfaces": {
    "interface": [
        "name": "L2Interface1",
        "description": "'Ethernet Interface 1'",
        "type": "iana-if-type:ethernetCsmacd"
        "name": "L2Interface2",
        "description": "'Ethernet Interface 2'",
        "type": "iana-if-type:ethernetCsmacd"
  "ietf-network:networks": {
    "network": [
        "network-id": "L2-network",
        "network-types": {
          "ietf-te-topology:te-topology": {
            "ietf-eth-te-topology:eth-tran-topology": {}
        "node": [
            "node-id": "L2-N1",
            "ietf-network-topology:termination-point": [
                "tp-id": "L2-N1-TP1",
                "ietf-te-topology:te-tp-id": "",
                "ietf-te-topology:te": {
            "node-id": "L2-N2",
            "ietf-network-topology:termination-point": [
                "tp-id": "L2-N2-TP2",
                "ietf-te-topology:te-tp-id": "",
                "ietf-te-topology:te": {
        "ietf-network-topology:link": [
            "link-id": "L2-N1-N2",
            "source": {
              "source-node": "L2-N1",
              "source-tp": "L2-N1-TP1"
            "destination": {
              "dest-node": "L2-N2",
              "dest-tp": "L2-N2-TP2"


This document was prepared using kramdown

The authors would like to thank ...

Authors' Addresses

Jonas Ahlberg
Ericsson AB
Lindholmspiren 11
SE-417 56 Goteborg
Scott Mansfield
Ericsson Inc
Min Ye
Huawei Technologies
No.1899, Xiyuan Avenue
Italo Busi
Huawei Technologies
Xi Li
NEC Laboratories Europe
Kurfursten-Anlage 36
69115 Heidelberg
Daniela Spreafico
Nokia - IT
Via Energy Park, 14
20871 Vimercate (MI)