A YANG Data Model for Interface Reference Topology

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Copyright Notice

Copyright (c) 2023 IETF Trust and the persons identified as the document authors. All rights reserved.¶

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Table of Contents

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.¶

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

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

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

module ietf-tp-interface-reference-topology {
  yang-version "1.1";
   namespace
  "urn:ietf:params:xml:ns:yang:ietf-tp-interface-reference-topology";

   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;
     reference
       "RFC 8343";
   }

   organization
     "Internet Engineering Task Force (IETF) CCAMP WG";
   contact
     "WG List: <mailto:ccamp@ietf.org>

      Editor: Jonas Ahlberg
              <mailto:jonas.ahlberg@ericsson.com>
      Editor: Scott Mansfield
              <mailto:scott.mansfield@ericsson.com>
      Editor: Min Ye
              <mailto:amy.yemin@huawei.com>
      Editor: Italo Busi
              <mailto:Italo.Busi@huawei.com>
      Editor: Xi Li
              <mailto:Xi.Li@neclab.eu>
      Editor: Daniela Spreafico

              <mailto:daniela.spreafico@nokia.com>
     ";

   description
     "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
     (https://trustee.ietf.org/license-info).

     This version of this YANG module is part of RFC XXXX
     (https://tools.ietf.org/html/rfcXXXX); see the RFC itself for
     full legal notices.";

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

   /*
    * Groupings
    */
   grouping tp-to-interface-ref {

     description
       "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';
       }
       description
         "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" {
     description
       "Augmentation to add possibility to reference an element
        in the list of interfaces as defined by RFC 8343.";
     uses tp-to-interface-ref;
   }
 }

<CODE ENDS>

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
    Namespace:
      urn:ietf:params:xml:ns:yang:ietf-interface-reference-topology
    Prefix: ifref
    Reference: RFC XXXX

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.¶

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

{
  "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": "10.10.10.1",
                "ietf-te-topology:te": {
  "ietf-tp-interface-reference-topology:tp-to-interface-path":
     "L2Interface1"
                }
              }
            ]
          },
          {
            "node-id": "L2-N2",
            "ietf-network-topology:termination-point": [
              {
                "tp-id": "L2-N2-TP2",
                "ietf-te-topology:te-tp-id": "10.10.10.2",
                "ietf-te-topology:te": {
  "ietf-tp-interface-reference-topology:tp-to-interface-path":
     "L2Interface2"
                }
              }
            ]
          }
        ],
        "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"
            }
          }
        ]
      }
    ]
  }
}

Acknowledgments

This document was prepared using kramdown¶

The authors would like to thank ...¶

Authors' Addresses