Internet-Draft Network Working Group March 2023
Chen, et al. Expires 9 September 2023 [Page]
Internet Research Task Force
Intended Status:
D. Chen
China Mobile
H. Yang
China Mobile
C. Zhou
China Mobile

Requirements for Interfaces of Network Digital Twin


The interfaces of Digital Twin Network can be divided as twin network southbound interface, internal interface and northbound interface. In order to build a digital twin network and realize its many advantages, different interfaces should be able to meet different requirements. And this memo introduces the requirements for the interfaces of the Digital Twin Network.

Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

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This Internet-Draft will expire on 9 September 2023.

Table of Contents

1. Introduction

As defined in the[I-D.irtf-nmrg-network-digital-twin-arch] , the digital twin network is defined as "a network system with a physical network entity and a virtual twin, and the two can interact with each other in real time". It should have four core elements: data, model, mapping and interaction. Accordingly, a "three-layer, three-domain and double-closed loop" architecture is adopted.) and the network telemetry technology

Based on the above architecture definition of three-layer, three-domain and double-closed-loop, the interfaces of each layer and their positions of the digital twin network are shown in Figure 1. The network elements in the physical entity network exchange network data and network control information with the twin network layer through the twin southbound interface. The twin network layer contains three key subsystems, which are data sharing warehouse, service mapping model and digital twin management. Through the corresponding interface protocol, the construction and interaction requirements of the three key subsystems should be met. And through the internal interface of the twin layer, the interaction between the three key subsystems and the physical network layer and network application layer is realized. Network applications input requirements to the twin network layer through the twin northbound interface, and deploy services in the twin network layer through the model example. To sum up, there are differences in interface protocol requirements between different layers of DTN and within twin layers.

|                                                                     |
|                      Network Application Layer                      |
|                                                                     |
        |                         |                      |
        |                         |                      |   Northbound
        |                         |                      |   Interface
|                        Twin Network Layer                          |
|                                                                    |
|  +------------+           +----------+          +---------------+  |
|  |   data     |           | service  |          |    digital    |  |
|  |  sharing   <-----------> mapping  <---------->     twin      |  |
|  |  warehouse |   Twin    |  model   |          |   management  |  |
|  +------------+  Internal +----------+          +---------------+  |
|                 Interface                                          |
         |                        |                       |  Twin
         |                        |                       | Southbound
         |                        |                       | Interface
|                                                                     |
|                      Physical Network Layer                         |
|                                                                     |
Figure 1: Schematic Representation of DTN Interface

2. Requirements for Different Interfaces

3. Suggestions on the applicability of common protocols

With the development of communication networks, many North-South and intra-network communication protocols have been formed in the network, such as RESTCONFRFC 8527 [RFC8527], NETCONFRFC 8526 [RFC8526], OpenFlow, XMPPRFC 7622 [RFC7622], East-West Bridge, etc.. Because different communication protocols have different characteristics, the existing protocols are suitable for different twin network interfaces. In this draft, we attempt to give some suggestions about the applicability of some existing general protocols suitable for DTN construction.

4. Security Considerations


5. IANA Considerations

This document has no requests to IANA.

6. References

6.1. Informative References

Zhou, C., Yang, H., Duan, X., Lopez, D., Pastor, A., Wu, Q., Boucadair, M., and C. Jacquenet, "Digital Twin Network: Concepts and Reference Architecture", Work in Progress, Internet-Draft, draft-irtf-nmrg-network-digital-twin-arch-02, , <>.

6.2. Normative References

Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <>.
Saint-Andre, P., "Extensible Messaging and Presence Protocol (XMPP): Address Format", RFC 7622, DOI 10.17487/RFC7622, , <>.
Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., and R. Wilton, "NETCONF Extensions to Support the Network Management Datastore Architecture", RFC 8526, DOI 10.17487/RFC8526, , <>.
Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., and R. Wilton, "RESTCONF Extensions to Support the Network Management Datastore Architecture", RFC 8527, DOI 10.17487/RFC8527, , <>.

Authors' Addresses

Danyang Chen
China Mobile
Hongwei Yang
China Mobile
Cheng Zhou
China Mobile