Subject: [nmrg] DTN Open issue1: Why distinguish data from model?

From: Qin Wu <[email-masked]>
Date: Thu, 22 Apr 2021 08:11:20 +0000

Hi,
In IETF110 NMRG session, one issue we brought up for Digital Twin Networking Draft is why distinguish data from model?
As we discussed in the meeting, Data and models are usually the two common and separated components/elements in other industrial digital twin entities (e.g., manufacturing, factory-floor).
Of course, data can be structured to follow a set of well-known data models.
Similarly in digital twin networks defined in draft-zhou-nmrg-digitaltwin-network-concepts:
Data and model are two core technical elements for Digital Twin Network and will be leverage by Analyze, Emulate, Diagnose, Control four functional blocks
Data: A digital twin network should contain historical data and/or real time data (configuration data, operational state data, topology data, trace data, metric data, process data etc.) about its real-world twin (i.e., physical network) that are required by the models to represent and understand the states and behaviors of the real-world twin. The data is characterized as the single source of the "truth" and populated in the data warehouse, which provides timely and accurate data service support for "Analyze" functional block.

Models: Techniques that involve collecting data from one or more sources in the real-world twin (i.e., physical network) and developing a comprehensive representation of the data (e.g., system, entity, process) in a model. It is used as emulation and diagnosis basis to provides dynamics and elements on how live physical network operates and develop reasoning data utilized for decision making. Various models such as service models, data models, dataset models, or knowledge graph can be used to represent the physical network assets and instantiated to serve various network applications.

Two type of models can be specified:
a. computational or analytic models that are required to describe, understand, and predict the twins' operational states and behaviors,
b. and models that are used to prescribe actions based on service logic and objectives about the corresponding real-world object.

Therefore Data is the source to Analyze functional block and models is more related to emulation. We plan to clarify this in the next version of draft-zhou-nmrg-digitaltwin-network-concepts.

-Qin (on behalf of authors)