3. Gaia-X Conceptual Model

The Gaia-X conceptual model, shown in the figure below, describes all concepts in the scope of Gaia-X and relations among them. Supplementary, more detailed models may be created in the future to specify further aspects. Minimum versions of important core concepts in the form of mandatory attributes for Self-Descriptions are presented in Appendix A3. The general interaction pattern is further described in the section Basic Interactions of Participants.

The Gaia-X core concepts are represented in classes. An entity highlighted in blue shows that an element is part of Gaia-X and therefore described by a Gaia-X Self-Description. The upper part of the model shows different actors of Gaia-X, while the lower part shows elements of commercial trade and the relationship to actors outside Gaia-X.

Gaia-X conceptual model

3.1 Participants

A Participant is an entity, as defined in ISO/IEC 24760-1 as “item relevant for the purpose of operation of a domain that has recognizably distinct existence”1, which is onboarded and has a Gaia-X Self-Description. A Participant can take on one or more of the following roles: Provider, Consumer, Federator. Section Federation Services demonstrates use cases that illustrate how these roles could be filled. Provider and Consumer present the core roles that are in a business-to-business relationship while the Federator enables their interaction.

3.1.1 Provider

A Provider is a Participant who provides Resources in the Gaia-X Ecosystem. The Provider defines the Service Offering including terms and conditions as well as technical Policies. Furthermore, it provides the Service Instance that includes a Self-Description and associated Policies. Therefore, the Provider operates different Resources.

3.1.2 Federator

Federators are in charge of the Federation Services and the Federation which are independent of each other. Federators are Gaia-X Participants. There can be one or more Federators per type of Federation Service.

A Federation refers to a loose set of interacting actors that directly or indirectly consume, produce, or provide related Resources.

3.1.3 Consumer

A Consumer is a Participant who searches Service Offerings and consumes Service Instances in the Gaia-X Ecosystem to enable digital offerings for End-Users.

3.2 Service Composition

Gaia-X conceptual model

3.3 Resources and Resource Templates

Resources describe in general the goods and objects of a Gaia-X Ecosystem. A Resource can be a Data Resource, a Software Resource, a Node or an Interconnection. Each resource is characterized by endpoints and access rights and belongs to a Resource owner. The different categories of Resources are visualized in Figure 3 and defined below:

classDiagram class Resource{ } class Data Resource{ } class Software Resource{ } class Node{ } class Interconnection{ } Resource <|-- Data Resource Resource <|-- Software Resource Resource <|-- Node Resource <|-- Interconnection

Resource Categories

A Data Resource consists of data in any form and necessary information for data sharing.

A Node is a Resource that represents a computational or physical entity that hosts, manipulates, or interacts with other computational or physical entities.

A Software Resource is a Resource consisting of non-physical functions.

An Interconnection is a Resource presenting the connection between two or more Nodes. These Nodes are usually deployed in different infrastructure domains and owned by different stakeholders, such as Consumers and/or Providers. The Interconnection between the Nodes can be seen as a path which exhibits special characteristics, such as latency, bandwidth and security guarantees, that go beyond the characteristics of a path over the public Internet.

Resource templates are the entities provided by a Provider to make the Resource available for order. They depend on the respective Resources and are characterized by a specification, e.g., of data schema, and by usage rights. Resource templates are therefore used to compose Service Offerings.

3.3.1 Policies

Policy is defined as a statement of objectives, rules, practices, or regulations governing the activities of Participants within Gaia-X. From a technical perspective Policies are statements, rules or assertions that specify the correct or expected behaviour of an entity23.

The Policy Rules Document explains the general Policies defined by the Gaia-X association for all Providers and Service Offerings. They cover, for example, privacy or cybersecurity policies and are expressed in the conceptual model indirectly via Gaia-X Federation Service Compliance and as attributes of the Resources, Service Offerings, and Service Instances.

These general Policies form the basis for detailed Policies for a particular Service Offering, which can be defined additionally and contain particular restrictions and obligations defined by the respective Provider or Consumer. They occur either as a Provider Policy (alias Usage Policies) or as a Consumer Policy (alias Search Policy):

  • A Provider Policy/Usage Policy constraints the Consumer’s use of a Resource. For example, a Usage Policy for data can constrain the use of the data by allowing to use it only for x times or for y days.

  • A Consumer Policy describes a Consumer’s restrictions of a requested Resource. For example, a Consumer gives the restriction that a Provider of a certain service has to fulfil demands such as being located in a particular jurisdiction or fulfil a certain service level.

In the conceptual model, they appear as attributes in all elements related to Resources. The specific Policies have to be in line with the general Policies in the Policy Rules Document.

graph TD; A[Policy Rules] --> |defines| B[general Gaia-X Policies] B --> |basis for| C[Resource-specific Policies] C -->D[Provider Policy/ Usage Policy] C -->E[Consumer Policy/ Search Policy]

3.4 Federation Services

Federation Services are services required for the operational implementation of a Gaia-X Data Ecosystem. They are explained in greater detail in the Federation Service section.

They comprise four groups of services that are necessary to enable Federation of Resources, Participants and interactions between Ecosystems. The four service groups are Identity and Trust, Federated Catalogue, Sovereign Data Exchange and Compliance.

3.5 Service Offering

A Service Offering is defined as a set of Resources which a Provider aggregates and publishes as a single entry in a Catalogue. Service Offerings may themselves be aggregated realizing service composition. The instantiation of a Service Offering is the deliverable of a Provider to a Consumer. The Federation Services provide the foundation for Service Offerings and the Service Offering uses and conforms to the Federation Services.

3.6 Additional Concepts

In addition to those concepts and their relations mentioned above, further ones exist in the conceptual model that are not directly governed by Gaia-X. These concepts do not need to undergo any procedures directly related to Gaia-X, e.g., do not create or maintain a Gaia-X Self-Description.

First, the Service Instance realizes a Service Offering and can be used by End-Users while relying on a contractual basis.

Second, Contracts are not in scope of Gaia-X but present the legal basis for the Services Instances and include specified Policies. Contract means the binding legal agreement describing a Service Instance and includes all rights and obligations. This comes in addition to the automated digital rights management embedded in every entity’s Self-Description.

Further relevant actors exist outside of the Gaia-X scope in terms of End-Users and Resource Owners.

Resource Owners describe a natural or legal person, who holds the rights to Resources that will be provided according to Gaia-X regulations by a Provider and legally enable its provision. As Resources are bundled into a Service Offering and nested Resource compositions can be possible, there is no separate resource owner either. Resources can only be realized together in a Service Offering and Service Instance by a Provider, which presents no need to model a separate legal holder of ownership rights.

End-Users use digital offerings of a Gaia-X Consumer that are enabled by Gaia-X. The End-User uses the Service Instances containing Self-Descriptions and Policies.

3.7 Examples

3.7.1 Personal Finance Management example

This example describes the various Gaia-X concepts using the Open Banking scenario of a Personal Finance Management service (PFM) in SaaS mode.

Let’s suppose that the service is proposed by a company called MyPFM to an end user Jane who have bank accounts in two banks: Bank1 and Bank2.
MyPFM is using services provided by Bank1 and Bank2 to get the banking transactions of Jane and then aggregates these bank statements to create Jane’s financial dashboard.

Jane is the End-User.

Bank1 and Bank2 are Providers defining the Service Offerings delivering the banking transactions and operating the corresponding Service Instances. They are also Resource Owners for the bank statements, which are Resources composing the Service Offerings (Jane is the data subject as per GDPR4).
The associated Resource Policies are in fact predefined by the PSD25 directive from the European Parliament.

MyPFM is the Consumer which consumes the Service Instances provided by Bank1 and Bank2 in order to create a financial dashboard and to offer it to Jane.
MyPFM is also likely consuming Service Instances from a PaaS Provider in order to run its own code, such as dashboard creation.

  1. ISO/IEC. IT Security and Privacy — A framework for identity management: Part 1: Terminology and concepts (24760-1:2019(en)). ISO/IEC. https://www.iso.org/obp/ui/#iso:std:iso-iec:24760:-1:ed-2:v1:en 

  2. Singhal, A., Winograd, T., & Scarfone, K. A. (2007). Guide to secure web services: Guide to Secure Web Services - Recommendations of the National Institute of Standards and Technology. Gaithersburg, MD. NIST. https://csrc.nist.gov/publications/detail/sp/800-95/final https://doi.org/10.6028/NIST.SP.800-95 

  3. Oldehoeft, A. E. (1992). Foundations of a security policy for use of the National Research and Educational Network. Gaithersburg, MD. NIST. https://doi.org/10.6028/NIST.IR.4734 

  4. Rights of the data subject https://gdpr-info.eu/chapter-3/ 

  5. Payment services (PSD 2) https://ec.europa.eu/info/law/payment-services-psd-2-directive-eu-2015-2366_en