> For the complete documentation index, see [llms.txt](https://open-dataspaces.gitbook.io/ods-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://open-dataspaces.gitbook.io/ods-docs/ods-ram/03-layers.md). # 3. Layers **"Layers"** separate the DPQM into logical tiers according to functional purpose. ODS-RAM consists of four layers: **(1) Data**, **(2) Transaction**, **(3) Identity**, and **(3) Semantics**. In ODS-RAM, **each layer is independent of the others and fulfills its distributed data management functions in a loosely coupled manner**. That is, **ODS-RAM layers possess "detachability", allowing those who adopt ODS-RAM to selectively determine the number of layers required according to the nature and characteristics of each domain**. For example, if the data addressability and semantics within a given cross-cutting domain are already clear, one may begin by implementing Data Product first using L3 through L1, omitting the implementation of Ontology Product — i.e., the set comprising L4 through L2. **ODS-RAM places a strong emphasis on flexibility tailored to each domain and use case, and by ensuring "backward compatibility", it allows for subsequent opt-in as needed, thereby providing options commensurate with the level of maturity**. The following sections describe in detail the functions of each of the four layers. ## **3.1 Data Layer (L1)** The **Data Layer** (hereinafter "L1") is the layer that addresses the problems of **Usage Control**, **Data Tampering**, and **Data Quality**, and selectively adopts Closed World Assumption (CWA) behavior. L1 requires functions for data usage control exercised by the data provider and for handling data with guaranteed integrity and quality: * **Regarding usage control exercised by data providers**: opportunities for self-determination must be provided within the scope defined in data sharing agreements, and the exercise of such control must be appropriately reflected. * **Regarding data integrity and quality**: the integrity and quality characteristics of each piece of data vary across target domains, and rather than establishing uniform standards, it is assumed that integrity and quality appropriate to the characteristics of the data will be guaranteed. Accordingly, the integrity and quality of data itself are not stipulated; only the methods and results of their evaluation and calculation must be provided in a form accessible to data consumers. ## **3.2 Transaction Layer (L2)** The **Transaction Layer** (hereinafter "L2") is the layer that addresses the problems of **Modal**, **Query**, and **Protocol**. L2 must be capable of **controlling the transaction process between data providers and data users in a manner that is agnostic to data modal (structured, semi-structured, unstructured, etc.) as well as to request and protocol type (synchronous, asynchronous, etc.)**. ## **3.3 Identity Layer (L3)** The **Identity Layer** (hereinafter "L3") is the layer that addresses the problems of **Authentication** and **Authorization**. L3 requires the necessary level of authentication and authorization through providing **Credentials** in a verifiable form: * Verification of the existence of data providers and users and authentication must ensure the required level of trustworthiness. * Access control based on the storage, usage conditions, and granularity self-determined by the data provider must ensure the required level of confidentiality. ## **3.4 Semantics Layer (L4)** The **Semantics Layer** (hereinafter "L4") is the layer that addresses the problems of **Addressability** and **Semantics**, and adopts Open World Assumption (OWA) behavior. L4 requires semantic and ontological interoperability through providing **Metadata** in an accessible form: * Metadata related to destinations must be provided in order to access data or services. * Metadata related to meaning must be defined in a unique and accessible format with respect to the meaning of the information (input/output data) necessary to use the data or services. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://open-dataspaces.gitbook.io/ods-docs/ods-ram/03-layers.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.