# 3 Layers of the Reference Architecture Model

- [3.1 Business Layer](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3-1-business-layer.md)
- [3.1.1 Roles in the International Data Spaces](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3-1-business-layer/3_1_1_roles_in_the_ids.md)
- [3.1.2 Interaction of Roles](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3-1-business-layer/3_1_2_interaction_of_roles.md)
- [3.1.3 Digital Identities](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3-1-business-layer/3_1_3_digital_identities.md)
- [3.1.4 Usage Contracts](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3-1-business-layer/3_1_4_usage_contracts.md)
- [3.2 Functional Layer](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3_2_functionallayer.md)
- [3.3 Information Layer](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3_3_informationlayer.md)
- [3.4 Process Layer](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3_4_process_layer.md)
- [3.4.1 Onboarding](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3_4_process_layer/3_4_1_onboarding.md)
- [3.4.2 Data Offering](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3_4_process_layer/3_4_2_data_offering.md)
- [3.4.3 Contract Negotiation](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3_4_process_layer/3_4_3_contract_negotiation.md)
- [3.4.4 Exchanging Data](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3_4_process_layer/3_4_4_exchanging_data.md)
- [3.4.5 Publishing and using Data Apps](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3_4_process_layer/3_4_5_publishing_and_using_data_apps.md)
- [3.4.6 Policy Enforcement](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3_4_process_layer/3_4_6_policy_enforcement.md)
- [3.5 System Layer](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3_5_0_system_layer.md)
- [3.5.1 Identity Provider](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3_5_0_system_layer/3_5_1_identity_provider.md)
- [3.5.2 IDS Connector](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3_5_0_system_layer/3_5_2_ids_connector.md)
- [3.5.3 App Store and App Ecosystem](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3_5_0_system_layer/3_5_3_app_store_and_data_apps.md)
- [3.5.4 Metadata Broker](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3_5_0_system_layer/3_5_4_metadata_broker.md)
- [3.5.5 Clearing House](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3_5_0_system_layer/3_5_5_clearing_house.md)
- [3.5.6 Vocabulary Hub](/ids-knowledgebase/ids-ram-4/layers-of-the-reference-architecture-model/3-layers-of-the-reference-architecture-model/3_5_0_system_layer/3_5_6_vocabulary_hub.md)