Deliverable D3.3 is the first deliverable dealing with the implementation of the Interworking Framework. As defined in the proposal, this deliverable is basically a software deliverable that contains part of the services and features of the I/W Framework. In addition to the software delivery, we have produced this document in order to explain details about the internal architecture and to also provide updates of the previous deliverables. The high-level design of the Interworking Framework, as well as its services, capabilities and features are defined in previous deliverables of the WP3 (D3.1 and D3.2); and they are the foundations of the I/W Framework development. For each of the components defined in the I/W Framework architecture we include an open definition of the implemented API, regardless of whether the API is public or for internal use. This information follows the openness and modular principles that we follow in the design and development of the I/W Framework. The APIs are defined using the OpenAPI specifications and they are available in a the 5G EVE public repository1. This deliverable includes the first release of the Multi-Site Catalog and the Multi-Sire Network Orchestrator. For both components, this document describes the supported services in this deliverable. We also include a description of the internal component architecture, design and workflows of the services implemented by: Multi-Site Catalog, Multi-Site Network Orchestrator and Adaptation Layer. In the case of Runtime Configurator and Data Collection Manager, we update in this deliverable the design included in D3.2, with more detailed workflows and descriptions. This document also contains the roadmap of the I/W Framework for the next project year, mapping the service, capabilities and features required for the I/W Framework with the status in each of the deliveries. According to the proposal, the I/W Framework design has two deliverables: this one and the final delivery in M24. We foresee the need of intermediates deliveries of the I/W Framework for supporting the MS8 (M18) and for supporting the WP4 deliverables. For that reason, we include two additional deliveries: Drop 1 and Drop 2. Finally, we include some updates about the status of the inter-site connectivity and the technical solution adopted to provide this interconnection.