## 4 Proposed Orchestrator
### Description of the Architecture
#### 4.1.2 E2E Network Slice Orchestration Plane  
The _E2E Network Slice Orchestration Plane_ block is under the ETSI MANO framework [40], and thus, the modules that compose it implement the framework functionalities. In general, an NS is negotiated directly between the end-user (slices are dedicated per UE) and the network operator, as described in the previous section. The end-user requests using its consumption profile (QoS requirements), and the slice is allocated according to the defined SLA with the operator [97].  
In this sense, several platforms present features and functionalities that provide the orchestration service, highlighting here the Open Source Mano (OSM) ([[https://osm.etsi.org/](https://osm.etsi.org/)]([https://osm.etsi.org/](https://osm.etsi.org/)) accessed on 7 December 2021) based on ETSI-NFV Management and Orchestration (MANO), Open Baton ([[https://openbaton.github.io/](https://openbaton.github.io/)]([https://openbaton.github.io/](https://openbaton.github.io/)) accessed on 7 December 2021), and ONAP ([[https://www.onap.org/](https://www.onap.org/)]([https://www.onap.org/](https://www.onap.org/)) accessed on 7 December 2021). Using these platforms as a base, the other orchestration solutions implement an upper layer of functionality, proposing standardization interfaces, integration, and regulatory models, which is the case of the solution proposed in this work and also in [28; 74; 84; 85; 86; 98].  
Here, the additional modules are being tested on ONAP and OSM due to the acceptance by the technical-scientific community, good documentation of these solutions,and the adoption by major players in the market. The comparison between these platforms is outside the scope of this work but can be obtained from [83; 99; 100].  
The operation of this block is defined as follows: The _Service Manager_ module receives multiple requests from slice templates and dynamic resource allocation. Our Orchestrator considers 3 GPP REST as per TS. 32.158 ([https://portal.3 gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=3396](https://portal.3 gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=3396) accessed on 7 December 2021), which will facilitate the integration with regional orchestrators implemented on the ONAP and OSM platforms.  
The _Service Manager_ module then processes the template files and starts the necessary actions for provisioning the requested resources. Note that the standard components of the ETSI framework are maintained through the sub-modules: _Slice Life-Cycle Manager_, _Virtualized Infrastructure Manager (VIM)_, _VNF Manager (VNFM)_, and _NFV Orchestrator (NFVO)_ (see Figure 4). These modules together implement the reference architecture and provide the necessary virtualization technologies for implementing the orchestration service. In addition to the NFV MANO specification module, the block integrates the connectivity verification and provisioning network resources using the _SDN Controller_ module, responsible for managing and executing the necessary controls to establish the transport layer of the service slice requested [100; 101].  
Finally, a set of REST APIs (southbound clients) connect to the virtual resources of the Cloud, Multi-access Edge Computing, and NFV architecture in multiple providers in order to subsidize the provisioning and delivery of the E2E slice. In this context, E2E slices creation and quality assurance involve several virtualization technologies, access networks, transports, and core networks. It also needs different virtualization technologies (e.g., containers or VMs) and different types of Orchestrators (e.g., vertical and horizontal) [85; 99].