# Digital Twin-Driven Virtual Network Architecture for Enhanced Extended Reality Capabilities
## 3 Architecture's Proposed Approach
### Extended Reality Functions' Deployment Approach and DTN Operation--Integration
* Feedback: The integration of XR monitoring services can be realized as immersive feedback mechanisms to enable users to visualize real-time network data and achieve a real-time comprehension of configuration changes in the DTN. The XR service creation process is depicted in Figure 15. The XRM Service Interface receives the creation request regarding a new XR service named as service \"A\" and forwards the request to the XRM Service Controller, which has to identify the smaller network functions that comprise the requested service. The Service Builder has to access the DTN model to build the XR service based on the NFV architecture. Once the service is constructed, the DTM modeler has to process the service and store the \"Extended Network Model\" identified with a unique XR ID: \"Extended Model A\". Since the XR services may exhibit the DTN inner and sensible information, it is essential to consider the necessity of ensuring a secure environment for DTN clients, enabling them to utilize the XR services in a safe manner. Consequently, robust security implementations have to be considered, as is addressed in [50]. In order to guarantee data integrity, the following security techniques should be considered:  
* Data Encryption: the encryption algorithms can ensure that the data transmitted between the DTM and XRM, as well as the data transmitted between the ONM and DTM, and the data that are shared within the DTN are protected. * Authentication APIs: as was illustrated in Section 3.2, APIs can be adopted as an approach to address the user's authentication to XR services, as well as DTN resources. * Bio-metric Authentication: the XRM module can be utilized to build an authentication service based on bio-metric signals and then ensuring the user's authenticity. * Secure Protocols: secure protocols such as TLS/SSL can be adopted to guarantee the user's data integrity. Moreover, a super-user XR Service can be deployed that requests the creation of DTN instances from the main DTN, which is dedicated to providing networking services to users of the space station. The objective of creating multiple DTN instances is to establish a testing and training environment for the XR functions that have been deployed. This enables the analysis of the impact that an XR service may incur on the DTN, facilitating the testing and training of XR services or the deployment of new XR services in a controlled environment. With this approach, the risk of degrading or damaging the main DTN is mitigated. To achieve this, the DTM Builder has to be designed with the ability of managing multiple DTN instances. Finally, the operation of the XR service \"A\" is explained. Two possible XR service natures are considered, as referred to in Section 3.2: reading and writing services. * Reading XR Service: The reading services retrieve the \"Extended Network Model\" for the visualization of DTN information. The XRM Service Interface receives the request to utilize the previously created \"XR Service A\". This request is forwarded to the XRM Service Controller which processes the request and sends it to the DTM Modeler. The Modeler retrieves the stored \"Extended Network Model A\" and forwards it to the DTM Network Builder to retrieve the requested XR service information. Finally, the information is transmitted to the XRM Service Interface, which has the responsibility of processing the out-coming information. Figure 16 depicts the aforementioned process. * Writing XR Service: The writing services modify the current DTN model by the \"Extended Network Model\". The initial operation is similar to the reading services' scenario. Once the DTM Modeler has retrieved the \"Extended Network Model A\", this model replaces the current operating DTN model and a \"Network Re-generation\" request is transmitted from the DTM Modeler to the DTM Network Builder. Finally, the XRM Service Interface processes the output information. Figure 17 illustrates the writing XR service process. Figure 15: General creation of any Extended Reality Service.