How does PrEstoCloud address the constraint of vendor lock-in problem?

This issue is a significant barrier to the adoption of multi-cloud computing frameworks, due to the lack of standardisation. However, limited numbers of research studies are conducted to analyse and highlight the complexity of vendor lock-in issue in the cloud environment. For example, public cloud providers, such as Amazon AWS and Microsoft Azure, offer dedicated VPN (Virtual Private Network) solutions, so that their customers can use these public cloud infrastructures as an extension of their own private infrastructure. To address this constraint, the “Inter-Site Network Virtualization” component defined in the PrEstoCloud architecture uses standardised VPN technologies, such as IPsec and OpenVPN, to overcome the limitations of interoperability due to the implementation of proprietary protocols.