This is the simple top-level view of any company having a Hybrid infrastructure Connectivity ( Cloud + On-premises ). But in reality, big companies have like multiple clouds and on-prem offices. And connectivity with hundreds of clients and other companies 😊 . That green tunnel can be a site-to-site VPN or an ExpressRoute. Also, there can be a single or multiple point-to-site VPN services. I have 5+ years of experience working in an International company and handling all this infrastructure connectivity, reliability, and security along with my team.