You purchase a VM on a public cloud and plan to create a VPN tunnel to the cloud provider. Your IP network is 172.16.0.0/12, and the provider has assigned an IP address in the 10.0.0.0/8 network. What virtual network function (VNF) will you need from the provider to communicate with the VM?

You will need a virtual router to route between the two different networks. This type of service is called a virtual network function, or VNF. A virtual switch is built into just about every virtualization platform, since layer 2 communications are normally required. A virtual firewall is a piece of software that allows you to protect your virtualization infrastructure, just like their hardware counterparts. Another IP scheme at the provider could help, but a router would still be required for connectivity.