As discussed in Chapter 2, Delving into Azure Virtual Networks, you can create a peer between two virtual networks within the same region to let the services within these two virtual networks communicate with each other seamlessly. At the time of writing you can peer two virtual networks within different regions, but this feature is still in preview, and not supported in all regions, and not even as highly available and reliable as the traditional peering. Therefore, we only have one way to do such a connection now: using VNet2VNet.

Creating a VNet2VNet connection is not similar to the model of VNet peering, because it uses a Site-to-Site IP Sec connection, which is similar to VPN communication with on-premises. Virtual network peering uses the Microsoft backbone network to communicate. As a result, when you want to deploy a VNet2VNet connection, you will need a VPN gateway to provide secure tunneling.