This chapter introduces Azure Virtual WAN (vWAN) service. It offers a single deployment, management, and monitoring pane for connectivity services such as Inter-VNet, Site-to-Site VPN, and Express Route. In this chapter, we are focusing on S2S VPN and VNet connections. The Site-to-Site VPN solutions in vWAN differ from the traditional model, where we create resources as an individual components. In this solution, we only deploy a vWAN resource and manage everything else through its management view. Figure 11-1 illustrates our example topology and deployment order. The first step is to implement a vWAN resource. Then we deploy a vHub. It is an Azure-managed VNet to which we assign a CIDR, just like we do with the traditional VNet. We can deploy a vHub as an empty VNet without associating any connection. A vHub deployment process launches a pair of redundant routers, which exchange reachability information with the VNet Gateway router and VGW instances using BGP. We intend to allow Inter-VNet data flows between vnet-swe1, vnet-swe2, and Branch-to-VNet traffic. For Site-to-Site VPN, we deploy VPN Gateway (VGW) into vHub. The VGW started in the vHub creates two instances, instance0, and instance1, in active/active mode. We don’t deploy a GatewaySubnet for VGW because Azure handles subnetting and assigns public and Private IP addresses to instances. Besides, Azure starts a vHub-specific BGP process and allocates a BGP ASN 65515 to the VGW regardless of the selected S2S routing model (static or dynamic). Note that when we connect VNets and branch site to vHub, the Hub Router exchanges routing information with VNet’s GWs and VGW instance using BGP. After the vHub and VGW deployment, we configure VPN site parameters such as IPsec tunnel endpoint IP address, BGP ASN, and peering IP address for the branch device. Then we connect VPN Site to vHub and download the remote device configuration file. The file format is JSON and presents the values/parameters for Site-to-Site VPN and BGP peering but not the device-specific configuration. As a last deployment step, we connect VNets to vHub. The VGW in vHub is associated with a default Route Table (RT), and VNets are associated with none by default. During the connection setup, we need to associate VNets also to default RT. When everything is in place, we verify that each component has the necessary routing information and that the IP connectivity is ok.
Figure 11-1: vWAN Diagram.
