###Does Azure charge for traffic between VNets? VNet-to-VNet traffic within the same region is free for both directions. Cross region VNet-to-VNet egress traffic is charged with the outbound inter-VNet data transfer rates based on the source regions. Refer to the pricing page for details.
###Does VNet-to-VNet traffic travel across the Internet? No. VNet-to-VNet traffic travels across the Microsoft Azure backbone, not the Internet.
Yes, it is protected by IPsec/IKE encryption.
###Do I need a VPN device to connect VNets together? No. Connecting multiple Azure virtual networks together doesn't require a VPN device unless cross-premises connectivity is required.
###Do my VNets need to be in the same region? No. The virtual networks can be in the same or different Azure regions (locations).
###Can I use VNet-to-VNet along with multi-site connections? Yes. Virtual network connectivity can be used simultaneously with multi-site VPNs.
See Gateway requirements table.
###Can I use VNet-to-VNet to connect VMs or cloud services outside of a VNet? No. VNet-to-VNet supports connecting virtual networks. It does not support connecting virtual machines or cloud services that are not in a virtual network.
###Can a cloud service or a load balancing endpoint span VNets? No. A cloud service or a load balancing endpoint can't span across virtual networks, even if they are connected together.
###Can I used a PolicyBased VPN type for VNet-to-VNet or Multi-Site connections? No. VNet-to-VNet and Multi-Site connections require Azure VPN gateways with RouteBased (previously called Dynamic Routing) VPN types.
No, both virtual networks MUST be using route-based (previously called Dynamic Routing) VPNs.
###Do VPN tunnels share bandwidth? Yes. All VPN tunnels of the virtual network share the available bandwidth on the Azure VPN gateway and the same VPN gateway uptime SLA in Azure.
###Are redundant tunnels supported? Redundant tunnels between a pair of virtual networks are supported when one virtual network gateway is configured as active-active.
###Can I have overlapping address spaces for VNet-to-VNet configurations? No. You can't have overlapping IP address ranges.
Can there be overlapping address spaces among connected virtual networks and on-premises local sites?
No. You can't have overlapping IP address ranges.