Azure Virtual WAN provides a highly scalable and resilient networking solution that connects your on-premises datacenters, remote offices, and branch locations to Azure. A key aspect of Virtual WAN is its ability to facilitate private, secure connectivity between these resources, avoiding the public internet. This document delves into the concepts surrounding private connectivity within Azure Virtual WAN.
Understanding Private Connectivity
Private connectivity ensures that your network traffic remains within the Microsoft backbone network or your dedicated connections, offering enhanced security, performance, and predictability compared to internet-based transit. In the context of Virtual WAN, this typically involves:
Site-to-Site VPN Connections: Securely connecting your on-premises network to a Virtual WAN hub using IPsec/IKE VPN tunnels.
ExpressRoute Connections: Establishing dedicated, private connections between your on-premises network and Azure, with Virtual WAN acting as the central orchestration point.
VNet Peering: Connecting virtual networks within Azure, allowing them to communicate privately. When peered with a Virtual WAN hub, VNets can leverage the hub for transit and connectivity to other connected sites.
Azure Firewall and Network Security Groups (NSGs): Implementing security policies to control and inspect traffic flowing through the Virtual WAN.
Key Components for Private Connectivity
Virtual WAN Hub
The Virtual WAN hub is the central transit point for your network. It's a managed service deployed in an Azure region that hosts various networking components, including VPN gateways, ExpressRoute gateways, and routing capabilities. All your connected sites and VNets connect to this hub, enabling them to communicate with each other privately.
Virtual Hub Routing
The routing capabilities within the Virtual WAN hub are crucial for directing traffic between different connection types (VPN, ExpressRoute, VNet). You can configure static routes or leverage BGP (Border Gateway Protocol) to dynamically exchange routes, ensuring optimal path selection for your private traffic.
Hub-and-Spoke Architecture
Virtual WAN inherently supports a hub-and-spoke architecture. VNets are configured as spokes and connect to the Virtual WAN hub. This design simplifies network management and allows for centralized security and policy enforcement. Private connectivity is the backbone of this model, ensuring spokes can communicate with each other and with on-premises locations through the hub.
Scenarios for Private Connectivity
Connecting On-Premises Datacenters: Establish secure VPN tunnels or ExpressRoute circuits from your datacenters to the Virtual WAN hub. This allows your on-premises resources to access Azure services and vice-versa without traversing the public internet.
Connecting Branch Offices: Deploy Virtual WAN VPN devices at branch locations to create site-to-site VPN connections to the hub. This provides reliable and secure connectivity for remote users and distributed offices.
Interconnecting VNets: By connecting VNets to the Virtual WAN hub, you enable private communication between them. The hub acts as the transit router, eliminating the need for complex VNet-to-VNet VPN configurations.
Centralized Security Enforcement: Deploy Azure Firewall within the Virtual WAN hub. All traffic from connected sites and VNets can be routed through the firewall for unified security policies, threat protection, and inspection, all within your private network path.
Benefits of Private Connectivity with Virtual WAN
Enhanced Security: Traffic remains on the Microsoft backbone, reducing exposure to internet-based threats.
Improved Performance: Predictable latency and higher bandwidth compared to VPNs over the public internet.
Simplified Management: A single pane of glass for managing all your network connections.
Scalability: Built to handle large-scale deployments with a high number of sites and users.
Cost-Effectiveness: Can be more cost-effective than managing multiple individual VPN gateways and complex routing configurations.
Example Configuration Snippet (Conceptual)
Below is a conceptual example of how a connection might be represented. Actual configurations involve Azure portal or CLI commands.