ExpressRoute and Azure Virtual WAN
Azure ExpressRoute provides a private, dedicated connection between your on‑premises infrastructure and Microsoft Azure. When combined with Azure Virtual WAN, you can extend this private connectivity across a global, unified network architecture, simplifying the management of branch‑to‑branch, branch‑to‑datacenter, and user‑to‑cloud traffic.
Key Benefits
- Private, high‑throughput connectivity with predictable performance.
- Unified global routing – a single hub-and‑spoke model across regions.
- Integrated security with Azure Firewall, security policies, and DDoS protection.
- Seamless failover between ExpressRoute and VPN tunnels.
- Simplified operations through Azure portal, PowerShell, and ARM templates.
How It Works
When you associate an ExpressRoute circuit with a Virtual WAN hub, the hub acts as a bridge, advertising routes learned from the circuit to all spokes and vice‑versa. This creates a meshed topology without the need for explicit point‑to‑point connections.
| Component | Description |
|---|---|
| ExpressRoute Circuit | Dedicated, private connection to Microsoft edge. |
| Virtual WAN Hub | Regional routing point that aggregates connectivity. |
| Spokes (VNets/Branch VPN) | Resources that communicate via the hub. |
| Route Server (optional) | Enables dynamic BGP routing with on‑prem devices. |
Prerequisites
- An active Azure subscription.
- Provisioned ExpressRoute circuit with at least Standard SKU.
- Virtual WAN resource created in the desired region.
- Network permissions to create and associate resources.
Configuration Steps
Follow these steps in the Azure portal or via Azure CLI/PowerShell.
# Azure CLI example
az network express-route create \
--name MyERcircuit \
--resource-group MyRG \
--location eastus \
--sku Standard_MeteredData \
--provider Microsoft \
--peering-location "Silicon Valley"
# Create Virtual WAN and hub
az network vwan create --name MyWAN --resource-group MyRG --location eastus
az network vhub create --name MyHub --resource-group MyRG --vwan MyWAN --address-prefix 10.0.0.0/24
# Associate ExpressRoute circuit with the hub
az network vhub connection create \
--name ER-to-Hub \
--resource-group MyRG \
--vhub-name MyHub \
--express-route-circuit MyERcircuit \
--authorization-key
Best Practices
- Use Standard SKU for production workloads to ensure SLA.
- Enable ExpressRoute Global Reach if you need inter‑region private connectivity.
- Implement Azure Firewall in the hub for centralized security enforcement.
- Leverage Azure Monitor and Network Watcher for performance and health insights.
- Consider redundancy with dual‑circuit or dual‑region hub deployment.
FAQ
- Can I have multiple ExpressRoute circuits attached to a single hub?
- Yes. You can associate multiple circuits for higher bandwidth or redundancy.
- Is traffic between a spoke and the on‑premises network routed through the hub?
- All traffic traverses the hub, which provides a single point for policies and monitoring.
- How does failover to VPN work?
- Virtual WAN automatically creates a VPN tunnel as a fallback. If the ExpressRoute link fails, traffic is seamlessly rerouted over the VPN.