Migrating ExpressRoute Connections to Azure Virtual WAN
This document outlines the process and considerations for migrating your existing Azure ExpressRoute connections to Azure Virtual WAN. Virtual WAN provides a unified networking platform that optimizes connectivity and management for your distributed Azure and on-premises environments.
Overview
Azure Virtual WAN consolidates multiple networking features into a single operational window, offering optimized and automated global transit and routing. Migrating from direct ExpressRoute connections to Virtual WAN can simplify management, improve performance, and enhance security posture. This migration is particularly beneficial for organizations with complex hub-and-spoke topologies or those looking to achieve unified connectivity across multiple regions and on-premises sites.
Benefits of Migrating to Virtual WAN
- Simplified Management: A single pane of glass for managing all your network connections.
- Global Transit Network: Enables seamless routing between your virtual networks, branch offices, and remote users.
- Optimized Routing: Leverages Azure backbone for efficient traffic flow.
- Scalability and High Availability: Built for enterprise-grade scalability and resilience.
- Integrated Security Features: Incorporates Azure Firewall and Network Security Groups for enhanced security.
- Cost Efficiency: Potential for reduced data transfer costs due to optimized routing.
Migration Steps
The migration process typically involves several key phases:
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Planning and Design
Understand your current network topology, traffic patterns, and compliance requirements. Design your Virtual WAN topology, including the number of hubs, regions, and connectivity types (VPN, ExpressRoute).
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Create Virtual WAN and Hubs
Provision a Virtual WAN resource in Azure. Deploy Virtual WAN hubs in the desired regions. These hubs will serve as the central points of connectivity.
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Configure ExpressRoute Gateway in Hubs
Deploy an ExpressRoute gateway within each Virtual WAN hub. This gateway will connect your existing ExpressRoute circuits to the Virtual WAN fabric.
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Establish ExpressRoute Circuit Connections
Associate your existing ExpressRoute circuits with the Virtual WAN hubs. This involves updating your peering configurations with your connectivity provider.
Important: Ensure your ExpressRoute circuit is provisioned with a sufficient bandwidth to accommodate your expected traffic through Virtual WAN. -
Configure VNet Connectivity
Connect your existing virtual networks to the Virtual WAN hubs. This is typically done by creating VNet connections to the hubs.
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Route Propagation and Policy Configuration
Configure routing policies within Virtual WAN to control traffic flow between connected environments. Azure Route Server or VNet gateway transit capabilities may be leveraged.
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Testing and Validation
Thoroughly test connectivity, routing, and application performance after the migration. Monitor traffic flow and troubleshoot any issues.
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Decommission Old Resources (Optional)
Once confident in the new Virtual WAN setup, you may choose to decommission your legacy direct ExpressRoute peering configurations.
Key Considerations
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Service Provider Coordination:
Engage with your ExpressRoute connectivity provider early in the process to coordinate circuit updates and configurations.
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IP Addressing and Routing:
Carefully plan IP address spaces and routing configurations to avoid conflicts and ensure proper traffic flow.
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Downtime Tolerance:
Develop a migration strategy that minimizes downtime. Phased migrations or parallel setups might be necessary.
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Azure Firewall Integration:
Consider integrating Azure Firewall with your Virtual WAN hubs for centralized security policy enforcement.
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BGP Peering:
Understand how BGP peering works with Virtual WAN and ensure compatibility with your on-premises routers.
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Cost Analysis:
Evaluate the cost implications of Virtual WAN compared to your current ExpressRoute setup, considering data transfer, gateway, and hub costs.