What is Azure ExpressRoute Global Reach?
Azure ExpressRoute Global Reach extends the benefits of ExpressRoute connectivity from your on-premises network to the Azure backbone network. This allows you to extend your on-premises network to your Azure virtual networks, and vice-versa, across different Azure regions. It's an ideal solution for scenarios where you need to connect your geographically dispersed on-premises datacenters to your Azure environments.
Key Benefits:
- Global Connectivity: Seamlessly connect your on-premises networks and Azure virtual networks located in different geographic regions.
- Simplified Networking: Reduces the complexity of managing cross-region connectivity by leveraging the Azure backbone.
- Enhanced Performance: Utilizes the high-bandwidth, low-latency Azure backbone for inter-region traffic.
- Cost-Effective: Often more cost-effective than traditional public internet routing for large-scale inter-region data transfers.
- Secure: Leverages the security of your existing ExpressRoute connection.
How it Works
ExpressRoute Global Reach works by enabling your circuits to exchange traffic between your on-premises network and your Azure virtual networks. When you enable Global Reach, your on-premises routers that are connected to ExpressRoute circuits in different locations can communicate directly with each other over the Azure backbone network.
The core components involved are:
- ExpressRoute Circuits: You need ExpressRoute circuits in each location you wish to connect.
- On-Premises Network: Your physical datacenter network.
- Azure Virtual Networks: Your cloud environments in Azure.
- ExpressRoute Gateway: Deployed in your Azure virtual networks.
Configuration Steps:
- Ensure you have ExpressRoute circuits established for each on-premises location you want to connect.
- Configure your on-premises routers to advertise the address prefixes for your local networks and to accept routes for remote networks.
- Create or configure ExpressRoute gateways in your Azure virtual networks in the respective regions.
- Establish connections between your on-premises network and your Azure virtual networks using ExpressRoute.
- Enable ExpressRoute Global Reach on your ExpressRoute circuits and peerings.
- Configure routing to allow traffic to flow between your on-premises networks and Azure virtual networks across regions.
Use Cases
- Connecting disaster recovery sites in different regions to your primary datacenter or Azure environment.
- Establishing a consistent network for applications deployed across multiple Azure regions and on-premises datacenters.
- Centralizing management of hybrid cloud connectivity for global organizations.
- Facilitating data replication and synchronization between geographically separated systems.
Technical Considerations
IP Addressing
Ensure that your on-premises IP address spaces and Azure virtual network address spaces do not overlap. Global Reach relies on the Azure backbone to route traffic between these distinct address spaces.
Border Gateway Protocol (BGP)
BGP is used to exchange routing information. You will need to configure BGP peering between your on-premises routers and the Azure ExpressRoute gateways. The maximum number of prefixes you can advertise depends on your ExpressRoute SKU.
# Example BGP configuration snippet (conceptual)
router bgp 65001
neighbor 10.100.1.2 remote-as 65501
neighbor 10.100.1.2 update-source Vlan100
!
address-family ipv4 unicast
network 192.168.1.0 mask 255.255.255.0
exit-address-family
Service Provider Integration
Your chosen ExpressRoute service provider plays a crucial role. They will assist in provisioning the circuits and can help with the peering and routing configurations required for Global Reach.
Getting Started
To get started with ExpressRoute Global Reach:
- Review the official Azure ExpressRoute Global Reach documentation.
- Work with your network team and ExpressRoute service provider to plan your connectivity.
- Provision and configure your ExpressRoute circuits and Azure resources.
- Enable Global Reach through the Azure portal, Azure CLI, or PowerShell.
By leveraging ExpressRoute Global Reach, you can build a robust, high-performance, and secure hybrid network that spans your on-premises infrastructure and the Azure cloud across the globe.