Connecting your on-premises infrastructure to the cloud doesn’t have to mean sacrificing speed, security, or reliability. With ExpressRoute, enterprises gain a dedicated, private pathway to Microsoft Azure and other cloud services—bypassing the public internet entirely. This game-changing solution is redefining how businesses scale, secure, and streamline their hybrid environments.
What Is ExpressRoute and How Does It Work?
Microsoft ExpressRoute is a premium network connectivity service that enables organizations to establish private, high-speed connections between their on-premises data centers or branch offices and Microsoft cloud services such as Azure, Microsoft 365, and Dynamics 365. Unlike traditional internet-based connections, ExpressRoute bypasses the public internet, offering more predictable performance, enhanced security, and lower latency.
Core Architecture of ExpressRoute
ExpressRoute operates by leveraging Layer 3 or Layer 2 network circuits provided by telecommunications carriers or cloud exchange providers. These circuits create a direct bridge from your network to Microsoft’s global backbone. The connection is established through peering locations—strategically placed data centers where your network provider interconnects with Microsoft’s infrastructure.
- Connections are established via Ethernet circuits or virtual cross-connections (VXCs) in cloud exchanges.
- Microsoft supports multiple peering types: Private, Microsoft, and Azure Public (now largely deprecated in favor of global reach and virtual networks).
- Traffic flows directly into Microsoft’s network, avoiding public internet hops.
Key Components of an ExpressRoute Connection
To set up and maintain an ExpressRoute circuit, several components must be in place. These include the circuit itself, routing configurations, and peering settings.
ExpressRoute Circuit: A logical representation of the connection, created and managed in the Azure portal.It acts as a container for your connection details.Service Provider: A telecom or network provider (like AT&T, BT, or Equinix) that delivers the physical connectivity.Peering Locations: Physical sites where your provider connects to Microsoft’s network..
BGP (Border Gateway Protocol): Used to exchange routing information between your network and Microsoft’s edge routers.”ExpressRoute provides a more reliable and consistent network experience by removing the variability inherent in public internet routing.” — Microsoft Azure Documentation
ExpressRoute vs.VPN: Understanding the Critical Differences
When connecting to Azure, organizations often face a choice between using a site-to-site VPN over the public internet or deploying ExpressRoute.While both enable hybrid connectivity, their performance, security, and use cases differ significantly..
Performance and Latency Comparison
One of the most compelling reasons to choose ExpressRoute over a standard VPN is performance. Because ExpressRoute avoids the public internet, it offers lower latency and higher throughput.
- Typical site-to-site VPNs experience latency between 50–150 ms depending on geographic distance and internet congestion.
- ExpressRoute connections often achieve sub-10 ms latency when connected through a local peering location.
- Bandwidth options for ExpressRoute range from 50 Mbps to 100 Gbps, far exceeding typical VPN limits.
Security and Data Privacy
Security is a top concern for enterprises moving to the cloud. ExpressRoute enhances data privacy by ensuring traffic never traverses the public internet.
- Site-to-site VPNs encrypt data but still route it over shared, public networks, making them susceptible to DDoS attacks and packet sniffing.
- ExpressRoute connections are private by design—data moves through dedicated circuits, reducing the attack surface.
- While encryption isn’t built into ExpressRoute itself, organizations can implement IPsec or other encryption layers at the application or network level.
Reliability and SLA Guarantees
ExpressRoute comes with a robust Service Level Agreement (SLA) that guarantees uptime and performance—something traditional internet-based connections cannot match.
- Microsoft offers a 99.9% uptime SLA for ExpressRoute circuits.
- Many service providers offer additional SLAs for circuit availability and repair times.
- In contrast, standard internet connections have no guaranteed uptime or performance metrics.
The 7 Powerful Benefits of Using ExpressRoute
ExpressRoute isn’t just a faster connection—it’s a strategic enabler for digital transformation. Below are seven key advantages that make ExpressRoute indispensable for enterprise cloud strategies.
1. Predictable Network Performance
One of the biggest pain points with internet-based connections is unpredictability. Bandwidth can fluctuate, latency can spike during peak hours, and packet loss can disrupt critical applications. ExpressRoute eliminates these issues.
- Guaranteed bandwidth with no contention from other users.
- Consistent latency, essential for real-time applications like VoIP, video conferencing, and database replication.
- Ideal for latency-sensitive workloads such as SAP HANA, SQL Server Always On, and high-frequency trading platforms.
2. Enhanced Security and Compliance
For industries like finance, healthcare, and government, data sovereignty and compliance are non-negotiable. ExpressRoute helps meet these requirements by keeping data off the public internet.
- Reduces exposure to common internet threats like man-in-the-middle attacks and DNS spoofing.
- Supports compliance with regulations such as HIPAA, GDPR, and FedRAMP by minimizing data transit risks.
- Can be integrated with Azure Firewall, Network Security Groups (NSGs), and private endpoints for defense-in-depth security.
3. Higher Bandwidth and Scalability
As organizations migrate large datasets, run data-intensive analytics, or deploy AI/ML workloads, bandwidth becomes a bottleneck. ExpressRoute offers scalable bandwidth options to support growing demands.
- Available in increments: 50 Mbps, 100 Mbps, 500 Mbps, 1 Gbps, 2 Gbps, 5 Gbps, 10 Gbps, and up to 100 Gbps via ExpressRoute Direct.
- Bandwidth can be upgraded without changing physical infrastructure.
- Supports massive data migrations using Azure Data Box over ExpressRoute for faster, secure transfers.
4. Cost Efficiency for High-Volume Data Transfer
While ExpressRoute has higher upfront costs than a standard internet connection, it becomes more cost-effective for high-volume data transfer scenarios.
- Azure data transfer costs are significantly lower over ExpressRoute compared to internet egress.
- Eliminates the need for expensive bandwidth upgrades on internet links to handle cloud traffic.
- Reduces reliance on third-party CDN or caching solutions due to improved direct connectivity.
5. Support for Hybrid Cloud and Multi-Cloud Strategies
ExpressRoute is a cornerstone of hybrid cloud architectures, enabling seamless integration between on-premises systems and Azure services.
- Enables hybrid identity with Azure AD Connect over a secure, reliable link.
- Supports disaster recovery setups with Azure Site Recovery (ASR) and backup services.
- Facilitates multi-cloud connectivity when combined with services like AWS Direct Connect via partner solutions.
6. Global Reach and Inter-Region Connectivity
ExpressRoute Global Reach allows organizations to connect their on-premises networks to Azure regions worldwide through a single circuit.
- Enables private connectivity between branches in different countries without routing through a central hub.
- Uses Microsoft’s global backbone to provide low-latency inter-region communication.
- Ideal for multinational corporations with distributed offices and data centers.
7. Integration with Azure Services
ExpressRoute isn’t just for VMs and storage—it integrates deeply with a wide range of Azure services, unlocking advanced capabilities.
- Enables private access to Azure Storage, Azure SQL Database, and Azure Kubernetes Service (AKS) via Private Endpoints.
- Supports Azure Virtual WAN for simplified global network management.
- Integrates with Azure Monitor and Network Watcher for end-to-end visibility and troubleshooting.
ExpressRoute Peering Types Explained
Peering is the mechanism that allows your network to exchange routes with Microsoft’s network. ExpressRoute supports three types of peering, each serving different purposes.
Private Peering
Private peering is the most commonly used peering type. It allows access to Azure services deployed in virtual networks (VNet).
- Uses RFC1918 private IP addresses (e.g., 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16).
- Enables secure, private connectivity to IaaS and PaaS services within Azure VNets.
- Configured using BGP with AS numbers 65515 for Microsoft and a customer-defined ASN.
Microsoft Peering
Microsoft peering allows direct access to Microsoft online services such as Office 365, Dynamics 365, and Azure Public IPs.
- Uses public IP addresses on the customer side.
- Provides better performance and more predictable routing for SaaS applications.
- Requires compliance with Microsoft’s routing and IP address requirements.
Azure Public Peering (Deprecated)
Azure public peering was used to access Azure services over public IP addresses but has been deprecated in favor of private peering and service endpoints.
- No longer available for new circuits as of January 2021.
- Existing circuits can still operate but are encouraged to migrate.
- Migration typically involves setting up private peering and using Azure Private Link or service endpoints.
How to Set Up an ExpressRoute Circuit
Deploying ExpressRoute involves several steps, from selecting a provider to configuring routing and testing connectivity. Here’s a step-by-step guide.
Step 1: Choose a Connectivity Model
ExpressRoute offers three connectivity models depending on your infrastructure and requirements.
- Carrier Connectivity: Partner with telecom providers like Verizon, AT&T, or NTT for dedicated circuits.
- Cloud Exchange Co-location: Use providers like Equinix, Digital Realty, or Interxion to establish virtual cross-connections in data centers.
- ExpressRoute Direct: For enterprises needing 10 Gbps or 100 Gbps connections, this offers direct physical ports into Microsoft’s network.
Step 2: Provision the Circuit
Once you’ve selected a model, you’ll need to provision the circuit through the Azure portal or API.
- Create an ExpressRoute circuit resource in Azure, specifying location, bandwidth, and service provider.
- Provide the Service Key to your provider to activate the physical connection.
- Wait for the provider to confirm circuit provisioning (can take days to weeks).
Step 3: Configure Routing and Peering
After the circuit is active, configure BGP peering and routing settings.
- Enable private peering in the Azure portal.
- Configure BGP sessions with Microsoft’s edge routers using your ASN and IP addresses.
- Advertise your on-premises routes to Azure and learn Azure routes via BGP.
Step 4: Connect to Virtual Networks
Finally, link your ExpressRoute circuit to one or more Azure VNets.
- Use the Azure portal to authorize VNet connections to the circuit.
- Ensure VNet routing tables are configured to route traffic via ExpressRoute.
- Test connectivity using tools like
ping,tracert, or Azure Network Watcher.
Troubleshooting Common ExpressRoute Issues
Even with its reliability, ExpressRoute connections can encounter issues. Understanding common problems and how to resolve them is crucial for maintaining uptime.
Peering Isn’t Established
If BGP peering fails to come up, check the following:
- Verify that both sides are using correct IP addresses and ASNs.
- Ensure that firewalls or routers aren’t blocking TCP port 179 (BGP).
- Check if the circuit is in an “Enabled” state in the Azure portal.
No Traffic Flow Despite Active Peering
Sometimes peering is up, but traffic doesn’t flow. This can be due to routing misconfigurations.
- Confirm that your on-premises router is advertising the correct routes to Microsoft.
- Check if Azure is learning your routes (visible in the Azure portal under “Learned Routes”).
- Ensure that VNet route tables and NSGs aren’t blocking traffic.
High Latency or Packet Loss
While rare, performance degradation can occur.
- Use Azure Network Watcher’s Connection Monitor to diagnose latency and packet loss.
- Contact your service provider to check for physical layer issues.
- Verify that your on-premises router isn’t oversubscribed or experiencing CPU spikes.
Best Practices for Managing ExpressRoute
To get the most out of ExpressRoute, follow these proven best practices for deployment and ongoing management.
Design for Redundancy
Always deploy ExpressRoute with redundancy in mind.
- Use two separate circuits from different providers or different peering locations.
- Configure BGP with multiple paths for failover.
- Combine ExpressRoute with a site-to-site VPN for a resilient hybrid setup (known as “forced tunneling” or “backup over VPN”).
Monitor Performance Continuously
Leverage Azure’s monitoring tools to keep tabs on your ExpressRoute health.
- Use Azure Monitor and Log Analytics to track circuit utilization, latency, and errors.
- Set up alerts for BGP session drops or high packet loss.
- Integrate with third-party tools like SolarWinds or PRTG for enterprise-wide visibility.
Plan for Capacity and Growth
Start with the right bandwidth but plan for future needs.
- Monitor bandwidth usage trends to anticipate upgrades.
- Consider ExpressRoute Direct for large-scale, predictable growth.
- Use QoS policies to prioritize critical traffic over less important data.
What is ExpressRoute used for?
ExpressRoute is used to establish private, high-speed connections between on-premises infrastructure and Microsoft cloud services like Azure, Microsoft 365, and Dynamics 365. It enables secure, reliable, and low-latency access to cloud resources without traversing the public internet, making it ideal for hybrid cloud deployments, data migration, and enterprise applications.
How much does ExpressRoute cost?
The cost of ExpressRoute varies based on bandwidth, peering location, and service provider. Azure charges for circuit usage and data transfer, while providers charge for the physical circuit. For example, a 1 Gbps circuit in the US might cost $200–$500/month from the provider, plus Azure fees based on data volume. ExpressRoute Direct (10/100 Gbps) has higher costs but offers greater scalability. Detailed pricing can be found on the official Microsoft Azure pricing page.
Can ExpressRoute connect to Office 365?
Yes, ExpressRoute can connect to Office 365 through Microsoft peering. However, not all Office 365 traffic benefits equally—only specific endpoints (like Exchange Online and SharePoint Online) are accessible via ExpressRoute. Microsoft recommends using ExpressRoute for predictable performance but emphasizes that internet connectivity is still required for other services and updates. More details are available in the Office 365 network connectivity principles.
What is the difference between ExpressRoute and ExpressRoute Direct?
ExpressRoute is a general term for private connectivity to Azure, typically delivered via a service provider. ExpressRoute Direct is a premium offering that provides physical 10 Gbps or 100 Gbps ports directly into Microsoft’s global network, giving enterprises greater control, scalability, and visibility. It’s designed for large organizations with high bandwidth demands and the need for direct connectivity. Learn more at Microsoft’s ExpressRoute Direct documentation.
Is ExpressRoute encrypted?
ExpressRoute itself does not provide encryption, as it relies on the physical isolation of dedicated circuits for security. However, organizations can implement encryption at the application or network layer using IPsec, TLS, or Azure Private Link to protect data in transit. This layered approach ensures both performance and confidentiality.
ExpressRoute is far more than just a network connection—it’s a strategic asset for enterprises embracing the cloud. By delivering predictable performance, enhanced security, and seamless integration with Azure services, ExpressRoute empowers organizations to build resilient, scalable, and high-performing hybrid environments. Whether you’re migrating workloads, supporting global teams, or ensuring compliance, ExpressRoute provides the foundation for a modern cloud network. With proper planning, redundancy, and monitoring, it becomes a cornerstone of digital transformation—proving that when it comes to cloud connectivity, private is powerful.
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