Azure ExpressRoute: Private Connections Between Microsoft Datacenters and Your On-Premises Infrastructure
For enterprises that demand predictable performance, strict data sovereignty, and secure hybrid connectivity, Azure ExpressRoute establishes private, dedicated network connections between on-premises infrastructure and Microsoft Azure datacenters. Unlike site-to-site VPNs that traverse the public internet, ExpressRoute circuits operate over Layer 2 or Layer 3 connections through authorized connectivity providers, delivering lower latency, higher throughput, and built-in redundancy. EPC Group has architected ExpressRoute deployments for Fortune 500 organizations across healthcare, financial services, and government sectors where network reliability and compliance are non-negotiable.
How Azure ExpressRoute Works
Azure ExpressRoute creates a private circuit between your on-premises network (or colocation facility) and Microsoft's global network through an authorized connectivity partner such as Equinix, AT&T, Megaport, or Verizon. Traffic never touches the public internet, eliminating exposure to internet-based threats and removing the unpredictability of shared bandwidth.
ExpressRoute supports three connectivity models depending on your existing network topology:
- CloudExchange Co-location: If your facility is co-located at a cloud exchange (such as Equinix), you order virtual cross-connections directly to Microsoft's edge routers through the exchange provider's Ethernet infrastructure.
- Point-to-Point Ethernet: A dedicated Ethernet link from your datacenter to the nearest Microsoft peering location, provided by your carrier as a point-to-point circuit.
- Any-to-Any (IPVPN / MPLS): Integrates Azure as another branch location in your existing MPLS WAN. Traffic from any site connected to your MPLS network can reach Azure through the ExpressRoute circuit without additional hardware.
ExpressRoute Pricing and Circuit Options
ExpressRoute pricing is based on circuit bandwidth, peering type, and whether you select metered or unlimited data plans:
- Circuit Bandwidth: Available in 50 Mbps, 100 Mbps, 200 Mbps, 500 Mbps, 1 Gbps, 2 Gbps, 5 Gbps, and 10 Gbps options. The monthly port fee increases with bandwidth. For burst scenarios, ExpressRoute Direct offers 10 Gbps and 100 Gbps dedicated ports.
- Metered Plan: Lower monthly port fee with per-GB egress charges for data leaving Azure. Best for workloads with predictable or moderate outbound data volumes.
- Unlimited Plan: Higher monthly port fee with no egress charges. Ideal for data-intensive workloads such as backup/replication, large-scale analytics, or media streaming where outbound volumes are high or unpredictable.
- ExpressRoute Premium Add-on: Extends connectivity beyond the local geopolitical region, enabling access to Azure resources in any region worldwide. Required for global organizations that need cross-region connectivity from a single circuit.
- ExpressRoute Global Reach: Connects two ExpressRoute circuits together, allowing data to flow between on-premises sites in different regions via Microsoft's backbone instead of traversing the public internet.
Organizations should also budget for connectivity partner charges (cross-connect fees, port fees from the exchange provider) which are billed separately from Microsoft's ExpressRoute charges.
Peering Types and Routing
Each ExpressRoute circuit supports multiple peering types, allowing segmentation of traffic by service:
- Azure Private Peering: Connects to Azure IaaS and PaaS resources (Virtual Machines, Storage, SQL Database, AKS) via private IP addresses. This is the most common peering type and extends your on-premises network directly into Azure VNets.
- Microsoft Peering: Connects to Microsoft 365 services, Dynamics 365, and Azure PaaS services that use public IP addresses. Requires route filters to control which Microsoft service prefixes are advertised to your network.
BGP (Border Gateway Protocol) is used for route exchange between your edge routers and Microsoft's peering routers. EPC Group configures BGP communities, AS path prepending, and route filters to ensure optimal traffic engineering and failover behavior.
High Availability and Redundancy
Microsoft requires each ExpressRoute circuit to have two BGP sessions (primary and secondary) to separate Microsoft Enterprise Edge (MSEE) routers. For production workloads, EPC Group recommends additional redundancy layers:
- Dual Circuits: Provision two ExpressRoute circuits at different peering locations for geographic redundancy. If one peering location goes down, traffic automatically fails over to the second circuit.
- ExpressRoute + VPN Failover: Configure a site-to-site VPN as a backup path. Azure VNet gateways support coexistence of ExpressRoute and VPN connections with automatic failover.
- Zone-Redundant Gateways: Deploy ExpressRoute gateways across Availability Zones to protect against datacenter-level failures within an Azure region.
- BFD (Bidirectional Forwarding Detection): Enable BFD over ExpressRoute for sub-second failover detection, reducing convergence time from minutes to milliseconds when a link fails.
Compliance and Security Considerations
ExpressRoute is the preferred connectivity option for compliance-sensitive workloads because traffic stays on private infrastructure:
- HIPAA: Private circuits satisfy the requirement for encrypted or controlled network paths for ePHI transmission. Combined with VNet-level NSGs and Azure Private Link, organizations can ensure end-to-end private data flows.
- PCI DSS: Eliminates public internet exposure for cardholder data environments, simplifying network segmentation requirements and reducing the scope of PCI assessments.
- FedRAMP / Government: ExpressRoute with Azure Government regions provides dedicated connectivity for federal workloads. ExpressRoute Direct offers physical port-level isolation for classified or high-impact workloads.
- Data Residency: Route filters and peering controls ensure data stays within specified geopolitical boundaries, satisfying GDPR and other data sovereignty requirements.
Why EPC Group for ExpressRoute Architecture
Designing and deploying ExpressRoute at enterprise scale involves complex decisions around peering locations, bandwidth sizing, routing topology, and failover strategy. EPC Group provides:
- Network Assessment: We analyze your existing WAN topology, application traffic patterns, and latency requirements to recommend the optimal ExpressRoute configuration.
- Connectivity Partner Selection: We work with exchange providers to negotiate pricing, provision circuits, and establish cross-connects based on your geographic requirements.
- BGP Design and Implementation: Our network engineers configure BGP routing policies, AS path manipulation, and community tagging to ensure deterministic traffic flows and optimal failover behavior.
- Monitoring and Optimization: We deploy Azure Network Watcher, Connection Monitor, and ExpressRoute monitoring to provide real-time visibility into circuit health, bandwidth utilization, and latency metrics.
- Hybrid Architecture: We integrate ExpressRoute into your broader Azure landing zone architecture, including hub-and-spoke VNet topologies, Azure Firewall, and Private Link configurations.
Design Your Private Cloud Connectivity
Contact EPC Group for an ExpressRoute architecture assessment. We will evaluate your bandwidth requirements, compliance needs, and geographic footprint to design a private connectivity solution that delivers enterprise-grade performance and reliability.
Frequently Asked Questions
How does ExpressRoute differ from a site-to-site VPN?
A site-to-site VPN encrypts traffic and sends it over the public internet, which means performance is subject to internet congestion and latency variability. ExpressRoute uses dedicated private circuits that bypass the internet entirely, providing consistent latency, higher bandwidth (up to 100 Gbps with ExpressRoute Direct), and an SLA-backed 99.95% uptime guarantee. VPNs are appropriate for dev/test or low-bandwidth scenarios, while ExpressRoute is the standard for production enterprise workloads.
Can I use ExpressRoute for Microsoft 365 connectivity?
Yes, but Microsoft generally recommends internet-based connectivity for Microsoft 365 due to its globally distributed architecture. ExpressRoute Microsoft Peering can route Microsoft 365 traffic over your private circuit, but this requires Microsoft approval, route filter configuration, and careful capacity planning. It is most commonly used by organizations with strict security policies that prohibit any internet-bound traffic from their corporate network.
What bandwidth should I provision?
Start by analyzing your current Azure traffic patterns using VNet flow logs and Network Watcher. Factor in peak vs. average utilization, replication traffic (ASR, SQL AlwaysOn), backup windows, and planned growth. EPC Group typically recommends starting at 1 Gbps for mid-size enterprises and scaling up based on observed utilization. ExpressRoute circuits can be upgraded to higher bandwidth tiers without downtime, so right-sizing at deployment and scaling later is a practical approach.
Is ExpressRoute encrypted by default?
No. ExpressRoute provides a private circuit but does not encrypt traffic at the network layer by default. For organizations requiring encryption (HIPAA, PCI DSS), you can enable MACsec (IEEE 802.1AE) on ExpressRoute Direct ports for Layer 2 encryption, or configure IPsec VPN tunnels over the ExpressRoute circuit for Layer 3 encryption. Application-layer encryption (TLS/HTTPS) provides an additional layer regardless of network-level encryption.
How long does it take to provision an ExpressRoute circuit?
The Azure-side provisioning (circuit creation in the portal) takes minutes. However, the connectivity provider must provision the physical cross-connect, which typically takes 2-6 weeks depending on the provider and peering location. EPC Group manages the end-to-end provisioning process including provider coordination, BGP configuration, and validation testing to ensure the circuit meets performance and redundancy requirements before production traffic is migrated.