ExpressRoute

ExpressRoute is a Microsoft Azure networking service that enables private, dedicated connections between an enterprise’s on-premises infrastructure or colocation facilities and Microsoft Azure data centers. By routing traffic over a private circuit rather than the public Internet, ExpressRoute aims to provide more predictable latency, higher bandwidth, and improved reliability for hybrid cloud deployments.

Connections are established through ExpressRoute circuits, which can be provisioned via a connectivity provider or directly through ExpressRoute Direct. Private peering links to one or more Azure virtual networks (VNets) and uses Border Gateway Protocol (BGP) for dynamic route exchange. Microsoft peering (formerly called public peering) grants access to Azure public services such as Storage, SQL Database, and other PaaS offerings over the private connection.

ExpressRoute circuits come in various bandwidth levels and can be configured as metered data or unlimited data, depending on the provider and subscription. ExpressRoute Direct provides a direct connection to Microsoft's backbone at very high speeds, suitable for large-scale workloads. Global Reach expands connectivity to on-premises networks in other regions through a single ExpressRoute circuit, enabling cross-region hybrid connectivity.

Security and compliance considerations include the fact that traffic on ExpressRoute does not traverse the public Internet. However, encryption in transit is not provided by ExpressRoute itself; customers may add IPsec VPNs or application-layer encryption if required. Microsoft offers service-level agreements (SLAs) for ExpressRoute, reflecting its role in enterprise-grade hybrid networking, disaster recovery, and data residency strategies. Typical use cases include private cloud extensions, large-scale data transfers, and mission-critical workloads requiring consistent network performance.