Azure ExpressRoute Circuits

Understanding Azure ExpressRoute Circuits

An Azure ExpressRoute circuit is a logical connection that you establish between your on-premises infrastructure or co-location environment and Microsoft Azure. It enables high-throughput, low-latency connectivity that is more reliable than typical internet connections.

Key Components of an ExpressRoute Circuit:

• Service Key: A unique identifier for your ExpressRoute circuit, used for provisioning by your network service provider.
• Provider: The network service provider (e.g., AT&T, Lumen, Equinix) that facilitates the physical connection.
• Port: The physical connection point at an ExpressRoute location.
• Bandwidth: The data transfer rate of your circuit (e.g., 50 Mbps, 100 Mbps, 1 Gbps, 10 Gbps).
• Peering Locations: The specific data center locations where your circuit connects to the Azure network.
• Circuit Status: Indicates whether the circuit is provisioned, enabled, or in a transitional state.

Circuit Provisioning and Lifecycle:

Provisioning an ExpressRoute circuit involves several steps:

1. Order a Circuit: You initiate an order for an ExpressRoute circuit through the Azure portal or Azure CLI, specifying your desired bandwidth and peering location.
2. Provider Configuration: Microsoft shares the Service Key with your chosen network service provider. The provider then configures the physical circuit and establishes connectivity to the Azure edge routers.
3. Azure Activation: Once the provider confirms connectivity, Azure activates the circuit. This process can take a few business days.
4. Peering Configuration: After the circuit is active, you configure the necessary peering (Microsoft, Azure private, or Azure public) to route traffic.

Circuit States:

An ExpressRoute circuit can be in various states during its lifecycle:

• Not Provisioned: The circuit has been created in Azure but not yet configured by the network service provider.
• Provisioning: The circuit is being configured by the network service provider.
• Provisioned: The physical circuit is active and ready for peering configuration.
• Deleting: The circuit is in the process of being deprovisioned.

Managing Your Circuits:

You can manage your ExpressRoute circuits through the Azure portal, Azure CLI, or PowerShell. Key management tasks include:

• Viewing circuit details (status, provider, bandwidth).
• Configuring and managing peering.
• Monitoring circuit performance and utilization.
• Decommissioning circuits when they are no longer needed.

Example: Creating an ExpressRoute Circuit (Conceptual)

While this is a conceptual example, creating a circuit typically involves specifying details like location, SKU, and bandwidth.

# Azure CLI Example (Conceptual)
az expressroute create --circuit-name MyExpressRouteCircuit \
    --resource-group MyResourceGroup \
    --location westus \
    --plan azure \
    --sku Standard_MeteredData \
    --bandwidth 100  # in Mbps