Tutorial: Connect a virtual network to an ExpressRoute circuit using the portal

This tutorial helps you create a connection to link a virtual network to an Azure ExpressRoute circuit using the Azure portal. The virtual networks that you connect to your Azure ExpressRoute circuit can either be in the same subscription or be part of another subscription.

In this tutorial, you learn how to:

  • Connect a virtual networking to a circuit in the same subscription.
  • Connect a virtual networking to a circuit in a different subscription.
  • Delete the link between the virtual network and ExpressRoute circuit.

Prerequisites

  • Review the prerequisites, routing requirements, and workflows before you begin configuration.

  • You must have an active ExpressRoute circuit.

    • Follow the instructions to create an ExpressRoute circuit and have the circuit enabled by your connectivity provider.
    • Ensure that you have Azure private peering configured for your circuit. See the Create and modify peering for an ExpressRoute circuit article for peering and routing instructions.
    • Ensure that Azure private peering gets configured and establishes BGP peering between your network and Microsoft for end-to-end connectivity.
    • Ensure that you have a virtual network and a virtual network gateway created and fully provisioned. Follow the instructions to create a virtual network gateway for ExpressRoute. A virtual network gateway for ExpressRoute uses the GatewayType 'ExpressRoute', not VPN.
  • You can link up to 10 virtual networks to a standard ExpressRoute circuit. All virtual networks must be in the same geopolitical region when using a standard ExpressRoute circuit.

  • A single VNet can be linked to up to 16 ExpressRoute circuits. Use the following process to create a new connection object for each ExpressRoute circuit you're connecting to. The ExpressRoute circuits can be in the same subscription, different subscriptions, or a mix of both.

  • If you enable the ExpressRoute premium add-on, you can link virtual networks outside of the geopolitical region of the ExpressRoute circuit. The premium add-on will also allow you to connect more than 10 virtual networks to your ExpressRoute circuit depending on the bandwidth chosen. Check the FAQ for more details on the premium add-on.

  • In order to create the connection from the ExpressRoute circuit to the target ExpressRoute virtual network gateway, the number of address spaces advertised from the local or peered virtual networks needs to be equal to or less than 200. Once the connection has been successfully created, you can add additional address spaces, up to 1,000, to the local or peered virtual networks.

  • You can view a video before beginning to better understand the steps.

Connect a VNet to a circuit - same subscription

Note

BGP configuration information will not appear if the layer 3 provider configured your peerings. If your circuit is in a provisioned state, you should be able to create connections.

To create a connection

  1. Ensure that your ExpressRoute circuit and Azure private peering have been configured successfully. Follow the instructions in Create an ExpressRoute circuit and Create and modify peering for an ExpressRoute circuit. Your ExpressRoute circuit should look like the following image:

    ExpressRoute circuit screenshot

  2. You can now start provisioning a connection to link your virtual network gateway to your ExpressRoute circuit. Select Connection > Add to open the Add connection page.

    Add connection screenshot

  3. Enter a name for the connection and then select Next: Settings >.

    Create connection basic page

  4. Select the gateway that belongs to the virtual network that you want to link to the circuit and select Review + create. Then select Create after validation completes.

    Create connection settings page

  5. After your connection has been successfully configured, your connection object will show the information for the connection.

    Connection object screenshot

Connect a VNet to a circuit - different subscription

You can share an ExpressRoute circuit across multiple subscriptions. The following figure shows a simple schematic of how sharing works for ExpressRoute circuits across multiple subscriptions.

Cross-subscription connectivity

Note

Connecting virtual networks between Azure sovereign clouds and Public Azure cloud is not supported. You can only link virtual networks from different subscriptions in the same cloud.

Each of the smaller clouds within the large cloud is used to represent subscriptions that belong to different departments within an organization. Each of the departments within the organization uses their own subscription for deploying their services--but they can share a single ExpressRoute circuit to connect back to your on-premises network. A single department (in this example: IT) can own the ExpressRoute circuit. Other subscriptions within the organization may use the ExpressRoute circuit.

Note

Connectivity and bandwidth charges for the dedicated circuit will be applied to the ExpressRoute circuit owner. All virtual networks share the same bandwidth.

Administration - About circuit owners and circuit users

The 'circuit owner' is an authorized Power User of the ExpressRoute circuit resource. The circuit owner can create authorizations that can be redeemed by 'circuit users'. Circuit users are owners of virtual network gateways that aren't within the same subscription as the ExpressRoute circuit. Circuit users can redeem authorizations (one authorization per virtual network).

The circuit owner has the power to modify and revoke authorizations at any time. Revoking an authorization results in all link connections being deleted from the subscription whose access was revoked.

Circuit owner operations

To create a connection authorization

The circuit owner creates an authorization, which creates an authorization key to be used by a circuit user to connect their virtual network gateways to the ExpressRoute circuit. An authorization is valid for only one connection.

Note

Each connection requires a separate authorization.

  1. In the ExpressRoute page, select Authorizations and then type a name for the authorization and select Save.

    Authorizations

  2. Once the configuration is saved, copy the Resource ID and the Authorization Key.

    Authorization key

To delete a connection authorization

You can delete a connection by selecting the Delete icon for the authorization key for your connection.

Delete authorization key

If you want to delete the connection but retain the authorization key, you can delete the connection from the connection page of the circuit.

Note

Connections redeemed in different subscriptions will not display in the circuit connection page. Navigate to the subscription where the authorization was redeemed and delete the top-level connection resource.

Delete connection owning circuit

Circuit user operations

The circuit user needs the resource ID and an authorization key from the circuit owner.

To redeem a connection authorization

  1. Select the + Create a resource button. Search for Connection and select Create.

    Create new resources

  2. Make sure the Connection type is set to ExpressRoute. Select the Resource group and Location, then select OK in the Basics page.

    Note

    The location must match the virtual network gateway location you're creating the connection for.

    Basics page

  3. In the Settings page, Select the Virtual network gateway and check the Redeem authorization check box. Enter the Authorization key and the Peer circuit URI and give the connection a name. Select OK.

    Note

    The Peer Circuit URI is the Resource ID of the ExpressRoute circuit (which you can find under the Properties Setting pane of the ExpressRoute Circuit).

    Settings page

  4. Review the information in the Summary page and select OK.

    Summary page

Configure ExpressRoute FastPath

You can enable ExpressRoute FastPath if your virtual network gateway is Ultra Performance or ErGw3AZ. FastPath improves data path performance such as packets per second and connections per second between your on-premises network and your virtual network.

Configure FastPath on a new connection

When adding a new connection for your ExpressRoute gateway, select the checkbox for FastPath.

Screenshot of FastPath checkbox in add a connection page.

Note

Enabling FastPath for a new connection is only available through creating a connection from the gateway resource. New connections created from the ExpressRoute circuit or from the Connection resource page is not supported.

Configure FastPath on an existing connection

  1. Go to the existing connection resource either from the ExpressRoute gateway, the ExpressRoute circuit, or the Connection resource page.

  2. Select Configuration under Settings and then select the FastPath checkbox. Select Save to enable the feature.

    Screenshot of FastPath checkbox on connection configuration page.

Note

You can use Connection Monitor to verify that your traffic is reaching the destination using FastPath.

Enroll in ExpressRoute FastPath features (preview)

FastPath support for virtual network peering is now in Public preview. Enrollment is only available through Azure PowerShell. See FastPath preview features, for instructions on how to enroll.

Note

Any connections configured for FastPath in the target subscription will be enrolled in this preview. We do not advise enabling this preview in production subscriptions. If you already have FastPath configured and want to enroll in the preview feature, you need to do the following:

  1. Enroll in the FastPath preview feature with the Azure PowerShell command above.
  2. Disable and then re-enable FastPath on the target connection.

Clean up resources

You can delete a connection and unlink your VNet to an ExpressRoute circuit by selecting the Delete icon on the page for your connection.

Delete connection

Next steps

In this tutorial, you learned how to connect a virtual network to a circuit in the same subscription and a different subscription. For more information about the ExpressRoute gateway, see: