Configure a failover group for VBRs - Express Connect - Alibaba Cloud Documentation Center

When the system detects a failure in an Express Connect circuit, the system performs a failover within a few seconds. To accelerate failovers, you can add virtual border routers (VBRs) to a failover group. After the system detects failures on a VBR by using Bidirectional Forwarding Detection (BDF), the system can seamlessly switch workloads to the standby VBR in the failover group within less than one second. This accelerates route convergence.

Limits

You can add only VBRs that have BFD enabled to failover groups.
Each failover group can contain only two VBRs and each VBR can be added to only one failover group.
VBRs in the same failover group must be deployed in the same region and associated with the same Express Connect Router (ECR) or Cloud Enterprise Network (CEN) instance.
Note
If you want to configure a failover group for VBRs associated with an ECR, the autonomous system number (ASN) of the ECR must be 45104.
You must configure the VBRs in a failover group as active and standby VBRs and configure load balancing for the VBRs.

Prerequisites

Two VBRs are created in the same region and each VBR is connected to your data center over an Express Connect circuit. For more information, see Create and manage a VBR and Add and manage routes.
Two VBRs are associcated with the same ECR or CEN instance. For more information, see Create and manage an ECR and Create a VBR connection.
BFD is configured for the VBRs. For more information, see Configure and manage BGP.

Create a failover group

Log on to the Express Connect console.
In the top navigation bar, select a region and click Virtual Border Routers (VBRs) in the left-side navigation pane.
On the Virtual Border Routers (VBRs) page, click the ID of the VBR.
On the VBR details page, click the Failover Groups tab, and click Configure Backup Next Hop.

In the Configure Backup Next Hop dialog box, set the following parameters and click OK:

Parameter	Description
Forwarding Gateway	The system automatically displays the ECR or CEN instance that is associated with the VBR. If the VBR is not associated with an ECR or CEN instance, click Attach Now and procced as prompted.
Region	The system automatically displays the region where the VBR is deployed.
Failover Group Name	Enter a name for the failover group. The name must be 2 to 128 characters in length and can contain letters, digits, underscores (_), and hyphens (-). It must start with a letter but cannot start with `http://` or `https://`.
Description	Enter a description for the failover group.
Standby VBR	Select a standby VBR from the drop-down list. The system automatically lists all VBRs that are deployed in the same region, associated with the same ECR or CEN instance, and have BFD enabled.

After you complete the preceding steps, the status of the failover group changes to Normal.

Note

You cannot modify the configuration of a failover group after the failover group is created. If the configuration of a failover group does not meet your business requirements, click Delete in the Actions column to delete the failover group. Then, create another failover group that meets your business requirements.

Test the failover group

After you complete the preceding steps, you can perform the following operations to test the failover group:

Log on to an Elastic Compute Service (ECS) instance. For more information, see Connection method overview.
Run the ping command on the ECS instance to check the connectivity between the ECS instance and your data center.
If you can receive echo reply packets, it indicates that the connection is established.
Disconnect the active VBR from the data center.
Run the ping command again on the ECS instance to check the connectivity between the ECS instance and your data center.
If you can receive echo reply packets, it indicates that the connection is switched to the standby VBR in the failover group.