This topic describes how to smoothly migrate from Express Connect peering connections for which virtual border routers (VBRs) are created to Express Connect Router (ECR) connections. ECRs support automatic route distribution and learning and provide better paths to lower forwarding latency. You can use ECRs to establish connections between virtual private clouds (VPCs) and data centers.
Prerequisites
An ECR is created. For more information, see Create and manage ECRs.
Comparison between VBR-to-VPC and ECR connections
The following table describes the differences between the features supported by VBR-to-VPC and ECR connections.
Feature | VBR-to-VPC | ECR |
Static routing | Supported | Not supported |
Dynamic routing | Not supported | Supported |
Multi-access points | Not supported | Supported |
Bidirectional Forwarding Detection (BFD) | Not supported | Supported |
Nearby forwarding with low latency | Not supported | Supported |
Pay-as-you-go billing method | Not supported | Supported |
Migration scenarios
Scenario 1: Migrate from an active/standby VBR-to-VPC connection
In this scenario, VBR 1 and VBR 2 are deployed and connect to the same VPC. Static routes that point to the VPC are added to VBR 1 and VBR 2. Static routes that point to VBR 1 and VBR 2 are also added to the VPC. The weight of VBR 1 is set to 100 and the weight of VBR 2 is set to 0 to establish active/standby connections. The VBRs connect with your data center over Border Gateway Protocol (BGP).
In this case, the following conditions must be met before the migration. For information about the migration process, see the Migration process section of this topic.
The data center and VBRs are specified as BGP peers and the BGP routes are advertised. For more information, see Configure and manage BGP.
The autonomous system number (ASN) of Alibaba Cloud is 45104. The data center can use 2-byte or 4-byte ASNs.
BGP routing is configured in the data center, and the BGP routes are advertised to Alibaba Cloud. The autonomous system (AS) path attribute is specified to determine the route weights to establish an active/standby connection between the data center and Alibaba Cloud.
The AS path of the active route must be longer than that of the standby route.
This is because the length of the AS path determines the priority of a route. A shorter AS path indicates a higher priority. For information about the commands that are used to configure BGP routing, contact your service provider.
Scenario 2: Migrate from an active/active VBR-to-VPC connection
In this scenario, VBR 1 and VBR 2 are deployed and connect to the same VPC. Static routes that point to the VPC are added to VBR 1 and VBR 2. Static routes that point to VBR 1 and VBR 2 are also added to the VPC. The weight is set to 100 for both VBR 1 and VBR 2 to establish active/active connections. The VBRs connect with your data center over BGP.
In this case, the following conditions must be met before the migration. For information about the migration process, see the Migration process section of this topic.
The data center and VBRs are specified as BGP peers and the BGP routes are advertised. For more information, see Configure and manage BGP.
The autonomous system number (ASN) of Alibaba Cloud is 45104. The data center can use 2-byte or 4-byte ASNs.
BGP routing is configured in the data center, and the BGP routes are advertised to Alibaba Cloud. The AS path attribute is specified to determine the route weights to establish an active/active connection between the data center and Alibaba Cloud.
The AS path lengths of the two routes must be the same. This is because the length of the AS path determines the priority of a route. The same AS path length indicates the same priority. For information about the commands that are used to configure BGP routing, contact your service provider.
Migration process
If you have configured health checks for your VBRs, delete the health check settings in the Express Connect console. For more information, see Configure and manage health checks.
Log on to the Express Connect console.
In the left-side navigation pane, click Express Connect Router (ECR). On the page that appears, click the name of the ECR that you want to manage.
On the details page of the ECR, add the VBRs that you want to migrate on the VBR tab and the VPC that you want to connect on the VPC tab. For more information, see the Add a VBR and Associate a VPC sections of the "Create and manage ECRs" topic.
Delete the static routes between the VPC and VBRs. For more information, see the Add and delete routes section of the "Create and manage a route table" topic and the Delete a custom route section of the "Add and manage routes" topic.
NoteAfter you add the VBRs and VPC to the ECR, the VBRs and VPC have static and dynamic routes that point to each other.
If you want to access services that reside in multiple VPCs from your data center, you must configure the route prefixes to allow data transfer between the specified VPCs and your data center. For more information, see the Update route prefixes section of the "Create and manage ECRs" topic.