Connect VPCs in the same region using a CEN transit router - Cloud Enterprise Network

Cloud Enterprise Network (CEN) creates private connections between VPCs, enabling cross-VPC resource sharing over internal networks.

Connect two VPCs in the same region through CEN. The same approach scales to additional VPCs.

Example scenario

This example assumes two VPCs in the China (Hangzhou) region:

VPC1
- IPv4 CIDR block: 10.0.0.0/16
- vSwitch 1 in Zone J, CIDR block 10.0.0.0/24
- vSwitch 2 in Zone K, CIDR block 10.0.1.0/24 (two zones for high availability)
- ECS1 address: 10.0.0.1 (used to test connectivity)
VPC2
- IPv4 CIDR block: 172.16.0.0/16
- vSwitch 1 in Zone J, CIDR block 172.16.0.0/24
- vSwitch 2 in Zone K, CIDR block 172.16.1.0/24
- ECS2 address: 172.16.0.1

Connecting both VPCs to a CEN transit router enables private communication between them.

Important

Ensure the CIDR blocks of the VPCs you want to connect do not overlap.

Log on to the CEN console. In the left-side navigation pane, under CEN Instance, click Create CEN Instance.
On the Create CEN Instance page, enter `cen1` for Name and click OK.
When the message The CEN instance is created. appears, click View Details.

On the details page of the CEN instance, click Create Transit Router.
In the Create Transit Router panel, select China (Hangzhou) for the region, keep other parameters as default, and click OK.
When the message The transit router is created. appears, close the panel.
The transit router now appears on the CEN instance details page.

In the Actions column of the transit router, click Create Connection > Create Intra-Region Connection.
On the Create Intra-Region Connection page, configure the following parameters: Set Network Type to VPC. Enter `attach1` for Attachment Name. Select `VPC1` for Networks. Keep other parameters as default and click OK. Note For cross-zone high availability, the system selects vSwitches in both zones automatically. If your VPC has a vSwitch in only one zone, create at least one more in a different zone.
When the page displays The connection is created., VPC1 is connected to the transit router. Click Create More Connections, follow the same steps to connect `VPC2` to the transit router, and set the Attachment Name to `attach2`.
After you connect `VPC2` to the transit router, click Return to the List.
Click the Instance ID of the transit router in the China (Hangzhou) region to view the two VPC connections: `attach1` and `attach2`.

Note

Ensure the security group rules for both ECS instances allow traffic between them. View security group rules and Add security group rules.

Log on to ECS1 and run ping to test connectivity to ECS2:

ping 172.16.0.1

A successful ping confirms that VPC1 and VPC2 are connected.