Before you use Cloud Enterprise Network (CEN), note the limits in the following table.

Item Default limit Adjustable
The number of CEN instances that can be created under each account 5.

Yes. Submit a ticket.

The number of network instances that can be attached to a CEN instance in each region 10.

Yes. Submit a ticket. Upper limit: 15.

The number of bandwidth plans that you can purchase for each CEN instance when the interconnection areas are the same 1. No.
The number of regions that each CEN instance supports 5.

Yes. Submit a ticket.

The number of route entries that can be created for each CEN instance 100. Yes. Submit a ticket.
Limits on virtual private clouds (VPCs) that have ClassicLink enabled The VPCs cannot use the CIDR block 10.0.0.0/8. No.
Network instances The network instances attached to a CEN instance cannot communicate with each other by using Express Connect. No.
Allow network instances to share NAT gateways through CEN Not supported. No.
Access cloud services across regions

Cloud services are services deployed in VPCs and use the CIDR block 100.64.0.0/10. Cloud services provided by Alibaba Cloud include Log Service, Object Storage Service (OSS), and Data Transmission Service (DTS). For more information, see Access cloud services through CEN.

Not supported. No.
Allow cloud services to access the network instances attached to CEN Not supported. No.
Attach one cloud connect network (CCN) in each region. When a CEN instance attaches a network instance, the CCN that can be attached to the CEN instance must be deployed in the area that contains the region of the network instance.

For more information, see Introduction to CCN.

Not supported. No.
Subnet routing
For a VPC that learns routes from a CEN instance:
  • If the VPC is attached to the CEN instance before October 22, 2019, only the system route table of the VPC learns routes from the CEN instance. To enable the custom route tables of the VPC to learn routes from the CEN instance, you must reattach the VPC to the CEN instance or submit a ticket. Note: reattaching the VPC may cause service disruption.
  • If the VPC is attached to the CEN instance after October 22, 2019, all route tables of the VPC, including the system route table and custom route tables, learn routes from the CEN instance.

For a CEN instance that learns routes from a VPC:

If the VPC has multiple route tables, the CEN instance learns only the routes in the system route table of the VPC.

No.