Before using CEN, read the limits first.

Resource Default limit Exception
The number of CEN instances per account 5 Open a ticket
The number of attached networks per region 5 Open a ticket
Note You can apply for up to 3 more, and the total number cannot exceed 8.
The number of bandwidth packages in the same connected areas per account 1 No exception
The number of associated regions per CEN instance 5 Open a ticket
Limits on VPC with ClassicLink enabled The VPC cannot use the IP address range No exception
Networks You cannot attach VPCs or VBRs that are using Express Connect to a CEN instance. No exception
The number of route entries per CEN instance 100 Open a ticket
Share NAT Gateway through CEN No No exception
Cross-region access to cloud resources No No exception
Cloud resources access networks attached to CEN No No exception
Subnet routing If a VPC has more than one route table, CEN only learns route entries of the primary route table and does not learn route entries from the customized route tables. Similarly, the route entries that a VPC learned from CEN are added to the primary route table only. No exception
Ant Financial Cloud No No exception