Help Center/ Enterprise Router/ Best Practices/ Practice Suggestions on Using Enterprise Routers
Updated on 2025-06-18 GMT+08:00

Practice Suggestions on Using Enterprise Routers

This section provides some practical suggestions for you to use enterprise routers to build networks. Before using the enterprise router, get familiar with these suggestions.

  • If you use an enterprise router to connect different VPCs, the subnet CIDR blocks of the VPCs cannot overlap or communications may fail.

    If your VPCs overlap, do not use propagated routes for VPC attachments of an enterprise router. Instead, manually add static routes to the route table of the enterprise router. The destination of the routes can be VPC subnet CIDR blocks or smaller ones. Propagated routes of the VPC attachments are automatically added by the system to the route table of an enterprise router and use a VPC CIDR block as the destination. Therefore, overlapping VPC CIDR blocks at both ends of the communication will cause route conflicts.

  • If you use Enterprise Router and Direct Connect to build a hybrid cloud network, a VPC subnet and an on-premises subnet cannot overlap, or communications will fail.
  • If you use an enterprise router to migrate a network set up through VPC peering connections that connect VPCs from different accounts, you can use the sharing function to migrate the VPCs from different accounts to the same enterprise router. If the networking with VPC peering connections is complex, services may be interrupted due to the migration. You are advised to submit a service ticket to contact the customer service to evaluate the migration solution before the migration.
  • If the networking with Direct Connect is complex, services may be interrupted due to the migration. You are advised to submit a service ticket to contact the customer service to evaluate the migration solution before the migration.
  • If a service VPC is being used by a shared load balancer, VPC endpoint, private NAT gateway, Distributed Cache Service (DCS), or hybrid DNS, do not attach this VPC to an enterprise router.
  • Traffic cannot be forwarded from a VPC to its attached enterprise router if the destination of a route with an enterprise router as the next hop is set to 0.0.0.0/0 in the VPC route table and if:
    • An ECS in the VPC has an EIP bound.
    • The VPC is being used by ELB (either dedicated or shared load balancers), NAT Gateway, VPC Endpoint, or DCS.

For more constraints on using enterprise router, see Notes and Constraints.