Transit routers are enterprise-class network devices that are used to forward traffic. A transit router is used to forward data within the same region or across different regions. You can configure custom policies to enable cross-region communication, traffic isolation, and traffic redirect. This allows you to create a flexible, reliable, and large-scale enterprise network on Alibaba Cloud. This topic describes common networking scenarios of transit routers.

Same-region networking

Transit routers allow you to connect network instances in the same region.

After you create a transit router, you can connect virtual private clouds (VPCs) in the same region by using the transit router.

Same-region networking

Cross-region networking

Transit routers allow you to connect network instances in different regions.

For example, If you want to connect a VPC in the China (Beijing) region to a VPC in the China (Shanghai) region, you must first create two transit routers. Then, associate each VPC with a transit router, purchase a bandwidth plan, and then establish a cross-region connection.

Cross-region networking

Hybrid-cloud networking

Transit routers allow you to connect cloud resources to on-premises networks.

You can use transit routers to connect network instances of different types, including VPCs, virtual border routers (VBRs), and Cloud Connect Network (CCN) instances. By connecting the preceding network instances, transit routers can establish private connections between VPCs and data centers. This way, networks in the cloud can communicate with on-premises networks.

Hybrid-cloud networking

Enterprise-class networking

Transit routers allow you to configure custom communication, isolation, and traffic redirect policies within a region. You can use transit routers to establish an enterprise-class network.

For example, you can use transit routers to create custom route maps to enable the VPCs to access the Internet from the same egress. This facilitates network management and improves the security of your workloads.

Enterprise-class networking