Transit routers support route advertisement. You can advertise the routes of a virtual private cloud (VPC) to the transit router to which the VPC is connected. Other network instances connected to the transit router can learn the advertised routes if no route conflict exists.

Background information

The following table lists the default status of VPC routes of different types on a transit router and whether you can advertise or withdraw the routes.
Route type Network instance Advertised to a transit router by default Supports advertisement and withdrawal
Routes that point to Elastic Compute Service (ECS) instances VPC No Yes
Routes that point to VPN gateways VPC No Yes
Routes that point to high-availability virtual IP addresses (HAVIPs) VPC No Yes
Routes that point to router interfaces VPC No Yes
Routes that point to elastic network interfaces (ENIs) VPC No Yes
Routes that point to IPv6 gateways VPC No Yes
Routes that point to NAT gateways VPC No Yes
Routes that point to transit routers VPC No No
System routes of VPCs VPC Yes Yes

By default, Cloud Connect Network (CCN) instances and virtual border routers (VBRs) advertise routes to the transit router to which they are connected. You cannot advertise or withdraw the routes of a CCN instance or a VBR.

Advertise routes to a transit router

  1. Log on to CEN console.
  2. On the Instances page, find the CEN instance that you want to manage and click its ID.
  3. On the Basic Information > Transit Router tab, find the transit router in the target region and click the ID of the target transit router.
  4. On the transit router details page, click the Network Instance Route Table tab.
  5. On the Network Instance Route Table tab, select the network instance and the route table that you want to manage, find the route that you want to advertise, and then click Publish in the Publishing Progress column.
  6. In the PublishRoute message, confirm the information and click OK.

Withdraw routes from a transit router

  1. Log on to CEN console.
  2. On the Instances page, find the CEN instance that you want to manage and click its ID.
  3. On the Basic Information > Transit Router tab, find the transit router in the target region and click the ID of the target transit router.
  4. On the transit router details page, click the Network Instance Route Table tab.
  5. On the Network Instance Route Table tab, select the network instance and the route table that you want to manage, find the route that you want to withdraw, and then click Withdraw in the Publishing Progress column.
  6. In the Withdraw Route message, confirm the information and click OK.