After a network instance establishes route learning with a transit router route table, routes propagate automatically. However, some VPC routes are not propagated by default. You can manually advertise these routes as needed.
Background information
The following table lists the default propagation status of VPC route entries and whether they support manual advertisement or withdrawal.
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Route entries in VPC custom route tables cannot be advertised to a transit router.
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Route entries that use a prefix list cannot be advertised to a transit router.
|
Route type |
Source instance |
Default propagation |
Manual actions |
|
Routes to an ECS instance |
VPC |
No |
Yes |
|
Routes to a VPN gateway |
VPC |
No |
Yes |
|
Routes to a high-availability virtual IP address (HAVIP) |
VPC |
No |
Yes |
|
Routes to an IPv4 gateway |
VPC |
No |
Yes |
|
Routes to an elastic network interface (ENI) |
VPC |
No |
Yes |
|
Routes to an IPv6 gateway |
VPC |
No |
Yes |
|
Routes to a NAT gateway |
VPC |
No |
Yes |
|
Routes to a transit router |
VPC |
No |
No |
|
Routes to a router interface (towards a Virtual Border Router (VBR)) |
VPC |
No |
No |
|
Routes to a VPC peering connection |
VPC |
No |
No |
|
Routes to a gateway for Express Connect |
VPC |
No |
No |
|
Routes to a Gateway Load Balancer (GWLB) endpoint |
VPC |
No |
No |
|
System route entries of a VPC |
VPC |
Yes |
Yes |
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The CIDR block
100.64.0.0/10in VPC system route entries is reserved for Alibaba Cloud services and cannot be advertised to a transit router. -
For Basic Edition transit routers, routes from Cloud Connect Network (CCN) and Virtual Border Router (VBR) instances with an Express Connect circuit as the next hop are propagated by default and cannot be manually advertised or withdrawn. Basic Edition transit routers do not forward IPv6 traffic by default. For VPCs attached to a Basic Edition transit router, the preceding table applies to all route types except IPv6.
Advertise routes to a transit router
Log on to the CEN console.
On the CEN Instance page, click the ID of the CEN instance that you want to manage.
Go to the tab and click the ID of the transit router that you want to manage.
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On the transit router details page, click the Network Instance Route Table tab.
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On the Network Instance Route Table tab, select the network instance and route table, find the route entry, and click Publish in the Publishing Progress column.
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In the PublishRoute dialog box, confirm the route information and click OK.
Withdraw routes from a transit router
Log on to the CEN console.
On the CEN Instance page, click the ID of the CEN instance that you want to manage.
Go to the tab and click the ID of the transit router that you want to manage.
-
On the transit router details page, click the Network Instance Route Table tab.
-
On the Network Instance Route Table tab, select the network instance and route table, find the route entry, and click Withdraw in the Publishing Progress column.
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In the Withdraw Route dialog box, confirm the route information and click OK.
Related topics
Route learning: Routes automatically propagated from network instances to an Enterprise Edition transit router.