Routing policies filter routes and modify route attributes to customize your cloud network connectivity. This topic describes how to add, modify, and delete a routing policy.
Background
A transit router is available in two editions: Basic and Enterprise.
A Basic Edition transit router has only one system route table. When you create a routing policy, the system automatically associates it with the system route table.
An Enterprise Edition transit router includes one system route table and also lets you create custom route tables. When you add a routing policy, you can associate it with either the system route table or a custom route table. The routing policy affects route propagation only in the associated route table.
To learn how to view the edition of your transit router, see transit router edition differences.
Add a routing policy to an Enterprise Edition transit router
Log on to the CEN console.
On the Instances 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 details page of the transit router, click the Route Table tab.
In the left-side navigation pane, click the ID of the route table.
On the route table details page, click the Routing Policies tab.
On the Routing Policies tab, click Add Routing Policy.
On the Add Routing Policy page, set the parameters for the routing policy and click OK.
Parameter
Description
Policy Priority
The priority of the routing policy. Valid values: 1 to 100. A smaller value indicates a higher priority.
Within an Enterprise Edition transit router, each routing policy must have a unique priority for a given region and direction. When the system executes routing policies, it starts with the policy that has the highest priority (smallest value). Therefore, when you specify the priority, ensure the matching order meets your requirements.
Description
Enter a description for the routing policy.
Associated Route Table
Select the route table to associate with the routing policy.
You can associate the routing policy with a system route table or a custom route table.
Direction
Select the direction in which the routing policy applies.
Ingress: The direction for routes propogated to the local transit router. For example, routes are propogated from a network instance in the current region to the local transit router, or routes from other regions are propogated to the local transit router.
Egress: The direction for routes propogated from the local transit router. For example, routes are propogated from the local transit router to other network instances in the current region, or to transit routers in other regions.
Match Conditions
The match conditions for the routing policy.
Click
Add Match Condition to add match conditions. For more information, see Match conditions.Policy Action
Select an action for the policy.
Allow: Permits routes that match all conditions.
If you set the action to Allow, you can configure the following parameters:
Route Priority: The priority of the permitted routes. Valid values: 1 to 100. The default value is 50. A smaller value indicates a higher priority.
Community: The Community attribute. You can choose to Add or Replace th value.
Append AS Path: The AS Path attribute that is prepended to the AS_PATH attribute of the route when the transit router receives or propogates a route.
The requirements for prepending an AS Path vary based on the direction of the routing policy:
For an Ingress policy, you must specify a list of source instance IDs and a source region in the match conditions. The source region must be the same as the region in which the routing policy is applied.
For an Egress policy, you must specify a list of destination instance IDs in the match conditions.
Reject: Blocks routes that match all conditions.
If you set the action to Reject, you cannot configure other parameters.
Associated Policy Priority
The priority of the next routing policy to apply.
You can set this parameter only when the action is set to Allow. The allowed routes continue to be matched against the next routing policy.
The next routing policy must be in the same region and apply to the same direction as the current routing policy.
The priority of the next routing policy must be lower than the priority of the current routing policy (meaning its priority value must be numerically greater).
Add a routing policy to a Basic Edition transit router
Log on to the CEN console.
On the Instances 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 tab.
On the Routing Policies tab, click Add Routing Policy.
On the Add Routing Policy page, set the parameters for the routing policy and click OK.
Configuration
Description
Policy Priority
The priority of the routing policy. Valid values: 1 to 100. A smaller value indicates a higher priority.
Within a transit router, each routing policy must have a unique priority for a given region and direction. When the system executes routing policies, it starts with the policy that has the highest priority (smallest value). Therefore, when you specify the priority, ensure the matching order meets your requirements.
Description
Enter a description for the routing policy.
Region
Select the region where the routing policy is applied.
Direction
Select the direction in which the routing policy applies.
Ingress: The direction for routes propogated to the local transit router. For example, routes are propogated from a network instance in the current region to the local transit router, or routes from other regions are propogated to the local transit router.
Egress: The direction for routes propogated from the local transit router. For example, routes are propogated from the local transit router to other network instances in the current region, or to transit routers in other regions.
Match Conditions
The match conditions for the routing policy.
Click
Add Match Condition to add match conditions. For more information, see Match conditions.Policy Action
Select an action for the policy.
Allow: Permits routes that match all conditions.
If you set the action to Allow, you can configure the following parameters:
Route Priority: The priority of the permitted routes. Valid values: 1 to 100. The default value is 50. A smaller value indicates a higher priority.
Community: The Community attribute. You can choose to Add or Replace th value.
Append AS Path: The AS Path attribute that is prepended to the AS_PATH attribute of the route when the transit router receives or propogates a route.
The requirements for prepending an AS Path vary based on the direction of the routing policy:
For an Ingress policy, you must specify a list of source instance IDs and a source region in the match conditions. The source region must be the same as the region in which the routing policy is applied.
For an Egress policy, you must specify a list of destination instance IDs in the match conditions.
Reject: Blocks routes that match all conditions.
If you set the action to Reject, you cannot configure other parameters.
Associated Policy Priority
The priority of the next routing policy to be associated. This parameter is optional.
You can set this parameter only when the action is set to Allow. The allowed routes continue to be matched against the next routing policy.
The next routing policy must be in the same region and apply to the same direction as the current routing policy.
The priority of the next routing policy must be lower than the priority of the current routing policy (meaning its priority value must be numerically greater).
Modify a routing policy
Before you modify a routing policy, take note of the following:
After creating a routing policy for an Enterprise Edition transit router, you cannot modify the associated route table or the direction.
After creating a routing policy for a Basic Edition transit router, you cannot modify the region or the direction.
For both Basic and Enterprise Edition transit routers, you cannot modify the default system-generated routing policies (those with a priority value greater than 1000). To override a default policy, add a custom routing policy with a higher priority (a smaller priority value).
Log on to the CEN console.
On the Instances 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 details page of the transit router, click the Route Table tab.
On the Route Table tab, find the target routing policy.
For a Basic Edition transit router, click the Routing Policies tab and find the routing policy.
For an Enterprise Edition transit router, click the ID of the target route table in the left-side navigation pane. On the route table details page, click the Routing Policies tab and find the routing policy.
In the Actions column of the routing policy, click Modify.
On the Edit Route Map page, modify the policy priority, description, match conditions, or action. Then, click OK.
Delete a routing policy
Log on to the CEN console.
On the Instances 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 details page of the transit router, click the Route Table tab.
On the Route Table tab, find the target routing policy.
For a Basic Edition transit router, click the Routing Policies tab and find the routing policy.
For an Enterprise Edition transit router, click the ID of the target route table in the left-side navigation pane. On the route table details page, click the Routing Policies tab and find the routing policy.
In the Actions column of the routing policy, click Delete.
In the Delete Routing Policy dialog box, click OK.
References
CreateCenRouteMap: Creates a routing policy.
ModifyCenRouteMap: Modifies a routing policy.
DeleteCenRouteMap: Deletes a routing policy.
DescribeCenRouteMaps: Queries routing policies.