import-route isis level-2 into level-1
Function
The import-route isis level-2 into level-1 command configures route leaking from Level-2 areas to Level-1 areas.
The undo import-route isis level-2 into level-1 command prohibits route leaking from Level-2 areas to Level-1 areas.
By default, Level-2 routing information is not leaked to Level-1 areas.
Format
import-route isis level-2 into level-1 [ filter-policy { acl-number | acl-name acl-name | ip-prefix ip-prefix-name | route-policy route-policy-name } | tag tag | direct { allow-filter-policy | allow-up-down-bit } * ] *
undo import-route isis level-2 into level-1 [ filter-policy { acl-number | acl-name acl-name | ip-prefix ip-prefix-name | route-policy route-policy-name } | tag tag | direct { allow-filter-policy | allow-up-down-bit } * ] *
Parameters
| Parameter | Description | Value |
|---|---|---|
| filter-policy | Specifies a filtering policy. | - |
| acl-number | Specifies the number of a basic ACL. | The value is an integer that ranges from 2000 to 2999. |
| acl-name acl-name | Specifies the name of a named ACL. | The value is a string of 1 to 32 case-sensitive characters without spaces. |
| ip-prefix ip-prefix-name | Specifies the name of an IP prefix list. Only the routes that match the specified IP prefix can be imported. | The value is a string of 1 to 169 case-sensitive characters without spaces. |
| route-policy route-policy-name | Specifies the name of a route-policy. | The value is a string of 1 to 40 case-sensitive characters without spaces. |
| tag tag | Specifies the administrative tag value of imported routes. | The value is an integer that ranges from 1 to 4294967295. |
| direct allow-filter-policy | Indicates a filtering policy to filter the direct routes. If the parameter is configured, only the IS-IS Level-2 area direct routes that matches the filtering policy can leak to a Level-1 area. If the parameter is not configured, all Level-2 area direct routes will leak to a Level-1 area. |
- |
| direct allow-up-down-bit | Indicates that the Up or Down bit is used during direct route leaking. If direct allow-up-down-bit is specified, the direct routes that have already leaked to a Level-1 area cannot leak back. |
- |
Usage Guidelines
Usage Scenario
When multiple Level-1-2 wireless access controllers in a Level-1 area are connected to a Level-2 area, Level-1 wireless access controllers are unable to know the network topology of the Level-2 area, but forward traffic to the nearest Level-1-2 wireless access controller (based on the route with the smallest cost). For Level-2 wireless access controllers, however, this route may not be the optimal one. Therefore, you need to allow some Level-2 routes to be leaked to the Level-1 area to help Level-1 wireless access controllers select the optimal route for forwarding traffic to the Level 2 area.
To solve the preceding problem, IS-IS provides the route leaking function to enable Level-1 devices to choose the best path for traffic forwarding.
The import-route isis level-2 into level-1 command can be run only on Level-1-2 routers to allow all or some Level-2 routes to be leaked to the Level-1 area.
Precautions
For an ACL, when the rule command is used to configure a filtering rule, the filtering rule is effective only with the source address range that is specified by the source parameter and with the time period that is specified by the time-range parameter.
