The ip large-community-filter basic command sets a basic Large-Community filter.
The undo ip large-community-filter basic command deletes a configured basic Large-Community filter.
By default, no basic Large-Community filter is configured.
| Parameter | Description | Value |
|---|---|---|
| large-comm-filter-name |
Specifies the name of a basic Large-Community filter. |
The value is a string of 1 to 51 case-sensitive characters. The string cannot be all digits. |
| index index-number |
Specifies the index of a Large-Community filter. |
The value is an integer ranging from 1 to 4294967295. |
| matchMode |
Sets the matching mode of a Large-Community filter. |
The value is an enumerated type:
|
| cmntyStr |
Specifies a value of the Large-Community attribute. |
The value is in the format of aa:bb:cc. The values of aa, bb, and cc are integers ranging from 0 to 4294967295. |
| basic |
Sets a basic Large-Community filter. |
- |
Usage Scenario
The Large-Community attribute is a private attribute of BGP and can be flexibly applied to route-policies. The ip large-community-filter command works with the if-match large-community-filter command so that a filtering rule based on a specific Large-Community filter can be used to filter BGP routes.
Follow-up Procedure
Run the display ip large-community-filter command to view detailed configuration of the Large-Community filter.
Precautions
The relationship between the rules in a Large-Community filter is "AND", which is different from that in an RD filter. This is because each route has only one RD but can have multiple Large-Community values.
Large-Community filters in different formats lead to different matching results. Take the following formats as an example: Format 1: ip large-community-filter basic a permit 100:1:1 200:1:1 300:1:1 The relationship between 100:1:1, 200:1:1, and 300:1:1 is AND. Format 2: ip large-community-filter basic a permit 100:1:1 ip large-community-filter basic a permit 200:1:1 300:1:1 The relationship between 200:1:1 and 300:1:1 is AND. The relationship between 100:1:1 and 200:1:1 is OR, and the relationship between 100:1:1 and 300:1:1 is also OR. In format 2, the Large-Community value in each matching rule must be a subset of the Large-Community set in BGP routes. However, the RD filters in the following formats have the same matching result: Format 1: ip rd-filter 100 permit 100:1 200:1 2.2.2.2:1 3.3.3.3:1 Format 2: ip rd-filter 100 permit 100:1 200:1 ip rd-filter 100 permit 2.2.2.2:1 ip rd-filter 100 permit 3.3.3.3:1 By default, a Large-Community filter works in deny mode. BGP routes that fail one of the filtering rules do not match the Large-Community filter. If all matching rules in a Large-Community filter work in deny mode, all BGP routes are denied by the filter. To prevent this problem, configure a matching rule in permit mode after one or more matching rules in deny mode so that the routes except for those denied by the preceding filtering rules match the filter.