permit (bgp-as-path-list)
Creates and configures a permit as-path-list rule. The permit rule
specifies a regular expression to match. This regular expression is matched against the BGP
AS paths contained in routing updates. AS paths matching the provided string are filtered
and a permit action is applied.
Supported in the following platforms:
- Service Platforms — NX9500, NX9600
Syntax
permit as-path <REG-EXP>
Parameters
permit as-path <REG-EXP>
| permit as-path <REG-EXP> |
Configures a match criteria (regular expression).
- <REG-EXP> – Specify the regular expression to match (should not exceed 64
characters and should be unique to the AS path list rule)
Regular expressions are treated as a ‘ASCII string‘ and not as a sequence of
numbers. Create a regular expression which is ideally suited to filter the
required AS paths.
|
Usage Guidelines
The following table lists some of the characters used in forming regular
expressions:
Table 1.
| Character to use |
Description |
| ^ |
Indicates the start of a string |
| $ |
Indicates the end of a string |
| _ (underscore) |
Indicates a comma, left brace, right brace, start and
end of an input string, or a space. For example, “_ _”. |
Examples
nx9500-6C8809(config-bgp-as-path-list-test)#permit as-path _200_
nx9500-6C8809(config-bgp-as-path-list-test)#permit as-path _323_
nx9500-6C8809(config-bgp-as-path-list-test)#show context
bgp as-path-list test
deny as-path ^100$
permit as-path _323_
permit as-path _200_
nx9500-6C8809(config-bgp-as-path-list-test)#
