Reference Guide

Border Gateway Protocol IPv4 (BGPv4) | 229
Expressions accepted in FTOS
Table 12-4, "Regular Expressions," in Border Gateway Protocol IPv4 (BGPv4) lists the Regular As seen in
In the example above, the expressions are displayed when using the
show commands. Use the show
config
command in the CONFIGURATION AS-PATH ACL mode and the show ip as-path-access-list
command in EXEC Privilege mode to view the AS-PATH ACL configuration.
For more information on this command and route filtering, refer to Filter BGP routes.
Redistribute routes
In addition to filtering routes, you can add routes from other routing instances or protocols to the BGP
process. With the
redistribute command syntax, you can include ISIS, OSPF, static, or directly connected
routes in the BGP process.
Use any of the following commands in ROUTER BGP mode to add routes from other routing instances or
protocols.
Table 12-4. Regular Expressions
Regular
Expression Definition
^ (caret) Matches the beginning of the input string.
Alternatively, when used as the first character within brackets [^ ] matches any number except the ones
specified within the brackets.
$ (dollar) Matches the end of the input string.
. (period) Matches any single character, including white space.
* (asterisk) Matches 0 or more sequences of the immediately previous character or pattern.
+ (plus) Matches 1 or more sequences of the immediately previous character or pattern.
? (question) Matches 0 or 1 sequence of the immediately previous character or pattern.
( ) (parenthesis) Specifies patterns for multiple use when followed by one of the multiplier metacharacters: asterisk *,
plus sign +, or question mark ?
[ ] (brackets) Matches any enclosed character; specifies a range of single characters
- (hyphen) Used within brackets to specify a range of AS or community numbers.
_ (underscore) Matches a ^, a $, a comma, a space, a {, or a }. Placed on either side of a string to specify a literal and
disallow substring matching. Numerals enclosed by underscores can be preceded or followed by any of
the characters listed above.
| (pipe) Matches characters on either side of the metacharacter; logical OR.