Policy Framework Configuration Guide - Juniper Networks

Junos 10.4 Policy Framework Configuration Guide
Community regular expressions evaluate the string specified in term on a
character-by-character basis. For example, if you specify 1234:5678 as term, the regular
expressions see nine discrete characters, including the colon (:), instead of two sets of
numbers (1234 and 5678) separated by a colon.
NOTE: In Junos OS Release 9.1 and later, you can specify 4-byte AS numbers
as defined in RFC 4893, BGP Support for Four-octet AS Number Space, as
well as the 2-byte AS numbers that are supported in earlier releases of the
Junos OS. For more information about configuring AS numbers, see the Junos
OS Routing Protocols Configuration Guide.
Table 17: Community Attribute Regular Expression Operators
Operator
Match Definition
{m,n}
At least m and at most n repetitions of term. Both m and n must be positive integers,
and m must be smaller than n.
{m}
Exactly m repetitions of term. m must be a positive integer.
{m,}
m or more repetitions of term. m must be a positive integer.
*
Zero or more repetitions of term. This is equivalent to {0,}.
+
One or more repetitions of term. This is equivalent to {1,}.
?
Zero or one repetition of term. This is equivalent to {0,1}.
|
One of the two terms on either side of the pipe.
–
Between a starting and ending range, inclusive.
^
Character at the beginning of a community attribute regular expression. We
recommend the use of this operator for the clearest interpretation of your community
attribute regular expression. If you do not use this operator, the regular expression
123:456 could also match a route tagged with 5123:456.
$
Character at the end of a community attribute regular expression. We recommend
the use of this operator for the clearest interpretation of your community attribute
regular expression. If you do not use this operator, the regular expression 123:456
could also match a route tagged with 123:4563.
[ ]
Set of characters. One character from the set can match. To specify the start and
end of a range, use a hyphen (-). To specify a set of characters that do not match,
use the caret (^) as the first character after the opening square bracket ([).
( )
Group of terms that are enclosed in parentheses. If enclosed in quotation marks with
no intervening space ("()" ), indicates a null. Intervening space between the
parentheses and the terms is ignored.
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