Policy Framework Configuration Guide - Juniper Networks

Chapter 5: Extended Match Conditions Configuration
Table 16: Examples of AS Path Regular Expressions (continued)
AS Path to Match
Regular
Expression
Sample Matches
Zero or one occurrence of AS number 1234
1234? or 1234{0,1}
1234
Null AS path
One through four occurrences of AS number 1234
1234{1,4}
1234
1234 1234
1234 1234 1234
1234 1234 1234 1234
One through four occurrences of AS number 12,
followed by one occurrence of AS number 34
12{1,4} 34
12 34
12 12 34
12 12 12 34
12 12 12 12 34
Range of AS numbers to match a single AS number
123–125
123
124
125
[123–125]*
Null AS path
123
124 124
125 125 125
123 124 125 123
Path whose second AS number must be 56 or 78
(. 56) | (. 78) or
. (56 | 78)
1234 56
1234 78
9876 56
3857 78
Path whose second AS number might be 56 or 78
. (56 | 78)?
1234 56 52
34 56 1234
1234 78 39
794 78 2
Path whose first AS number is 123 and second AS
number is either 56 or 78
123 (56|78)
123 56
123 78
Copyright © 2010, Juniper Networks, Inc.
99