BGP Regular Expression

Tuesday, 15 April 2008 10:25 |

1. Atom An atom is a single character, such as the following

.	- Matches any single character
^(Carat)	- Matches the beginning of the input string ex) ^5 it will match with the below 5 100 712 500 3000 6577 548 453 343 ex) show ip bgp regexp 5 it will match with the below 500 4390 4000 100 598 4130 200 453 3400
$	- Matches the end of the input string ex) 500$ it will match with the below 100 768 500 100 675 3500 343 233 4572 345 500
\	- Matches the character
_	- Matches a comma (,), left brace ({), right brace (}), the beginning of the input string, the end of the input string, or a space. ex) _10_ 1230 10 344 7119 10 2323 3000 5003 345 7001 10
[ ]	- Define a range ex) [1-9]346 1346 2346 3346 : ex) 2[1234]7 217 227 237

2. Piece A piece is an atom followed by one of the following symbols

*	Matches 0 or more sequences of the atom
+	Matches 1 or more sequences of the atom
?	Matches the atom or the null string

3. Branch A branch is a 0 or more concatenated pieces

a*	Any occurrence of the letter "a", including none
a+	At least one occurrence of the letter "a" should be present)
ab?a	This matches "aa" or "aba
_100_	Via AS100 ex) 100 3345 768 232 2300 100 244 716
^100$	Origin AS100 ex) sh ip bgp regexp ^100$ 100
^100 .*	Coming from AS100
^.100	ex) sh ip bgp regexp ^.100 1100 4100 8100
_[1-9]567$	ex) 344 1567 50 232 3567 100 4546 8567
^5[1-4]7_	ex) 517 456 537 400 234 527 300 232
^100_	ex) sh ip bgp regexp ^100_ 100 345 213 100 200
^$	Originated from this AS

Last Updated (Sunday, 14 June 2009 23:56)

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