From: El FroggitosSyv Ritch (syv@911networks.com)
Date: Wed May 25 2005 - 10:51:32 GMT-3
Dennis J. Hartmann wrote:
> I created this E-Mail before stumbling across this quote in the BGP
> Configuration Guide:
Here are a few more:
^_250.*[0-9]$: 1 AS next away
^250_[0-9]*$: 1 AS next away, 250 = connected + next away [or
none next away]
^250_(.+_)*888$: Originated by 888, connected to 250 and
anything in between
^250(_.+)_*888$: Originated by 888, connected to 250 and
anything in between
http://www.911networks.com/node/59
>
> See the "Regular Expressions" appendix in the Cisco IOS Terminal Services
> Configuration Guide for more information on forming regular expressions
>
> Does anyone know if there is documentation on Regular Expressions
> somewhere on the UNIVERCD site? Please disregard now that I know it's in
> the termal services configuration guide.
>
> I don't like to post to the list with just a question, so I'll share
> some of my regular expression information below:
>
> Matches any single character
> * Matches zero or more sequences of the pattern
> ^ Begins with
> $ End with
> [5-9] or [56789] Matches one character in the range of 5 through 9
> (123) Matches AS 123
> + Matches one or more sequences of the pattern
> _ Matches the following: , { } ( ) ^ $ Blank Space
>
> Examples
>
> _200_ Matches an instance of AS 200 ANYWHERE in the AS-PATH
>
> ^200_ AS-Path begins with (originated from) AS 200
>
> ^200(_200)*$ Begins with and ends with (directly connected to) AS 200
> with one (or more) instances of AS 200 due to AS-PATH prepending
>
> 200$ AS-PATH ends with AS 200 (AS 200 is the last AS that the BGP
> path traversed).
>
> ^([0-9]+)(_\1)*$ Matches one or more instance of a neighboring AS. I
> don't understand the (_\1) myself. If anyone has a better understanding of
> this, please share.
>
> * Permit ANY
>
> \(200 Matches (200 which could be seen in a BGP Community's
> AS-PATH. The \ matches any one special character. In this case, the
> special character is the (.
-- Thanks http://www.911networks.com When the network has to work
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