Re: IP BGP REGEXP

Thanks. Got it.

On Sat, Jan 7, 2012 at 2:55 AM, Yuri Bank <yuribank_at_gmail.com> wrote:

> Actually, both regular expressions will match routes originated by AS54
>
> The important distinction between these two regular expressions is that
> the first will match *any* AS_PATH_SEQ that starts with AS54. The second
> regular expression will match any AS_PATH_SEQ that starts with AS54,
> followed by *one* or *none* additional AS numbers.
>
> _ underscore will match space or end of string
>
> -Yuri
>
>
> On Fri, Jan 6, 2012 at 5:04 AM, Keller Giacomarro <keller.g_at_gmail.com>wrote:
>
>> They are similar, but not the same.
>>
>> The first says...
>> Match from the start of the line
>> Match 54
>> Match a space
>> I don't care about the rest
>>
>> The second says...
>> Match from the start of the line
>> Match 54
>> Match a space
>> Match a number 0 to 9, one or more times (as few characters as needed,
>> ungreedy)
>> I don't care about the rest
>>
>> The big difference is that the second regex will require that the next AS
>> must be a normal AS number, 0 to 9. If it is an AS_SET next
>> (parenthesis),
>> or a confederacy (squiggly brackets) next, the second regex will not match
>> but the first will.
>>
>> Also, note that neither regex will match for AS54-originated routes, as
>> you
>> a requiring a space after 54.
>>
>> When I'm trying to create regexes, http://gskinner.com/RegExr/ is my best
>> friend.
>>
>> Keller Giacomarro
>> keller.g_at_gmail.com
>>
>>
>> On Fri, Jan 6, 2012 at 5:42 AM, Vincent Tay <vtay.75_at_gmail.com> wrote:
>>
>> > Hi all,
>> >
>> > Any differences between the below BGP regexp?
>> >
>> > ^54_ and ^54(_[0-9]+)?$ to match originated from AS54 and its directly
>> > connected customers?
>> >
>> >
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>> >
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Received on Sat Jan 07 2012 - 12:08:46 ART