From: Sidalo (sidalo@gmail.com)
Date: Thu Feb 15 2007 - 16:16:29 ART
^54$ = coming only from AS 54 and passing though no other AS whether before
or after AS 54
_54$ = anything that started in AS 54 and could have passed through
additional AS before reaching you.
^54_ = anything that is coming directly from AS 54 and could have originated
somewhere before reaching AS 54.
On 2/15/07, Curt Gregg (cugregg) <cugregg@cisco.com> wrote:
>
> Question:
>
> Wouldn't these two expressions be the same or you trying to match
> anything originating in AS 54?
>
> ip as-path access-list 1 permit ^54$
> ^ = start of a line
>
> or
>
> ip as-path access-list 1 permit _54$
> _ = beginning of the line (or end of the line or a space)
>
>
> Wouldn't _54$ also be considered the end of the path or originating AS
> as the as-path describes the AS systems it has passed thru beginning
> with the most recent and ending with the originating AS.
>
> In this case AS 54 is the directly connected AS.
>
> Are there pros or cons to using either or?
>
> TIA
>
> Curt
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
This archive was generated by hypermail 2.1.4 : Thu Mar 01 2007 - 07:38:46 ART