From: glmorris (glmorris48@xxxxxxxxxxx)
Date: Mon Apr 15 2002 - 02:29:41 GMT-3
Good catch Manny. Right on three counts. As for the _100_200 example, it
doesn't imply the AS path would end with AS200 so I believe the example and
description are fine.
Apologies for my previously hasty descriptions. Thanks to all contributors
for once again pointing out and discussing wrong or misleading information.
Here are the modified examples and descriptions:
^$ local AS only
_10[5-9]$ received via AS 105, 106, 107, 108 or 109
^10[569]$ received directly from AS 105, 106, or 109
^100$ only from AS 100
^100_ received directly from AS 100 and any ASs' after it in the chain
_100_ via AS 100 (AS 100 was somewhere in the chain of ASs')
_100_200 via link between 2 AS (AS 100 and 200 were somewhere in the
chain of ASs')
^1_[0-9]*$ AS 1 & its directly connected ASs'
----- Original Message -----
From: "Manny Gonzalez" <manny@nyp.org>
To: "glmorris" <glmorris48@hotmail.com>
Cc: <ccielab@groupstudy.com>
Sent: Sunday, April 14, 2002 7:25 PM
Subject: Re: BGP Reg Exp
> glmorris,
>
> I believe your second and third entries are misleading. The actually
> mean ORIGINATING from those ASs but they do not necessarily need to be
> connected to you. For that to be true, you would need a "^" instead of
> "_"
>
> so:
>
> ^10[5-9]$
> ^10[569]$
>
> mean that they were received DIRECTLY from this AS(s)
>
> Also, in your example for _100_200 I also feel that could be misleading.
> If you do not place that underscore also at the end of the string, it
> will also match the following:
>
> 50 100 200 30
> 10 30 100 200 15
> 25 100 2002 200 10
> 100 2000 200 10 5
>
> etc. etc. Meaning that if you do not somehow close the string on the
> right hand side, it can match anything there that looks like
> "200(anythingelse)"
>
> For the last example, I believe the correct expression would be:
>
> ^1_[0-9]*$
>
> Once again, if you leave a space and not the "_" it will match 1, 11,
> 100, 1938, etc. etc.
>
> If I am incorrect, an expert will probably chime in shortly :-)
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