From: David Timmons (masterdt@yahoo.com)
Date: Tue Sep 12 2006 - 16:49:14 ART
Well,
In your examples you show sample with more then 2 AS's. This regular expression should only match an AS Path that came from a neighbor 100 and or originated from another AS. For example, you do this queiry on lookingglass you get something like this:
sh ip bgp regexp ^852(_[0-9]+)?$
*> 4.0.0.0/9 154.11.63.85 0 852 3356 i
*> 4.0.0.0 154.11.63.85 0 852 3356 i
*> 4.21.206.0/24 154.11.63.85 0 852 4323 i
*> 4.36.100.0/23 154.11.63.85 0 852 4323 i
*> 4.38.104.0/23 154.11.63.85 0 852 4323 i
*> 4.128.0.0/9 154.11.63.85 0 852 3356 i
*> 8.0.0.0/9 154.11.63.85 0 852 3356 i
*> 8.0.0.0 154.11.63.85 0 852 3356 i
*> 8.128.0.0/9 154.11.63.85 0 852 3356 i
<snip>
*> 209.235.255.176/29
154.11.63.85 0 852 ?
*> 216.226.41.176/30
154.11.63.85 0 852 ?
*> 216.226.41.208/30
154.11.63.85 0 852 ?
*> 216.226.42.200/29
154.11.63.85 0 852 i
*> 216.226.43.152/29
154.11.63.85 0 852 ?
*> 216.226.44.224/27
154.11.63.85 0 852 ?
0 852 4134 i
----- Original Message ----
From: Victor Cappuccio <cvictor@protokolgroup.com>
To: David Timmons <masterdt@yahoo.com>
Cc: ccielab@groupstudy.com
Sent: Tuesday, September 12, 2006 2:34:41 PM
Subject: RE: Regular Expressions
Hi David, Sorry but I would thing that both Regular Expression are not the
same.
The first Regular Expression matches this: ^100(_[ 0-9]+)?$
100
100 12
100 12 1 1 1
100 12 1 2
100 12 1 3
100 12 21
100 52 1 2
And the second regular expression ^100_[0-9]*$ matches this
100
100 32
100 33
100 44
100 66
100 X <- Only One Time
Please correct me if I'm wrong, but that is what I can understand from the
output from this route-server.gt.ca
Also there is a nice explanation of Regular Expression at IEWB-RS Solutions
Guide Lab 12
Thanks
Victor.-
-----Mensaje original-----
De: nobody@groupstudy.com [mailto:nobody@groupstudy.com] En nombre de David
Timmons
Enviado el: Martes, 12 de Septiembre de 2006 03:14 p.m.
Para: Tim Chan; Fabio Rodrigues; ccielab@groupstudy.com
Asunto: Re: Regular Expressions
Hi,
Think these two lines produce the same results. Really it is just saying the
that the originating AS can contain 1 or more numbers between for zero to
nine; however, the set should include the empty string. I would guess that
this type of regular expression would take a little extra processing power.
dt
----- Original Message ----
From: Tim Chan <timanji@yahoo.com>
To: Fabio Rodrigues <fleandror2@gmail.com>; ccielab@groupstudy.com
Sent: Tuesday, September 12, 2006 2:01:16 PM
Subject: Re: Regular Expressions
Search for "lookingglass router". You can telnet into these routers and
play with
regular expressions to see how each one differs.
This is one for example. Telnet to "route-server.ip.att.net". They have a
peering with
AS7018, so make sure that is the AS you're using in your expressions.
^7018(_[ 0-9]+)?$
^7018_[0-9]*$
-tim
----- Original Message ----
From: Fabio Rodrigues <fleandror2@gmail.com>
To: ccielab@groupstudy.com
Sent: Tuesday, September 12, 2006 8:11:42 AM
Subject: Regular Expressions
Hi All,
does anyone knows to say the difference of the effect (if exists) of these
two
regular expressions?
^100(_[ 0-9]+)?$
^100_[0-9]*$
Tks,
Fabio.
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