RE: Regexp for BGP

From: Scott Morris (swm@emanon.com)
Date: Sun Mar 11 2007 - 23:15:16 ART


Read what you are trying to accomplish.

^100$ means the AS Path ONLY contains AS 100.
_100$ means the AS Path just ENDS with AS 100 (could be anything before it).

 
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE
#153, CISSP, et al.
CCSI/JNCI-M/JNCI-J
IPexpert VP - Curriculum Development
IPexpert Sr. Technical Instructor
smorris@ipexpert.com
http://www.ipexpert.com
 
 

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Jeff
Mullan
Sent: Sunday, March 11, 2007 8:28 PM
To: Cisco certification
Subject: Regexp for BGP

Folks,
R1-R2-R3,

R1 = AS 100
R2 = AS 200
R3 = AS 300

If the question is, AS200 should not provide transit services to AS300 for
networks originated from "CUSTOMERS" of AS100. And we are bound to use
as-path list, would both of the following regexp satisfy the question ?

on R2 outbound towards R3 permit : ^100$ OR;
on R2 outbound towards R3 permit : _100$

Thanks,
-JM



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