[c-nsp] as-path access-list question

[Joe Provo]

On Tue, Sep 26, 2006 at 08:26:56AM -0400, Paul Stewart wrote:
> Pardon my ignorance but I can't seem to find an answer on this...
> 
> I've been playing around with our BGP reach to an upstream provider and
> I'm trying to find something *between* 
> 
> ip as-path access-list 20 permit ^6539$
> 
> and
> 
> ip as-path access-list 20 permit ^6539_[0-9]*$
> 
> Is there a syntax that is "in between" these two?  Any references on
> Cisco for this?

There's a lot of things 'between', though you're not at all clear 
what you're trying to do so I'm not sure in what sense "between" 
you mean.  First, try + instead of *.  Depending on what you're 
trying to do, you might be using the wrong wend of the stick and 
would want broadwing to send you community-tagged routes so you can 
pick & choose paths based on more detailed criteria than number of
AS hops away.

Some references for the cisco version of regular expressions useful
for policies are
 http://www.cisco.com/warp/public/459/bgp-toc.html#asregexp
 http://www.cisco.com/warp/public/459/bgp-toc.html#pathfilter
 http://www.cisco.com/warp/public/459/26.html

Cheers,

Joe

--
Joe Provo                                            Voice  617.670.2904
Senior Manager, Internet Planning & Design           Fax    617.670.2920
Network Engineering, RCN                             <joe.provo at rcn.com>