[j-nsp] as-path rewrite

Sorin CONSTANTINESCU consta at gmail.com
Tue Sep 27 07:43:49 EDT 2005


On 9/27/05, Jaroslaw Adam Gralak <rsh at man.szczecin.pl> wrote:
> On Tue, 2005-09-27 at 13:16 +0300, Sorin CONSTANTINESCU wrote:
> > Hi, all.
> >
> > I have the following topology:
> >
> > AS1 - AS99 (L3 Mpls VPN) - AS2 - AS99 - INTERNET
> >
> > My customer (AS2 - public AS Number) buys from the company i work for
> > 2 services:
> >
> > 1) Internet Access
> > 2) VPN between his location, and AS1 (also public AS Number).
> >
> > The problem i have is that when i receive a prefix originated by AS1
> > on the Internet Transit BGP session, the AS-PATH is: 1 99 2 . Our
> > network is a mixture of Juniper and Cisco routers. I used "allowas-in"
> > on the neighbor to the customer, but the Juniper routers won't import
> > this prefix throughout the network. I know i can use
> >
> > a at R1# set loops ?
> > Possible completions:
> >   <loops>              Maximum number of times this AS can be in an AS
> > path (1..10)
> > [edit routing-options autonomous-system]
> > a at R1# set loops
> >
> > ... but i don't consider this an option.
> >
> > Has anyone ever ran into this problem? As far as i see it, i have the
> > following options:
> >
> > - use private "local-as" for the BGP sessions between AS99 and AS1/AS2
> > for the MPLS VPN BGP sessions (haven't tested this one so far)
> > - ask the customer to configure EBGP Multihop between AS1 and AS2, so
> > that my own AS won't be in the AS-PATH
> >
> > I wish i could AS-PATH rewrite :))
>
> You probably looking for:
>
> as-override          Replace neighbor AS number with our AS number
>

Thanks, i'm working on it :)

> Best regards,
>
>
> --
> Jaroslaw Adam Gralak
> Technical University of Szczecin / Academic Center of Computer Science
> JG1991-RIPE * http://www.man.szczecin.pl http://www.aci.com.pl
>
>
>
>


--
Sorin CONSTANTINESCU
Cisco CCNP / JNCIA #845
consta at gmail.com



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