[j-nsp] Cisco advertise-map in juniper

[xinyu zeng]

But seems this can not work in following scenario:

R1(Route:10/8)---R2(Route:10/24)---R3

R1/R2, R2/R3 are all bgp peers.

R2 will advertise 10/8 to R3 if R1/R2 BGP connection is up, and
advertise 10/24 to R3 if R1/R2 BGP connection is down.

So, requirement is: R2 will advertise 10/24 to R3 if 10/8 route is not
in R2's BGP local-rib.

This is from the book "BGP design and implementation"  Chapter 4.2,
and I am wondering how it is made in JUNOS.

On 9/16/06, xinyu zeng <xinyu.zeng at gmail.com> wrote:
> Thanks you. I had missed that point...
>
> On 9/16/06, Vladimir S. Blazhkun <v.blazhkun at pcs-net.net> wrote:
> >
> > > IOS have 'advertise-map/non-exist-map' to control which routes to be
> > > advertsed if some other routes not available. Is there any way Junos
> > > can do that?
> >
> > Sure, use aggregated/generated routes with some policies.
> >
> > Example (search this list for more):
> >
> > protocols bgp {
> >      group ebgp {
> >         type external;
> >         neighbor 10.1.0.1 {
> >             description primary;
> >             export announce-conditional-generate;
> >             peer-as 10;
> >         }
> >         neighbor 20.1.0.1 {
> >             description backup;
> >             export announce-conditional-aggregate;
> >             peer-as 20;
> >         }
> >     }
> > }
> >
> > routing-options {
> >      aggregate {
> >         route 192.168.0.0/16 {
> >             policy check-contributing-routes;
> >             discard;
> >         }
> >      }
> >      generate {
> >         route 192.168.0.0/16 {
> >             policy check-contributing-routes-2;
> >             discard;
> >         }
> >      }
> >      static {
> >         route 192.168.0.0/32 {
> >             next-hop 10.1.0.2;
> >             qualified-next-hop 20.1.0.2 {
> >                 preference 6;
> >             }
> >             resolve;
> >         }
> >      }
> > }
> >
> > policy-options {
> >      policy-statement announce-conditional-generate {
> >         term 1 {
> >             from {
> >                 protocol aggregate;
> >                 route-filter 192.168.0.0/16 exact;
> >             }
> >             then accept;
> >         }
> >         term 2 {
> >             then reject;
> >         }
> >      }
> >      policy-statement announce-conditional-aggregate {
> >         term 1 {
> >             from {
> >                 protocol aggregate;
> >                 route-filter 192.168.0.0/16 exact;
> >             }
> >             then accept;
> >         }
> >         term 2 {
> >             then reject;
> >         }
> >      }
> >      policy-statement check-contributing-routes {
> >         term 1 {
> >             from {
> >                 protocol static;
> >                 route-filter 192.168.0.0/32 exact;
> >                 preference 6;
> >             }
> >             then accept;
> >         }
> >         term 2 {
> >             then reject;
> >         }
> >      }
> >      policy-statement check-contributing-routes-2 {
> >         term 1 {
> >             from {
> >                 protocol static;
> >                 route-filter 192.168.0.0/32 exact;
> >                 preference 5;
> >             }
> >             then accept;
> >         }
> >         term 2 {
> >             then reject;
> >         }
> >      }
> > }
> >
> > --
> > Vladimir S. Blazhkun,
> > JNSS-M JNCIA-M #773 JNCIS-M #1100 JNCIP-M #289 JNCI-M
> > JNCIA-J JNCI-J
> >
>
>
> --
> Best Regards,
> Yours Xinyu.Zeng
>


-- 
Best Regards,
Yours Xinyu.Zeng