[c-nsp] BGP Route Nailing & Reoriginating

[Sergio D.]

You can if R1 is a private AS, you can then remove private on R2 before
advertising to R3, AFAIK you can't "delete" a public AS. In regards to your
second question, you can create an aggregate or static route pointing to
Null on R2 and always advertise that to R3, but not sure why you wouldn't
withdraw the routes if R1 to R2 go down, since you will be black holing
traffic.


Dear gurus,

I have an environment as follows:

       (R1 / AS1) <-> (R2 / AS2) <-> (R3 / AS3)


R1 (router 1) has AS number 1 (AS 1) and advertises the routes 1.1.1.0/24and
2.2.2.0/24 to R2 which inturn advertises to R3. All advertisement is done
via eBGP.

Is it possible to configure R2 such that the routes 1.1.1.0/24 and
2.2.2.0/24 are advertised to R3 under AS2 instead of AS1? At the same time,
can R2 "nail" down the routes so that in the event the (physical & BGP) link
between R1 and R2 is down, the route continues to be advertised to R3 (and
under AS2)?

The objective is to "hide" AS1 and also to prevent BGP dampening at R3
caused by flapping link between R1 & R2.


TIA!

-- 
Sergio Danellli
JNCIE #170