[c-nsp] BGP default route

[Gary Roberton]

Hi

I have three routers, R1 > R2 >  R3.

R1 advertises a default route to R2 by using default-originate
R2 advertises a default route to R3 by using default-originate

However, I only want R2 to advertise to R3 if it receives the default route
from R1.  In other words if connectivity is lost between R1 and R2 I dont
want R2 adveetising the default route to R3 as the path won't be valid.

Ideas?