Good afternoon,
I searched & searched for information about BGP aggregates & distributing a default route to BGP peers but everything I found was REALLY old.
Hopefully somebody can help me out.
Running 2.9.50 x86.
#1)
OSPF is running all the internal network stuff. We have two providers on either side of the network. Currently, the only way I’ve found to distribute the default network in BGP is to add it to the
/router bgp network 0.0.0.0/0
This obviously creates a problem when ISP1 goes down. Because the other network devices still receive word that this route is active, and won’t switch to go the other way.
How can I make it so when there is an OSPF learned default route, it will send this to the BGP peers. But if that route goes away, so does the BGP peer advertisement?
#2)
Currently because ospf has so many smaller networks (need to setup more OSPF summary areas), the BGP session is advertising all the small networks. I would like aggregate them to advertise the single 10.100.0.0/16 that needs to be advertised.
/ routing bgp aggregate
add instance=default prefix=10.100.0.0/16 summary-only=yes \
inherit-attributes=yes attribute-filter="" suppress-filter="" \
advertise-filter="" disabled=no
But apparently that doesn’t want to work. Is there something else I need to do for this to happen, or is it just broken?
Thanks for any help & if the answer is running v3, I have no problems with that.. as long as it Works! 
-Keith-