Advertising BGP route learned back to same AS

[Paul Dougherty]

I have a situation where my Internet edge routers learn 0.0 from ATT (AS 7018) my provider.  I then wish to advertise these learned routes via WAN.  However my WAN MPLS provider is also ATT and they use AS 7018 for that as well.  When I try to push 0.0 to my other WAN sites 0.0 is suppressed to avoid loops.

What's the best way to tell the WAN routers to advertise 0.0 back to the same AS originally learned from?

Thanks for your suggestions.

You've all been more helpful than I ever expected.  Since this has turned more detailed I've added a drawing

Thank you.

[Roman Rodichev]

You are absolutely correct. SoO should be implemented to prevent AT&T from readvertising default route into the other backup site and vice versa, that's of course if we assume that MPLS is not the only method of connectivity between his two Internet gateway sites.

The use of default-originate should be carefully reviewed based on the route flow, Internet gateway locations, etc. A drawing would probably help us determine the most efficient failover mechanism. It's especially important to know where the firewalls are, what his DMZs look like, and what level of failover are required, as we want to avoid any asynchronous flows through firewalls.

[Paul Dougherty]

I've added a drawing above, if that gererates any additional thoughts.

Thank you.

[gerald.suiza]

ahh..so you do have 2 internet gateways..now the question is do you want your internet traffic to failover if the primary goes down? If you do i would suggest SoO. Also with SoO you can "regionalize/load balance traffic on the internet GW's since your service provider can implement SoO in such a way that the sites which you choose can go to a specific gateway and make the other the backup. in this way you get more bang for your buck becasue all your subscribed circuits get utilized and no sleeping assets not to mention redundancy...

HTH