[c-nsp] OSPF and BGP relationship

[CWO Network Operations]

I have a question about the common practice of using OSPF and (i)bgp.

Here is my setup:


I have 4 Cisco routers (A, B, C & D). All routers are connected to each other through metro ethernet connections. The 4 routers have other “stuff” behind them speaking only OSPF and require a injected default route.
Router A and B are connected to different internet backbone providers using BGP.
Internally I use iBGP and OSPF. I do not redistribute OSPF routes into BGP, nor do I do the opposite.
Router A injects a default route into the network using OSPF’s default-information originate metric 100.
Router B also injects a default route into the network using OSPF’s default-information originate metric 110.

So, right now all my outbound traffic goes out through router A (because of the metric 100). Inbound traffic comes through both internet connections, based on the preferred BGP route.
Since the IGP (ospf) has the lower IGP metric (in comparison to ibgp) the ospf default routes (0.0.0.0/0) routes determine the flow of outbound traffic. Because of that, I can’t seem to “direct” outbound traffic using a local route map (local-preference). Ideally I would like to be able to direct outbound traffic as specific as I like.

What is the common setup, in terms of BGP and OSPF, on networks that resemble ours?

Thanks
JB