Need some advice on the best way to implement the attached.
So R1A and R1B will be advertising their local networks (10.0.10.0/24 and 10.0.20.0/24) There is a 100Mb interconnect between R2A and R2B and then somewhere within the MPLS cloud there is another 30Mb link which is the backup
Now I want to run my IGP as OSPF, R2A and R2B will be sending out a default route via OSPF, the routers within the "cloud" should pick up their default gateways automatically via metrics, weights etc. However the problem that I have is that if R2A dies, R1A will still be advertising 10.0.10.0/24. So traffic will go out via R1B but try to get back in via R1A. How can I get around this problem?
The second problem is that I do not know the best way to connect R1A with R2A, should I expand my OSPF area 0 to R1A or use a default route with something like IP SLA?
Any help will be much appreciated,