With the OSPF super backbone architecture, the continuity of OSPF routing is preserved.
The OSPF intra-area LSAs (type-1 and type-2) advertised bye the CE are inserted into the MPLS-VPRN super backbone by redistributing the OSPF route into MP-BGP by the PE adjacent to the CE.
The MP-BGP route is propagated to other PE-routers and inserted as an OSPF route into other OSPF areas. Considering the PEs across the super backbone always act as ABRs they generate inter area route OSPF summary LSAs, Type 3.
The inter-area route can now be propagated into other OSPF areas by other customer owned ABRs within the customer site.
Customer Area 0 (backbone) routes when carried across the MPLS-VPRN using MPBGP appear as Type 3 LSAs even if the customer area remains area 0 (backbone).
A BGP extended community (OSPF domain ID) provides the source domain of the route. This domain ID is not carried by OSPF but carried by MP-BGP as an extended community attribute.
If the configured extended community value matches the receiving OSPF domain, then the OSPF super backbone is implemented.
From a BGP perspective, the cost is copied into the MED attribute.