Have a hub and spoke design where each Branch has a single router with a WAN connection to DataCenter1 Hub and another WAN connection to DataCenter2 Hub. There is no OSPF running elsewhere in the DataCenters.

Trying to determine optimal Area design for OSPF for this situation - and to ensure Branch Routers do not become transit for other Branch networks. Should Area0 be run across both WAN links w/ each branch having its own Area defined as a stub on the Branch router. Since there are no connections between the DataCenter WAN routers - wasn't sure of implications of having 'two' Area0s in this manner?

  • 3
    You can't have two area 0's. They have to be connected into one. A Hub and spoke network is the one case where OSPF doesn't do well. If you can, consider using EIGRP. It works much better for this scenario. If EIGRP is not an option, BGP might also be an alternative.
    – Ron Trunk
    Commented Apr 27, 2018 at 14:24
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide and accept your own answer.
    – Ron Maupin
    Commented Dec 25, 2018 at 8:20

1 Answer 1


As Ron Trunk points out, you cannot have more than one Area 0 for one AS. You could use virtual links to connect separate Area 0s in the same AS.

Think about it this way, Area 0 is the backbone area. What is the backbone of your network. That is where you put Area 0. That may be the WAN connections. It may be that you configure and Area 0 at each site, and you connect the sites with BGP, another OSPF instance, static routes, or another routing protocol, and you redistribute routes. You could also have a main site that is Area 0, and all the other sites are in different areas, with the main site WAN connections for the other areas in those areas. With a main site, you could simply have default routes for the branch sites.

You need to step back and understand where the network backbone is or should be.

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