In OSPF, which area is the central hub that connects all other areas?

• A. Regular Area
• B. Stub Area
• C. Backbone
• D. Not Applicable

Answer: (C)

OSPF routes between different areas by funneling inter-area information through a central backbone area. This backbone, Area 0, acts as the hub that connects every other area and carries the summary routes between them. All non-backbone areas must attach to the backbone, directly or via a virtual link, so that inter-area routing remains consistent across the entire OSPF domain. A regular area is just a standard area with its own full link-state database; a stub area is a special type that reduces external routing information and relies on a default route to reach networks outside the area. Not applicable isn’t a valid area type in OSPF. So the central hub that connects all other areas is the backbone.