Which statement best describes the purpose of dividing an OSPF domain into areas?

Which statement best describes the purpose of dividing an OSPF domain into areas?

• A. To enforce ACLs at area boundaries
• B. To optimize routing by reducing LSAs, limiting SPF calculations, and improving scalability
• C. To isolate only intra-area traffic from inter-area
• D. To require separate routing protocols per area

Answer: (B)

Hierarchical design in OSPF with areas is all about scalability. By dividing the domain into smaller areas, most of the routing information and the SPF calculations stay contained within each area. That keeps the link-state databases per router smaller, reduces how often SPF runs are needed, and lowers CPU and memory use as the network grows. The backbone area (area 0) connects all other areas, and area border routers summarize inter-area routes so you still get reachability without forcing every router to process the entire domain’s LSAs. So, the statement that best describes the purpose is that dividing into areas optimizes routing by reducing LSAs, limiting SPF calculations, and improving scalability. ACLs at area boundaries aren’t part of OSPF’s design, traffic isn’t inherently isolated by area in this way, and OSPF uses the same routing protocol across all areas rather than requiring separate protocols per area.

Hierarchical design in OSPF with areas is all about scalability. By dividing the domain into smaller areas, most of the routing information and the SPF calculations stay contained within each area. That keeps the link-state databases per router smaller, reduces how often SPF runs are needed, and lowers CPU and memory use as the network grows. The backbone area (area 0) connects all other areas, and area border routers summarize inter-area routes so you still get reachability without forcing every router to process the entire domain’s LSAs.

So, the statement that best describes the purpose is that dividing into areas optimizes routing by reducing LSAs, limiting SPF calculations, and improving scalability. ACLs at area boundaries aren’t part of OSPF’s design, traffic isn’t inherently isolated by area in this way, and OSPF uses the same routing protocol across all areas rather than requiring separate protocols per area.