A large enterprise network has two data centers and a WLAN edge with a large hub-and spoke network. The complete network is configured as a single OSPF area, and spoke routers are connected to unrelia

Regular stub areas still permit Type 3 inter-area summary LSAs, so spoke routers on unreliable links would still receive significant LSA flooding compared to totally stubby areas.

Hub routers must become ABRs (Area Border Routers) to sit between the OSPF backbone (Area 0) and the new stub areas, enabling them to filter LSAs and inject a default route toward the spoke areas.

ASBRs redistribute external routing information into OSPF and do not control LSA flooding toward spoke routers on unreliable links.

Totally stubby areas block all Type 3, 4, and 5 LSAs from entering the spoke area, replacing them with a single default route from the ABR, which minimizes LSA churn caused by unreliable WAN links.

Leaving spoke routers in a normal OSPF area means they receive all LSA types, maximizing overhead and instability on unreliable WAN links.