ATotally Stubby Areain OSPF is a special type of stub area where onlyintra-area (Type 1) LSAs,router LSAs, anddefault routes (Type 3 LSA with 0.0.0.0/0)are allowed to be injected. Itblocks inter-area routes (Type 3 LSAs for specific prefixes)andType 5 LSAs (external routes)to reduce the size of the Link-State Database (LSDB) and enhance router performance.
Explanation of the Options:
A. Type 3 specific LSA–❌Correct Answer. These LSAs represent inter-area routes. Totally Stubby Areasdo not allow Type 3 LSAs for specific routes, only for the default route (0.0.0.0/0).
B. Type 1 LSA–✅Allowed. These are Router LSAs generated by routers within the area and are necessary for OSPF to function.
C. Type 3 LSA that describes a default route–✅Allowed. This is the only Type 3 LSA permitted in a Totally Stubby Area. It provides a default route (0.0.0.0/0) to reach external destinations.
D. Type 2 LSA–✅Allowed if there are broadcast or NBMA networks in the area. These describe the network segment in multi-access environments and are generated by the DR.
Official Huawei Reference:
????Huawei HCIP-Datacom-Core Technology Study Guide–
Chapter: OSPF Special Areas
"A totally stub area does not allow inter-area Type 3 LSAs or external Type 5 LSAs to enter. Only a default route is injected in the form of a Type 3 LSA (0.0.0.0/0), which greatly reduces the LSDB size."
????Also refer to:
Huawei VRP Command Guide > OSPF > Configuration Notes > OSPF Special Areas
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