Cisco Enterprise Network Core Technologies (ENCOR) Practice Exam

Type 7 LSAs (Link-State Advertisements) are specifically used in OSPF (Open Shortest Path First) for advertising external routes within Not-So-Stubby Areas (NSSAs). NSSAs are an OSPF area type that does not allow external routes by default, but can import external routes from other OSPF areas while still functioning as a stub area.

When Type 7 LSAs are utilized, they allow the external route information to be carried into the NSSA, where it can then be transformed into Type 5 LSAs for propagation to other areas of the OSPF network. This functionality is crucial for network designs that require specific configurations of routing behavior within NSSAs, enabling the seamless integration of external routing information while adhering to the constraints and benefits of both NSSAs and stub areas.

The other answer choices relate to different types of LSAs that serve various purposes in OSPF. Intra-area routes are advertised by Type 1 LSAs, summary routes across areas are associated with Type 3 LSAs, and inter-area routes are advertised by Type 4 LSAs. Each of these LSAs has distinct roles and does not include the specific conditions and configurations of external route advertisement found