Cisco ENCOR Practice Exam 2025 – All-in-One Comprehensive Guide to Mastering Enterprise Network Core Technologies!

The Type 5 LSA, also known as the AS External LSA, is specifically utilized to advertise routes that have been redistributed into an OSPF (Open Shortest Path First) domain from other routing protocols, such as EIGRP, BGP, or static routes. This LSA type enables OSPF to carry external route information, which is vital for network interoperability when different routing protocols are used within an organization.

Type 5 LSAs contain information such as the external route metrics and the type of the external route (E1 or E2), which indicates how the metric is calculated. E1 considers both the internal OSPF cost to reach the ASBR (Autonomous System Boundary Router) and the external cost, while E2 is based only on the external cost.

Other LSA types, while critical for the overall OSPF operation, serve different purposes. For example, Type 1 LSAs are used for advertising intra-area router information, Type 4 LSAs are used to advertise the location of ASBRs to other areas, and Type 7 LSAs are employed in NSSA (Not So Stubby Area) to handle external routes before they are converted to Type 5 LSAs in the O