Description: Not So Stubby Area, known as NSSA, is a type of area in the OSPF (Open Shortest Path First) protocol that allows the import of external routes into an area that would otherwise be considered ‘stub’. In OSPF, stub areas are those that do not allow the propagation of external routes, meaning they can only know internal routes and cannot access external networks. However, NSSA was designed to overcome this limitation, allowing a stub area to receive information about external routes through a boundary router (ASBR – Autonomous System Boundary Router). This is particularly useful in situations where an area needs to maintain the simplicity of a stub but also requires access to certain external routes. NSSA allows external routes to be injected into the area without compromising the efficiency and simplicity of the OSPF topology. This approach provides a balance between the need to maintain a more controlled area and the flexibility to access external resources, making it a valuable option for more complex network architectures.
