Which statement describes IS-IS operation?

The statement that to advertise Level 2 routes into a Level 1 area, an export policy must be configured accurately reflects the operational characteristics of the Intermediate System to Intermediate System (IS-IS) protocol. In IS-IS, the Level 1 area represents a smaller, hierarchical region that typically provides routing within a single administrative domain, while Level 2 areas are intended for inter-area routing across multiple Level 1 areas.

By default, Level 2 routes are not automatically advertised to Level 1 areas. This behavior necessitates the explicit configuration of an export policy to manage how information flows between the two levels. The need for export policy helps maintain control over routing information and ensures that the network operates efficiently without unnecessary routing advertisements that could affect stability or performance.

Thus, configuring an export policy to control Level 2 to Level 1 routing behavior is a critical aspect of IS-IS operations, making this option the correct choice. Understanding this nuance is vital for network design and implementation where multi-level routing architecture is employed.