Level-1-2 IS can transmit Level-2 LSPs to a level-1 area. If the ATT bit in the Level-2 LSPs is set to 1, the Level-1 IS in the area can communicate with devices in other areas through the Level-1-2 IS.

Question

Quizplus · Accepted Answer

The ATT (Attached) bit in IS-IS indicates that a Level-1-2 IS is connected to other areas, allowing Level-1 ISs to route traffic to other areas through it.

Level-1-2 IS Can Transmit Level-2 LSPs to a Level-1 Area