JNCIP-SP: Juniper Networks Certified Professional – Service Provider (2023) — Question 77

Which three statements about IS-IS in a multi-area network are correct? (Choose three.)

Answer options

• A. Internal L1 PDUs are flooded to all L1 routers in other areas.
• B. External L2 PDUs are only flooded to the local area’s L2 routers.
• C. Internal L1 PDUs are flooded to the local area’s L2 routers.
• D. External L2 PDUs are flooded to all L2 routers in other areas.
• E. Internal L1 PDUs are only flooded to the local area's L1 routers.

Correct answer: C, D, E

Explanation

The correct answers C, D, and E accurately describe the behavior of IS-IS PDUs in a multi-area environment. Internal L1 PDUs are only sent to L1 routers within the same area, while external L2 PDUs are flooded to all L2 routers across the network. Options A and B are incorrect because they misrepresent how PDUs are flooded between areas.