Designing Cisco Enterprise Networks (ENSLD) — Question 317

A network engineer must segregate three interconnected campus networks using IS-IS routing. A two-layer hierarchy must be used to support large routing domains and to avoid more specific routes from each campus network being advertised to other campus network routers automatically. Which two actions does the engineer take to accomplish this segregation? (Choose two.)

Answer options

• A. Designate two IS-IS routers as BDR routers at the edge of each campus, and configure one BDR for all Level 1 routers and one BDR for all Level 2 routers.
• B. Designate two IS-IS routers from each campus to act as Level 1/Level 2 backbone routers at the edge of each campus network.
• C. Assign the same IS-IS NET value for each campus, and configure internal campus routers with Level 1/Level 2 routing.
• D. Utilize different MTU values for each campus network segment. Level 2 backbone routers must utilize a larger MTU size of 9216.
• E. Assign a unique IS-IS NET value for each campus, and configure internal campus routers with Level 1 routing.

Correct answer: B, E

Explanation

Option B is correct because designating Level 1/Level 2 backbone routers at the edge helps create the required hierarchy for routing. Option E is also correct as assigning unique IS-IS NET values for each campus ensures that routing information remains segregated. The other options either do not support the required segregation or do not align with the IS-IS routing principles necessary for this scenario.