| 1. | Why is a loop-free inter-area architecture required in OSPF and IS-IS networks? |
| 2. | What technological factors limit the size of an area? |
| 3. | What are some of the less-tangible factors to consider when determining the size of an area? |
| 4. | What is a stub area? Why are ASBRs illegal in a stub area? |
| 5. | How do routers indicate to each other that they are in a stub area? |
| 6. | Can area 0 be a stub area? |
| 7. | What is the difference between a stub area and a totally stubby area? |
| 8. | How many type 3 LSAs are in the database of a totally stubby area? |
| 9. | What is an NSSA? What LSA type is unique to an NSSA, and what does it do? |
| 10. | When is the N/P bit in the Options field used as an N bit, and when is it used as a P bit? |
| 11. | What does the N bit indicate? |
| 12. | What does the P bit indicate? |
| 13. | Why should an ABR use a type 7 LSA rather than a type 3 LSA to advertise a default route into an NSSA? |
| 14. | Why can summary routes be originated by only ABRs and ASBRs? |
| 15. | What is a virtual link? What are its applications? |
| 16. | Can a virtual link transit multiple areas? |
| 17. | Can a virtual link transit area 0? |
| 18. | How does a router indicate that it has one or more fully adjacent virtual links? |
| 19. | Is it possible to have an L2 adjacency between the same two IS-IS routers when their AIDs match? |
| 20. | Is it possible to have both an L1 adjacency between the same two IS-IS routers when their AIDs differ? |
| 21. | Is it possible to have both an L1 and an L2 adjacency between the same two IS-IS routers, on the same link? |
| 22. | Why is an IS-IS L1 area considered "totally stubby" by default? |
| 23. | What is the purpose of the ATT bit? |
| 24. | What is the primary advantage of prefix summarization? What is its primary disadvantage? |
| 25. | What is the purpose of the I/E bit associated with the IS-IS metric field? |
| 26. | What is the purpose of the U/D bit? |
| 27. | Why might a prefix redistributed into an IS-IS domain be given an "internal" metric? |
