| 1. | What four mechanisms are used by both OSPF and IS-IS to make flooding reliable? |
| 2. | What events cause an OSPF router to send an LSA to one or more of its neighbors? |
| 3. | Under what circumstances is the destination address of an OSPF Update packet unicast, and under what circumstances is it a multicast address? |
| 4. | What is the flooding scope of an OSPF Update message? |
| 5. | What is the difference between an explicit and implicit OSPF acknowledgment? |
| 6. | What are the advantages and disadvantages of direct and delayed acknowledgments? |
| 7. | Under what two circumstances is an LSA directly acknowledged? |
| 8. | What is the purpose of the OSPF retransmit list and retransmit timer? |
| 9. | Why are retransmitted LSAs always unicast, regardless of network type? |
| 10. | What are the initial and maximum OSPF sequence number values? |
| 11. | What is the OSPF InfTransDelay? What is the usual default value of this variable? |
| 12. | What are the minimum and maximum values of the OSPF Age variable? |
| 13. | What is the value of the OSPF constant LSRefreshTime? |
| 14. | How does a router flush an LSA that it previously originated? |
| 15. | What is the value of the OSPF constant MaxAgeDiff, and how is the constant used? |
| 16. | Which fields in an LSA header identify a particular LSA, and which fields identify a specific instance of a particular LSA? |
| 17. | If two LSAs are received with identical Type, LS ID, Advertising Router, and Sequence Number fields, but different Checksum fields, which is the newer LSA? |
| 18. | Does OSPF practice strict split horizon on LSAs during flooding, or is there any case in which an LSA is flooded back out the interface on which it was received? |
| 19. | What events cause IS-IS to originate and flood an LSP? |
| 20. | How is an IS-IS LSP like an OSPF Update message? How is it different? |
| 21. | How is an IS-IS LSP like an OSPF LSA? How is it different? |
| 22. | How does the IS-IS remaining lifetime differ from the OSPF age? |
| 23. | What are the maximum and minimum values of the IS-IS remaining lifetime? What is the typical default value? |
| 24. | How does an IS-IS router flush an LSP it has previously originated? |
| 25. | How does the linear IS-IS sequence number space differ from the linear OSPF sequence number space? |
| 26. | Why might an IS-IS router originate an LSP with a sequence number of 0? |
| 27. | If one LSP has a sequence number of 0 and one LSP has a sequence number of 10, and they are otherwise identical, which LSP is considered more recent? |
| 28. | What does an LSP number of 0x03 signify? |
| 29. | What is the IS-IS SRM flag? |
| 30. | What PDUs does IS-IS use for acknowledging the receipt of an LSP? |
| 31. | Is an LSP received on a point-to-point link implicitly or explicitly acknowledged? What about an LSP received on a broadcast link? |
| 32. | What is the difference between an ABR and an ASBR? |
| 33. | What is an L1/L2 router? |
| 34. | If two IS-IS neighbors are both L1-Only and their AIDs differ, can an adjacency be established? |
| 35. | Under what circumstances can both an L1 and an L2 adjacency be established between the same two IS-IS neighbors? |
| 36. | What is an OSPF reference bandwidth? |
| 37. | What is the difference between OSPF E1 and E2 metrics? |
| 38. | If an OSPF router receives two routes to the same prefix, one with an E1 metric and one with an E2 metric, which route is chosen? |
| 39. | What does the I/E bit associated with IS-IS metrics signify? |
| 40. | What are wide metrics? What TLV supports them? |
| 41. | What are the five "essential" LSAs, what are their type numbers, and what is the function of each? |
| 42. | What do the E and B bits signify in a type 1 LSA? |
| 43. | How many prefixes can be carried in a type 3 LSA? How prefixes can be carried in a type 5 LSA? |
| 44. | What is the flooding scope of a type 5 LSA? |
| 45. | What are the "essential" TLVs in an IP-only IS-IS network? How is each used? |
