| 1. | Describe the modification to the simplistic SPF algorithm of Chapter 2 that allows ECMP. |
| 2. | Why is per-destination load balancing better than per-packet load balancing? |
| 3. | Why is per-flow load balancing better than per-destination load balancing? |
| 4. | What modification to the basic SPF algorithm is required, when there are equal costs involving both point-to-point links and broadcast links, to avoid disruption of ECMP? |
| 5. | What is Incremental SPF, and in what two general cases can it improve the efficiency of SPF in an area? |
| 6. | What is partial route calculation, and how does it improve the efficiency of SPF calculations? |
| 7. | How does SPF delay improve the efficiency of SPF calculations? |
| 8. | How can an excessive SPF delay reduce the performance of a network? |
| 9. | What is adaptive SPF delay, and what is its advantage over a set delay period? |
| 10. | Why are individual refresh timers for each self-originated LSA or LSP in a database better than a single monolithic timer? |
| 11. | How does adding a delay period to the refresh timers of self-originated LSAs or LSPs reduce problems associated with heavy flooding? |
| 12. | Under what circumstances can increasing the time a router waits for an acknowledgement of a transmitted LSA or LSP before retransmitting improve flooding efficiency? |
| 13. | What is a mesh group? |
| 14. | What are the advantages and disadvantages of using blocked mode in a mesh group? |
| 15. | What are the advantages and disadvantages of using set mode in a mesh group? |
| 16. | Can the three mesh group modes (inactive, blocked, and set) be used in the same network? |
| 17. | What is a demand circuit? |
| 18. | What is the OSPF DoNotAge bit? |
| 19. | What two changes are made to OSPF procedures in the extensions for support of demand circuits? |
| 20. | What is the purpose of the DC bit in the Options field of LSAs? |
| 21. | What is the purpose of the DC bit in the Options field of OSPF Hello and Database Description packets? |
| 22. | What does the presumption of reachability mean in regard to OSPF over demand circuits? |
| 23. | In what way can OSPF over demand circuits effect the consistency of LSA sequence numbers, and in what way can this be a problem? |
| 24. | What is OSPF flood reduction? |
| 25. | Why is fragmentation less of an issue with OSPF than with IS-IS? |
| 26. | What is the IS-IS ReceiveLSPBufferSize, and why are Hellos padded to this size during when attempting to form an adjacency? |
| 27. | What is the purpose of the LSP Number in the LSP header? |
| 28. | What happens if LSP Number 0 of a fragmented LSP is missing in a link state database? |
| 29. | What is the purpose of the IS-Alias-ID (type 24) TLV? |
| 30. | What does it mean when an IS-IS router is overloaded? |
| 31. | How is the OL bit useful in BGP transit networks? |
| 32. | What is the advantage of enabling an overload timeout option in BGP transit networks? |
| 33. | How can "overloading" behavior be created in an OSPF area? |
