Q&A

The questions and scenarios in this book are designed to be challenging and to make sure that you know the answer. Rather than allowing you to derive the answers from clues hidden inside the questions themselves, the questions challenge your understanding and recall of the subject.

You can find the answers to these questions in Appendix A. For more practice with exam-like question formats, use the exam engine on the CD-ROM.

1.Which system generates the pseudonode?
2.What is a CSNP? When is it used?
3.What is a PSNP? When is it used?
4.A new router comes online on a multiaccess link, and the priority is the same as that of the DIS for the segment. What action is taken?
5.What happens when the DIS is no longer available?
6.Integrated IS-IS can be used to send information about which routed protocols?
7.How often does the DIS send out a Hello packet?
8.What is the name of the link-state algorithm used to create entries for the routing table?
9.What is the relationship between the Hello timer and when the path is considered to have died?
10.Integrated IS-IS areas are similar to which OSPF area types?
11.Describe a design restriction in configuring Level 2 routing.
12.Given the address 49.0001.2222.2222.2222.00, is this a NET or NSAP address?
13.What is a pseudonode and what is its purpose?
14.State two reasons why a router might not be able to become logically adjacent to a neighbor.
15.Explain briefly why two routers cannot have the same system ID within the area.
16.What does TLV stand for? Briefly explain its purpose.
17.How many link-state databases does a Level 1-2 router have?
18.Integrated IS-IS packets run directly on top of which layer?
19.What is the NET address associated with in the IS-IS addressing scheme?
20.Describe the main characteristics of a Level 1 IS.
21.Which systems would you configure as Level 1-2?
22.What are the four stages of the routing process?
23.What does an LSP contain?
24.When are LSPs generated?
25.State at least one of the main steps of the flooding process on a point-to-point link.
26.Which three fields determine if a LSP is valid?
27.Once the link-state database is synchronized, the Dijkstra algorithm is run. Describe where the router places itself in the tree.
28.State two criteria in determining which paths are to be placed in the forwarding database.
29.What is a narrow metric?
30.Where is the IS-IS metric applied?
31.What action will the routing process take if it sees an incomplete LSP fragment?
32.What is a suboptimal routing decision?
33.Where does route summarization take place?
34.When is a DIS elected in a WAN environment?
35.Explain briefly how the IS-IS NBMA cloud is different than the configuration of the OSPF cloud.