This chapter covers the following topics:
Understanding OSPF Fundamentals—This section reviews fundamental concepts related to OSPF operation.
Configuring OSPF in a Single Area—This section describes required and optional commands for configuring OSPF in a single area.
Checking the Configuration of Single-Area OSPF—This section describes commands used to troubleshoot the OSPF configuration.
This chapter explores the routing protocol Open Shortest Path First (OSPF). You should already be familiar with the basic concepts of link-state routing protocols and single-area OSPF. This chapter briefly reviews single-area OSPF and then introduces multiple-area OSPF. The chapter concludes with techniques for configuring, verifying, and troubleshooting OSPF.
The purpose of the "Do I Know This Already?" quiz is to help you decide what parts of this chapter to use. If you already intend to read the entire chapter, you do not necessarily need to answer these questions now.
The 14-question quiz, derived from the major sections in the "Foundation Topics" portion of the chapter, helps you determine how to spend your limited study time.
Table 5-1 outlines the major topics discussed in this chapter and the "Do I Know This Already?" quiz questions that correspond to those topics.
|Foundation Topics Section||Questions Covered in This Section||Score|
|Understanding OSPF Fundamentals||1–10|
|Configuring OSPF in a Single Area||11–12|
|Checking the Configuration of Single-Area OSPF||13–14|
The goal of self-assessment is to gauge your mastery of the topics in this chapter. If you do not know the answer to a question or are only partially sure of the answer, you should mark this question wrong for purposes of the self-assessment. Giving yourself credit for an answer you correctly guess skews your self-assessment results and might provide you with a false sense of security.
|1.||What is a neighbor on a local LAN segment in OSPF?
|2.||What is an adjacency in OSPF?
|3.||What is a designated router?
|4.||By default, how often does OSPF send out hello packets on a broadcast multiaccess link?
|5.||When a router sends an LSA on a multiaccess link, to what is it sent?
|6.||What does it mean when an interface shows that it is in the init state?
|7.||If the network is stable and sees no changes, how often will it send LSAs? Why are these updates sent out periodically?
|8.||In learning a new route, what will an internal OSPF router do if a received LSA is not found in the topological database?
|9.||What would the default cost of a 1-Mbps link be?
|10.||If a router has an OSPF priority set to 0, what does this indicate?
|11.||Which of the following IP addresses are subsumed by this command:
Router(config-router)# network 10.1.32.0 0.0.31.255 area 0
|12.||What is the default OSPF cost for a T1 link?
|13.||On a LAN segment, what is the maximum number of neighbors that can be designated as DROTHER in the show ip ospf neighbor output?
|14.||Which command would include output such as "SPF algorithm executed 10 times?"
The answers to this quiz are found in Appendix A, "Answers to Chapter 'Do I Know This Already?' Quizzes and Q&A Sections." The suggested choices for your next step are as follows: