Chapter 12. Controlling Redistribution with Route Maps

This chapter covers the following topics:

Understanding Route Maps—Describes what route maps are and how to formulate them.
Configuring Route Maps—Describes how to configure route maps.
Monitoring the Configuration of Route Maps and Redistribution—Describes the commands used to monitor and troubleshoot route maps.

The topics in this chapter deal with controlling routing traffic with route maps, which are similar to, but more sophisticated than, access lists. This is an advanced topic that deals with programming the router to match criteria against assigned lists and to perform tasks based on the result of the match.

The chapter deals with why route maps are needed and how they work. This chapter also provides the configuration syntax with working examples.

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 10-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 12-1 outlines the major topics discussed in this chapter and the "Do I Know This Already?" quiz questions that correspond to those topics.

Table 12-1. "Do I Know This Already?" Foundation Topics Section-to-Question Mapping
Foundation Topics Section	Questions Covered in This Section	Score
Understanding Route Maps	1–5
Configuring Route Maps	6–8
Monitoring the Configuration of Route Maps and Redistribution	9–10
Total Score

Caution

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.	How are route maps more sophisticated than access lists? Access lists can change the destination address of the outbound data packet. Route maps take less CPU because of streamlined processing. Access lists either exclude or include, whereas route maps can change characteristics of the path. Access lists can only be applied on inbound updates.
2.	Route maps can be used for which of the following applications? NAT BGP OSPF Summarization Redistribution
3.	Which of the following best describes a match statement? The means by which a route is modified A list of selection criteria The method of discarding unwanted packets A list of network prefixes
4.	Which of the following best describes a set statement? The method used to determine the best metric The means of selecting a CoS A list of conditions to apply to chosen routes The means of changing routes that are matched

5.	Many match statements can be used in a route map. How many match statementsmust be matched for the set to be applied? At least one All the criteria None of them At least 50 percent of the criteria
6.	When using route maps for redistribution when a statement is configured to deny and there is a match, what action will be taken by the route map? The packet is dropped. The route is not redistributed. An ICMP packet is sent to the sender. The packet is sent to the normal routing process.
7.	How is a route map for redistribution initiated? The route-map command Under the incoming interface The redistribution command As a global configuration command
8.	The following route map configuration has what effect on OSPF routes redistributed into EIGRP? router eigrp 1 redistribute ospf 1 route-map ospf-to-eigrp default-metric 20000 2000 255 1 1500 ! route-map ospf-to-eigrp deny 10 match tag 6 match route-type external type-2 ! route-map ospf-to-eigrp permit 20 match ip address prefix-list pfx set metric 40000 1000 255 1 1500 ! route-map ospf-to-eigrp permit 30 set tag 8 ! Routes with a tag of 6 are redistributed unchanged. Routes matching prefix-list pfx are forward with EIGRP metric 20000 2000 255 1 1500. Routes without a tag of 6 and not matching prefix-list pfx have their tag set to 8. All routes are redistributed.

9.	Which command is useful for validating the path to the destination with a specified packet size? Extended ping show ip protocol show ip route show redistribution
10.	Which command is used to show the configured route maps? show ip route-map show route-map show ip map show ip policy

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:

6 or less overall score—Read the entire chapter. This includes the "Foundation Topics," "Foundation Summary," and "Q&A" sections.
7–8 overall score—Begin with the "Foundation Summary" section, and then go to the "Q&A" section. If you have trouble with these exercises, read the appropriate sections in "Foundation Topics."
9–10 overall score—If you want more review on these topics, skip to the "Foundation Summary" section, and then go to the "Q&A" section. Otherwise, move to the next chapter.