Chapter 21. IPv6 Routing Protocols, Configuration, and Transitioning from IPv4

This chapter covers the following topics:

  • IPv6 Routing Overview—Describes the various routing protocols that support IPv6.

  • Configuring and Verifying IPv6 and OSPFv3—Provides the commands to configure and verify IPv6 and OSPFv3.

  • Transitioning from IPv4 to IPv6—Discusses several transition mechanisms that may be used to move from an IPv4 network to an IPv6 network.

The main theme of this book is routing. This chapter first describes how routing can be accomplished within an Internet Protocol (IP) version 6 (IPv6) network. Next, the chapter explores, in detail, configuring and verifying an IPv6 network with Open Shortest Path First (OSPF) version 3 (OSPFv3) routing. The final part of this chapter examines how a mixture of IP version 4 (IPv4) and IPv6 protocols will be handled, since there obviously will not be an "IPv6 Conversion Day" when all networks change from IPv4 to IPv6.

The purpose of the "Do I Know This Already?" quiz is to help you decide which parts of this chapter to use. If you already intend to read the entire chapter, you do not necessarily need to answer these questions.

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 21-1 outlines the major topics discussed in this chapter and the corresponding quiz questions.

Table 21-1. "Do I Know This Already?" Foundation Topics Section-to-Question Mapping
Foundation Topics SectionQuestions Covered in This SectionScore
IPv6 Routing Overview1–5 
Configuring and Verifying IPv6 and OSPFv36–8 
Transitioning from IPv4 to IPv69–10 
Total Score  


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 the question wrong for purposes of the self-assessment. Giving yourself credit for an answer you correctly guessed skews your results and might provide you with a false sense of security.

1.Which of the following routing protocols support IPv6?
  1. RIPv2

  2. EIGRP for IPv6

  3. OSPFv3

  4. ODR

2.How is a default route represented in IPv6?
  1. 0/0

  2. 0:0:0:0:0:0:0:0/0

  3. ::/0

  4. 0::0/0

3.Which of the following is supported by OSPFv3 but not by OSPFv2?
  1. Multiple OSPF processes

  2. NBMA networks

  3. NSSAs

  4. 128-bit prefixes

4.Which multicast addresses are used by OSPFv3?
  1. and

  2. FF02::5 and FF02::6


  4. FF::FFFF

5.Which of the following OSPFv3 LSAs carry IPv6 prefixes?
  1. Type 1

  2. Type 2

  3. Type 3

  4. Type 9

6.Which command is necessary to enable IPv6 routing on a Cisco router?
  1. ipv6 address

  2. ipv6 unicast-routing

  3. ipv6 routing

  4. None, IPv6 routing is enabled by default.

7.At which prompt is the command that specifies the OSPFv3 area configured?
  1. Router(config)#

  2. Router(config-router)#

  3. Router(config-rtr)#

  4. Router(config-if)#

8.Which command output displays OSPFv3 timers?
  1. show ipv6 route

  2. show ipv6 ospf

  3. show ipv6 ospf database

  4. show ipv6 ospf database database-summary

9.Dual stack is best described by which of the following statements?
  1. Running IPv4 and IPv6 at the same time

  2. Translating IPv4 traffic to IPv6

  3. Passing IPv6 through UDP

  4. Process interception

10.How is a 6-to-4 tunnel different than a manually configured tunnel?
  1. It uses NAT-PT.

  2. IPv6 addresses are embedded in IPv4 addresses.

  3. Automatic tunnel creation.

  4. It is not a dual-stack solution.

The answers to the "Do I Know This Already?" quiz are found in Appendix A, "Answers to Chapter 'Do I Know This Already?' Quizzes and Q&A Sections." Compare your score with the suggestions below to proceed:

  • 7 or less overall score—Read the entire chapter. This includes the "Foundation Topics," "Foundation Summary," "Q&A," and "Scenarios" sections.

  • 8 or 9 overall score—Begin with the "Foundation Summary" section and then go to the "Q&A" and "Scenarios" sections at the end of the chapter. If you have trouble with these exercises, read the appropriate sections in "Foundation Topics."

  • 10 overall score—If you want more review on these topics, skip to the "Foundation Summary" section and then go to the "Q&A" and "Scenarios" sections at the end of the chapter.