## Qa

As mentioned in the introduction, you have two choices for review questions. The questions that follow give you a bigger challenge than the exam itself by using an open-ended question format. By reviewing now with this more difficult question format, you can exercise your memory better and prove your conceptual and factual knowledge of this chapter. The answers to these questions are found in Appendix A.

For those of you who want more questions and practice with subnetting, you have a couple of options. You can look at the appendix on the CD titled "Subnetting Practice: 25 Subnetting Questions." Also, if you bought the two-book set and you already own the CCNAICND Exam Certification Guide, you can look at the questions at the end of Chapter 4 of that book. Chapter 4 of the other book repeats what is inside this chapter, for readers who buy just that book. However, more than half of the questions at the end of that chapter are different than the ones in this chapter, so you can get some more practice.

For more practice with exam-like question formats, including questions using a router simulator and multiple-choice questions, use the exam engine on the CD.

1. Name the parts of an IP address.

2. Define the term subnet mask. What do the bits in the mask whose values are binary 0 tell you about the corresponding IP address(es)?

3. Given the IP address 134.141.7.11 and the mask 255.255.255.0, what is the subnet number?

4. Given the IP address 193.193.7.7 and the mask 255.255.255.0, what is the subnet number?

5. Given the IP address 200.1.1.130 and the mask 255.255.255.224, what is the subnet number?

6. Given the IP address 220.8.7.100 and the mask 255.255.255.240, what is the subnet number?

11. Given the IP address 134.141.7.11 and the mask 255.255.255.0, what are the assignable IP addresses in this subnet?

12. Given the IP address 193.193.7.7 and the mask 255.255.255.0, what are the assignable IP addresses in this subnet?

13. Given the IP address 200.1.1.130 and the mask 255.255.255.224, what are the assignable IP addresses in this subnet?

14. Given the IP address 220.8.7.100 and the mask 255.255.255.240, what are the assignable IP addresses in this subnet?

15. Given the IP address 134.141.7.7 and the mask 255.255.255.0, what are all the subnet numbers if the same (static) mask is used for all subnets in this network?

16. Given the IP address 220.8.7.100 and the mask 255.255.255.240, what are all the subnet numbers if the same (static) mask is used for all subnets in this network?

17. How many IP addresses could be assigned in each subnet of 134.141.0.0, assuming that a mask of 255.255.255.0 is used? If the same (static) mask is used for all subnets, how many subnets are there?

18. How many IP addresses could be assigned in each subnet of 220.8.7.0, assuming that a mask of 255.255.255.240 is used? If the same (static) mask is used for all subnets, how many subnets are there?

19. You design a network for a customer, and the customer insists that you use the same subnet mask on every subnet. The customer will use network 10.0.0.0 and needs 200 subnets, each with 200 hosts maximum. What subnet mask would you use to allow the largest amount of growth in subnets? Which mask would work and would allow for the most growth in the number of hosts per subnet?

20. Referring to Figure 12-7, Fred has been configured with IP address 10.1.1.1, Router A's Ethernet has been configured with 10.1.1.100, Router A's Serial interface uses 10.1.1.101, Router B's serial uses 10.1.1.102, Router B's Ethernet uses 10.1.1.200, and the web server uses 10.1.1.201. Mask 255.255.255.192 is used in all cases. Is anything wrong with this network? What is the easiest thing that could be done to fix it? You can assume any working interior routing protocol.

Figure 12-7 Example Network for Subnetting Questions

Figure 12-7 Example Network for Subnetting Questions

Fred

21. Referring to Figure 12-7, Fred has been configured with IP address 10.1.1.1, mask 255.255.255.0; Router A's Ethernet has been configured with 10.1.1.100, mask 255.255.255.224; Router A's serial interface uses 10.1.1.129, mask 255.255.255.252; Router B's serial uses 10.1.1.130, mask 255.255.255.252; Router B's Ethernet uses 10.1.1.200, mask 255.255.255.224; and the web server uses 10.1.1.201, mask 255.255.255.224. Is anything wrong with this network? What is the easiest thing that could be done to fix it? You can assume any working interior routing protocol.

22. Referring to Figure 12-7, Fred has been configured with IP address 10.1.1.1, mask 255.255.255.240; Router A's Ethernet has been configured with 10.1.1.2, mask 255.255.255.240; Router A's Serial interface uses 10.1.1.129, mask 255.255.255.252; Router B's serial uses 10.1.1.130, mask 255.255.255.252; Router B's Ethernet uses 10.1.1.200, mask 255.255.255.128; and the web server uses 10.1.1.201, mask 255.255.255.128. Is anything wrong with this network? What is the easiest thing that could be done to fix it? You can assume any working interior routing protocol.

23. What are the valid private IP network numbers, according to RFC 1918?

24. How large are IPv6 addresses?

25. How does CIDR help reduce the size of Internet routing tables?