Chapter 12 IP Addressing and Subnetting
• Exam Preparation Tools for Subnetting
• IP Addressing and Routing
• Math Operations Used When Subnetting
• Analyzing and Choosing Subnet Masks
• Analyzing Existing Subnets
• Design: Choosing the Subnets of a Classful Network
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Go through the Quiz-
5 minutes
1. Which of the following are private IP networks?
a. 172.31.0.0
b. 172.32.0.0
c. 192.168.255.0
d. 192.1.168.0
e. 11.0.0.0
1. Which of the following are private IP networks?
a. 172.31.0.0
b. 172.32.0.0
c. 192.168.255.0
d. 192.1.168.0
e. 11.0.0.0
Answer: A & C
2. Which of the following is the result of a Boolean AND between IP address 150.150.4.100 and mask 255.255.192.0?
a. 1001 0110 1001 0110 0000 0100 0110 0100
b. 1001 0110 1001 0110 0000 0000 0000 0000
c. 1001 0110 1001 0110 0000 0100 0000 0000
d. 1001 0110 0000 0000 0000 0000 0000 0000
2. Which of the following is the result of a Boolean AND between IP address 150.150.4.100 and mask 255.255.192.0?
a. 1001 0110 1001 0110 0000 0100 0110 0100
b. 1001 0110 1001 0110 0000 0000 0000 0000
c. 1001 0110 1001 0110 0000 0100 0000 0000
d. 1001 0110 0000 0000 0000 0000 0000 0000
Answer: B
3. Which of the following shows the equivalent of subnet mask 255.255.248.0, but in prefix notation?
a. /248b. /24c. /28d. /21e. /20f. /23
3. Which of the following shows the equivalent of subnet mask 255.255.248.0, but in prefix notation?
a. /248b. /24c. /28d. /21e. /20f. /23Answer: D
4. If mask 255.255.255.128 were used with a Class B network, how many subnets couldexist, with how many hosts per subnet, respectively?
a. 256 and 256b. 254 and 254c. 62 and 1022d. 1022 and 62e. 512 and 126f. 126 and 510
4. If mask 255.255.255.128 were used with a Class B network, how many subnets couldexist, with how many hosts per subnet, respectively?
a. 256 and 256b. 254 and 254c. 62 and 1022d. 1022 and 62e. 512 and 126f. 126 and 510Answer: E
5. A Class B network needs to be subnetted such that it supports 100 subnets and 100 hosts/subnet. For this design, if multiple masks meet those design requirements, the engineer should choose the mask that maximizes the number of hosts per subnet. Which of the following masks meets the design criteria?
a. 255.255.255.0b. /23c. /26d. 255.255.252.0
5. A Class B network needs to be subnetted such that it supports 100 subnets and 100 hosts/subnet. For this design, if multiple masks meet those design requirements, the engineer should choose the mask that maximizes the number of hosts per subnet. Which of the following masks meets the design criteria?
a. 255.255.255.0b. /23c. /26d. 255.255.252.0Answer: B
6. If mask 255.255.255.240 were used with a Class C network, how many subnets could exist, with how many hosts per subnet, respectively?
a. 16 and 16b. 14 and 14c. 16 and 14d. 8 and 32e. 32 and 8f. 6 and 30
6. If mask 255.255.255.240 were used with a Class C network, how many subnets could exist, with how many hosts per subnet, respectively?
a. 16 and 16b. 14 and 14c. 16 and 14d. 8 and 32e. 32 and 8f. 6 and 30Answer: C
7. Which of the following subnet masks lets a Class B network have up to 150 hosts per subnet, and supports 164 subnets?
a. 255.0.0.0b. 255.255.0.0c. 255.255.255.0d. 255.255.192.0e. 255.255.240.0f. 255.255.252.0
7. Which of the following subnet masks lets a Class B network have up to 150 hosts per subnet, and supports 164 subnets?
a. 255.0.0.0b. 255.255.0.0c. 255.255.255.0d. 255.255.192.0e. 255.255.240.0f. 255.255.252.0Answer: C
8. Which of the following subnet masks let a Class A network have up to 150 hosts persubnet and supports 164 subnets?
a. 255.0.0.0b. 255.255.0.0c. 255.255.255.0d. 255.255.192.0e. 255.255.252.0f. 255.255.255.192
8. Which of the following subnet masks let a Class A network have up to 150 hosts persubnet and supports 164 subnets?
a. 255.0.0.0b. 255.255.0.0c. 255.255.255.0d. 255.255.192.0e. 255.255.252.0f. 255.255.255.192Answer: B, C, D, & E
9. Which of the following IP addresses are not in the same subnet as 190.4.80.80, mask 255.255.255.0?
a. 190.4.80.1b. 190.4.80.50c. 190.4.80.100d. 190.4.80.200e. 190.4.90.1f. 10.1.1.1
9. Which of the following IP addresses are not in the same subnet as 190.4.80.80, mask 255.255.255.0?
a. 190.4.80.1b. 190.4.80.50c. 190.4.80.100d. 190.4.80.200e. 190.4.90.1f. 10.1.1.1Answer: E & F
10. Which of the following IP addresses is not in the same subnet as 190.4.80.80, mask 255.255.240.0?
a. 190.4.80.1b. 190.4.80.50c. 190.4.80.100d. 190.4.80.200e. 190.4.90.1f. 10.1.1.1
10. Which of the following IP addresses is not in the same subnet as 190.4.80.80, mask 255.255.240.0?
a. 190.4.80.1b. 190.4.80.50c. 190.4.80.100d. 190.4.80.200e. 190.4.90.1f. 10.1.1.1Answer: F
11. Which of the following IP addresses are not in the same subnet as 190.4.80.80/25?
a. 190.4.80.1b. 190.4.80.50c. 190.4.80.100d. 190.4.80.200e. 190.4.90.1f. 10.1.1.1
11. Which of the following IP addresses are not in the same subnet as 190.4.80.80/25?
a. 190.4.80.1b. 190.4.80.50c. 190.4.80.100d. 190.4.80.200e. 190.4.90.1f. 10.1.1.1Answer: D, E & F
12. Each of the following answers lists a dotted decimal number and a subnet mask. The dotted decimal number might be a valid IP address that can be used by a host or it might be a subnet number or broadcast address. Which of the answers show an address that can be used by a host?
a. 10.0.0.0, 255.0.0.0b. 192.168.5.160, 255.255.255.192c. 172.27.27.27, 255.255.255.252d. 172.20.49.0, 255.255.254.0
12. Each of the following answers lists a dotted decimal number and a subnet mask. The dotted decimal number might be a valid IP address that can be used by a host or it might be a subnet number or broadcast address. Which of the answers show an address that can be used by a host?
a. 10.0.0.0, 255.0.0.0b. 192.168.5.160, 255.255.255.192c. 172.27.27.27, 255.255.255.252d. 172.20.49.0, 255.255.254.0Answer: B & D
13. Which of the following are valid subnet numbers in network 180.1.0.0 when using mask 255.255.248.0?
a. 180.1.2.0b. 180.1.4.0c. 180.1.8.0d. 180.1.16.0e. 180.1.32.0f. 180.1.40.0
13. Which of the following are valid subnet numbers in network 180.1.0.0 when using mask 255.255.248.0?
a. 180.1.2.0b. 180.1.4.0c. 180.1.8.0d. 180.1.16.0e. 180.1.32.0f. 180.1.40.0Answer: C, D, E & F
14. Which of the following are not valid subnet numbers in network 180.1.0.0 when using mask 255.255.255.0?
a. 180.2.2.0b. 180.1.4.0c. 180.1.8.0d. 180.1.16.0e. 180.1.32.0f. 180.1.40.0
14. Which of the following are not valid subnet numbers in network 180.1.0.0 when using mask 255.255.255.0?
a. 180.2.2.0b. 180.1.4.0c. 180.1.8.0d. 180.1.16.0e. 180.1.32.0f. 180.1.40.0Answer: A
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Subenetting Prep
• Load ROM and get familiar with test engine. Look at appendices
• Read chapter through IP Addressing and Routing
• Read each section and do exercises• If you need practice, ask for more
examples• Visit CCNA Prep
center-http://www.cisco.com/go/prepcenter
Use Subnet Calculator
• If you want to check your work, use a subnet calculator
IP Addressing and Routing
• IPv 4 is mostly in use
• Need to know– Address Class Ranges– Default Subnet Masks– Reserved Addresses– General idea of number of hosts and networks
IP Address details
Default Subnet Masks
Private Addresses
• Cannot be used on Public Internet– NAT or Proxy server must hide address– Can be used within a company/home
IP v 6 overview
IP Subnetting Review
• Lets us break larger networks into smaller ones
• Save addresses
• Network + Subnet defines grouping
• We “steal” bits from the host portion
IP Routing Review
• Routers list destination networks– Network address and subnet mask
• Routers list next best hop– How to get to that network if not connected
Math and Subnetting
• Converting IP addresses and masks from binary to decimal, and decimal to binary
• Performing a binary math operation called a Boolean AND
• Converting between two formats for subnet masks: dotted decimal and prefix notation
Decimal To Binary
• Take Decimal Number and use binary values
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